Encyclopedia Health of Diseases and Disorders

Burns and Scalds

2011-03-22T03:11:00.001+03:00

Definition

Burns are injuries caused to the skin or underlying tissues by direct heat or

extreme cold; scalds are burns caused by hot liquids or gases (such as steam).

The severity of burns is measured in two ways: by the depth of the

burn (see sidebar) and by the size of the affected area. Doctors use the

“

(TBSA) has been burned. In adults, the head and neck together count as

9 percent of the body; each arm also counts as 9 percent. The front of the

trunk, the back, and each leg are considered to each represent 18 percent

of the TBSA. Doctors count only second- and third-degree burns in estimating

the affected areas of the body.

Thermal burns (and scalds) are defined as burns caused directly by

heat or by chemical reactions that release heat. They are divided into several

categories according to the specific cause:

rule of nines” to evaluate how much of a person’s total body surface area

•

fire. Flame burns may take the form of a sudden flash burn produced

by a flammable liquid or gas igniting. Pouring lighter fluid

on burning charcoal is a common cause of flash burns.

Flame burns. This type of burn results from direct contact with

•

like a heated iron or cooking pan. Scalds are contact burns caused

by hot liquids or gases.

Contact burns. These burns are caused by touching a hot object

•

wire or in rare cases by lightning. Electrical burns are serious

because they can cause serious injury to internal organs that is not

obvious from the size of the skin burn.

•

caused by welding equipment, radiation

therapy for cancer, or overexposure to

sunlight or tanning equipment. Sunburn

is a common form of radiation burn.

Radiation burns. Radiation burns can be

•

caused by either strongly alkaline materials

like lye, or by strong acids like sulfuric

acid and nitric acid. Some acids are

strong enough to eat through the skin and

muscles down to the underlying bone.

Thermal burns affecting a person

be as dangerous as burns affecting the surface of

the body. The tissues of the airway can be burned

by breathing in superheated air from a fire, toxic

gases, smoke, or steam. In the United States, most

people who die in house or office fires die from

smoke inhalation rather than from skin burns.

Skin can also be burned by exposure to cold,

either by lengthy exposure to cold outdoors

(frostbite) or by brief exposure to extremely cold

materials like dry ice.

Chemical burns. Chemical burns can be’s airway can

Description

The experience of a burn varies considerably

depending on the cause of the burn, the parts

of the body that are affected, the severity of the

burn, and the situation in which the burn

occurred. Human soft tissue will burn at any

temperature above 115°F (46°C). Most burns

are accidental; however, about 10 percent of

cases of child abuse involve intentional burning

or scalding of the child.

Demographics

Burns are commonplace injuries worldwide, partly because they have so

many potential causes. In the United States, about one million people

seek treatment for burns in hospital emergency rooms each year. This

figure actually represents a decline from the early 1960s, when the

number was about two million. About 40,000 people are hospitalized for

burn injuries each year rather than being treated as outpatients; of those

admitted to hospitals, 60 percent, or 25,000 people, are sent to one of

the 125 hospitals in the United States with specialized burn centers.

According to the American Burn Association, there are about 4,000

deaths from burns each year in the United States, 3,500 from house fires

and the remaining 500 from automobile and aircraft crashes, contact

with electricity, chemicals or hot liquids and substances. About 75 percent

of these deaths occurred at the scene of the accident or on the way to the

hospital.

Burn injuries vary according to age group:

•

and younger are caused by scalds (65 percent) and contact burns

(20 percent). These injuries often occur when children pull

pots and pans containing hot food or boiling water from a stove

top.

Infants and children: most burn injuries in children four years

•

about 88,000 are treated in hospital emergency rooms each year.

The most common causes in this age group are hair curlers, curling

irons, room heaters, ovens and ranges, clothing irons, gasoline,

and fireworks.

Adolescents and children between the ages of four and fourteen:

•

injuries than women; 70 percent of patients admitted to specialized

burn centers are male. Forty-three percent of these severe injuries

occurred at the person

8 percent in the workplace; and 32 percent in other locations.

Among adults, men are more likely to require hospitalization for burn’s home; 17 percent on the street or highway;

Causes and Symptoms

Burns are caused by exposure to a source of heat, whether direct flame,

electricity, radiation, contact with a hot object, or chemicals. Airway

burns are caused by breathing in steam, heated air from a fire, or smoke

and toxic gases.

Symptoms of first-degree burns include pain and reddening of the

affected area. Second-degree burns produce blisters as well as reddened

skin and pain. Third-degree burns are painless because the nerve endings

in the affected area have been destroyed. The affected skin may be white

or charred, and is usually dry or leathery.

The symptoms of airway burns include:

•

Charred or burned mouth and lips; burns on the face or neck

•

Wheezing and difficulty breathing

•

Singed nose hairs or eyebrows

•

Coughing

•

Dark soot-colored mucus being coughed up

•

Changed voice

Diagnosis

The diagnosis of burns and scalds is usually obvious from the patient

situation and the appearance of the injury. Patients taken to the emergency

room will usually be given a chest x ray to check for evidence of

smoke inhalation or other injury to the airway.

Most of the evaluation in the hospital consists of determining the

extent of the patient

area of body surface covered by second- or third-degree burns. Another

quick measurement that can be used to estimate the size of the burn is

the area covered by an adult

body area. Emergency room doctors use these rules to tell whether a

patient should be sent to a specialized burn center:

’s’s injuries. The rule of nines is used to estimate the’s palm, which is about 1 percent of total

•

area (BSA)

Third-degree burns covering more than 5 percent of body surface

•

Second-degree burns covering more than 10 percent of BSA

•

or skin covering a major joint

Any second- or third-degree burn on the face, genitals, hands, feet,

•

Burns caused by electrical currents, lightning, or chemicals

•

broken bones, etc.)

Burns occurring together with other major injuries (head trauma,

•

Burns in patients with inhalation injuries

Treatment

Minor first-degree burns can be treated at home by cooling the injured

part by holding it under cool tap water for several minutes. Ice should not

be used because it can make the injury to the skin worse. Butter or margarine

should not be applied because oily substances will not help heal

the burn and may increase the danger of infection. Aspirin or Tylenol can

be taken to ease pain, and an antibiotic ointment can be applied to the

skin to reduce the risk of infection.

If a person

and roll

object or open flame and their clothing removed if possible. Burned

clothing that is stuck to the skin should not be removed, however. The

burned person should be doused with water and covered with a clean

sheet or other cloth while emergency services are called. Severe burns

should never be treated with ointments or other household remedies

while waiting for emergency help.

Treatment of severe burns in the hospital begins with an evaluation of

the patient

burned clothing and careful inspection of the burns. After the patient

burns have been washed with sterile solution, he or she will be given

intravenous fluids to prevent shock and dehydration. Painkillers are also

given intravenously to relieve the patient

The next step in burn treatment is surgical debridement (cutting

away) of open blisters and dead tissue. If the person

enough to require transfer to a burn center, they will be kept in the hospital

overnight to make sure that their airway has not been injured.

’s clothing is on fire, they should be told to “stop, drop,” to put out the fire. They should be pulled away from the hot’s airway and their blood circulation. The next step is removal of’s’s pain as quickly as possible.’s burns are not severe

Prognosis

The prognosis of burns and scalds varies from excellent to poor

depending on the location of the burn, its cause, the patient

overall health, and how quickly they received treatment. Minor burns

rarely cause long-term complications. Second-degree burns, however, can

become infected and the infection can spread into the bloodstream if not

treated promptly. Patients can also become dehydrated after a burn

injury. Anyone with a burn who notices red streaks or pus in the burned

area, increased pain, swollen lymph nodes near the burn, or fever; or

anyone who feels dizzy, lightheaded, extremely thirsty, or cannot urinate

after a burn should see their doctor at once.

According to the American Burn Association, 95 percent of patients

treated in specialized burn centers survive their injuries.

’s age and

Prevention

Prevention is one of the most important aspects of burn care, as public

health doctors estimate that 75 percent of burns are preventable. The

Centers for Disease Control and Prevention (CDC) recommend the following

preventive steps:

•

regularly.

Install smoke detectors in the home and check their batteries

•

matches and fireworks.

Teach small children about fire safety, including the dangers of

•

accidental scalding in the tub or shower.

Set the household water heater at 120°F (49°C) or lower to prevent

•

of pots and frying pans toward the back of the stove to prevent

children from grabbing them.

Keep small children from climbing up on the stove; turn the handles

•

Place fire extinguishers in key locations in the home and workplace.

•

off the floor.

Keep electrical appliances in good repair and keep electrical cords

•

Practice fire escape routes in the home, school, and workplace.

The Future

Burns are likely to continue to be a common form of accidental injury.

Better education as well as further research into burn treatment may

help to lower the number of injuries and deaths caused by burns. One

of the most important factors in lowering the rate in the last twenty years

is the increased use of smoke detectors. A major new area of research is

the development of skin substitutes for covering major burns instead of

using grafts taken from the patient

’s own skin.

SEE ALSO

Child abuse; Frostbite; Smoke inhalation; Smoking; Sunburn

For more information

BOOKS

American Academy of Pediatrics (AAP).

MA: Jones and Bartlett Publishers, 2008.

Cook, Allan R.

Various Types of Burns and Scalds

Pediatric First Aid for Parents. Sudbury,Burns Sourcebook: Basic Consumer Health Information about. Detroit, MI: Omnigraphics, 1999.

PERIODICALS

Nagourney, Eric.

January 4, 2005. Available online at http://www.nytimes.com/2005/01/04/

health/04haza.html?_r=1&oref=slogin (accessed September 7, 2008).

WEB SITES

American Academy of Family Physicians (AAFP).

Available online at http://familydoctor.org/online/famdocen/home/healthy/

firstaid/after-injury/638.html (accessed September 6, 2008).

American Burn Association.

Sheet

(accessed September 6, 2008).

American College of Emergency Physicians (ACEP).

Available online at http://www3.acep.org/patients.aspx?id=25990 (accessed

September 6, 2008).

Centers for Disease Control and Prevention (CDC).

Fact Sheet

(accessed September 6, 2008).

eMedicine Health.

www.emedicinehealth.com/thermal_heat_or_fire_burns/article_em.htm

(accessed September 7, 2008).

National Institute of General Medical Sciences (NIGMS).

Available online at http://www.nigms.nih.gov/Publications/Factsheet_Burns.

htm (accessed September 6, 2008).

National Library of Medicine (NLM).

nlm.nih.gov/medlineplus/tutorials/burns/htm/index.htm (accessed September

6, 2008). This is an online tutorial with voiceover; viewers have the

option of a self-playing version, a text version, or an interactive version with

questions.

Nemours Foundation.

kidshealth.org/parent/firstaid_safe/sheets/burns_sheet.html (accessed

September 6, 2008).Burns: Taking Care of Burns.Burn Incidence and Treatment in the US: 2007 Fact. Available online at http://www.ameriburn.org/resources_factsheet.phpAvoiding Household Burns.Fire Deaths and Injuries. Available online at http://www.cdc.gov/ncipc/factsheets/fire.htmThermal (Heat or Fire) Burns. Available online at http://Burns Fact Sheet.Burns. Available online at http://www.Burns Instruction Sheet. Available online at http://“Hazards: Of Hot Pots and Back Burners.” New York Times,Electrical burns. These can be caused by contact with a live electrical

Burns and Scalds

Bulimia

2011-03-22T03:07:00.002+03:00

Bulimia is defined as an eating disorder characterized by recurrent episodes

of binge eating followed by self-induced vomiting, laxative or

diuretic abuse, vigorous exercise, or fasting.

Description

The

(DSM-IV), the reference that doctors use to diagnose mental illness, specifies

that a person must have an eating binge and try to compensate for

it on average twice a week for three months to meet the diagnostic criteria

for bulimia. A binge is an episode in which someone consumes a

larger amount of food within a limited period of time than most people

would eat in similar circumstances. Most bulimics report feelings of loss

of control associated with bingeing. A second criterion of bulimia is

excessive concern with one

There are two subtypes of bulimia, purging and nonpurging,

according to the methods used by the patient to prevent gaining weight

after a binge. People who have the purging subtype use vomiting, laxatives,

enemas, or diuretics to keep from gaining weight; in the nonpurging

subtype, the person fasts or overexercises to prevent weight gain. The

important point is that bulimics do something after a binge to compensate

for their eating. There is another type of eating disorder called

binge eating disorder, in which the person has eating binges but does not

try to vomit, exercise, or do anything else to prevent gaining weight.

Demographics

There is some disagreement about the demographics of bulimia, partly

because the rules for diagnosing it have changed over time. The usual

figure given for bulimia in the United States is 1

school- and college-age women. Many doctors think, however, that

bulimia is underdiagnosed because most people with the disorder are of

average weight or only slightly overweight. In addition, there are large

numbers of teenagers and young adults who have disordered eating patterns

but do not meet the full criteria for bulimia; there may be twice as

many young people in this second group as those who meet the full

DSM-IV definition.

The gender ratio is usually given as ten females to every one male

affected, but some people think that as many as 15 percent of bulimics

are male. Gay men appear to be at greater risk of developing bulimia than

heterosexual men.

At one time bulimia was thought to affect mostly Caucasian women,

but the rates among African American and Hispanic women have risen

faster than the rate of bulimia for the female population as a whole, at least

in the United States. Occupation appears to be a major risk factor for bulimia.

Women whose careers depend on appearance or a certain body build, such as

ballet dancers, models, and professional athletes, are reported to be four times

as likely to develop bulimia as women in the general population.

Causes and Symptoms

The causes of bulimia are not known for certain, but are thought to be a

combination of genetic factors (possibly unusual sensitivity to foods high in

carbohydrates); the emotional climate in the patient

in the wider society to live up to a standardized image of beauty. In terms

of family patterns, people with bulimia often describe their families as conflicted

and their parents as either distant and uncaring or hostile and critical.

Bulimia is associated with a number of physical symptoms. Binge

eating by itself rarely causes serious medical complications, but it is associated

with nausea, abdominal bloating and cramping, slowed digestion,

and weight gain.

Bulimics who force themselves to vomit after a binge may develop

serious medical problems, including:

’s family; and pressures

•

vomited material.

Erosion of the enamel on the teeth, caused by stomach acid in the

•

Enlargement of the salivary glands.

•

teeth.

Scars and calloused areas on the knuckles from contact with the

•

Irritation of the throat and esophagus.•

•

can deplete the body

sodium, and magnesium. The loss of these chemicals in turn can

sometimes affect heart rhythm.

Electrolyte imbalances. The loss of fluids from repeated vomiting’s stores of hydrogen chloride, potassium,

Diagnosis

Bulimia is usually diagnosed during an office visit to the patient

care doctor, although she or he may be sent to a psychiatrist for

an additional evaluation. Primary care doctors are now encouraged to

give a screening test to an adolescent or young adult who seems unusually

concerned about their weight or asks the doctor a lot of questions

about weight loss. These screeners are short sets of five questions about

eating habits that the patient can quickly answer. If the doctor thinks

that the patient may have bulimia, he or she can look for some of the

physical signs that accompany the disorder, such as whether the teeth

and salivary glands are normal. In most cases the doctor will order laboratory

tests of the patient

chemistry is normal. Most doctors will also give the patient an electrocardiogram

(ECG) to check the patient

because some types of chemical imbalances in the blood (from

vomiting or using diuretics) can lead to irregular heart rhythms.

Another important part of evaluating a patient for bulimia is a

mental status examination. The doctor will need to check the patient for

signs of anxiety disorders or depression, because a high proportion of

bulimics have a mood disorder. In addition, people with bulimia are

more likely to be treated successfully for their eating disorder when their

anxiety or depression is also being treated.

’s primary’s blood and urine to make sure that her blood’s heart rhythm. This test is important

Treatment

Treatment for bulimia consists of psychotherapy combined with medications.

The type of psychotherapy most often recommended for bulimics

is cognitive-behavioral therapy (CBT), along with interpersonal therapy.

In CBT, the patient is helped to recognize the distortions in their mental

image of their body and to correct irrational beliefs about food and

eating. Family therapy may be recommended if the patient

appears to be a major cause of his or her emotional distress; as of late

2007, there was some evidence that family therapy is more helpful for

some patients with bulimia than individual therapy. Some bulimics also

benefit from group therapy or support group meetings.

The medications most often prescribed for bulimics are antidepressants,

in particular such drugs as fluoxetine (Prozac) and sertraline

(Zoloft). Scientists do not fully understand how these drugs help in

treating bulimia, but some think that they help to regulate chemical

imbalances in the patient

’s central nervous system.

Prognosis

The prognosis of bulimia depends on several factors, including the

patient

close friendships that she or he has. Patients who are diagnosed early,

have good relationships with their parents, and have several close friends

are more likely to recover. About half of bulimics have good outcomes

after treatment, 18 percent have intermediate outcomes, and 20 percent

have poor outcomes.

’s age at diagnosis, the quality of family life, and the number of

Prevention

While it is difficult to change an entire society and its overly high valuation

of physical attractiveness, parents can certainly lower a child

bulimia in later life by creating a warm and loving home. It is important

to convey to children that they are loved as whole persons with minds

and spirits, not just outwardly pleasing faces and bodies.

’s risk of

The Future

It is not known with certainty whether bulimia is increasing in the

United States, partly because it overlaps with other eating disorders in

some people and partly because doctors are looking more closely at men

who may be bulimic but were not diagnosed with the disorder in the

past. Although doctors are looking for better treatments of bulimia,

including new medications, further research in the chemistry of the brain

is needed.

SEE ALSO

Anorexia; Depression; Obesity

For more information

BOOKS

Hall, Lindsey, and Leigh Cohn.

CA: Gürze Books, 1999.

Hornbacher, Marya.

HarperPerennial, 1999.

PERIODICALS

Bakalar, Nicholas.

“Therapies: Family Sessions Found to Help Treat Bulimia.”

New York Times

nytimes.com/2007/09/04/health/04ther.html?_r=1&sq=bulimia&st=

nyt&adxnnl=1&oref=slogin&scp=2&adxnnlx=1207166511-3dUW3ny1

e8NabVf2POt6Ow (accessed March 2, 2008).

, September 4, 2007. Available online at http://www.

WEB SITES

Gürze Books.

publisher that specializes in books and other educational materials on

bulimia.

National Eating Disorders Association (NEDA).

edap.org/p.asp?WebPage_ID=286&Profile_ID=41141.

Public Broadcasting Service (PBS).

Family

website to a PBS series of programs on bulimia and other eating

disorders.

Bulimia.com. http://www.gurze.com/. This is the website of aBulimia Nervosa. http://www.Perfect Illusions: Eating Disorders and the. http://www.pbs.org/perfectillusions/index.html. This is the companionSomething Fishy: Website on Eating Disorders. http://www.something-fishy.org/Bulimia: A Guide to Recovery. 5th ed. Carlsbad,Wasted: A Memoir of Anorexia and Bulimia. New York:’s familyLow blood pressure and slowed heart rate.–3 percent of highDiagnostic and Statistical Manual of Mental Disorders, fourth edition’s body shape and weight.

Bulimia

Definition

Bronchitis

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Definition

Bronchitis is a condition in which the tissues lining the bronchi

two main divisions of the airway that lead into the right and left

lungs

a temporary illness that clears up in three weeks or less; or chronic, a

recurrent condition in which the person suffers coughing attacks for

at least three months over two successive years. Chronic bronchitis is

grouped together with emphysema as a form of chronic obstructive

pulmonary disease (COPD).

—the—become inflamed. Doctors define bronchitis as either acute,

Description

Bronchitis can be caused by a wide range of disease organisms and other

irritants that inflame the tissues of the bronchi, including viruses, bacteria,

parasites, smoking, chemical pollutants, or dust particles. Acute

bronchitis is caused most often by viruses, while chronic bronchitis is

caused most often by smoking.

In acute bronchitis, the tissues lining the bronchi become swollen

and irritated by the disease organism or chemical. The air passages slowly

become clogged by dead cells and leaking tissue fluid, which further irritates

the bronchial tissues. The tissues begin to secrete mucus in response

to the inflammation. As the mucus accumulates

in the airways, the person starts to cough in

order to clear the breathing passages. The

coughing, the sputum (mucus and other matter)

that is brought up by coughing, and wheezing or

shortness of breath are classic symptoms of acute

bronchitis. Chest pain may develop after several

days of severe coughing.

Demographics

According to the National Center for Health Statistics,

about 14 million Americans have chronic

bronchitis. In an average year, there are 12

cases of acute bronchitis reported in the United

States, compared to 91 million cases of influenza,

66 million cases of the common cold, and 31 million

cases of other acute upper respiratory infections.

Acute bronchitis is more common in the

winter months in most parts of the United States.

Children are more likely to develop acute

bronchitis, while chronic bronchitis is largely a

disease of adults. The male/female ratio for

chronic bronchitis is about three to two. As far

as is known, both acute and chronic bronchitis are

equally common in all races and ethnic groups.

Some people are at increased risk of developing

bronchitis:

–13 million

•

Smokers and people who live with smokers.

•

(GERD). GERD is a condition in

which stomach acid backs up into the esophagus,

which can trigger the coughing reflex.

People with gastroesophageal reflux disease

•

that irritate the airway. These may include cotton and

other textiles, wheat and other grains, ammonia, sulfur dioxide,

chlorine, and a few other strong chemicals.

People whose jobs expose them to chemicals, dust, or other substances

•

People exposed to high levels of automobile exhaust.•

Causes and Symptoms

The basic cause of bronchitis, whether acute or chronic, is a disease

organism or substance that irritates the tissues lining the bronchi.

The symptoms of acute bronchitis are similar to those of a bad cold

or other upper respiratory infection:

•

Sore throat

•

A feeling of tightness or congestion in the chest

•

Overall feeling of tiredness

•

Low-grade fever and chills

•

Difficulty breathing

•

Wheezing

Diagnosis

Acute bronchitis is essentially a diagnosis of exclusion, which means that

the doctor must rule out such other illnesses as influenza, strep throat,

pneumonia, whooping cough, or tonsillitis. The diagnosis is based on a

combination of the patient

respiratory tract infections or exposure to others with such infections,

and a physical examination. During the physical examination, the doctor

will listen to the patient

may be ordered to rule out pneumonia.

The doctor will sometimes collect a sample of the patient

there is reason to suspect that the bronchitis is caused by bacteria. Most

cases of acute bronchitis are caused by the same types of virus that cause

the common cold and cannot be treated with antibiotics; however, bacterial

infections can be effectively treated by antibiotic medications. If the

patient has a severe sore throat in addition to wheezing and coughing, the

doctor may order a rapid strep test to rule out the possibility of strep

throat, another type of bacterial infection.

If the patient has had several episodes of acute bronchitis or the

doctor has other reasons for suspecting chronic bronchitis, the doctor

will order pulmonary function tests (PFTs). These are tests in which the

patient is asked to breathe into a device called a spirometer. The spirometer

measures how much air the patient

air moves in and out of the lungs. It can also be used to determine how

well the lungs are exchanging oxygen and carbon dioxide. Another way

the spirometer can be used is to test the effectiveness of inhaled medications

in treating chronic bronchitis.

Treatment

Acute bronchitis is usually treated at home with a combination of bed

rest; over-the counter pain-relievers like aspirin, Advil, Tylenol, or

Motrin to lower the fever; and over-the counter cough medications.

Some of these medications (Robitussin, Mucinex) are intended to loosen

the mucus in the bronchial passages while others (Benylin, Pertussin) are

intended to suppress (quiet) the coughing. Patients should drink plenty

of clear fluids to loosen the mucus and use a humidifier or cool-mist

vaporizer to reduce the irritation in the bronchi.

Because the overuse of antibiotics can create drug-resistant organisms,

the doctor may not prescribe an antibiotic for acute bronchitis

unless he or she has test results indicating that the patient

caused by a bacterium and not a virus.

People with chronic bronchitis may need stronger medications:

’s illness is

•

up the airways, which allows for more efficient exchange of carbon

dioxide and oxygen. Some are taken in tablet form while others are

dispensed in inhalers.

Bronchodilators. Bronchodilators are drugs that work by opening

•

in the tissues lining the airways. These drugs can also be

taken in pill form or through inhalers.

Steroids. This type of medication works by lowering the inflammation

•

to lower the risk of developing complications.

Antibiotics. People with chronic bronchitis may be given antibiotics

•

need to go to the hospital for oxygen therapy. There are also oxygen

tanks that can be used in the home; some of these are portable units.

Oxygen. Patients who have severe attacks of chronic bronchitis may

Prognosis

Most cases of acute bronchitis clear up completely in two to three weeks with

no long-term complications. Chronic bronchitis, however, increases a person

risk of permanently weakened lungs, heart disease, and a shortened life span.

’s

Prevention

The best way to prevent chronic bronchitis is to quit smoking; parents

can protect their children from bronchitis by quitting or by not smoking

in the first place. In some cases, people whose jobs expose them to

chemicals, dust, or other materials that irritate the breathing passage may

benefit from changing their occupation.

Acute bronchitis is more difficult to prevent because its most

common cause is upper respiratory viruses that are hard to avoid. Regular

hand washing and the use of hand sanitizers can reduce the spread of

these viruses within a family, school, or day care center. Some people can

lower the risk of bronchitis by getting annual flu shots. In addition,

people who are over sixty-five or who have diabetes or emphysema may

benefit from getting immunized against the most common cause of

bacterial pneumonia.

The Future

Acute bronchitis is likely to continue to be a commonplace health problem

because the viruses that are its most common cause are widespread,

particularly during cold and flu season. Chronic bronchitis is expected to

affect an even larger proportion of the adult population in the years

ahead because many long-term smokers are now reaching the age at

which the symptoms of chronic obstructive pulmonary disease are most

likely to appear.

SEE ALSO

disease; Pneumonia; Smoking; Tonsillitus; Whooping cough

Asthma; Common cold; Emphysema; Gastroesophageal reflux

For more information

BOOKS

Jacoby, David B., and Robert M. Youngson.

ed. Tarrytown, NY: Marshall Cavendish, 2004.

Matthews, Dawn D.

Detroit, MI: Omnigraphics, 2002.

WEB SITES

American Academy of Family Physicians (AAFP).

online at http://familydoctor.org/online/famdocen/home/common/infections/

common/mulitsource/677.html (updated January 2006; accessed June

19, 2008).

American Academy of Family Physicians (AAFP).

online at http://familydoctor.org/online/famdocen/home/articles/280.html

(updated April 2008; accessed June 20, 2008).

Children

childrenshospital.org/az/Site561/mainpageS561P0.html (accessed June 19, 2008).

eMedicine Health.

bronchitis/article_em.htm (updated February 22, 2008; accessed June 20, 2008).

Mayo Clinic.

bronchitis/DS00031 (updated April 20, 2007; accessed June 20, 2008).

TeensHealth.

common/bronchitis.html (updated October 2007; accessed June 19, 2008).Acute Bronchitis. AvailableChronic Bronchitis. Available’s Hospital Boston. Bronchitis, Acute. Available online at http://www.Bronchitis. Available online at http://www.emedicinehealth.com/Bronchitis. Available online at http://www.mayoclinic.com/health/Bronchitis. Available online at http://kidshealth.org/teen/infections/Encyclopedia of Family Health. 3rdLung Disorders Sourcebook: Basic Information for Consumers.’s history, including a history of recent upper’s breathing through a stethoscope. A chest x ray’s sputum if’s lungs can hold and how fast theInfants, elderly people, and others with low resistance to infections.

Bronchitis

Breast Cancer

2011-03-22T02:59:00.003+03:00

Description

Breast cancer is one of the most feared cancers for women, not

only because it is potentially fatal but also because it can lead to disfigurement

and worries about the loss of femininity. It can also develop

for a long time before obvious symptoms appear. One reason why periodic

screening for changes in breast tissue is so important for women

over the age of twenty is that breast cancer is highly treatable when

caught early.

In the early stages of breast cancer, a woman (or man) may not

notice any differences in the size and shape of the breasts. The most

noticeable symptom of breast cancer is a lump or thickened area in the

breast. Not all such lumps are cancerous; many women notice that the

texture of their breasts changes during pregnancy or their menstrual

periods. Lumps in the breast can also be caused by noncancerous cysts.

Nonetheless, a woman (or man) who notices a lump in the breast

should tell their doctor.

Demographics

Breast cancer is one of the most common cancers in women, affecting

one in every eight women in the United States in the course of her lifetime.

According to the American Cancer Society, there are about

68,000 cases of carcinoma in situ (noninvasive

or stage 0 breast cancer) in the United States

each year, and 183,000 cases of invasive breast

cancer (stages I through IV). About 2,000 American

men will be diagnosed with breast cancer.

Breast cancer is the second leading cause

of death from cancer among women in the

United States; only lung cancer is deadlier.

About 41,000 American women and 450 men

die each year from breast cancer. The death

rate has decreased in recent years, largely as a

result of earlier detection. There were an estimated

2.5 million survivors of breast cancer

in the United States as of 2008.

Risk factors for breast cancer include:

•

cancer is 99:1.

Sex. The female/male ratio for breast

•

are found in women over fifty-five.

Age. Two out of three invasive breast cancers

•

of breast cancers are thought to be

caused by inherited mutations in two

genes known as BRCA1 and BRCA2. Women with either of

these mutations have an 80 percent chance of developing breast

cancer in their lifetime.

Genetic mutations. Between 5 and 10 percent

•

or daughter with breast cancer has double the risk of developing

breast cancer herself.

Family history of breast cancer. A woman who has a mother, sister,

•

cancer than women of other races; however, breast cancers in

African American women are often more aggressive. The reason

for this difference is not known.

Race. Caucasian women are slightly more likely to develop breast

•

age fifty-five).

Early menstruation (before age twelve) or late menopause (after

•

First pregnancy after age thirty or no pregnancy.

•

Obesity.•

•

Exposure to radiation during adolescence.

•

menopause.

Use of birth control pills or hormone replacement therapy after

•

Heavy drinking.

•

History of precancerous changes in the breast.

Causes and Symptoms

The cause of breast cancer is not known. Most researchers think that the

disease results from a combination of genetic factors and environmental

influences.

Breast cancer has no symptoms in its earliest stages. The first noticeable

symptoms may include:

•

during a breast self-examination.

A lump or thickened area in the breast large enough to be felt

•

A watery, bloody, or yellowish discharge from the nipple.

•

A change in the shape or size of the breast.

•

A flattened, puckered, or indented area in the skin of the breast.

•

An orange-peel appearance to the skin of the breast.

Diagnosis

Regular screening for breast cancer is important. All women over twenty

should learn to perform breast self-examination and check their breasts

once a month after the menstrual period. Other screening tests include

a breast examination by the doctor as part of a routine office visit, and

a mammogram, which is an x-ray study of the breast. Imaging studies

(magnetic resonance imaging [MRI] or ultrasound) are done when a

mammogram yields abnormal findings.

The definitive test for diagnosing breast cancer is a biopsy. The

doctor may remove some tissue through a fine needle (aspiration biopsy)

or if a larger sample is needed, through a larger needle (core biopsy). The

most accurate technique is a surgical biopsy, in which the surgeon

removes all or part of a lump for examination under a microscope.

Treatment

The first step in treating any kind of cancer is staging. Staging is a

description of the location of the cancer, its size, how far it has penetrated

into healthy tissue, and whether it has spread to other parts of the body.

Breast cancer is classified into five stages:

•

beyond it. Breast cancer in this stage is called carcinoma in situ.

This type of breast cancer is considered noninvasive.

Stage 0: The cancer is in a lobule or a duct but has not spread

•

across and has not spread beyond the breast.

Stage I: The cancer is no more than three-quarters of an inch

•

across and may have spread to the lymph nodes under the arm.

Stage II. The cancer is between three-quarters and two inches

•

the breast, is larger than two inches across, and has spread to

lymph nodes behind the breastbone and under the arm.

Stage III. The cancer has grown into the chest wall or the skin of

•

Surgery is usually the first line of treatment for breast cancer. Complete

removal of the breast and underlying chest muscle, called a radical

mastectomy, while more common in the past, is now rarely performed.

Surgeons are more likely to recommend one type or another of breastsparing

surgery:

Stage IV. The cancer has spread to other parts of the body.

•

cancer itself and a small amount of tissue around it.

Lumpectomy. In this type of surgery, the surgeon removes the

•

tissue surrounding it, and some of the underlying muscle.

Partial mastectomy. The surgeon removes the cancer, the breast

•

Simple mastectomy. The surgeon removes the entire breast.

•

breast and nearby lymph nodes but leaves the chest muscles

in place.

Modified radical mastectomy. The surgeon removes the entire

•

time as a mastectomy or as a later operation to restore the shape

of the original breast. The surgeon may use an artificial implant

or the patient

Other treatments for breast cancer that may be used after surgery

include:

Reconstruction. Many women have plastic surgery at the same’s own tissue to reconstruct the breast.

•

outside the body or from implanted plastic tubes containing a

radioactive substance. The tubes remain in place for several days

and are removed before the patient leaves the hospital.

•

Chemotherapy.

•

drugs by mouth to block the production of estrogen and other

female hormones. Estrogen encourages the growth of some breast

cancers, and hormone blockers are effective in slowing these

tumors in some patients.

Hormone therapy. This approach to treatment involves taking

•

the body

attacking them directly. It can also be used to control side effects

from chemotherapy and radiation therapy, which often include

nausea, vomiting, hair loss, and fatigue.

Biological therapy. Also called targeted therapy, this approach stimulates’s immune system to fight cancer cells rather than

Prognosis

The prognosis for breast cancer depends on its stage at the time of diagnosis

and the number of lymph nodes that were involved when the cancer was

discovered. Women whose tumors were smaller than three-quarters of an

inch with no lymph node involvement have a survival rate of 96 percent

five years after diagnosis; those with tumors larger than two inches with several

lymph nodes involved have a five-year survival rate of only 45 percent.

Prevention

There are no guarantees that a specific woman will not get breast cancer,

but there are some steps women can take to reduce their risk:

•

get tested for a mutation in the BRCA gene. They can then consult

their doctor about their own risk of developing breast cancer.

Genetic testing. Women with a family history of breast cancer can

•

cancer. These include tamoxifen and raloxifene.

Taking drugs that have been shown to reduce the risk of breast

•

cancer can develop is a treatment sometimes undertaken by

women who are at very high risk of breast cancer or who have been

diagnosed with a lobular carcinoma in situ.

Preventive mastectomy. Surgical removal of both breasts before

•

of estrogen in a woman

recommended for women with a known BRCA mutation.

Other preventive measures recommended by the American Cancer

Society include getting regular exercise, limiting alcohol intake, keeping

weight at a healthy level, and avoiding the use of hormone replacement

therapy after menopause.

The Future

Researchers are investigating different types or combinations of hormone

therapy as a treatment for breast cancer. One large clinical trial is known

as the Study of Tamoxifen And Raloxifene or STAR trial. Other research

involves new diagnostic techniques for catching breast cancer early.

SEE ALSO

Alcoholism; Klinefelter syndrome; Obesity; Prostate cancer

For more information

BOOKS

American Cancer Society.

Answered / from the Experts at the American Cancer Society

American Cancer Society Health Promotions, 2008.

Brown, Zora K., and Karl Boatman.

Cancer

Willis, Jack.

University of Oklahoma Press, 2008.

Breast Cancer Clear and Simple: All Your Questions. Atlanta, GA:100 Questions and Answers about Breast. Sudbury, MA: Jones and Bartlett Publishers, 2009.Saving Jack: A Man’s Struggle with Breast Cancer. Norman, OK:

PERIODICALS

Harmon, Amy, Alissa Krimsky, and Kassie Bracken.

Hoping for the Best.

http://video.on.nytimes.com/?fr_story=0aff7eb1147f98a41e989541f3fc114

c8e71dcd2 (accessed on September 23, 2008). This is an online video about

when she learned she has a high risk of developing breast cancer. It takes

about six and a half minutes to play.

“Preparing for the Worst,” New York Times, September 2007. Available online at“previvor,” a young woman who chose to have a preventive mastectomy

WEB SITES

American Cancer Society (ACS).

online at http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?dt=5 (updated

September 11, 2008; accessed on September 23, 2008).

Centers for Disease Control and Prevention (CDC).

Available online at http://www.cdc.gov/cancer/breast/ (updated July 11,

2008; accessed on September 23, 2008).

KidsHealth.

grownup/conditions/breast_cancer.html (updated June 2007; accessed on

September 23, 2008).

Mayo Clinic.

health/breast-cancer/DS00328 (updated September 26, 2007; accessed on

September 23, 2008).

National Cancer Institute (NCI).

Available online at http://www.cancer.gov/cancertopics/wyntk/breast/

allpages (updated November 1, 2007; accessed on September 23, 2008).

National Library of Medicine (NLM).

www.nlm.nih.gov/medlineplus/tutorials/breastcancer/htm/index.htm

(accessed on September 23, 2008). This is an online tutorial with voiceover;

viewers have the option of a self-playing version, an interactive version with

questions, or a text version.Breast Cancer Home Page.Breast Cancer. Available online at http://kidshealth.org/kid/Breast Cancer. Available online at http://www.mayoclinic.com/What You Need to Know about Breast Cancer.Breast Cancer. Available online at http://Detailed Guide: Breast Cancer. AvailableSurgical removal of the ovaries. Since the ovaries are the main source’s body, this type of operation is sometimesRadiation therapy. The radiation may come from a large machineSmoking.

Breast Cancer

Definition

Breast cancer is cancer that starts in the tissues of the human breast. It is

the second most common cancer in women, but can also affect men.

There are two main types of breast cancer. The more common of the

two, ductal carcinoma, begins in the ducts, or tubes, that carry milk from

the interior of the breast to the nipple. The other major type is lobular

carcinoma. It begins in the lobules, which are the parts of the breast that

secrete milk.

Avian Influenza

2011-03-22T02:39:00.001+03:00

Definition

Avian influenza, or bird flu, is a form of flu caused by a strain of the influenza

A virus that ordinarily affects only birds. Avian influenza is considered

a zoonosis because it can be transmitted from animals to humans.

It is also considered an emerging disease because it has been identified

as a major public health problem within the last twenty years and threatens

to get worse in the near future.

Wild birds carry many types of the influenza A virus in their digestive

tract but do not usually get sick from it. Infected wild birds can, however,

infect chickens, turkeys, and other domesticated birds through contact

with their nasal secretions or droppings. The infection can be spread by

contaminated bird feed, water, or soil as well as by direct contact between

wild birds and domesticated poultry. There are

two subtypes of avian flu in birds: a relatively

mild form that causes symptoms such as feather

loss and a severe form that can kill entire flocks

of chickens, geese, or turkeys within forty-eight

hours.

Most cases of avian flu in humans as of

2008 have occurred in farmers or other people

who were exposed to sick birds. There are very

few cases of human-to-human transmission of

this form of influenza. The primary reason for

concern is that one specific form of the flu virus

that causes avian flu

widespread sickness and death if it mutates into

a form that can spread easily and directly from

human to human. It was a different form of the

influenza A virus (H1N1) that caused the flu

pandemic of 1918

of millions of people worldwide.

—H5N1—could cause–1920, which took the lives

Description

Avian influenza is similar to seasonal influenza. The person develops a

cough, a fever, an inflammation of the tissues lining the eyelid, a runny

nose, and a headache. The incubation period in humans varies between

two and seventeen days, with five days being the most common length

of time. In fatal cases, the patient begins to have trouble breathing and

may cough up blood about five days after symptoms of illness appear.

Death usually results from viral pneumonia.

Some patients also have abdominal pain, vomiting, and bloody diarrhea

in addition to respiratory symptoms.

Demographics

The first cases of bird flu in humans were reported in Hong Kong in

1997. Of the eighteen people taken ill, six died from the infection. The

disease has spread westward among the bird populations of Asia, Europe,

and northern Africa, with cases of human illness following. In Europe,

however, there have been instances of infected birds discovered without

any cases of human disease. As of September 10, 2008, the World Health

Organization (WHO) reported that 387 confirmed cases of avian influenza

in humans have occurred since 2003; more than half of the patients died.

There have been no confirmed cases of avian influenza caused by the

H5N1 subtype in the United States in either birds or humans as of September

2008. There were, however, outbreaks of a different flu virus among

American poultry in 2003 and 2004. Given the fact that the broadened

spread of any subtype of flu virus increases the danger to public health in

all countries around the world, many researchers think that it is only a

matter of time until the H5N1 type of avian flu reaches the United States.

The risk factors for getting bird flu are not completely understood,

although contact with infected birds or their droppings appears to be the

single most important factor.

•

be infected.

People of all races and both genders appear to be equally likely to

•

are most likely to die from avian flu if they become infected.

According to WHO, people between the ages of ten and thirtynine

•

twenty years of age or younger; 40 percent of cases have been

reported in people between twenty and forty years of age.

As of 2008, 50 percent of reported cases have been in people

Causes and Symptoms

The cause of avian influenza in humans is a variant of the H5N1 influenza

virus that has somewhat adapted itself to infecting people. There is

some evidence that the same strain that infects birds also infects pigs and

can jump the species barrier into humans from pigs as well as birds.

Avian influenza may affect the lower airway in humans more severely

than seasonal influenza. The most common symptoms are:

•

Fever above 100.4°F (38°C)

•

Cough

•

Sore throat

•

Difficulty breathing

•

Headache

•

Conjunctivitis (inflammation of the tissues lining the eyelid)

Diagnosis

Diagnosis of suspected cases of avian flu was complicated until 2006

because samples of the patient

health laboratories or the Centers for Disease Control and Prevention

(CDC) in Atlanta, Georgia, for analysis. In February 2006, however, the

Food and Drug Administration (FDA) approved a new test for diagnosing

strains of bird flu in people who might have the virus. The test

is called the Influenza A/H5 (Asian lineage) Virus Real-time RT-PCR

Primer and Probe Set. The test gives results within four hours.

Treatment

The CDC recommends two antiviral drugs, Tamiflu and Relenza, for

treating any suspected case of bird flu in the United States. It is not

known, however, whether the H5N1 influenza virus might become resistant

to these drugs. In addition, the drugs must be taken within two days

of the appearance of symptoms to be fully effective. Two experimental

antiviral drugs were being tested in Russia and China in 2008, but

neither had yet become available in the United States.

Patients with a severe case of avian influenza may need to be placed

on a respirator. In addition, public health officials currently recommend

that patients suspected of having avian flu should be placed in isolation to

reduce the risk of the infection spreading to other people.

Prognosis

Avian influenza in humans is a serious disease, with a mortality rate close

to 60 percent. There is little information available about the long-term

effects of the illness on survivors.

Prevention

There was no effective vaccine against avian influenza that was available

to the general public in late 2008, although some were undergoing clinical

trials. One of the difficulties of producing a vaccine against this type

of flu in large quantities is that the virus is so powerful that it cannot

easily be cultured in chicken eggs, which is the usual method for making

vaccines. In June 2008, the

an experimental vaccine that produced a satisfactory immune response in

75 percent of the subjects who were injected with it. The vaccine

appeared to be safe for widespread use in humans and could be made

in cell cultures rather than in eggs.

Until an effective vaccine for avian flu is available, the most important

preventive measures people can take are to wash their hands

frequently and avoid open-air markets, raw or undercooked eggs or

poultry, and close contact with live poultry when visiting Asia or other

countries where cases of avian flu have been reported. Travelers may also

want to ask their doctor about getting a flu shot before they take their

trip. Standard flu shots will not prevent bird flu, but they can protect

people against being infected with seasonal flu.

The Future

Because of the potential disaster of an avian influenza pandemic,

researchers are working on developing new antiviral medications and

effective vaccines as quickly as possible. No one knows if or when the

H5N1 virus will mutate into a form that can be easily transmitted from

one person to another. Public health officials around the world are

hoping that they will be prepared if that mutation does occur.

SEE ALSO

Influenza; Pneumonia; Severe acute respiratory syndrome

For more information

BOOKS

Goldsmith, Connie.

First Century Books, 2007. Chapter 6 is about avian influenza.

Grady, Denise.

Fever to Avian Flu

Siegel, Marc.

Hoboken, NJ: Wiley, 2006.

Influenza: The Next Pandemic? Minneapolis, MN: Twenty-Deadly Invaders: Virus Outbreaks around the World, from Marburg. Boston, MA: Kingfisher, 2006.Bird Flu: Everything You Need to Know about the Next Pandemic.

WEB SITES

Center for Food Safety and Applied Nutrition (CFSAN).

to Know about Avian Influenza

~dms/avfluqa.html (updated October 19, 2006; accessed September 14,

2008). This page provides basic information about the safe preparation of

foods containing eggs or poultry.

Centers for Disease Control and Prevention (CDC).

Home Page

7, 2007; accessed September 13, 2008).

KidsHealth.

health_problems/infection/bird_flu.html (updated February 2007; accessed

September 14, 2008).

Mayo Clinic.

com/health/bird-flu/DS00566 (updated July 11, 2008; accessed September

13, 2008).

National Institute of Allergy and Infectious Diseases (NIAID).

Flu, Avian (Bird) Flu, and Pandemic Flu?

www3.niaid.nih.gov/topics/Flu/understandingFlu/DefinitionsOverview.htm

(updated November 28, 2006; accessed September 14, 2008).

National Library of Medicine (NLM).

online at http://www.nlm.nih.gov/medlineplus/tutorials/avianflu/htm/index.

htm (accessed September 14, 2008). This is an online tutorial with voiceover;

viewers have the option of a self-playing version, a text version, or an interactive

version with questions.

Public Broadcasting Service (PBS).

online at http://www.pbs.org/wgbh/amex/influenza/index.html

(accessed September 14, 2008). Web site includes a transcript of the television

program, a timeline and interactive maps, and reflections by a presentday

scientist on the possibility of another pandemic.Avian Influenza (Bird Flu). Available online at http://www.cdc.gov/flu/avian/ (updated MayBird Flu (Avian Flu). Available online at http://kidshealth.org/kid/Bird Flu (Avian Influenza). Available online at http://www.mayoclinic.What Are SeasonalAvailable online at http://Avian Influenza or Bird Flu. AvailableAmerican Experience: Influenza 1918. AvailableWhat Consumers Need. Available online at http://www.cfsan.fda.gov/New England Journal of Medicine reported on’s throat secretions had to be sent to state

Avian Influenza

Autism

2011-03-22T02:29:00.001+03:00

Definition

Autism is classified by the American Psychiatric Association as a pervasive

developmental disorder (PDD). It is characterized by difficulties in social

interaction; problems with verbal and nonverbal communication; and

patterns of repetitive behaviors coupled with a

narrow range of interests

the child is three years old. Autism is considered

a spectrum disorder, because children diagnosed

with it vary widely in the severity of their

symptoms; some may be only mildly affected

and eventually live independently, while others

suffer from severe mental retardation and

require lifelong care.

—all beginning before

Description

Though defined as a disorder for less than a

century, autism has certainly existed for a much

longer period of time. The term

appears to have been coined independently by

Hans Asperger (1906

pediatrician who first used it in a German-language

medical journal in 1938, and Leo

Kanner (1894

who had moved to the United States and published

a paper on what he called infantile

autism in 1943. Since the 1940s, the definition

has expanded to include children who might

have simply been described as odd or strange in the 1960s, as well as children

who are severely disabled by the disorder.

With regard to social interaction, children with autism are commonly

described as loners who are unaware of other people

not respond to their names or make eye contact, and they dislike being

held or cuddled. In terms of behaviors, autistic children prefer sameness

and are upset by change. They may make repetitive gestures like flapping

their hands, spinning, or rocking back and forth. They are often unusually

sensitive to lights, noises, or touch, but at the same time they may be completely

unaware of danger. Many autistic children seem to be insensitive to

pain and do not tell their parents when they are hurt or sick.

Language skills are the third major area in which autistic children are

different from others. They often start talking later than other children and

may speak in a mechanical, sing-song, or robot-like voice. A child with

autism may repeat someone else

how to form a sentence of their own. He or she may have trouble asking

for something in words, using gestures or

pointing instead. In some cases children with

autism do not refer to themselves as

“I” or

“

me,” but use their names instead.

Demographics

There has been considerable controversy in

recent years because the rate of autism in

the United States appears to be rising fairly

rapidly. For many years, doctors estimated that

autismaffected only four or five children in every

10,000. When the Centers for Disease Control

and Prevention (CDC) released a report in February

2007 stating that the rate of autism among

American children had increased to one in 150

(and one in every 94 boys), many people were

quite upset. Although the CDC acknowledges

that some of the increase is due to changes in the

definition and classification of autistic spectrum

disorders or ASDs, some is likely to represent a

true increase in the number of affected children.

Autism is presently the second most common

developmental disability in the United States

after mental retardation. The CDC estimates

that there are about 560,000 persons in the

United States between the ages of one and

twenty-one years who have an ASD.

Boys are more likely than girls to have

autism; the male/female ratio in the United

States is four to one. The reason for the gender

difference is not known. Autism is thought to

be equally common in all racial and ethnic

groups in the United States.

The Autism Society of America estimates that the lifetime cost of

caring for an autistic person ranges from $3.5 to $5 million, and that

autism costs the United States an average of $90 billion each year

(including special education, housing, and transportation services as well

as direct health care costs).

Causes and Symptoms

The causes of autism are not well understood. In the 1950s many psychiatrists

thought that autism was caused by cold or distant parenting

“

disorder. This theory has been disproved by careful studies of families with

autistic children. In the 1990s some people theorized that autism is caused

by childhood immunizations, particularly the measles-mumps-rubella or

MMR vaccine. In 2007, however, a report published in the

Journal of Medicine

that the early symptoms of autism often appear at the age when children are

given the MMR vaccine.

Other possible causes of autism that are still being investigated

include:

—refrigerator mothers” was a common term—and blamed parents for theNew Englandshowed that vaccines do not cause autism; it is simply

•

an increased risk (one chance in twenty) of having a second child

with the disorder. No specific gene or genes associated with autism

has been identified, however.

Genetic factors. It is known that parents of an autistic child have

•

pregnancy have an increased risk of having an autistic child.

Viruses or other disease agents. Women who have rubella during

•

child was born are six times as likely to have an autistic child as

fathers who were thirty or younger. The mother

to make a difference.

Father’s age. One study showed that fathers over forty when their’s age doesn’t seem

•

damage to a baby

in autism.

Difficult pregnancy or childbirth. Some doctors think that’s brain before or during birth may play a role

•

evidence from two studies done in California in 2007 that women

exposed to certain pesticides during the first three months of pregnancy

have an increased risk of having autistic children.

Common symptoms of autism have already been described; others

are listed in the sidebar. Conditions that are often found in children with

autism include:

Exposure to pesticides and other toxic chemicals. There is some

•

mentally retarded, which complicates diagnosis of the disorder.

Mental retardation. About 75 percent of children with autism are

•

Seizures.•

•

appears to develop normally until about fourteen months of age

and then starts losing his or her ability to talk and interact with

others.

A loss of previously attained language or social skills. The child

Diagnosis

The diagnosis of autism is complex; there is no single diagnostic test for

the disorder. In many cases the parents start noticing problems in the

child

and eighteen months old. The diagnosis may not be made, however,

until the child is two to three years of age because of the number of evaluations

that may be needed. It usually takes a team of experts in child

development to make the diagnosis, including a psychiatrist, a neurologist,

a speech therapist, and a pediatrician, all of whom should have specific

experience in evaluating and treating children with autism. There are

several checklists and screeners for symptoms of autism that these health

care professionals may use. In addition, they may order imaging studies, a

hearing test, or (in a few cases) a blood test to rule out other possible

causes of the child

Even though the diagnosis of autism can be complicated, it is important

for parents to have their child evaluated as soon as they notice indications

that the child may be autistic. The reason for early evaluation is

that it improves the child

Studies have shown that children who begin treatment at or before age

three do better than those diagnosed and treated later.

’s speech and interactions with them when the child is between fourteen’s behaviors.’s chances of making good progress in therapy.

Treatment

There is no cure for autism. Treatment usually involves several different

types of therapy. An important form of therapy is behavior and communication

therapy, which is aimed at improving the child

problem behaviors and to interact with others. In some cases the

parents are taught new ways of interacting with their child while he or she

is still a toddler. After the child enters school, highly structured education

programs have been shown to increase the child

skills.

Medications may be prescribed to treat seizures, depression, anxiety,

and other behavioral problems that the child may have.

Because autism is a disorder that places heavy emotional as well

as financial burdens on other members of the family, many families with

autistic children benefit from family therapy or joining a support group.

Prognosis

The prognosis of autism depends largely on the child

and symptom severity. Some autistic children with above-average intelligence

and relatively mild symptoms have successfully completed college,

married, and started families; severely retarded autistic children, however,

may require lifelong care at home or in an institution. Autistic children

who start losing previously acquired language skills before age three are

at increased risk of seizures as they grow older.

’s intelligence level

Prevention

There is no known way to prevent autism.

The Future

Researchers are looking in a number of different directions for new treatments

for autism and improved diagnostic techniques. Some are studying

serotonin, a chemical in the brain that affects the transmission of

impulses from one cell to another, to see whether the high levels of this

chemical in the blood of some children with autism are related to the disorder

in some way. Other scientists are continuing to look for genes that

may be linked to autism. In terms of behavior, researchers are testing the

effectiveness of a program that combines parent training and medication

to reduce the aggressive or disruptive behavior of some children with

autism.

SEE ALSO Asperger syndrome; Rubella; Seizure disorder’s ability to control’s social as well as communicationSelf-injury or aggressive behaviors toward others.autism itself–1980), an Austrian–1981), an Austrian psychiatrist’s feelings. They may’s words or sentences but may not know

Autism

Attention-Deficit Hyperactivity

2011-03-22T02:25:00.001+03:00

Definition

Attention-deficit hyperactivity disorder, or ADHD, is a developmental

disorder usually associated with children but increasingly recognized

in adults too. People with ADHD are easily distracted, have trouble

focusing or paying attention, are disorganized, and frequently behave in

impulsive ways.

The disorder has been known to doctors for over a century. The earliest

description of it was written by a German doctor in 1845, about his

own son. In 1902 a British doctor named George Still gave a series of lectures

to other doctors, in which he described children who would now be

called hyperactive and impulsive. Still thought that the disorder might be

genetic in origin. He emphasized the fact that the behavioral problems in

these children did not result from bad parenting.

There are three basic types of ADHD: inattentiveness; impulsiveness;

and a combination of the two.

Description

The central characteristic of all three types of ADHD is that the child (or

adult) diagnosed with the disorder has fallen behind in school and in social

relationships. Children diagnosed with the inattentive type of ADHD daydream

in school; do not seem to listen when someone speaks directly to

them; do not follow instructions and fail to complete chores or homework

assignments; have trouble with tasks that require concentration; and are in

general disorganized. They are more easily overlooked by parents and teachers,

however, because their behavior is not as disruptive as the hyperactivity

or impulsiveness of other children diagnosed with ADHD.

Children diagnosed with the hyperactive or impulsive type of ADHD

are the ones who cannot sit still in school. They call out answers or talk all

the time, get up and walk around the room, or try to do several things at

once. They do not think before they speak, act without considering the

consequences of their actions, or have trouble taking turns with other children.

Teenagers with this type of ADHD may say that they feel inwardly

restless much of the time or need to find things to do to keep busy.

One important thing to keep in mind about ADHD is that the

behaviors

both

months or longer. Not every episode of absentmindedness or fidgeting in

school means that a child has ADHD. In addition, children

differ, including their level of activity and their level of interest in

certain activities. For example, some children have no difficulty finishing

their homework in a subject that interests them but may have trouble

focusing on an assignment in a subject they do not like.

The signs of ADHD in adults are often harder to recognize than in

children. Adults with ADHD are more likely to say that they have

trouble relaxing than feeling that they have to race around physically.

Inattentiveness may take the form of forgetting meetings, work deadlines,

or social get-togethers. Impulsiveness may take the form of moodiness,

temper tantrums, or impatience in traffic jams.

—whether inattentiveness, hyperactivity, or a combination of—must be inappropriate to the child’s age and must continue for six’s personalities

Demographics

According to the National Institute of Mental Health (NIMH), between

3 and 7 percent of children in the United States have ADHD. This group

would include about 2 million children as of 2008. Worldwide, the rate of

ADHD in children is thought to be somewhere between 8 and 12 percent.

Boys are three to five times more likely than girls to be diagnosed

with ADHD. The inattentiveness subtype is more common in girls than

in boys, however. As far as is known, ADHD is equally common in all

racial and ethnic groups in the United States.

In adults, the gender ratio is virtually equal. The rate of ADHD in

American adults is thought to be between 2 and 7 percent.

Causes and Symptoms

The causes of ADHD are not completely understood, but studies of brain

function using positron emission tomography (PET) scans indicate that

the brains of children with ADHD may be structured differently from

those of children without the disorder. More specifically, some

researchers think that the parts of the brain that govern attentiveness do

not have normal levels of dopamine, a chemical produced by the brain

that allows nerve cells to transmit signals from one cell to another. The

fact that medications that stimulate the release of dopamine are beneficial

to children with ADHD supports this theory.

There are also genetic factors involved in ADHD even though no

specific gene has been identified as a cause of the disorder. It is known

that the disorder runs in families. The parents and siblings of children

with ADHD are two to eight times more likely to develop ADHD than

the general population.

Some researchers think that environmental toxins, particularly lead,

and a mother

ADHD in the child. There is also some evidence that very low birth

weight or premature birth may be risk factors for ADHD. It is not known

whether the emotional climate in the child

although some doctors think that mood or anxiety disorders in

other family members may make the child

unproven theories include the idea that ADHD is caused by head injuries,

allergic reactions to food additives, or a diet high in sugary foods.

Symptoms of inattentiveness related to ADHD include:

’s drinking or smoking during pregnancy are risk factors for’s family contributes to the disorder,’s symptoms worse. Other

•

mistakes.

Failing to pay close attention to details; frequently making careless

•

minutes.

Having difficulty paying attention to tasks for more than a few

•

Appearing not to listen when spoken to.

•

homework or other tasks.

Not following through on instructions and failing to complete

•

Having difficulty organizing tasks.

•

homework or other tasks.

Frequently losing pencils, books, or other items necessary to complete

•

Being forgetful.

•

Symptoms of impulsiveness and hyperactivity include:

Being easily distracted.

•

Fidgets or squirms in seat.•

•

Has difficulty playing quietly.

•

Seems to be constantly on the go.

•

Talks a lot; finds it hard to keep quiet.

•

Blurts out answers in class.

•

Finds it hard to take turns or wait in line.

•

Butts in on conversations or intrudes on the privacy of others.

Diagnosis

The diagnosis of ADHD is complicated, not only because the child

overall personality, and medical history must be taken into account, but

also because about 45 percent of children with ADHD have at least one

other psychiatric disorder, most commonly anxiety disorders, depression,

Tourette syndrome, or bipolar disorder. There is no single laboratory test,

imaging study, or neurological test that can be used to diagnose ADHD,

although there are behavioral checklists and questionnaires that doctors

can use to narrow the diagnostic possibilities. The diagnosis usually follows

a series of interviews with psychiatrists and psychologists as well as

the child

to rule out vision problems, hearing loss, seizure disorder, or hyperthyroidism

as possible causes of the child

The diagnosis of ADHD in children is based on whether the child

meets the criteria specified in a diagnostic manual on mental disorders:

’s age,’s pediatrician. A complete physical examination is important’s behavior.

•

years old.

The symptoms must have started before the child was seven

•

months.

The child must have had the symptoms over a period of at least six

•

or hyperactivity/impulsiveness listed in the previous section.

The child must have six ormore of the signs or symptoms of inattentiveness

•

to function in at least two areas of life, usually home, relationships

with friends, and schoolwork. Thus, a child who is impulsive or

inattentive at school but relates well to friends or other family

members would not be diagnosed with ADHD.

A set of criteria called the Wender Utah Rating Scale is commonly

used to diagnose ADHD in adults:

The symptoms must be shown to have affected the child’s ability

•

A history of ADHD in childhood•

•

Difficulty completing tasks

•

Mood swings

•

Difficulty controlling temper

•

Inability to handle stress

•

Impulsive behaviors

Treatment

Treatment for ADHD usually includes a combination of medications

and behavior therapy. The use of medications has been controversial.

However, children treated with both medications and behavior therapy

have been found to do better than those treated with behavior therapy

alone. It is important to understand that the medications prescribed for

ADHD do not cure the disorder. The medications only help the child

control the symptoms, and they must be taken every day.

The medications most commonly used to treat ADHD are psychostimulants,

which work by targeting the parts of the brain that produce

dopamine. These drugs include Ritalin, Adderall, and Dexedrine. More

recently, the Food and Drug Administration (FDA) approved the use

of a non-stimulant medication called Strattera, which works on another

brain chemical called norepinephrine. Norepinephrine is a hormone that

affects a person

stress. Although medications for ADHD generally work well, they do

have side effects, such as sleep problems, weight loss, appetite loss, and

nervousness.

In addition to behavior therapy, children with ADHD may receive

social skills training and attend support groups. Many doctors recommend

parenting skills training for the parents of children with ADHD

and family therapy for the entire family.

Adults with ADHD are also treated with a combination of drugs and

psychotherapy. However, because adults need larger doses of psychostimulants

than children do, they must see their doctor periodically to make

sure that the drugs are not interfering with other medications they may

be taking, particularly drugs to control high blood pressure.

Some forms of alternative medicine that have been suggested as

treatments for ADHD include special diets, vitamin supplements, and

various herbal preparations. There is no evidence, however, that any

of these alternative approaches are useful for children or adults with the

disorder.

Prognosis

Doctors think that between 30 and 70 percent of children diagnosed

with ADHD will continue to have some symptoms of the disorder as

adults. Most children diagnosed with the disorder benefit from appropriate

treatment, although they have a higher risk of alcohol and drug

abuse in adolescence. As many as 65 percent may continue to have problematic

symptoms of ADHD that keep them from reaching their full

academic or work potential in adult life.

Prevention

There is no known way to prevent ADHD because the causes of the disorder

are still not completely understood.

The Future

Doctors are not certain whether the rate of ADHD in the American

population is likely to increase or remain at its present level. Current

research on the disorder includes studies comparing newer drugs for

ADHD to older psychostimulants; studies of ADHD in adults; studies

of the relationship of childhood ADHD to substance abuse in adolescence

and adulthood; and evaluations of new diagnostic questionnaires

for ADHD.

SEE ALSO

Tourette syndrome

Bipolar disorder; Lead poisoning; Prematurity; Seizure disorder;

For more information

BOOKS

Brynie, Faith Hickman.

MN: Twenty-First Century Books, 2008.

Peirce, Jeremy.

House, 2008.

Silverstein, Alvin, Virginia Silverstein, and Laura Silverstein Nunn.

Update: Understanding Attention-Deficit/Hyperactivity Disorder

Heights, NJ: Enslow Publishers, 2008.

The ADHD. Berkeley

PERIODICALS

Baruchin, Aliyah.

“Attention Deficits That May Linger Well Past Childhood.”

New York Times

nytimes.com/ref/health/healthguide/esn-adhd-ess.html (accessed

September 3, 2008).

, January 10, 2008. Available online at http://health.

“

http://www.nytimes.com/interactive/2008/05/21/health/healthguide/

TE_ADHD_CLIPS.html (accessed September 3, 2008). This is an interactive

site with voice recordings and slide shows of nine children and adults

coping with ADHD.

Patient Voices: ADHD.” New York Times, May 21, 2008. Available online at

WEB SITES

Children and Adults with Attention-Deficit/Hyperactivity Disorder

(CHADD).

org/AM/Template.cfm?Section=Understanding (accessed September 4,

2008).

KidsHealth.

health_problems/learning_problem/adhdkid.html (updated May 2006;

accessed September 3, 2008).

Mayo Clinic.

at http://www.mayoclinic.com/health/adhd/DS00275 (updated February

16, 2007; accessed September 3, 2008).

National Alliance on Mental Illness (NAMI).

Disorder

By_Illness&template=/ContentManagement/ContentDisplay.cfm&

ContentID=22571 (updated May 2003; accessed September 3, 2008).

National Institute of Mental Health (NIMH).

Disorder (ADHD)

topics/attention-deficit-hyperactivity-disorder-adhd/index.shtml (updated

April 3, 2008; accessed September 3, 2008).

WORDS TO KNOW
Dopamine: A brain chemical that helps to regulate
movement.
Norepinephrine: Another brain chemical that
affects a person’s ability to pay attention.
Psychostimulant: A type of drug that increases the
activity of the parts of the brain that produce
dopamine.Understanding AD/HD. Available online at http://www.chadd.What Is Hyperactivity? Available online at http://kidshealth.org/kid/Attention-Deficit Hyperactivity Disorder (ADHD). Available onlineAttention-Deficit/Hyperactivity. Available online at http://www.nami.org/Template.cfm?Section=Attention Deficit Hyperactivity. Available online at http://www.nimh.nih.gov/health/ADHD: Attention-Deficit/Hyperactivity Disorder. Minneapolis,Attention-Deficit/Hyperactivity Disorder. New York: Chelsea’s ability to pay attention and respond appropriately toHyperactivity and poor ability to focus or concentrateLeaves classroom seat and runs around.

Attention-Deficit Hyperactivity

Disorder

Astigmatism

2011-03-22T02:16:00.001+03:00

Definition

Astigmatism is a condition in which either the cornea or the lens of the

eye has an abnormal curvature, causing out-of-focus vision.

Description

Astigmatism is a common refractive error in which a person cannot see

objects with complete clarity. In some cases the person can see vertical

lines more clearly than horizontal lines; this is called with-the-rule astigmatism.

In other cases the person can see horizontal lines clearly while

vertical lines look blurred; this is called against-the-rule astigmatism.

Children are more likely to have with-the-rule astigmatism while adults

are more likely to have against-the-rule astigmatism.

Demographics

Astigmatism is a very common visual defect. It often exists together with

nearsightedness (myopia) or farsightedness (hyperopia). It is estimated

that as many as a third of the general American population has some

degree of astigmatism. Mild astigmatism is considered normal and may

not require corrective lenses.

Astigmatism is equally common in men and women and in all races

and ethnic groups.

Causes and Symptoms

The exact cause of astigmatism is not known; it

is usually present from birth. In a few cases,

astigmatism may result from an injury to the

eye or from keratoconus, an eye disorder that

causes the tissue of the cornea to become

thinner over time. In an astigmatic eye, the irregularly

shaped cornea or lens prevents light

from focusing properly on the retina, the

light-sensitive tissue layer that lines the back

of the eye. When the cornea is irregularly

curved, the eye focuses light on two different

points inside the eye rather than one. If the

person is nearsighted, one of the two focal

points will lie in front of the retina; if the

person is farsighted, the second focal point will

lie behind the retina.

In simple astigmatism, one of the two

focal points will lie on the retina itself. If the

person has compound myopic astigmatism,

however, both focal points lie in front of the

retina. Similarly, in compound hyperopic

astigmatism, both focal points lie behind the

retina. A few people have what is called mixed

astigmatism, in which one focal point falls in front of the retina and the

other behind it.

The basic symptom of astigmatism is that objects look blurred at any

distance. People who are severely astigmatic may also develop headaches,

eye strain, and fatigue along with blurring of vertical, diagonal, or horizontal

lines if their refractive error is not corrected.

Diagnosis

Astigmatism and other refractive errors are evaluated by a series of vision

tests. After the examiner takes a history of the patient

(including a family history of eye problems), the patient is usually asked

to read the letters on an eye chart known as a Snellen chart. The examiner

may also shine lights into the eyes or administer eye drops that allow him

or her to see all the structures inside the eye clearly. This part of the

examination allows the doctor to evaluate the patient for nearsightedness

or farsightedness.

To determine the degree of astigmatism, the examiner will use a keratometer,

a device that measures the curvature of the cornea. The examiner

will measure the steepest and flattest curves on the cornea. Another

technique that can be used to evaluate astigmatism is called corneal topography

and uses a device called a videokeratoscope. The keratoscope part

of the machine projects rings of light onto the cornea while the examiner

studies the pattern of the reflected light and records it with a video

camera. Corneal topography provides a more detailed picture of the shape

of the patient

contact lenses.

Treatment

Mild astigmatism may not need corrective treatment. A person should see

their eye doctor, however, if they are developing headaches or eye strain,

or if blurry vision is interfering with daily activities.

People whose astigmatism is severe enough to require correction have

several options:

•

uneven curvature of the lens as well as the cornea. Eyeglasses are

prescribed by an optometrist or ophthalmologist but made and

fitted by an optician.

Eyeglasses. These can be used to correct astigmatism caused by

•

of astigmatism than soft contact lenses.

Hard contact lenses. These usually provide more effective correction

•

wears hard contact lenses for several hours overnight in order to gradually

correct the curvature of the cornea. The lenses are removed

during the day. Ortho-K is also referred to as corneal molding. It

does not permanently improve vision; if the patient stops wearing

the retainer lenses, their vision may return to its original condition.

Orthokeratology (Ortho-K). This is a procedure in which the person

•

cornea either by making a flap in the surface of the cornea and

reshaping the tissue of the cornea under the flap, or by completely

removing the upper layer of tissue in the cornea before reshaping

the lower layers of tissue.

There are drawbacks to surgical correction of refractive errors, however.

These include the risks of infection, development of haze in the

cornea, or dry eyes. In some cases the surgeon may need to perform a

second operation if the first one either overcorrected or undercorrected

the shape of the patient

It is important for a patient with astigmatism to discuss all the treatment

options with the optometrist or ophthalmologist, as no two people

will have exactly the same degree of visual blurring or the same lifestyle.

Laser surgery. An ophthalmologist can use lasers to reshape the’s cornea.

Prognosis

Astigmatism may either improve over time or grow worse; it also changes

from with-the-rule astigmatism in childhood to against-the-rule astigmatism

in adulthood in some people. Most people with astigmatism who

need corrective lenses or other types of treatment, however, do very well.

About 20 percent of people with keratoconus, however, will eventually

need a corneal transplant.

Prevention

Astigmatism is largely a matter of heredity and cannot be prevented.

People can, however, live comfortably with it by visual screening in childhood,

regular eye checkups at all ages, and wearing corrective lenses if

necessary.

The Future

Astigmatism is such a common refractive error in the general population

that it is not likely to disappear in the near future. It is possible that the

present variety of treatment options will be improved or expanded by

further research.

SEE ALSO

For more information

BOOKS

Bakri, Sophie J., ed.

Clinic, 2007.

Viegas, Jennifer.

Group, 2002.

Mayo Clinic Guide to Better Vision. Rochester, MN: MayoThe Eye: Learning How We See. New York: Rosen Publishing

WEB SITES

American Optometric Association (AOA).

http://www.aoa.org/x4698.xml?Play=true (accessed May 6, 2008). The page

includes three animations about astigmatism that have a total playing time of

about 90 seconds.

Art, Vision, & the Disordered Eye.

http://www.psych.ucalgary.ca/PACE/VA-Lab/AVDE-Website/ElGreco.html

(accessed May 7, 2008). This is a fascinating website maintained by the

Vision and Aging Laboratory of the Department of Psychology at the University

of Calgary in Canada. Viewers can study eight different artists from

Mary Cassatt to Vincent van Gogh from the standpoint of the influence of

vision disorders on their art.

Mayo Clinic.

health/astigmatism/DS00230 (updated January 18, 2007; accessed May 6,

2008).

Montreal Vision Clinic.

www.eyemotion.com/eyemotion/library/_montrealeyefr.php?src=1 (accessed

May 6, 2008). This is a one-minute animation of the refractive errors

involved in astigmatism.

National Eye Institute (NEI).

Available online at http://www.nei.nih.gov/CanWeSee/qa_refractive.asp

(updated December 2006; accessed May 6, 2008).

TeensHealth.

.kidshealth.org/teen/your_body/take_care/vision_care.html (updated

January 2008; accessed May 6, 2008).

WORDS TO KNOW
Against-the-rule astigmatism: A type of astigmatism
in which the eye sees horizontal lines more
clearly than vertical lines.
Astigmatism: A refractive error caused by irregularities
in the shape of the cornea or the lens of
the eye.
Cornea: The transparent front part of the eye
where light enters the eye.
Hyperopia: The medical term for farsightedness.
Keratoconus: An eye disorder in which the
tissue of the cornea grows thinner over
time.
Myopia: The medical term for nearsightedness.
Ophthalmologist: A doctor who specializes in
diagnosing and treating eye disorders and can
perform eye surgery.
Optician: An eye care professional who fills
prescriptions for eyeglasses and corrective lenses.
Optometrist: An eye care professional who diagnoses
refractive errors and other eye problems
and prescribes corrective lenses.
Orthokeratology: A treatment for astigmatism
that consists of wearing hard contact lenses
overnight to reshape the cornea during sleep.
The lenses are removed during the day.
Refractive error: A general term for vision problems
caused by the eye’s inability to focus light
correctly.
Retina: The light-sensitive layer of tissue at the
back of the eyeball.
With-the-rule astigmatism: A type of astigmatism
in which the eye sees vertical lines more clearly
than horizontal lines.Astigmatism. Available online atEl Greco (1541–1614). Available online atAstigmatism. Available online at http://www.mayoclinic.com/EyeMotion: Astigmatism. Available online at http://Questions and Answers about Refractive Errors.Taking Care of Your Vision. Available online at http://wwwHyperopia; Myopia’s cornea and can be used to determine the proper fit for’s symptoms

Astigmatism

Asthma

2011-03-22T02:11:00.001+03:00

Definition

Asthma is an inflammatory disorder of the airways leading to the lungs.

The disease causes the airways to constrict and produce mucus that

makes breathing difficult. Asthma is considered an atopic disease along

with eczema and hay fever.

Description

The symptoms of asthma vary from person to person. Some people diagnosed

with asthma have occasional episodes of mild wheezing or

coughing but are able to breathe normally in between such episodes.

Others may have life-threatening attacks in which they turn blue for lack

of oxygen, experience severe chest pain, and may even lose consciousness.

Doctors classify asthma into four categories of severity:

•

week; can breathe normally between episodes; and does not need

daily medication.

Intermittent: The patient has asthma episodes less than once a

•

week but less than once a day; the episodes sometimes affect sleep

and activity levels; and the patient can control symptoms by using

an inhaler.

Mild persistent: The patient has episodes more often than once a

•

affect sleep and activity levels; and the patient needs longacting

oral medications as well as an inhaler.

Moderate persistent: The patient has episodes every day; the symptoms

•

disturbed at night and must limit daytime activity; needs

steroid medications as well as oral drugs and long-acting inhalers.

Severe persistent: The patient has continuous symptoms; is frequently

Demographics

Asthma is one of the most common chronic (long-term) diseases around

the world and is the single most common cause of hospitalization for children

in the United States. According to American Academy of Allergy,

Asthma and Immunology (AAAAI), 20 million people in the United States

have asthma, with 9 million children under the age of eighteen diagnosed

with the disease. Two-thirds of all cases of asthma in North America are

diagnosed in children before age eighteen.

Asthma is responsible for about 500,000 hospitalizations each year in

the United States and 5,000 deaths. There are about 13 million physician

office visits and 1.2 million outpatient department visits due to asthma.

Children with asthma miss about 13 million days of school each year and

adults with asthma miss 25 million work days. The annual costs to the

American economy for asthma are $11.5 billion for direct health care and

$5 billion for lost productivity.

Risk factors for asthma include:

•

A family history of asthma.

•

Living in a large city.

•

Exposure to secondhand smoke in the home.

•

hairdressing, and other occupations.

Exposure to chemicals used in farming, manufacturing, dry cleaning,

•

have higher levels of asthma than members of other races,

including Native Americans and Pacific Islanders.

•

but by adolescence the numbers are equal. Women are more

likely than men to be diagnosed with asthma as adults.

Gender. Boys are twice as likely as girls to develop asthma in childhood,

•

Obesity.

•

Low birth weight.

Causes and Symptoms

The basic cause of asthma is the hypersensitivity of the person

some trigger in the environment. When the tissues in the airway react to

the trigger, they constrict (become narrower), which reduces the amount

of air that can flow into, and especially out of, the lungs. The inflamed

tissues also secrete mucus, which further limits the airflow in the bronchi

and adds to the wheezing, coughing, and feeling of tightness in the chest

that are part of an asthma attack.

Most doctors think that genetic factors are partly responsible for the

sensitivity of the lung tissues in asthma patients. It is known that the disorder

runs in families. At least twenty-five different genes have been associated

with an increased risk of asthma in six or more separate groups of

people. Researchers still do not understand, however, exactly how these

genes (or others that may be discovered in the future) interact with triggers

in the environment to produce the symptoms of asthma.

Specific triggers that can produce asthma attacks in patients include:

•

dander, and cockroach droppings.

Allergens carried in the air. These include pollen, dust, mold, pet

•

Getting a cold or other upper respiratory infection.

•

Physical exercise. This is called exercise-induced asthma or EIA.

•

Cold dry air.

•

Tobacco smoke and other air pollutants.

•

drugs (NSAIDs), and beta blockers (heart drugs).

Medications, particularly aspirin, other nonsteroidal anti-inflammatory

•

shellfish, and eggs.

Foods that cause allergic reactions. Common offenders are peanuts,

•

Gastroesophageal reflux disease (GERD).

•

The menstrual cycle in some women.

•

Emotional stress or tension.

•

shaving lotion, scented tissues, and similar personal and

household products.

Shampoo, hair gel, fabric softener, deodorant, cologne, air freshener,

•

Chlorinated swimming pool water.

Diagnosis

Asthma can be difficult to diagnose, particularly in children younger than

five years, because the symptoms can vary considerably in frequency and

severity. In some cases, the person

bad cold, pneumonia, or emphysema. To narrow the diagnostic possibilities,

the doctor will take a family history as well as the patient

history and give the patient a complete physical examination.

The next step in diagnosis is to test the patient

are several tests that can be done:

’s lung function. There

•

amount of air that a person can breathe out after taking a very deep

breath.

Spirometry. A spirometer is a machine that measures the largest

•

part of an asthma action plan to detect minor changes in lung capacity

before the symptoms of an asthma attack appear. The meter

can be used in the doctor

patient may be asked to use the meter before and after taking a

dose of a bronchodilator, which is a type of drug that opens up the

airway. If the patient

after taking the bronchodilator, he or she is likely to have asthma.

Peak airflow meter. This is a device that can be used at home as’s office to measure lung function. The’s reading on the peak airflow meter improves

•

drug that is known to trigger asthma is given to the patient. If the

patient

with asthma. The bronchial challenge test is particularly

useful in identifying patients with intermittent asthma.

Bronchial challenge test. In this type of test, a small amount of a’s airway narrows after taking the drug, he or she is diagnosed

Treatment

Treatment for asthma is based on the severity and frequency of the

patient

episodes of asthma. There is no cure for the disease currently.

Most asthma patients need a combination of long-term control medications

and quick-relief or rescue medications. The long-term drugs

are taken every day over long periods of time to prevent asthma

attacks. They may take several weeks to become fully effective. The

long-term medications given to control asthma include inhaled corticosteroids,

long-acting inhaled bronchodilators, or oral medications

like theophylline.

Quick-relief or rescue medications include oral corticosteroids and

short-term bronchodilators like Atrovent or albuterol. The effects of

rescue medications last between four and six hours. A patient who needs

these drugs very often probably needs to have his or her long-term medications

adjusted.

Asthma patients who are allergic to specific foods or airborne allergens

may need treatment for their allergies as well as their asthma.

Prognosis

About half of all children diagnosed with asthma outgrow their disease by

their late teens or early twenties and do not need further treatment.

Patients who develop asthma as adults are more likely to have chronic

health problems related to the disease.

Prevention

People cannot prevent getting asthma, but they can reduce the frequency

and severity of asthma attacks by following the recommendations of the

Centers for Disease Control and Prevention (CDC):

•

recommends the sample plan found at http://familydoctor.org/

online/famdocen/home/common/asthma/basics/696.html.

Draw up an asthma action plan with the family doctor. The CDC

•

Identify and avoid personal asthma triggers.

•

Learn to identify the warning signs of an asthma attack.

•

with a peak air flow meter.

Monitor breathing periodically by taking measurements at home

•

attack.

Treat attacks early. Quick action reduces the likelihood of a severe

•

without consulting the doctor even though the asthma seems to

be getting better.

Take asthma medications as directed. Do not stop taking them

The Future

Asthma is a concern to public health doctors because its rates have risen

rapidly in the United States since the 1960s. The number of children

under the age of five diagnosed with asthma rose 160 percent from 1980

to 2006. Similar increases have been reported in other developed countries,

including Canada, Australia, New Zealand, Germany, and the United

Kingdom. Some of the explanations that have been offered for the increase

include people moving from rural areas into cities; air pollution; increased

exposure to chemicals in the environment; and increased exposure to

tobacco smoke in the household. It is expected that asthma rates will continue

to rise in developed countries over the next several decades.

SEE ALSO

apnea; Smoking

For more information

BOOKS

Berger, William E.

Landau, Elaine.

Powell, Jillian.

Living with Asthma. New York: Facts on File, 2008.Asthma. New York: Marshall Cavendish Benchmark, 2009.Asthma. North Mankato, MN: Cherrytree Books, 2007.

PERIODICALS

Moran, W. Reed.

January 31, 2002. Available online at http://www.usatoday.com/news/

health/spotlight/2002/01/31/spotlight-kersee.htm (accessed September 21,

2008).

“Jackie Joyner-Kersee Races against Asthma.” USA Today,

WEB SITES

American Academy of Allergy, Asthma and Immunology (AAAAI).

Asthma

adultasthma.asp (accessed September 20, 2008).

American Academy of Allergy, Asthma and Immunology (AAAAI).

Asthma

childhoodasthma.asp (accessed September 20, 2008).

American Academy of Family Physicians (AAFP).

Available online at http://familydoctor.org/online/famdocen/home/

common/asthma/basics/696.html (updated May 2006; accessed September

20, 2008).

American Lung Association.

lungusa.org/site/apps/nlnet/content3.aspx?c=dvLUK9O0E&b=

4294229&ct=5314727 (accessed September 20, 2008).

Centers for Disease Control and Prevention (CDC).

Asthma

September 20, 2008).

Mayo Clinic.

asthma/DS00021 (updated May 31, 2008; accessed September 20, 2008).

National Heart, Lung, and Blood Institute (NHLBI).

online at http://www.nhlbi.nih.gov/health/dci/Diseases/Asthma/Asthma_

WhatIs.html (updated May 2008; accessed September 20, 2008).

TeensHealth.

asthma_basics/what/asthma.html (updated March 2007; accessed September

20, 2008). Page includes an animation of the way to use a peak flow meter.

WORDS TO KNOW
Allergen: A substance that causes an allergic reaction
in individuals who are sensitive to it.
Atopic disease: Any allergic disease that affects
parts of the body that are not in direct contact
with the allergen. Asthma, eczema, and hay
fever are all atopic diseases.
Bronchodilator: A type of drug that opens up the
bronchi, increasing airflow and relieving
wheezing and other asthma symptoms.
Bronchus (plural, bronchi): One of the two major
divisions of the airway that lead into the right and
left lungs.
Chronic: Long-term.
Peak airflow meter: A handheld device that
asthma patients can use at home to monitor their
lung capacity in order to treat the warning signs
of an asthma attack as soon as possible.
Spirometer: A device that is used to test the air
capacity of a person’s lungs and the amount of
air that enters and leaves the lungs during
breathing.
Wheezing: A continuous harsh whistling sound
produced by the airways of an asthma patient
when the air passages are partly blocked.You Can Control Your. Available online at http://www.cdc.gov/asthma/faqs.htm (accessedAsthma. Available online at http://www.mayoclinic.com/health/What Is Asthma? AvailableWhat’s Asthma?. Available online at http://kidshealth.org/teen/Adult. Available online at http://www.aaaai.org/patients/gallery/Childhood. Available online at http://www.aaaai.org/patients/gallery/Sample Asthma Action Plan.What Is Asthma? Available online at http://www.Eczema; Gastroesophageal reflux disease; Hay fever; Sleep’s symptoms and is aimed at controlling symptoms or preventing’s symptoms may be misdiagnosed as a’s medical’s airway toRace. African Americans and Puerto Ricans in the United States

Asthma

Asperger Syndrome

2011-03-22T01:59:00.001+03:00

Definition

Asperger syndrome is commonly defined as a pervasive developmental

disorder (PDD). PDDs are defined as a group of behavioral disorders that

have two common features: problems in social interaction and problems

with communication, both verbal and nonverbal.

Description

Children with AS are not mentally retarded. They learn to talk at the

usual age and often have above-average verbal skills. They have normal

or above-normal intelligence and the ability to feed or dress themselves

and take care of their other daily needs. The most distinctive features of

AS are problems with social interaction, particularly making friends with

others; difficulties with nonverbal communication (e.g., facial expressions);

peculiar speech habits that include repeating words or phrases or

talking in a flat tone of voice; an apparent lack of

a fascination with odd or obscure subjects (e.g., the parts of a clock or

small machine, railroad schedules, astronomical data, etc.) that may prevent

the child

Although AS is not a physical disorder as such, some children with

the syndrome are clumsy or make awkward repetitive physical movements.

They typically find team sports and skills like swimming or riding

a bicycle much more challenging than most children. They may also have

strange or eccentric behaviors like hand wringing, finger flapping, or

swaying in place. Some children with AS are unusually sensitive to bright

lights, loud sounds, and changes in temperature.

Demographics

The exact frequency of AS is not known, partly because doctors in different

countries disagree about its exact definition. Some think that AS

is a subtype of autism while others think it is a distinct disorder. Estimates

range between one child in 250 and one child in 10,000. What

is known is that the disorder affects four times as many boys as girls.

AS is thought to affect all racial and ethnic groups equally.

Causes and Symptoms

The cause of AS is not known, although

some think it may be related to a decreased

flow of oxygen to the baby

childbirth. Another theory is that AS is

genetic because it appears to run in families;

however, no specific gene has yet been identified

with the disorder. A team of German

researchers reported in January 2008 that

they had excluded a specific gene that other

scientists thought might be a partial cause

of AS.

The symptoms of AS vary somewhat

according to the child

with AS typically have problems picking up

social cues and understanding the basics of

interacting with other children. The child

may want friendships but find him- or herself

unable to make friends.

The symptoms of AS usually become

much more noticeable during the elementary

school years. It is at this point that

the child

making eye contact, unusual but restricted

interests, and odd behaviors increase his

or her difficulty making friends. Although

the child learns language easily, he or she

may speak in a rapid, jerky, or overly loud

way. Children with AS are also extremely

literal in their use of language; they often fail to understand the symbolic

or humorous uses of language, such as the saying that

cats and dogs.

’s brain during’s age. Young children’s physical clumsiness, difficulty“it’s raining”

Adolescence is one of the most painful periods of life for young

people with Asperger

this age group and require more finely tuned social skills. In addition,

teenagers with AS are often naïve and may be easily manipulated or

cheated by their more sophisticated peers.

Adults with AS are usually able to complete their education and

join the workforce. Some become exceptional scholars; one of the

children that Hans Asperger studied in the 1940s became a noted

astronomer, publishing a paper on an error in Isaac Newton

he had first noticed in childhood. The chief difficulties that men with

AS have in adult life are courtship and marriage. They may want very

much to marry and have a family but do not understand the many

social interactions that are part of the dating process leading to marriage.

One man with AS became a surgeon and accomplished musician,

but lived with his parents until he was fifty years old. He then married a

distant cousin half his age who lived in another country; the marriage

lasted only a few months.

’s work that

Diagnosis

AS is usually diagnosed when the child is between four and eleven years

old. There is no laboratory or imaging test that can detect AS, although

the child may be given a CT scan to rule out other disorders of the nervous

system or a hearing test to rule out partial deafness. Since a diagnosis

of AS is based on a pattern of behaviors rather than a set of

specific physical characteristics, the child is usually diagnosed by being

observed by several different doctors, including a psychiatrist and neurologist,

to look for recurrent patterns in the child

and interactions with other people. A test that is sometimes used to

screen for AS involves asking the child to carry out a task that depends

on the ability to predict how another person might respond to a given

situation. Children with AS usually lack the ability predict someone

else

’s speech, movements,’s thoughts and feelings.

Treatment

Treatment for AS depends on the specific child

and interests. There is no single set or series of treatments that will

work for every child with AS. Some children who are very clumsy

benefit from physical therapy that improves their coordination and

ability to participate in sports. Some children may need to work with

a speech therapist in order to learn to speak in a normal tone of voice.

Teachers and parents can often help a child with AS work on his or her

social skills.

Medications are not used to treat AS itself, although adults with

AS may be given antidepressant medications if they become depressed.

In some cases psychotherapy is useful for adults with AS who are

discouraged by their condition or who have developed other mental

disorders.

Prognosis

The prognosis of AS varies depending on the person

career interests, and the amount of support he or she receives

from friends and family. Divorce and family breakup can be very upsetting

to children with AS and complicate their educational and social

development. Career counseling can help a child with AS choose an

occupation that will make the most of his or her interests and preferably

allow him or her to work alone rather than as part of a team. In addition,

children with AS actually have an advantage in some fields, like

music or mathematics, because of their ability to spend hours developing

and practicing skills in their field of interest. People with AS

have become successful scientists, mathematicians, architects, medical

researchers, computer scientists, musicians, and engineers. Some famous

people who are thought to have had AS include such writers as Jonathan

Swift and Patricia Highsmith; such philosophers as Bertrand Russell and

Ludwig Wittgenstein; and such musicians as Bela Bartok, Erik Satie, and

Glenn Gould.

As far as is known, people with AS have the same life expectancy as

others of their age, race, or sex, but they do have a higher risk of developing

eating disorders, depression, schizophrenia, or Tourette syndrome.

Having another mental disorder then places them at a higher risk of suicide

than people in the general population.

’s level of intelligence,

Prevention

There is no known way to prevent AS because its causes are not completely

understood.

The Future

There are no new treatments for Asperger syndrome, nor is it known

whether the disorder is becoming more common, partly because of disagreement

about its definition.

One major change since 2000 is the development of an autistic rights

or autistic pride community. Rather than accepting the standard definition

of Asperger syndrome as a disease to be cured, some adults with

AS prefer to describe it as simply having a different type of brain

organization. A Web site for

called Wrong Planet was set up in 2004. As with many other disorders,

the Internet is offering people with AS the opportunity to form

their own communities, find support, share their personal experiences,

and learn about the latest research.

“aspies,” as they have nicknamed themselves,

SEE ALSO

Autism; Autism spectrum disorders; Tourette syndrome

For more information

BOOKS

Attwood, Tony.

Kingsley, 2007.

James, Ioan.

People

The Complete Guide to Asperger’s Syndrome. Philadelphia: JessicaAsperger’s Syndrome and High Achievement: Some Very Remarkable. Philadelphia: Jessica Kingsley, 2006.

PERIODICALS

Blume, Harvey.

in Cyberspace.

http://query.nytimes.com/gst/fullpage.html?res=9803E7DC1F31F933A05

755C0A961958260 (accessed March 2, 2008).

“Autistics, Freed from Face-to-Face Encounters, Are Communicating” New York Times, June 30, 1997. Available online at

WEB SITES

Autism Society of America.

www.autism-society.org/site/PageServer?pagename=life_aspergers (accessed

September 12, 2008).

KidsHealth.

brain/asperger.html (accessed September 12, 2008).

Wrong Planet.

(accessed September 12, 2008). Wrong Planet is an online discussion community

for people with AS.

WORDS TO KNOW
Aspie: An informal name for a person with
Asperger syndrome.
Autism: A developmental disorder that appears
by three years of age and is characterized by
limited communication skills, difficulties in
communicating with others, and difficulties
forming relationships. Some doctors think
that Asperger syndrome is a subtype of
autism.
Pervasive developmental disorder (PDD): A diagnostic
category for a group of childhood disorders
characterized by problems in communication skills
and social interactions. Asperger syndrome is
classified as a PDD.
Tourette syndrome: A neurological disorder characterized
by recurrent involuntary body
movements and repeated words or grunts.What’s Unique about Asperger’s Disorder? http://Asperger Syndrome. http://www.kidshealth.org/parent/medical/What Is Asperger’s Syndrome? http://www.wrongplanet.net/’s range of abilities’s, because social interactions are more complex in“common sense” and’s developing other interests.

Asperger Syndrome

Brain Tumors

2011-03-05T05:09:00.003+03:00

—most often the breasts, colon, kidneys, lungs, or skin—and

Description

Brain tumors vary considerably in their location in the brain, their speed

of growth, whether they are benign or malignant, and the specific symptoms

they produce. Brain tumors can cause damage by direct destruction

of normal brain tissue, by producing inflammation, or by growing so

large that they increase pressure inside the skull and interfere with the

functioning of other parts of the brain. Primary brain tumors can develop

within the brain tissue itself, within the meninges (the membranes that

cover and protect the brain and spinal cord), or within the nerves that

supply the brain and spinal cord.

In adults, the most common types of brain tumors are gliomas and

meningiomas. Gliomas, which account for 78 percent of malignant brain

tumors in adults, arise from glial cells, which are the supportive cells in

brain tissue that nourish nerve cells and hold them in place. Meningiomas

are tumors that arise in the meninges. Ninety percent of mengiomas

are benign; however, these tumors can still cause severe

complications and death because of their location.

The most widely used system for grading brain tumors was introduced

by the World Health Organization (WHO) in 1993. Grading
’s size, its location in the brain, and how fast

•

symptoms for many years. They do not usually spread to other

parts of the brain and can often be removed completely by

surgery.

Grade I. These are slow-growing tumors that may not produce

•

however, start to grow more rapidly and may spread into other

parts of the brain.

•

spread rapidly into surrounding tissue. Their cells look different

from those in healthy surrounding tissue.

Grade III. Tumors in this category are always malignant and

•

difficult to treat. Like Grade III tumors, their cells look very different

from healthy brain cells.

Grade IV. These tumors invade other tissues very quickly and are

Demographics

About 360,000 persons in the United States are living with a primary

brain tumor as of 2008, according to the National Institutes of Health,

with about 44,000 new cases of primary tumors reported each year. Primary

brain tumors account for about 2.5 percent of cancer deaths in the

United States each year

100,000 Americans die each year of metastatic brain tumors.

Brain tumors are the most common type of solid tumor in children,

and the second most common type of cancer in those below age fifteen.

Between 15 and 25 percent of all cancers in children are brain tumors. The

most common type of brain tumor in children is called a medullablastoma,

a highly malignant cancer that develops in the cerebellum (the part of the

brain just above the brain stem). This type of tumor is rare in adults.

Most types of brain tumors are equally common in men and women;

however, meningiomas occur slightly more often in women than in men.

Medulloblastomas are more common in boys than in girls. And although

most brain tumors are more common in Caucasians, meningiomas are

more common in African Americans than in members of other races.

Risk factors for brain tumors include:

—about 13,000 adults and children. About

•

adults over age forty-five. Brain tumors in children are rare within

the first year of life; they occur most often in children between five

and eight years of age.

Age. Most brain tumors, whether benign or malignant, occur in

•

of cancer.

Exposure to nuclear radiation or radiation therapy for another type

•

Family history of brain tumors.

•

Exposure to certain chemicals.

Causes and Symptoms

The causes of primary tumors of the brain were not completely understood

as of 2008; most researchers, however, think that defective genes are

responsible. Other theories include viruses, exposure to certain chemicals,

and disorders of the immune system.

Secondary brain tumors result from the spread of cancer that began

elsewhere in the body, with lung cancer the most common type. Brain

tumors can also develop from cancerous cells from the breast, kidneys,

colon, or skin. The cancerous cells break off from the primary tumor and

travel to the brain through the bloodstream.

The symptoms of a brain tumor may result from a primary tumor;

they may also be the earliest symptoms of a cancer that developed in

another organ. The most common warning signs include:

•

person, or grow worse over time

Headaches, which may be most severe in the morning, new for the

•

Nausea and vomiting

•

vision

Problems with eyesight, such as seeing double or having blurred

•

side of the body

Loss of sensation in an arm or leg, or weakness or paralysis on one

•

Difficulty thinking or speaking, having trouble finding words

•

Memory loss, confusion, or disorientation

•

Seizures or convulsions

•

Personality changes

•

Hearing loss

•

Difficulty walking normally, losing one’s balance, frequent falls

•

Weakness and fatigue

•

Symptoms of brain tumors in small children may include:

Hydrocephalus

•

Increased head size

•

In infants, bulging of the soft spot at the top of the skull

•

Breathing problems or problems swallowing

Diagnosis

Headaches are the single most common symptom of brain tumors

in older children and adults, and the one most likely to bring

patients to see their doctor

severe or more frequent than those that the person has experienced

in the past.

Diagnosing a brain tumor requires a series of tests and examinations.

•

doctor who specializes in treating disorders of the nervous system.

The neurologist will check the patient

reflexes, coordination, ability to speak clearly, changes in mood,

and ability to answer simple questions. These tests help to locate

the areas of the brain that might be affected by a tumor.

A family doctor will usually refer the patient to a neurologist, a’s balance, vision, hearing,

•

magnetic resonance imaging (MRI), and positron emission tomography

(PET).

Imaging tests. These include computed tomography (CT) scans,

•

electrical activity in different parts of the brain.

Electroencephalogram (EEG). This is a test that shows the levels of

•

response to treatment for the tumor.

Blood and urine tests. These are used to monitor the patient’s

•

rather than primary tumors.

Tests for cancer in other organs, since most brain cancers are metastatic

•

removed for study under a microscope. For a brain tumor, the

biopsy may be done as part of an operation to remove the tumor

or as a separate procedure.

Biopsy. A biopsy is a procedure in which a sample of tissue is

Treatment

Treatment of brain tumors depends on their grade and location. Surgery

is usually the first stage. Removing as much of the tumor as possible

helps to relieve symptoms as well as slow the growth of the tumor. Some

Grade I tumors can be completely removed by surgery.

If the tumor is located in a part of the brain where it cannot be

entirely removed by surgery without risk to the brain stem or other parts

of the brain that control sight or hearing, or if the tumor is difficult to

distinguish from surrounding healthy tissue, the second line of treatment

is usually radiation therapy.

Chemotherapy can be given before or after radiation therapy. A

newer type of chemotherapy is combined with surgery. After removing

as much of the tumor as is possible and safe, the surgeon inserts wafers

containing slow-release anticancer drugs.

Treatment for brain tumors may also include rehabilitation therapy

for physical aftereffects and supportive therapy to help the patient

manage pain and the side effects of cancer treatment.

Prognosis

The prognosis of a brain tumor depends on whether the tumor is benign

or malignant, its location and grade, and the patient

health. Patients with Grade I tumors that can be entirely removed may

recover completely. The prognosis is poorer in very young children and

in elderly patients.

The five-year survival rate for patients with malignant primary

tumors is less than 10 percent even when these cancers are treated aggressively.

Most patients with metastatic brain cancer die as a result of the

primary cancer rather than from the metastases in the brain.

’s age and overall

Prevention

Primary brain tumors are not preventable. Some metastatic brain

tumors may be prevented by not smoking, which lowers the risk of lung

cancer, or by avoiding overexposure to the sun, which lowers the risk of

melanoma.

The Future

The number of brain tumors diagnosed each year in both adults and children

in the United States has been gradually increasing since the 1960s.

The reasons for this increase are not yet clear. Theories include toxins in

the environment, viruses that have not yet been identified, and heavy

long-term use of cell phones.

Some newer treatments for brain tumors that are currently considered

experimental include drugs that block the growth of blood vessels

in tumors, thus starving them of nutrients. Other new drugs are intended

to make radiation therapy more effective by sensitizing the tumor cells to

radiation. Gene therapy and biological therapy (which works by stimulating

the patient

of research in treating brain tumors.

’s immune system) are other rapidly expanding areas

SEE ALSO

cancer; Skin cancer

Alcoholism; Breast cancer; Colorectal cancer; Headache; Lung

For more information

BOOKS

Clark, Arda Darakjian.

Hains, Bryan C.

PERIODICALS

Parker-Pope, Tara.

York Times

fullpage.html?res=9802E1D61438F930A35755C0A96E9C8B63 (accessed

on September 6, 2008).

“Experts Revive Debate over Cell Phones and Cancer.” New, June 3, 2008. Available online at http://query.nytimes.com/gst/

WEB SITES

American Brain Tumor Association (ABTA).

online at http://www.abta.org/index.cfm?contentid=146 (accessed on

September 5, 2008). Page contains links to eight diagrams of the various

parts of the brain as well as several videos and audio recordings about brain

tumors.

American Brain Tumor Association (ABTA).

Available online at http://www.abta.org/index.cfm?contentid=12 (accessed

on September 5, 2008). Detailed information about specific types of brain

tumors can be found on the menu at the right.

Mayo Clinic.

health/brain-tumor/DS00281 (updated May 15, 2008; accessed on

September 5, 2008).

National Brain Tumor Foundation (NBTF).

online at http://www.braintumor.org/BrainTumorFAQ/ (accessed on

September 6, 2008).

National Institute of Neurological Disorders and Stroke (NINDS).

Diagrams and Videos. AvailableTumor and Treatment Info.Brain Tumor. Available online at http://www.mayoclinic.com/Brain Tumor FAQ. AvailableBrain and Spinal Cord Tumors: Hope through Research

online at http://www.ninds.nih.gov/disorders/brainandspinaltumors/

detail_brainandspinaltumors.htm (updated August 11, 2008; accessed

on September 5, 2008).

Neurosurgery Today.

org/what/patient_e/brain2.asp (updated March 2006; accessed on

September 6, 2008). This is the patient education website of the American

Association of Neurological Surgeons (AANS).
WORDS TO KNOW
Benign: Not cancerous.
Brain stem: The lowest part of the brain that connects
directly to the spinal cord. It controls such
basic life functions as breathing, blood pressure,
and heart beat.
Cerebellum: The part of the brain at the lower
back of the head just above the brain stem.
Glial cells: Cells in brain tissue that hold nerve cells
in place, supply them with oxygen and nutrients,
and remove dead nerve cells.
Glioma: A type of brain tumor that starts in the
glial cells.
Hydrocephalus: Abnormal buildup of cerebrospinal
fluid within the brain.
Malignant: Cancerous.
Medulloblastoma: A type of malignant brain
tumor that develops in the cerebellum. It is the
cancer.
Meninges (singular, meninx): The protective
membranes that cover the brain and
spinal cord.
Meningioma: A type of brain tumor that starts in
the meninges.
Metastasis (plural, metastases): The spread of a
cancer from its original location to other organs
or parts of the body.
Tumor: An abnormal mass or growth of tissue that
may be either cancerous or noncancerous.Brain Tumors. Available online at http://www.neurosurgerytoday.. AvailableBrain Tumors. Detroit, MI: Thomson Gale, 2006.Brain Disorders. Philadelphia: Chelsea House Publishers, 2006.—particularly if the headaches are unusuallyGrade II. These tumors are also relatively slow-growing. They can,

is based on the tumor

it grows.

Brain Tumors

Definition

Brain tumors are abnormal growths of tissue within the brain; about

150 different types have been identified. Brain tumors can be primary or

secondary. Primary tumors are tumors that start to grow within the brain.

Some are benign, meaning that they are not cancerous. Other primary

tumors are malignant, or cancerous. Primary brain tumors are less common

than secondary tumors, with most occurring in adults rather than children.

Secondary or metastatic tumors are cancers that start in other

organs

then spread to the brain. Most brain tumors are metastatic cancers

rather than primary tumors; about a quarter of all adults being treated

for cancer in the United States eventually develop metastatic brain

tumors. It is rare, however, for primary tumors of the brain to spread

to other parts of the body.

Appendicitis

2011-03-05T04:45:00.001+03:00

Definition

Appendicitis is a condition in which the appendix, a finger-shaped projection

connected to the large intestine, becomes inflamed and its opening

blocked. It is a medical emergency.

Description

Appendicitis develops when the opening of the appendix is blocked. This

blockage can be caused by a number of different objects ranging from

intestinal parasites to fecal matter, or by an infection. As the blockage

progresses, the appendix begins to die from lack of blood flow. It is then

invaded by bacteria and forms pus. If the condition is not treated, the

appendix swells and eventually bursts, spreading the infection throughout

the abdomen. This spread of infection and inflammation to the tissues

lining the abdomen is called peritonitis and is a very dangerous condition.

The pain of appendicitis usually starts two to three days before the

appendix gets to the point of bursting. The person typically notices a

vague discomfort in the area underneath the navel. Over the next day the

pain gets worse and moves downward toward the lower right portion of

the abdomen, near the right hip. The

at this point are nausea, vomiting, low-grade fever, and loss of appetite.

Fewer than 50 percent of patients with appendicitis, however, have the

full set of classic symptoms. Children and the elderly are often misdiagnosed

because they have fewer of these symptoms. As a result, their treatment

can be delayed. The appendix ruptures before surgery in about 270

out of every 1,000 cases, and the rate of rupture is higher in children,

pregnant women, and older adults.

“classic” symptoms of appendicitis

Demographics

The National Institutes of Health (NIH) estimates that about 7 percent

of the general population in the United States will develop appendicitis at

some point in life. There are about 1.1 cases per 1,000 people each year.

The disorder is most common in people between the ages of ten and

thirty, but it can develop at any age. In a few cases, appendicitis has been

diagnosed in newborn babies. Appendicitis is equally common in persons

of all races and ethnic groups. It is slightly more common in men than in

women, however. Although appendicitis is not hereditary, it does appear

to be more common in some families.

Causes and Symptoms

The basic cause of appendicitis is inflammation of the appendix resulting

from an obstruction of some kind or an infection. The appendix can be

blocked by an overgrowth of lymphoid tissue, food wastes, small pieces

of hardened stool, worms or other parasites, foreign objects, or a cancerous

tumor. It may also become inflamed as a result of trauma or infection,

or as a complication of Crohn disease. The blocked appendix swells

up with mucus, shutting down the blood vessels that supply it with

blood. As its tissues die, bacteria from the intestine grow rapidly within

it. If the infection is not stopped by surgical removal of the organ, the

appendix will eventually burst and the bacteria inside it will spread to

other parts of the abdomen. There is no single symptom that is unique

to appendicitis, nor is there a

patients experience. The following are the most

common symptoms and the percentages of

patients who report having them:

•

navel to the right lower part of the

abdomen: 80 percent.

Pain in the abdomen moving from the

•

Nausea: 85 percent.

•

Fever: 60 percent.

•

Loss of appetite: 74 percent.

•

Diarrhea or constipation: 18 percent.

•

80 percent. About 2 percent of patients,

however, report pain in the abdomen

lasting as long as two weeks.

Symptoms lasting less than 48 hours:

•

abdomen: 23 percent.

A previous history of pain in the

Diagnosis

Diagnosis of appendicitis is tricky and complicated,

partly because there are many diseases

and disorders

pregnancy and Crohn disease

abdominal pain, fever, and vomiting; and

partly because at least half of all patients who

have appendicitis do not have the classic symptoms

of the condition. In addition, the size and

location of the appendix varies somewhat. In

some patients the appendix is located on the left side of the body rather

than the right, and in others the appendix is unusually long and extends

from the right side toward the left side. Diagnosis of appendicitis is based

on information from several different types of examinations and tests.

—particularly complications of—that cause

•

record their temperature, and perform an examination of the

abdomen. Patients with appendicitis typically feel what is called

rebound tenderness (soreness) when the doctor first presses on the

abdomen and then releases the pressure. The patient may also

stiffen the muscles of the abdomen in response to pressure; this

reaction is called guarding. In addition, the doctor may be able to

feel that the abdomen itself is rigid. Last, the doctor may move or

rotate the patient

these maneuvers.

’s right leg or hip in order to test for pain during

•

infection.

Blood test: A high white blood cell count indicates the presence of

•

tomography (CT) scans. The CT scan is the most commonly used

imaging test to diagnose appendicitis, but x-ray studies can be

useful for detecting foreign bodies or hardened stools that may

be blocking the appendix.

Imaging tests: These may include x rays, ultrasound, or computed

•

urinary tract infection, but can be abnormal if the appendix

inflammation is close to the urinary tract.

In a few cases involving women who may have a disorder of the

ovaries or the fallopian tubes, the doctor may need to perform an exploratory

type of surgery called a laparoscopy to see which organ is causing the

patient

Urine test: This test may be done to rule out kidney stones or a’s symptoms.

Treatment

In a few cases, if the doctor is not certain of the diagnosis, he or she may

prescribe a course of antibiotics to see whether the patient

caused by something other than an inflamed appendix and may not

require surgery. For most patients, however, surgery is the only cure for

appendicitis. The surgeon can perform an appendectomy (surgical

removal of the appendix) in several different ways. The oldest procedure

is called an open appendectomy. The surgeon makes an incision (cut)

between 2 and 4 inches (5.1 and 10.2 centimeters) and in length on the

lower right side of the abdomen. The appendix is removed from its location

and the area is rinsed with sterile fluid to prevent further infection.

A newer and more commonly used technique is called a laparoscopic

appendectomy. It requires much smaller incisions, only an inch (2.5 centimeters)

or so long. The surgeon inserts a laparoscope, which is an

instrument that allows the surgeon to see inside the abdomen, through

one incision, and surgical instruments to remove the appendix through

another small incision. If the surgeon finds that the infection has spread

or that there are other complications, the operation may have to be completed

as an open appendectomy. In March 2008, surgeons at a medical

center in California removed a woman

The procedure is still considered experimental but may allow female

patients to recover more rapidly.

’s appendix through her vagina.

Prognosis

Most people do very well after an appendectomy if their appendix was

removed before it ruptured. The average hospital stay is between one and

three days after surgery, but full recovery at home may take a few weeks

before the patient can return to vigorous exercise or lifting heavy objects. The

mortality rate for appendicitis in the United States is very low, between 0.2

and 0.8 percent of patients; most of these deaths are caused by complications

of peritonitis rather than by the appendectomy itself. The rate of complications

in appendicitis increases tenfold if the appendix bursts before surgery.

Prevention

There is some evidence that people from cultures whose diets have a high

level of fiber (the part of plants that is not digested) are less likely to develop

appendicitis than those whose diets are low in fiber. It is thought that

higher levels of fiber in the diet help the intestines push food along more

efficiently, thus lowering the likelihood that the appendix will become

blocked by fecal matter. Apart from increasing the amount of fiber in one

diet, however, there is no way to predict or prevent appendicitis.

’s

The Future

As of 2008, about 10 percent of patients with appendicitis were not correctly

diagnosed on their first visit to the doctor. Ongoing research may

help doctors lower the rate of missed diagnoses of appendicitis as well as

develop improved surgical instruments and techniques.

SEE ALSO

Crohn disease

For more information

BOOKS

King, John, ed.

Clinic, 2004.

Mayo Clinic on Digestive Health, 2nd ed. Rochester, MN: Mayo

PERIODICALS

“

30, 2008. Available online at http://www.sciencedaily.com/releases/2008/03/

080328135738.htm (accessed May 15, 2008).

Appendix Removed through Vagina: U.S. First.” Science News Daily, March

WEB SITES

American College of Surgeons (ACS).

Appendix.

info/operation/brochures/app.pdf (accessed May 16, 2008). This is a nine--

page illustrated patient brochure that tells patients about surgical removal of

the appendix, how to prepare for surgery, possible complications, and home

care during recovery.

Mayo Clinic.

health/appendicitis/DS00274 (updated August 15, 2007; accessed May 15,

2008).

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

“Appendectomy: Surgical Removal of the” Available online in PDF format at http://www.facs.org/public_“Appendicitis.” Available online at http://www.mayoclinic.com/

“

pubs/appendicitis/index.htm (updated May 2004; accessed May 15,

2008).

TeensHealth.

teen/infections/intestinal/appendicitis.html (updated May 2007; accessed

May 15, 2008).

WORDS TO KNOW
Appendectomy: Surgical removal of the appendix.
Guarding: Stiffening of the muscles in response to
a doctor’s touch.
Laparoscope: A fiberoptic instrument resembling a
telescope that can be inserted through a small
incision to allow a doctor to see the inside of the
abdomen during surgery.
Peritonitis: Inflammation of the membrane that
lines the abdominal cavity and covers some of
the internal organs.
Pus: A whitish-yellow material produced by the
body in response to a bacterial infection. It consists
of tissue fluid and dead white blood cells.
Rebound tenderness: Pain experienced when the
doctor releases pressure on the abdomen.Appendicitis.” Available online at http://digestive.niddk.nih.gov/ddiseases/“Appendicitis.” Available online at http://www.kidshealth.org/’s symptoms arePhysical examination: The doctor will take the patient’s history,“typical” group of symptoms that all

Appendicitis

Anthrax

2011-03-05T04:29:00.001+03:00

Definition

Anthrax is a disease caused by a rod-shaped bacterium called

anthracis

organism) that can live for decades in the soil. Robert Koch (1843

Bacillus. The bacterium forms spores (tough dormant forms of the–

1910), the German doctor who is considered the father of microbiology,

identified the bacteria as the cause of anthrax in 1877.

Anthrax is primarily a disease of grazing animals such as sheep, goats,

camels, and cattle. It rarely affects household pets like cats and dogs. It is

one of the oldest animal diseases known to humans and is probably one

of the ten plagues of Egypt described in the Book of Exodus in the Old

Testament of the Bible. Animals can become infected by anthrax through

eating grass coated with anthrax spores or getting the spores into open

wounds on their hides. Thousands of cattle in Europe and North

America died each year from anthrax until French scientist Louis Pasteur

(1822

–1895) developed an effective vaccine against the bacteria in 1881.

Description

Anthrax can take three different forms in humans. The most common

form, accounting for 95 percent of cases, is cutaneous (skin-related)

anthrax. It occurs when anthrax spores enter the body through a cut or

break in the skin, producing a painless sore with a black center. Cutaneous

anthrax is easily treated with antibiotics and is rarely fatal unless

the infection spreads into the bloodstream.

The second form is gastrointestinal anthrax. Humans can get it by

eating raw or undercooked meat from an infected animal. In this form

of anthrax, the bacteria cause inflammation of the intestines leading to

ulcers in the tissues lining the digestive tract. The infected person experiences

nausea, vomiting, and bloody diarrhea. Between 25 and 60 percent

of people with this form of anthrax die.

Inhalation anthrax is the third form, caused when anthrax spores enter

a person

lymphatic system and the lymph nodes in the central chest cavity. There,

the spores germinate into active bacteria. The bacteria enter the bloodstream

and are carried throughout the body. The bacteria

then produce toxins that cause bleeding,

tissue destruction, and eventual death.

Inhalation anthrax is fatal in about 75 percent

of cases even when treated. This form of

anthrax used to be called woolsorter

disease because it was most likely to

affect weavers and other people who worked with

wool or hair taken from infected animals. Inhalation

anthrax is the form most feared today

because it is the form that develops when anthrax

spores are used as a method of bioterrorism.

’s or ragpicker’s

Demographics

Anthrax is a relatively rare disease in humans in

developed countries since the introduction of

Pasteur

animals from the disease. Other safety measures

include the sterilization of animal waste

materials.

Prior to the 2001 anthrax mailings, the last

case of inhalation anthrax in the United States

took place in 1976, when a weaver in California

died after using wool imported from

Pakistan. In 2006 an artist in the United

Kingdom died from inhalation anthrax linked

to working with untreated animal skins. The

last known case of gastrointestinal anthrax in

the United States occurred in 2000, when several

people in Minnesota fell ill after eating

meat from an infected steer.

People of all races and ages are equally likely to get inhalation anthrax

when the bacillus is used as a weapon of bioterrorism. Cutaneous and gastrointestinal

anthrax are rare in the United States. Young adults are the

age group most commonly affected due to occupational exposure. People

in the following occupations are at some risk of cutaneous anthrax:

’s vaccine made it possible to protect

•

Veterinarians•

•

Forest rangers, field biologists, and others who study wildlife

•

products

People who work with wool, animal hides, hair, or bone meal

Causes and Symptoms

The cause of anthrax is a bacterium,

organ destruction and internal bleeding in animals and humans through

the release of toxins that target the tissues lining blood vessels, lymph vessels,

and the intestines. One of the toxins causes fluid to build up in the

tissues and damages the body

kills infected cells directly.

It is important to understand that humans cannot transmit anthrax

directly to one another, although a person

be contaminated by anthrax spores. People can be decontaminated after

exposure to anthrax spores by showering in hot water and using an antimicrobial

soap. Suspected articles of clothing should be boiled in water

for a minimum of thirty minutes or else burned. It is not necessary to isolate

or quarantine a living patient diagnosed with anthrax after he or she

has been decontaminated.

The symptoms of anthrax depend on the type:

B. anthracis. The bacteria cause’s immune system, while the other toxin’s skin, hair, or clothing can

•

the spores get into a cut or break in the skin. An itchy papule (raised

skin lesion) appears, followed by a blackish painless ulcer about an

inch across with a round, swollen edge. Nearby lymph nodes may

be swollen. The ulcer lasts for about two weeks before separating

from the skin and leaving a permanent scar. The infection spreads

into the bloodstream in about 5 to 10 percent of untreated patients.

Cutaneous: The incubation period is between two and five days after

•

eating infected meat. The patient experiences nausea, vomiting,

painful abdominal cramps, loss of appetite, vomiting blood, and

bloody diarrhea.

Gastrointestinal: Symptoms appear between two and five days after

•

three days after exposure. However, in some cases it may take as long

as forty-two days after exposure (and perhaps longer) for the person

to feel sick. The person first notices coughing and mild discomfort

around the breastbone, quickly followed by high fever, severe shortness

of breath, coughing or vomiting blood, heavy sweating, and

chest pain severe enough to be mistaken for a heart attack.

Diagnosis

There is no screening test for anthrax. Diagnostic tests for the various

forms of anthrax are ordered according to the patient

’s history—

including his or her occupational history

—and specific symptoms:

•

skin ulcer caused by cutaneous anthrax can be stained and

viewed under a microscope for evidence of the anthrax bacteria.

Skin scraping or biopsy: A sample of tissue fluid from the characteristic

•

inhalation anthrax can also be examined under a microscope.

Sputum culture. The secretions from the lungs of a patient with

•

suspected gastrointestinal anthrax.

Stool sample. Stool can be tested for anthrax bacteria in cases of

•

inserted into the throat or the intestines to look for the characteristic

ulcers caused by the anthrax bacteria.

Endoscopy. An endoscope is a lighted flexible tube that can be

•

studies can be done to look for signs of inhalation anthrax.

Chest x ray or computed tomography (CT) scan. These imaging

•

for any of the three forms of anthrax. The sample is cultured on

a material called blood agar, which is made from animal blood

combined with a gelatin-like substance derived from seaweed. If

Blood test and laboratory culture. This test can be done to check

B. anthracis

the bacterial colony will be destroyed.

is present, the red blood cells in the gelatin surrounding

Treatment

All three forms of anthrax are treated with oral or intravenous antibiotics.

Penicillin is usually effective for cutaneous anthrax. However, ciprofloxacin

and doxycycline are usually recommended for the other forms of the disease.

Inhalation anthrax requires hospitalization and treatment with intravenous

antibiotics. People who may have been exposed to anthrax may

be given antibiotics for as long as sixty days to prevent inhalation anthrax.

Prognosis

Cutaneous anthrax has the best prognosis; most people recover

without complications except for a scar where the ulcer appeared. Gastrointestinal

anthrax has a mortality rate of 25 to 60 percent, while

inhalation anthrax has a death rate between 45 and 75 percent even

when treated.

Prevention

Anthrax can be prevented in several ways. One preventive measure is

to give a sixty-day course of antibiotics to anyone exposed to the disease.

Another preventive measure is to avoid eating raw or undercooked

meat.

There is a vaccine against anthrax that was approved by the Food and

Drug Administration (FDA) in 1970, but it is not given to the general

public. Those who are eligible to receive the vaccine include:

•

exposure to anthrax.

Active-duty military personnel in areas that carry a high risk of

•

Researchers and laboratory assistants who work with anthrax.

•

world where livestock are not routinely vaccinated against

anthrax.

People who must work with animal products in parts of the

•

countries.

People or animals who die from anthrax must be buried or otherwise

disposed of carefully in order to prevent contaminating others. The body

of a person who is known to have died from anthrax is considered a biohazard

because the skin and any body fluids can contaminate healthcare

workers. The body must be placed in an airtight bag and preferably cremated,

as burial will not kill anthrax spores.

People who work with animal hides or wool imported from these

The Future

Anthrax is a major concern to public health officials because of its potential

as an agent of bioterrorism. The Centers for Disease Control and Prevention

(CDC) classifies anthrax as a Category A agent, the highest of

three levels. Category A agents are defined as disease organisms that pose

the greatest possible threat to public health; can be easily spread over a

large geographic area; and require a high level of planning in order to

protect the public. In addition, the fact that anthrax spores can survive

in the environment for years makes the disease even more dangerous. In

1942, during World War II, the British deliberately tested anthrax as a

bioweapon on a small island off the coast of Scotland. It took until

1990 for the island to be completely decontaminated.

SEE ALSO

For more information

BOOKS

Decker, Janet, and Alan Hecht.

2008.

Anthrax, 2nd ed. New York: Chelsea House,

Germ Wars: Battling Killer Bacteria and Microbes

Group, 2008.

Roueché, Berton.

Plume, 1988. Chapter 12,

death from cutaneous anthrax of an insulation installer. It was first published

in the

Tracy, Kathleen.

Lane Publishers, 2005.

. New York: Rosen PublishingThe Medical Detectives. New York: Truman Talley Books/“A Man Named Hoffman,” is an account of theNew Yorker in April 1965.Robert Koch and the Study of Anthrax. Hockessin, DE: Mitchell

PERIODICALS

Wade, Nicholas.

Times

URI=http://www.nytimes.com/2008/08/21/science/21anthrax.html&OQ

=_rQ3D1&OP=755ae399Q2FQ230fQ51Q23Q24k2VPkkQ3C6Q

236BBqQ23BqQ236FQ23V2Q2Af42fQ236Fz4Q3CMPzQ7BUMQ3C-Z

(accessed September 12, 2008).

“A Trained Eye Finally Solved the Anthrax Puzzle.” New York, August 20, 2008. Available online at http://www.nytimes.com/glogin?

WEB SITES

Centers for Disease Control and Prevention (CDC).

Available online at http://www.bt.cdc.gov/agent/anthrax/index.asp (updated

February 22, 2006; accessed September 12, 2008).

Mayo Clinic.

anthrax/DS00422 (updated June 8, 2007; accessed September 12, 2008).

National Institute of Allergy and Infectious Diseases (NIAID).

online at http://www3.niaid.nih.gov/topics/anthrax/default.htm

(updated August 22, 2008; accessed September 12, 2008).

NOVA Online.

org/wgbh/nova/bioterror/agen_anthrax.html (updated November 2001;

accessed September 12, 2008).

WORDS TO KNOW
Bioterrorism: The use of disease agents to frighten
or attack civilians.
Cutaneous: Pertaining to the skin.
Papule: A small cone-shaped pimple or elevation
of the skin.
Quarantine: The practice of isolating people with a
contagious disease for a period of time to prevent
the spread of the disease.
Spore: A dormant form of the anthrax bacteria
that can live for decades before being reactivated
and reproducing.Anthrax Home Page.Anthrax. Available online at http://www.mayoclinic.com/health/Anthrax. AvailableAgents of Bioterror: Anthrax. Available online at http://www.pbs.Ebola and Marburg hemorrhagic fevers; Plague; SmallpoxInhalation: The symptoms begin abruptly, usually within one toFarmers and ranchers’s nose and throat and are carried to the lungs. The spores enter the

Anthrax

Anorexia

2011-03-05T04:13:00.001+03:00

Definition

Anorexia is an eating disorder

gaining weight, a distorted mental picture of what one

looks like, and extreme dieting in order to lose weight. Many anorexics

also exercise for long periods or take diuretics (drugs that increase urine

output) in order to lose weight.

—a psychiatric condition marked by fear of’s body actually

Description

The

(DSM-IV), the reference that doctors use to diagnose mental illness, specifies

that a person must have a body weight that is only 85 percent of

normal for their sex, age, and height, combined with a fear of becoming

fat and a preoccupation with the size and shape of the body in order to be

diagnosed with anorexia. In addition, a girl must miss three or more menstrual

periods in a row to fit the diagnostic criteria.

Other signs that are commonly seen in young people with anorexia

include osteoporosis (brittle bones), slowed growth, hair loss, aches in the

joints and muscles, feeling cold much of the time, low blood pressure,

slowed heart rate, and dry skin.

Diagnostic and Statistical Manual of Mental Disorders fourth edition

Demographics

There are between eight and thirteen young people per 100,000 in the

United States and Canada who meet the strict DSM-IV criteria for anorexia.

On the other hand, many doctors think there are other adolescents

and young adults who have a milder form of anorexia but are not counted

because they do not meet all the DSM-IV criteria; thus the disorder may

be more widespread than the official figures indicate.

Anorexia is most common in teenagers and young adults; 40 percent of

diagnosed patients are between fifteen and nineteen years old. A few patients

begin to show signs of the disorder between the ages of seven and twelve. At

the upper end of the age spectrum, 10 percent of patients are women over

the age of forty; it is estimated that between 1 and 3 million women in the

so-called baby boomer generation are struggling with eating disorders. The

female/male ratio for anorexia is thought to be

nine females to every male. Although gay men are

at somewhat higher risk of anorexia, heterosexual

men can also develop the disorder.

At one time it was thought that anorexia is

primarily a disease of middle-class Caucasians;

however, in recent years, more cases of the disorder

are appearing in African American and

Hispanic women.

Causes and Symptoms

Although there is general agreement that anorexia

is caused by a combination of factors, doctors disagree

about which are the most important. There

is considerable evidence that genetic factors play

an important role. Another factor that is being

researched is the role of a brain chemical involved

in both anorexia and depression.

Other factors that have been cited by researchers

include personality traits, family issues,

and cultural values. Many anorexics are high

achievers with a tendency toward perfectionism,

and controlling their weight appears to be part of

a larger need to be in control of their lives. In terms of family issues, some

psychiatrists think that anorexia may be a way for the young person to

separate from their family and establish their own identity.

In addition, as many as 50 percent of girls hospitalized for anorexia

were sexually abused as children, leading doctors to think that they may

be afraid of growing into mature women and want to keep a childish

figure as long as possible. Last, cultural emphasis on thinness as a mark

of social status has been blamed for encouraging girls (and older women)

to lose more weight than is healthful.

The symptoms of anorexia include psychological as well as physical

symptoms. Anorexia affects most of the body

’s major organ systems:

•

episodes of weakness and dizziness, low levels of calcium and

magnesium in the blood, and anemia (red blood cell count that

is too low)

•

of scalp hair, sore muscles, swelling of

the joints caused by abnormal eating

patterns, risk of developing osteoporosis,

a bone disorder in which the bones break

or fracture more easily than is normal as

the result of the loss of minerals in bone

caused by starvation

Muscles, bones, and skin: dry skin, loss

•

ulcers, bleeding in the digestive tract,

and an increased risk of disorders of the

liver and pancreas

Digestive system: constipation, stomach

•

the loss of body fat means that the body

loses heat more rapidly

Temperature regulation: feeling cold, as

•

distorted notions of the body, and an

increased risk of suicide

Psychological symptoms: depression,

Diagnosis

Anorexia is usually diagnosed during an office

visit to the patient

although she or he may be sent to a psychiatrist

for an additional evaluation. Primary care doctors

are now encouraged to give a screening test to an adolescent or young

adult who seems unusually concerned about weight or asks the doctor a

lot of questions about weight loss. These screeners are short sets of five

questions about eating habits that the patient can quickly answer. Other

questionnaires that the doctor may use include the Clinical Eating Disorder

Rating Instrument (CEDRI) or the Eating Disorder Examination

(EDE); these take a little longer for the patient to fill out.

If the doctor thinks that the patient may have anorexia, he or she can

look for some of the physical signs that accompany the disorder after

weighing the patient. Besides extreme thinness, these signs typically

include a yellowish discoloration of the skin, signs of dehydration, an

abnormally low blood pressure reading, and a slow heartbeat. The doctor

will order laboratory tests of the patient

the blood chemistry and the red blood cell count are normal. The patient

will also be given an electrocardiogram (ECG) to check for abnormal

heart rhythms and other potential heart problems.

Treatment

The treatment of anorexia is difficult and complicated, partly because many

patients deny that they have a problem. It is common, in fact, for anorexics

to argue with the doctor that they simply have a different lifestyle and

should be left alone. Hospitalization may be necessary if the patient is

having serious medical complications related to starvation or has threatened

suicide. In the hospital she (or he) will be given fluids and nutrients intravenously

at first in order to stop the weight loss and bring other physical

problems under control. The patient will then be given psychotherapy

(usually cognitive-behavioral therapy or CBT) and education about nutrition.

Antidepressants may be given to treat anxiety or emotional depression,

but they are not considered effective in treating the eating disorder by itself.

Anorexics who do not need to be hospitalized for serious physical

conditions may be treated on an outpatient basis or in a day hospital.

They are often referred to a dietitian for personalized advice about

healthful eating patterns and sample menus. Group psychotherapy is

considered less effective than either individual treatment or family

therapy in treating anorexia because the patients in a treatment group are

likely to compete to see who can stay the thinnest. Family therapy is

particularly recommended for patients under eighteen and for families

in which the mother has an eating disorder.

Prognosis

Anorexia is a potentially life-threatening illness with one of the highest

death rates among psychiatric disorders; between 6 and 20 percent of

patients die either from starvation or suicide. Because treatment is complicated

and may take years, the prognosis varies. Most patients need

monitoring over a period of months to years to help them maintain a

healthy weight and not slip back into disordered eating habits. One very

real problem since the coming of the Internet is the rise of a number of

websites promoting anorexia, encouraging people with the disorder to

consider it a valid lifestyle decision rather than an illness.

Prevention

There is not likely to be any new medical or psychological treatment for

anorexia in the next few years. For now, prevention of anorexia depends

on early recognition of an unhealthy concern with weight, since girls as

young as five or six are known to worry about their weight, especially if

their mothers or older sisters are dieting. In some cases the child

can help detect the problem or offer advice.

’s pediatrician

The Future

It can be difficult to change an entire society

and a very limited notion of physical attractiveness. In addition, the availability

of Web sites promoting anorexia increases the difficulty of

teaching young people healthy eating habits even if they do not measure

up to celebrity-inspired notions of glamour or beauty. A 2006 study at

Stanford University found that 36 percent of the patients in the eating

disorders unit of the university

this percentage, 96 percent had learned new techniques for dieting or

losing weight from the Web sites.

’s obsession with thinness’s hospital visited these Web sites, and of

SEE ALSO

Bulimia; Osteoporosis

For more information

BOOKS

Lynette, Rachel.

Books, 1992. Written by the daughter of singer Pat Boone, this is a firstperson

account of recovery from anorexia.

Watson, Stephanie.

PERIODICALS

Baker, Ken.

Chronicle

article.cgi?f=/examiner/archive/1999/04/04/MAGAZINE2036.dtl (accessed

April 11, 2008).

Collier, Lorna.

“Heidi Guenther’s Short, Tragic Life—and Death.” San Francisco, April 4, 1999. Available online at http://www.sfgate.com/cgi-bin/“The Aging of Anorexia: Middle-Aged Women—and Older—

Fight the Devastating Disease.

online at http://www.lornacollier.com/anorexia.html (accessed April 12, 2008).

Kirby, Jane.

2008. Available online at http://news.scotsman.com/health/Dieting-jockeysrisk-

eating-disorders.3859401.jp (accessed April 11, 2008).

Udovitch, Mim.

Society of the Starving.

online at http://query.nytimes.com/gst/fullpage.html?res=9E0DE3DF173EF93BA3575AC0A9649C8B63&

sec=&spon=&pagewanted=all

(accessed April 8, 2008). Includes a discussion of pro-anorexia websites as

well as the disease itself.

” Chicago Tribune, October 24, 1999. Available“Dieting Jockeys Risk Eating Disorders.” Scotsman, March 10,“The Way We Live Now: 9-8-02: Phenomenon: The Secret” New York Times, September 8, 2002. Available

WEB SITES

Nemours Foundation TeenHealth.

org/teen/food_fitness/problems/triad.html (accessed April 11, 2008).

NOVA Online.

(accessed April 10, 2008). This is a companion website to a television program

first aired in 2000. The entire program can be viewed online in eight

video segments. The site also includes a male anorexic

experience and a presentation about anorexia among minority women.Female Athlete Triad. http://www.kidshealth.Dying to Be Thin. http://www.pbs.org/wgbh/nova/thin/’s account of hisAnorexia. Detroit, MI: KidHaven Press, 2006.’Neill, Cherry Boone. Starving for Attention. Minneapolis, MN: LifeCareAnorexia. New York: Rosen Publishing Group, 2007.’s primary care doctor,’s blood and urine to see whetherHeart and blood: abnormally slow heartbeat, low blood pressure,

Anorexia

Anemias

2011-03-05T04:06:00.001+03:00

The anemias are a group of blood disorders characterized by too little

hemoglobin in the blood. Hemoglobin is a substance contained in red

blood cells that carries oxygen from the lungs to other body tissues. Anemia

is often a sign or symptom of an underlying disease rather than a disease in

its own right. There are three tests commonly used to detect anemia: the

number of red blood cells can be counted; the amount of hemoglobin in

the red blood cells can be measured; or the proportion of blood cells to

serum (the liquid part of blood, called the hematocrit) can be assessed.

Anemia can develop in three ways: loss of blood through injury, diseases

of the digestive tract, or heavy menstrual flow in women; rapid

destruction of red blood cells (for example in sickle cell anemia); or inadequate

production of healthy red blood cells (for example in thalassemia).

The underlying causes of anemias range from poor nutrition (iron-deficiency

anemia) and digestive disorders (Crohn disease, celiac disease) to

colorectal cancer, parasitic diseases (hookworm), and genetic disorders

(sickle cell anemia, thalassemia).

The anemias are the most common type of blood disorder in the general

population, affecting 4 percent of men and 8 percent of women in

the developed countries, and two to five times as many people in the

poorer nations.

SEE ALSO

Lead poisoning; Prematurity; Restless legs syndrome; Sickle cell anemia;

Thalassemia; Ulcers

Celiac disease; Colorectal cancer; Crohn disease; Heart failure;

Anemias

Anaphylaxis

2011-03-04T07:08:00.000+03:00

Anaphylaxis

Definition

Anaphylaxis is a severe allergic reaction to a trigger (most commonly a

food, medication, insect sting, or latex) that involves most major body

systems.

Description

Anaphylaxis is a reaction that occurs in people who are severely allergic to

certain foods or other substances. People with individual or family histories

of hay fever, asthma, eczema, or food allergies are at increased risk

of having an anaphylactic reaction at some point in their lives. People

with asthma are particularly likely to have an anaphylactic reaction to

food at some point. Anaphylaxis is an overreaction to an allergen caused

by the body

IgE. When a person who is susceptible to allergies first comes into contact

with an allergen, the person

that are specific to that allergen. The IgE antibodies then attach

themselves to the surface of mast cells, which are specialized cells that lie

within the connective tissue near the blood vessels. The next time the

person encounters that specific allergen, the IgE antibodies trigger the

release of a compound called histamine from the mast cells. The histamine

in turn causes the tissue swelling, difficult breathing, and other

symptoms of anaphylaxis.

Some people have a recurrence of symptoms about six to eight hours

after an episode of anaphylaxis. This recurrence is called a biphasic or

delayed reaction.

Some substances are more likely to trigger anaphylactic reactions

than others. The most common triggers are:

•

sensitive to it; however, peanuts, nuts from trees (walnuts, cashews,

and Brazil nuts), shellfish, fish, milk, and eggs are the most common

offenders.

Foods. Almost any food can cause anaphylaxis in persons who are

•

and fire ants are the most likely to cause anaphylactic reactions.

Stinging insects. Yellow jackets, honeybees, paper wasps, hornets,

•

penicillin and other antibiotics; antiseizure medicines; fluids given

after surgery; antibodies made from horse serum; blood and blood

products; radiocontrast dyes used in certain types of imaging studies;

and morphine or similar pain medications.

Medications. The drugs most likely to cause problems include

•

often used to make surgical gloves and other medical products.

The greatest danger of anaphylaxis caused by latex occurs when the

rubber material touches moist areas of the body or internal surfaces

during surgery, because the allergen in latex can be absorbed by the

body much more quickly.

•

when they exercise within a few hours

of eating certain foods.

Exercise. Some people develop anaphylaxis

•

semen, hormones, and extreme temperatures

have been reported to trigger anaphylaxis

in some people.

Other causes. Although such cases are rare,

Demographics

The exact number of cases of anaphylaxis in the

United States each year is unknown, partly

because some doctors use the term to refer to relatively

mild allergic reactions while others use it to

describe only those severe enough to be considered

life-threatening. About 30,000 people are

taken to hospital emergency rooms with an anaphylactic

reaction in an average year. A commonly

cited statistic is that about 15 percent of the general

population is at risk of anaphylaxis, with

one percent of the population at specific risk

of anaphylaxis caused by medications and

another one percent allergic to latex. It is estimated

that there are between 500 and 1,000

deaths from anaphylaxis each year in the

United States; fifty of these deaths are caused

by insect stings. People of all races, both sexes,

and all age groups are equally at risk of anaphylaxis.

Elderly people, however, are more likely

than younger people to die from anaphylaxis because they often suffer

from other diseases or medical conditions. Research conducted at Harvard

in 2007 suggests that there may be geographical differences in the

rates of anaphylaxis in the United States, with a higher proportion of

cases in the Northeast and lower rates in the West and South. The

researchers are not certain of the reasons for these differences, however.

Causes and Symptoms

Anaphylaxis results from the release of histamine from mast cells in

response to the presence of an allergen. Histamine causes the blood vessels

to dilate (expand), which lowers blood pressure. It also causes fluid to leak

from the bloodstream into the tissues, which in turn causes the itchy skin

swellings known as hives, and also lowers blood volume. These effects can

lead to shock. Fluid can also leak into the air sacs in the lungs and make it

difficult to breathe. Angioedema, or hivelike swelling of the tissues around

the eyes or in the throat and mouth, can be severe enough to block the

patient

Anaphylaxis is considered a whole-body allergic reaction because so

many different body systems can be affected:

’s airway.

•

Skin: hives, angioedema, redness, itching, rash

•

diarrhea, itchy mouth or throat

Digestive tract: nausea, abdominal pain or cramping, vomiting,

•

dizzy or lightheaded, low blood pressure, loss of consciousness,

shock

Circulation: pale or bluish skin color, weak or rapid pulse, feeling

•

difficulty talking, chest pain or tightness, nasal congestion, trouble

swallowing

Breathing: wheezing, shortness of breath, throat tightness, cough,

•

Psychological: panic, feelings of doom, intense anxiety

Diagnosis

Diagnosis of anaphylaxis is based on the patient

cases, particularly if the reaction is sudden. In many cases it will be

obvious either from the patient

what triggered the reaction. The doctor or emergency crew will

usually take the patient

administer adrenaline (epinephrine), a hormone that counteracts the

effects of histamine. The patient

life support given until they can be taken to the hospital.

’s symptoms in most’s description or from friends or bystanders’s pulse, check breathing and blood pressure, and’s heart rate will be monitored and basic

Treatment

Treatment of anaphylaxis before the patient is taken to the hospital

usually consists of checking to see whether the patient

and administering oxygen or otherwise helping the patient breathe. Intravenous

fluids are given if the patient

and antihistamines are also given to help open the airway, relieve hives

and other skin reactions, and restore normal blood pressure. Once in the

hospital, the patient may be given further treatment, including emergency

surgery to open the airway if he or she is still having trouble

breathing. Steroid medications may be given in the hospital to lower the

risk of a delayed or biphasic reaction, and the patient will usually be kept

in the hospital for a few hours to make sure there will not be such a reaction

after returning home.

Prognosis

The prognosis for anaphylaxis is very good if the person carries and uses

an EpiPen or similar device, or receives prompt emergency treatment. In

some cases, however, people die from low blood pressure, shock, or cardiac

arrest. The elderly are at higher risk for death from anaphylaxis.

Prevention

People who have had a severe allergic reaction even once should consult

an allergist for evaluation and advice about preventive measures. This

precaution is particularly important if the patient does not know what

caused the anaphylaxis. The allergist can determine the patient

prescribe an EpiPen or TwinJect for self-treatment, advise the patient

about any medications that may increase the risk of anaphylaxis, and in

some cases give the patient allergy shots to decrease sensitivity to insect

stings or antibiotic medications. Other preventive measures that people

can take include: Wear a MedicAlert or similar tag that identifies the

allergy for bystanders or emergency rescuers. Learn to read food labels

carefully and asking restaurant staff about food ingredients when eating

out. Lower the risk of insect stings by wearing long-sleeved clothing and

avoiding bright colors and perfumes that attract insects. Be careful when

drinking sweetened beverages outdoors. Avoid walking barefoot in the

grass. If stinging insects appear, stay calm and avoid slapping or swatting

at them; move away from them slowly.

’s triggers,

The Future

Experts believe that the number of anaphylactic reactions in the United

States will rise in the future because of the increased number of potential

allergens to which people are exposed.

SEE ALSO Asthma; Eczema; Hay fever; Hives’s airway is open’s blood pressure is low. AdrenalineLatex. Latex is a natural material made from the rubber tree that is’s production of an antibody called immunoglobulin E or’s immune system produces IgE antibodies

Alzheimer

2011-03-04T06:22:00.001+03:00

Definition

Alzheimer disease, or AD, is a terminal disease of the central nervous

system that has no effective treatment or cure. Its most notable symptom

is dementia

beyond the effects of normal aging. It is named for Alois Alzheimer

(1864

disease at a medical meeting in 1906.

the loss of a person’s memory and other cognitive functions–1915), a German doctor who first described a patient with the

Description

AD affects a person

pay attention, and to solve problems. The disease is characterized by the

buildup of abnormal protein deposits in the brain, some of which look

like clumps or plaques under the microscope and others that look like

tangled fibers. Researchers do not yet know whether these abnormal

proteins are causes of AD or whether they are a consequence of the

disease.

In addition, the cells in the part of the brain called the cerebral

cortex begin to die and the tissue in that part of the brain begins to shrink.

The cortex is the part of the brain that governs memory, the ability to pay

attention, to use language, and to think; this helps to explain why these

mental functions are gradually lost in patients with Alzheimer disease.

As the disease progresses, the destruction of brain tissue spreads to

the areas of the brain that govern the emotions, and finally to the brain

stem, which controls basic body functions like breathing and swallowing.

Most patients with AD die from pneumonia or another infectious disease

before the brain stem is completely destroyed.

There are two basic forms of AD, an early-onset form that affects

people younger than 60 years of age and is transmitted within families;

and a late-onset form that affects people over 60.

Demographics

AD is presently the third leading cause of death in American adults, after

cancer and heart disease. It is thought to affect 5 million adults in the

United States as of the early 2000s

sixty-five. The frequency of Alzheimer disease increases with age; about

40 percent of people over eighty have AD. The lifetime risk of an individual

developing AD is between one chance in four and one chance

in two.

Women are at greater risk than men of developing AD in old age,

although the reasons for this difference are not clear. Race does not

appear to be a risk factor for AD.

Causes and Symptoms

The causes of AD are not fully understood. Early-onset AD, which is

sometimes called familial Alzheimer disease, is caused by mutations of certain

genes on chromosomes 1, 14, 19, and 21. This form of AD accounts

for only 4

sporadic, which means that they occur at random. Scientists think,

however, that as many as 80 percent of these sporadic cases are influenced

by genetic risk factors that have not yet been completely identified. Over

400 genes had been tested for links to AD as of 2007.

Other factors that have been identified as increasing a person

developing AD include:

–5 percent of cases, however. Most cases of Alzheimer’s are considered’s risk of

•

High blood pressure or high blood cholesterol levels

•

Heart disease or stroke

•

Head injury

•

Diabetes

•

Although some researchers in the 1970s thought that aluminum in

drinking water, antiperspirant deodorants, and the diet might be a risk

factor for AD, those theories have been disproved.

The symptoms of Alzheimer disease change as the disease progresses.

Doctors generally describe four stages in the development of AD:

Female sex

•

years before a person is diagnosed with AD. The affected individual

has some short-term memory loss and loses the ability to learn

new information.

Mild cognitive impairment. This phase can begin as long as eight

•

well as memory problems, although they can still communicate

with others. They may begin to need help with some activities of

daily life. Many patients are diagnosed at this point because family

and friends begin to notice changes in behavior or general loss of

functioning.

Early dementia. The person begins to have language problems as

•

and suffers further memory loss. Emotional control is

lost; some patients with AD become physically violent toward

others at this point as well as generally irritable or weepy. About

30 percent of patients in this stage have hallucinations and

become unable to identify close relatives.

Moderate dementia. The person loses the ability to live independently

•

occasional words, loses control of bowel and bladder functions,

becomes unable to feed him or herself, and may be completely

bedridden.

Diagnosis

There is no definitive test for AD except analyzing a sample of brain

tissue, which can only be performed after the person dies. When a person

first begins to show signs of dementia, however, doctors can arrive at a

tentative diagnosis of AD through a series of tests and imaging studies.

These may include:

•

to rule out infections or heart problems that might affect memory

and other cognitive functions.

Laboratory tests of blood and urine samples. These tests are done

•

rule out brain tumors, Parkinson disease, infections of the brain, or

stroke.

Imaging studies, usually an MRI or a CT scan. These are done to

•

person

to follow simple instructions; their short-term memory; and their

overall mood. The tests may include being asked to name the current

president, to spell a word backward, or to copy a design on a

piece of paper.

Mental status examination (MSE). This type of test evaluates the’s awareness of their location in time and place; their ability

•

used in imaging tests which was shown in 2007 to identify

the location of abnormal protein deposits in the brain of a patient

with AD. This technique is not yet widely available in the United

States, however.

A PiB PET scan. PiB stands for Pittsburgh Compound B, a chemical

Treatment

There is no effective treatment for AD. There are three drugs that

have been approved by the Food and Drug Administration (FDA)

to slow down the loss of brain function in patients with AD, but

these drugs work for only about six to twelve months, and benefit

only half the people who take them. Patients who become depressed,

agitated or violent can be given medications to help control these

symptoms. There are no effective surgical treatments for Alzheimer

disease.

Patients in the final stages of Alzheimer disease are kept clean and

made as comfortable as possible. They may be given fluids and nutrients

intravenously if they are unable to swallow. Death is most often caused

because the patient stops breathing.

Prognosis

There is no cure for Alzheimer disease. Most people live between three

and ten years after being diagnosed with the disorder, although some

have lived as long as twenty years after diagnosis. Death usually comes

as the result of pneumonia, a urinary tract infection, or complications

following a fall.

Prevention

There is no way to prevent the development of the familial form of AD in

people who have the genes for the disease. With regard to sporadic lateonset

AD, research is under way to identify steps that people can take

to lower their risk of developing Alzheimer disease in old age. What

researchers think as of the early 2000s is that the best way to protect the

brain is to protect the heart: eating a healthful diet rich in fruits and vegetables,

exercising regularly, getting treatment for high blood pressure, and

keeping mentally active are all recommended. Such activities as playing

chess, solving crossword puzzles, and social get-togethers with other

people have been reported to delay the onset of AD or reduce its severity.

Another suggestion is to take Advil or Motrin, as anti-inflammatory

drugs may also lower the risk of AD.

The Future

Alzheimer disease is a major concern to policy makers in the twenty-first

century as the proportion of elderly people in the general population continues

to increase. Since the risk of developing AD doubles every five

years after a person reaches 65, the possibility of having large numbers

of people requiring several years of skilled nursing care at the end of their

lives is worrisome to many doctors.

At present, many patients in the early and middle stages of the disease

are cared for by relatives. The stress of caring for a parent, sibling, or spouse

with AD is very high; many caregivers end up having to quit their jobs in

order to care for the sick family member. In addition, the emotional strain

of caring for someone who no longer recognizes the caregiver and may be

openly violent or wander away from home can be exhausting. Doctors are

increasingly aware that caregivers of Alzheimer patients have a high rate of

depression and physical illnesses related to stress.

Research on AD is focused on preventive strategies. One possibility is

developing a drug that can clear the abnormal proteins involved in

AD from the brain tissue or prevent them from forming in the first place.

Some experimental drugs of this type are currently undergoing clinical

trials. Some researchers predict that there will be a major breakthrough

in treating Alzheimer disease by 2020.

SEE ALSO Creutzfeldt-Jakob disease; Huntington diseaseAdvanced dementia. The person loses the ability to talk except for—14 percent of the population over’s’s ability to think clearly, to remember, to speak, to

Alzheimer Disease

Allergies

2011-03-04T06:12:00.001+03:00

Definition

An allergy or allergic reaction is the body

foreign substance that enters or comes into contact with the body. Normally,

the body

In an allergy, the body overreacts to the allergen, which may be something

rather harmless. Allergic reactions may be caused by the production

of an antibody called immunoglobulin E (IgE).

’s response to an allergen, a’s immune system produces antibodies to fight disease.

Description

The experience of an allergy depends on the body system or tissues that

are affected, the severity of the reaction, and whether the substance that

triggers the allergy can be eliminated from the patient

situation. Some allergies affect only a small part of

the body, like a skin rash on the wrist caused by

touching certain metals in inexpensive costume

jewelry. Other allergies may affect several major

body systems, as in the severe reactions that some

people have to bee stings or certain medications.

These reactions are especially related to IgE antibodies.

Some allergies are caused by substances

that can be avoided, such as certain foods, while

others may be triggered by exposure to plant or

tree pollens that are hard to avoid when the plants

are in season.

In general, when a person who has allergies

comes into contact with an allergen, the person

immune system produces IgE antibodies that

are specific to that allergen. The IgE antibodies

trigger the release of a chemical called histamine.

The histamine, in turn, causes the tissue

swelling, difficult breathing, skin rash, watery eyes,

runny nose, and other symptoms of an allergy.

The release of the histamine often attracts

other cells from the immune system to the

affected part of the body, increasing the inflammation,

tissue swelling, and production of large amounts of mucus

’s—

otherwise making the patient

Researchers do not yet fully understand why some substances produce

allergies in susceptible people and others do not, nor why some

people do get allergies and others do not.

The most common types of allergies among people in North

America are:

’s symptoms worse.

•

Hay fever.

•

eyelid).

Allergic conjunctivitis (inflammation of the tissue that lines the

•

Asthma.

•

a hypersensitivity reaction that affects a part of the body that is not

in direct contact with the allergen. Hay fever and asthma are also

considered atopic allergies.

•

Hives.

•

foods, and certain medications. This

type of severe allergic reaction is called anaphylaxis.

Severe reactions to insect stings, certain

•

are caused by just eight foods: eggs, fish,

milk, peanuts, shellfish, soy, tree nuts (walnuts,

hazelnuts, almonds, etc.), and wheat.

Food allergies. Most cases of food allergies

•

contact dermatitis is an inflammation of

the skin caused by direct contact with an

allergen or irritating substance, such as

poison ivy, certain dyes, or certain metals,

especially nickel.

Contact dermatitis. In contrast to eczema,

Demographics

Allergies are very common health problems in

all age groups in the general population. About

50 million people in the United States suffer

from some type of allergy, many of them from

more than one. For example, about 20 percent

of people who get hay fever eventually develop

asthma, and some develop eczema as well.

Some statistics for specific allergies are as follows:

•

Hay fever: 20 percent of the population in developed countries.

•

Asthma: 20 million people in the United States.

•

developed countries.

Anaphylaxis: Affects between 1 and 3 percent of the population in

•

Eczema: about 15 million people in the United States.

•

Hives: 20 percent of the population in developed countries.

•

There are two major types of risk factors for allergies: genetics and

the environment. Allergies run in families, with allergic parents likely to

have allergic children. Children are not necessarily allergic to the same

substances as their parents. For example, the parent could be allergic to

ragweed pollen while the child is allergic to peanuts. In general, allergies

are more severe in children than adults. Several studies have shown that IgE

levels are highest in young children and fall rapidly in people between the

ages of ten and thirty years. Among children, boys are almost twice as likely

as girls to develop allergies, but the sex difference disappears among adults.

Environmental factors are thought to explain why the rate of allergic

diseases has increased around the world since the 1980s. These factors

include dietary changes, a rise in air pollution, an increase in the levels

of other allergens in the environment, and the fact that children are

exposed to fewer infectious diseases than they were in the past. Some

doctors think that exposure to and recovery from these diseases made

children less susceptible to allergies.

Causes and Symptoms

An allergic reaction is caused by the individual person

to an allergen.

The symptoms of allergies may appear in one or more body systems:

’s immune response

•

blisters.

Skin: Redness, itching, bumps or wheals, crusting, weeping patches,

•

stuffy or runny nose.

Respiratory tract:Wheezing, sneezing, coughing, difficulty breathing,

•

Digestive tract: Nausea, vomiting, diarrhea, stomach cramps.

•

Eyes: Itching, watering, bloodshot or puffy appearance.

•

Other: Headache, dizziness, ringing in the ears.

Diagnosis

In some cases the allergen is easy to identify because the person has a pattern

of symptoms that appears after exposure to the food, substance, or

other trigger. In other cases the person may have to consult a specialist to

identify the allergens that are causing the symptoms. The usual method

of testing involves either a skin test, in which a small quantity of a possible

allergen is injected under the skin, or a blood test known as the radioallergosorbent

test (RAST). The RAST test is usually done in place of the skin

test when the patient has had severe reactions to the allergen.

Treatment

Anaphylaxis is a medical emergency that requires immediate treatment by

a medical professional or emergency rescue team.

There is no cure for allergies. However, most can usually be treated

with antihistamines and other medications that the doctor may recommend,

depending on which part of the body is affected. The most important

step in treatment, however, is avoiding the allergen if at all possible.

Minimizing exposure to the allergen may involve installing air filters in

the home, eliminating certain foods from the diet, cleaning the house frequently,

moving to a part of the country with fewer pollen-producing

plants, or other measures that the doctor may recommend.

Another approach to treating hay fever, asthma, allergic conjunctivitis,

and some other allergies is desensitization, which is also called immunotherapy.

In desensitization, patients are given a series of injections of

their specific allergen under the skin, with the concentration of allergen

in the shots being gradually increased. It takes an average of eight to twelve

months for the patient to see results, however, and the injections must be

taken for at least three years and sometimes closer to five years.

Although several alternative therapies

traditional Chinese medicine, and naturopathy

for allergies, a long-term study conducted by the Mayo Clinic in

2006 concluded that none of these was effective.

—including herbal medicine,—have been tried as treatments

Prognosis

Most allergies are not life-threatening, the exceptions being anaphylaxis

and asthma. About 5,500 people die each year in the United States from

asthma and another 500 from anaphylaxis. In general, allergies tend to

become less severe as people grow older. The major exception is food

allergies (especially to peanuts), which can last a lifetime.

Prevention

There is no way to prevent people from developing allergies because the

genetic factors that are involved in allergic reactions have not been fully

understood. Desensitization therapy and avoidance of specific allergens

are the only effective methods of prevention at present.

The Future

Public health experts expect allergies of all types to become more

common in the developed countries in the future as a result of lifestyle

changes and a larger proportion of the world

cities. As of 2008, some researchers were working on a vaccine that would

target the IgE antibody itself. The vaccine is expected to be more effective

than current desensitization therapy in preventing allergies.

SEE ALSO

Hay fever; HivesAnaphylaxis; Asthma; Conjunctivitis; Dermatitis; Eczema;’s population living in largeFood allergies: about 8 percent of school-age children.Eczema. Eczema is sometimes called atopic dermatitis because it is’s diet or living

Allergies

Alcoholism

2011-03-04T06:04:00.001+03:00

Definition

Alcoholism is a chronic (long-term) disease in which people become

physically dependent on alcohol and cannot control how much they

drink even though their drinking is damaging their health, schoolwork

or job performance, and friendships or family relationships. It is a

progressive disease, which means that without treatment, it gets worse

over time.

Some doctors use the term

that causes problems in the person

dependence on alcohol or complete loss of control over drinking.

Binge drinking refers to consuming a number of drinks in a row on a

single occasion, usually five drinks for men and four for women. A drink

is defined as one 12-ounce beer, one 4- to 5-ounce glass of wine, or one

mixed drink containing 1.5 ounces of whiskey or other liquors. Some

binge drinkers may claim that they do not have a problem with alcohol

because they do not drink every night.

Description

Alcoholism is a serious disease not only for the damage it does to the

health and lives of alcoholics but also to the burden it places on society

as a whole. It is the third leading cause of preventable death in the United

States, after smoking and obesity. Alcoholism is responsible for 85,000

deaths in the United States each year. About one in every twelve adults

in the United States

on it.

Around the world, alcoholism is responsible for a percentage of various

disease conditions:

—17.6 million people—abuse alcohol or are dependent

•

Cirrhosis of the liver: 32 percent

•

Motor vehicle crashes: 20 percent

•

Cancer of the esophagus: 29 percent

•

Liver cancer: 25 percent

•

Stroke: 10 percent

•

Homicide: 24 percent

•

Women who drink during pregnancy are at risk of having children

who are mentally retarded and underweight at birth. This condition,

known as fetal alcohol syndrome or FAS, affects one or two of every

1,000 babies born in the United States each year.

There is no single way that people become alcoholics. One reason

why the experience of the disease is so difficult to describe is that the

speed at which it develops and its consequences vary from person to

person. Some people say that they became alcoholics after their first few

drinks. Others drank responsibly for years and then became dependent

on alcohol in midlife or even old age. In addition, some people get help

before they get into serious trouble from drinking. They are sometimes

called

drinking while they still have a job or family. Alcoholics who have

found themselves in trouble with the law, are homeless, or have lost

their jobs and families sometimes refer to themselves as

“high-bottom” alcoholics—that is, they “hit bottom” with their“low-bottom”alcoholics.

Demographics

According to a study of adults in the United States conducted by the

National Longitudinal Alcohol Epidemiologic Study, 44 percent of

American adults are social drinkers; 22 percent drank at one time but

do not drink alcohol at present; and 34 percent have always abstained

from alcohol. Between 8 and 10 percent of adults are diagnosed with

alcohol abuse or dependency in an average year.

Risk factors for alcoholism include:

•

of alcoholism, a study done in 2006 estimated that genetic factors

account for 50 to 60 percent of a person

abuse.

Genetics. Although no specific genes have been identified as causes’s vulnerability to alcohol

•

Family history of alcoholism.

•

drink before age sixteen are at higher risk of alcohol abuse.

The age at which a person started to drink. People who began to

•

than women. Women, however, do not metabolize alcohol

as efficiently as men and can become intoxicated on smaller

amounts of alcohol than men of the same weight.

Gender. Men are two to three times more likely to become alcoholics

•

alcohol abuse, followed by Hispanics, Caucasians, African Americans,

and Asian Americans.

Race and ethnicity. Native Americans are at increased risk of

•

A history of depression or other mental disorders.

Causes and Symptoms

Alcoholism is the end result of a combination of factors that interact in

ways that are unique to each person with the disorder:

•

the cases.

Genetic factors. These are thought to account for at least half of

•

cope with anxiety, depression, posttraumatic stress disorder, or other

painful feelings. This misuse of alcohol is called self-medication.

Psychological and emotional stress. Some people turn to alcohol to

•

look grownup or because their friends are encouraging them to

drink. In some groups, heavy drinking may be seen as proof of

masculinity. In addition, many films and television shows make

drinking look glamorous or sophisticated.

•

chemicals in the brain, leading the person to crave alcohol either

to get rid of bad feelings or to restore good feelings. Some people

find that they eventually need alcohol just to feel normal.

The main symptomof alcoholism is denial; that is, alcoholics deny that

they have a drinking problem until a series of health problems, family arguments,

job losses, arrests, or other negative consequences force them to

admit their drinking is out of control. Other symptoms commonly include:

Body chemistry. Long-term drinking alters the levels of various

•

Drinking alone or in private.

•

Hiding alcohol in the car, office, or other secret places.

•

Feeling irritated or angry if unable to have a drink at the usual time.

•

Gulping drinks quickly or drinking just to feel normal.

•

Having problems with employment, finances, or the law.

•

get the same effects.

Building up tolerance to alcohol; that is, needing larger amounts to

•

a few days. These symptoms include shaking, insomnia, nausea,

and vomiting.

Having withdrawal symptoms after going without alcohol for

•

Feeling a need or compulsion to drink.

•

remember what happened while he or she was drinking but did not

pass out.

Having blackouts. A blackout describes when someone is unable to

Diagnosis

The diagnosis of alcoholism is usually made on the basis of the patient

history and a review of his or her answers to screening questionnaires. The

two screeners most often used are called the CAGE and AUDIT questionnaires

(see sidebar). They can be completed in the doctor

who answer yes to two of the four CAGE questions are seven times more

likely to have a drinking problem than people in the general population.

The AUDIT questionnaire assigns points ranging from zero to four

depending on the frequency of the behaviors mentioned in the questions.

A score of eight or higher indicates a high likelihood of alcoholism.

Although there are blood and urine tests that can detect the presence

of alcohol or its breakdown products in the body, these tests reflect only

whether the person was drinking at the time the test was given. Such tests

are not useful in detecting long-term drinking patterns.

In general, doctors often miss the diagnosis of alcoholism in their

patients. This occurs because of the patient

that the doctor will tell his or her employer or other family members.

’s denial or the patient’s fear

Treatment

Treatment of alcoholism is important not only for the disease itself but

also as a necessary first step toward treating other disorders. For example,

psychiatrists will not treat someone for a mental disorder like bipolar disorder

or depression as long as the person is still drinking. Patients with

liver disease and other physical problems related to drinking also need

to be treated for alcoholism before their physical health will improve.

Treatment of alcoholism usually proceeds in several stages.

•

to get help. It may be done by family members, the person

employer, a doctor, or others concerned about the person. The

reason that intervention is usually necessary is that only 15 percent

of alcoholics seek help on their own.

Intervention. Intervention is the term used for persuading the alcoholic’s

•

takes between four and seven days. The alcoholic is placed in a

treatment center where he or she is given medications (usually

tranquilizers) to control the symptoms of withdrawal from alcohol.

These symptoms may include sweating, nausea, vomiting, seizures,

or a severe reaction called delirium tremens (also called the DTs).

In delirium tremens, the person may hallucinate and have very high

blood pressure and rapid breathing. It can be fatal if not treated.

Detoxification. Sometimes nicknamed detox, this is a process that

•

about the effects of alcohol, support groups, psychological

counseling, and an emphasis on getting the patient to accept the

truth about his or her alcohol dependence.

Rehabilitation. Rehabilitation for alcoholics includes patient education

•

Antabuse and Campral, which work either by making the person

feel sick if he or she drinks or by lowering the craving for alcohol.

These drugs work best in highly motivated patients. However, they

are not magic cures for alcoholism.

Most doctors think that alcoholics should completely give up

drinking because of the danger of relapse (falling back into out-of-control

drinking). Although a few people who are not physically dependent

on alcohol but have found themselves in trouble for abusing it can

sometimes manage by simply cutting back on the amount they drink,

complete abstinence is the best option for recovery.

Prognosis

There is no cure for alcoholism. Recovery requires lifelong commitment to

abstaining from alcohol and being honest with oneself. The prognosis is

better for alcoholics who do not smoke and are not addicted to other drugs.

Nonetheless, only about 30 percent of alcoholics maintain their recovery

over the long term. Studies have shown that about half of those who complete

a detoxification program relapse within six to twelve months.

Prevention

People who have a family history of alcoholism can lower their risk of

becoming alcoholics by learning about alcoholism and building a strong

social support network. Parents can help by setting an example of responsible

use of alcohol and talking openly about the physical and mental

dangers of heavy drinking.

The Future

According to statistics kept by the National Institutes of Health (NIH),

the rate of alcoholism and alcohol abuse is rising in the United States

and other developed countries. Some of the reasons for this trend are

the easy availability of alcohol (including homemade alcoholic beverages);

the role of the mass media in promoting drinking; and the weakening of

family ties.

SEE ALSO Child abuse; Fetal alcohol syndrome; Smoking; StrokeMedications. There are several drugs, the best-known of which are’s’s office. PeopleSocial and cultural factors. People may begin to drink heavily toSuicide: 11 percent“alcohol abuse” to describe heavy drinking’s life but has not yet led to physical

Alcoholism

AIDS

2011-03-04T05:45:00.002+03:00

Definition

AIDS is the end stage of an infectious disease caused by the human

immunodeficiency virus, or HIV. The virus damages the person

immune system, leaving them vulnerable to certain cancerous tumors

and increasingly severe opportunistic infections. HIV can be transmitted

whenever a body fluid containing the virus (especially blood or sexual

fluids) comes into contact with a mucous membrane (soft tissues lining

various body cavities, like the mouth or vagina) or the bloodstream itself.

A person can get AIDS through sexual intercourse, anal or oral sex, childbirth,

breastfeeding, blood transfusion, or sharing hypodermic needles.

’s

Description

AIDS is now considered a pandemic because it has spread to every country in

the world. According to the World Health Organization (WHO), 33.2

million people around the world were living with HIV infection in 2007;

2.1 million people died in that year from the disease, 330,000 of them children.

Scientists think that the virus that causes AIDS originated somewhere

in the African rainforest as an infection of chimpanzees and Old World

monkeys. At some point in the twentieth century it jumped the species barrier

from monkeys into humans. AIDS was first defined as an epidemic

human disease in June 1981 by the Centers for Disease Control and

Prevention (CDC). The virus that causes AIDS was identified by two

teams of French and American scientists in 1983

HIV infection progresses in stages as the virus gradually weakens the

body

to progress to AIDS. AIDS is diagnosed when the count of certain white

blood cells in the patient

develops life-threatening tumors or opportunistic infections.

In the early stage of HIV infection, the patient may have no symptoms

at all or a mild flu-like illness with fever and headache within a few days or

weeks of getting infected. These symptoms usually go away without treatment

and the person feels normal, even though he or she can transmit the

infection to others. The infected person may continue to feel well for a

period ranging from a few months to several years.

Demographics

Worldwide, about 0.6 percent of the population is infected with HIV, or

about 35 million people. Ninety-five percent of these cases are in Africa

or southeastern Asia. About 25 million people have died of AIDS since

1981, making the disease one of the deadliest pandemics in history. In

the United States, the CDC

about 945,000 people have been diagnosed with AIDS since 1981, and

about 1.2 million are currently living with HIV infection. About a

quarter of these people are unaware that they are infected. The CDC estimates

that there are about 56,300 new cases of HIV infection in the

United States each year.

In terms of specific groups within the United States:

’s recently revised estimates indicate that

•

Worldwide, the figure is 50 percent.

•

are African American, 34 percent are Caucasian, 17 percent are

Hispanic, and 2 percent are Native American or Asian American.

In terms of race or ethnicity, 47 percent of persons with HIV infection

•

are men who had sex with men; 33 percent had high-risk heterosexual

sex; 13 percent are injection drug users; and the remainder

are people who engaged in more than one high-risk behavior.

In terms of method of transmission, 50 percent of infected persons

•

years of age; 15 percent are between the ages of thirteen and

twenty-four; 26 percent are between the ages of twenty-five and

thirty-four; 32 percent are between the ages of thirty-five and fortyfour;

20 percent are between the ages of forty-five and fifty-four;

8 percent are fifty-five or older.

Causes and Symptoms

The cause of AIDS is infection with human immunodeficiency virus or

HIV. HIV is a virus that reproduces by inserting its own genetic material

into a type of white blood cell called a CD4 lymphocyte. When the virus

copies break out of the infected white blood cell, they attack other CD4

cells and the cycle repeats. Eventually so many of the white blood cells

have been destroyed that the body

person can no longer fight off opportunistic infections. The person may

also develop certain cancers associated with a weakened immune system.

In the early stage of HIV infection, the patient may have no symptoms

or else a mild flu-like illness with headache, fever, and swollen

lymph nodes. Some patients have a second set of symptoms, often years

after the initial infection, characterized by diarrhea, weight loss, shortness

of breath, and coughing. To meet the official definition of AIDS, however,

the patient must develop an opportunistic infection and have a

CD4 cell count below 200. Opportunistic infections include diseases like

toxoplasmosis, yeast infections of the esophagus, pneumonia caused by

an organism known as

tract caused by parasites. Cancers associated with AIDS include Kaposi

sarcoma, a skin cancer; and non-Hodgkin lymphoma.

Other symptoms of full-blown AIDS include:

’s immune system is weakened and thePneumocystis, and various disorders of the digestive

•

Soaking night sweats

•

Fever over 100°F (37.7°C) that lasts for several weeks

•

Headaches

•

Blurred vision or other vision problems

•

Chronic diarrhea

•

Swelling in the lymph nodes that lasts for three months or longer

Diagnosis

The diagnosis of HIV infection and AIDS is complicated by the fact that

many people are afraid to be tested for the disease. They may fear that a

positive test will lead to the loss of housing, jobs, relationships, or the

chance to complete their education. Because many infected persons put

off getting tested and telling their partners, the disease continues to

spread. In 2006, the CDC recommended routine HIV screening for all

adults, adolescents, and pregnant women within health care settings, not

just those considered to be high-risk.

Testing for HIV is a two-step process. The first test is a screening

test, which usually involves taking a sample of the patient

are newer screening tests that can use a sample of the person

saliva. These rapid screening tests look for antibodies to the HIV virus

and give results in about twenty minutes. If the person tests positive

for HIV infection, a more specific second test, called a Western blot

test, is performed. This test uses a blood sample to identify antibodies

against HIV.

In 1996 the Food and Drug Administration approved a test kit that

people can use at home called the Home Access HIV-1 Test. The person

pricks their finger on a special blotting card and mails it back to the

company. The sample is identified only by a code number, which allows

the person to remain completely anonymous. The test costs about

$45.00 and results are available in seven days.

An important point to keep in mind is that it may take the body several

weeks to three months after a person is infected to produce enough

antibodies to HIV to be detected by a blood test. This period of time is

called the window period. A person who tests negative for HIV infection

after high-risk behaviors should wait three months and have another

blood test to make sure they are not infected.

’s blood. There’s urine or

Treatment

There currently is no cure for HIV infection or AIDS. When a person

tests positive for HIV infection, the doctor will measure the amount of

virus in the patient

load helps the doctor to decide when to start drug treatment for HIV.

The current method of treatment is called highly active antiretroviral

therapy or HAART. Introduced in 1996, HAART consists of combinations

of three or more different drugs from two or more of the classes

of antiretroviral drugs presently available. HAART is not a cure for AIDS,

but it reduces the viral load, improves the patient

and extends life expectancy.

HAART has several drawbacks. First, it can be very expensive form

of treatment. In addition, the drugs used in HAART have troublesome

side effects; as a result, some AIDS patients simply stop taking their medications.

Last, some patients develop resistance to the antiretroviral drugs

and no longer respond to treatment especially if the patient does not

follow the treatment course and misses dosages. The doctor can sometimes

switch one of the drugs in the patient

within the same class or another class.

’s combination to another drug

Prognosis

AIDS cannot be cured. Without treatment, HIV infection progresses to

AIDS in an average of eleven years. After diagnosis with AIDS, the patient

has a life expectancy of just over nine months without treatment.

A person diagnosed with HIV infection who begins treatment with

HAART can expect to live about twenty years or more after the diagnosis.

Unfortunately, about half of patients who begin treatment with HAART

fail to benefit from it as much as they had hoped and discontinue it.

Prevention

There is no vaccine against HIV infection; moreover, it is unlikely that an

effective vaccine will be developed in the foreseeable future because the

virus that causes AIDS mutates so rapidly. Although various vaccines

against HIV have been tested by the National Institutes of Health since

1996, none have so far been approved for use outside clinical trials.

People can lower their risk of HIV infection by taking the following

precautions recommended by the CDC:

•

and is faithful.

Limit sexual activity to a single partner who is known to be uninfected

•

unknown.

Use a condom when having sex with anyone whose HIV status is

•

Do not share needles or inject illegal drugs.

•

Do not exchange sex for drugs.

•

needle sticks and other accidental exposures to body fluids that

may be contaminated with HIV.

Health care workers should follow guidelines for protecting against

•

if the test results are positive, inform all current sexual

partners.

Get tested for HIV infection after engaging in high-risk activities;

The Future

The demographics of HIV infection within the United States are

changing somewhat, with women accounting for more new cases than

in 1998. A worrisome new trend is the return and increase of high-risk

behaviors among men who have sex with men. This trend appears to

have been triggered by the spread of methamphetamine addiction

from the West Coast to the Eastern Seaboard over the past several

years.

Researchers at the National Institutes of Health are continuing to

test various vaccines against HIV. They are also working on developing

new antiretroviral drugs for patients who have developed resistance to

those presently in use.

SEE ALSO

Syphilis; ToxoplasmosisDepression; Gonorrhea; Hemophilia; Lymphoma; Pneumonia;’s blood. This level is called the viral load. The viral’s overall quality of life,In terms of age group, 1 percent of infected persons are under thirteenMales account for 74 percent of persons with HIV infection.–1984.’s immune system. It takes an average of eleven years for HIV infection’s blood drops to a critical level or the patient

AIDS

Achondroplasia

2011-03-04T05:38:00.000+03:00

Achondroplasia

Definition

Achondroplasia, or short-limb dwarfism, is the most common form of

abnormally short stature in adults. It is caused by a mutation in a single gene

on chromosome 4 that regulates the conversion of cartilage to bone. This

gene is the only gene that is known to be associated with achondroplasia.

Description

Achondroplasia is basically a disorder of bone development. The skeleton

of a human fetus is composed primarily of cartilage, a dense and somewhat

elastic form of connective tissue that gradually turns to bone during

normal development. In a person with achondroplasia, a gene that is

involved in the process of bone formation produces too much of a protein

that limits bone growth. As a result, the person with achondroplasia has

unusually short bones in the arms and legs and other skeletal abnormalities.

They also usually have difficulties with posture, joint disorders, and

breathing problems in later life.

Demographics

Researchers estimate that achondroplasia occurs in one in every 15,000 to

40,000 live births. About 20 percent of cases are children who have one

parent with achondroplasia; however, 75

mutations of the gene responsible for the disorder.

These new mutations are more likely to occur in

the sperm of fathers over 35; the mother

not matter, as far as is presently known.

The disorder affects both sexes and all races

equally.

The average adult height of people with achondroplasia

is 4 feet 4 inches (1.3 meters) for men and

4 feet one-half inch (1.24 m) for women. The

shortest living person with achondroplasia as of

2008 was Jyoti Amge, a teenager from Nagpur,

India, who stands 23 inches (58 centimeters) tall

and weighs 11 pounds (5 kilograms).

’s age does

Causes and Symptoms

Achondroplasia is caused by a mutation in the

FGFR3 gene on chromosome 4. A normal gene

helps the body convert cartilage to bone. The

mutation in the gene related to achondroplasia

results in severely shortened bones and weak

muscle tone in the body.

The symptoms of achondroplasia are usually obvious by the first year

of life. They include:

•

Poor muscle tone.

•

walk until some point between 24 and 35 months.

Slowness in learning to walk; a child with achondroplasia may not

•

(temporary slowing or stopping of breathing), and overcrowding of

the teeth.

Abnormal skull structure leading to frequent ear infections, apnea

•

underdevelopment of the nose and midface.

Distinctive facial features, particularly a prominent forehead and

•

finger, giving the hand a distinctive trident (three-pronged) shape.

Greater than normal separation of the little finger from the ring

•

A tendency toward obesity.

•

in the lower back and bowed legs.

Postural problems, including a pronounced curvature of the spine•

Diagnosis

Babies with achondroplasia can be diagnosed before birth by ultrasound

measurements of the growth of their long bones and head size. After

birth, the diagnosis is usually based on x-ray studies of the child

and head size. The x-ray images usually reveal a small skull base, shortened

growth plates in the long bones, square-shaped long bones, and

normal-sized bones in the trunk area.

A genetic test can also be performed to confirm the diagnosis in children

whose symptoms may be less clear.

Treatment

The management of achondroplasia includes careful monitoring of the

child

charts that doctors use to evaluate the rate of growth in children with

achondroplasia. It is particularly important to prevent obesity if possible.

In addition, children with achondroplasia need social support because of

ongoing prejudice against people with dwarfism. Organizations such as

Little People of America can offer helpful advice on the education and

other future plans of children with achondroplasia.

Surgery may be performed if necessary to relieve pressure on the spinal

cord or the brain. In some cases, there may be a buildup of fluid in the

brain (hydrocephalus) that needs to be drained surgically. The child

and adenoids may be removed in order to lower the risk of apnea. The

shape of bowed legs can be corrected surgically, but doctors disagree about

the value of surgery intended to lengthen the legs.

Children with achondroplasia may need extra dental work because of

the mismatch between the size of their teeth and the size of the jaw. In

addition, they should be watched carefully for recurrent ear infections in

order to minimize the risk of deafness and later learning difficulties.

There is disagreement among doctors as of the early 2000s regarding

treatment with human growth hormone. It is considered an experimental

treatment. Many doctors are concerned that using growth hormone in

children with achondroplasia will lead to abnormal bone deposits and

worsening of the spinal curvature.

’s growth, head size, and weight pattern. There are special growth’s tonsils

Prognosis

The prognosis of a baby with achondroplasia depends on whether the

defective gene is inherited from only one parent or from both. A child

who inherits the gene from both parents will die before birth or shortly

after birth from respiratory failure. About 3 percent of children with

achondroplasia die suddenly and unexpectedly during the first year of life,

usually from compression of the spinal cord.

A child who has one normal copy of the gene will usually have

normal intelligence and a normal life expectancy in spite of bone and

joint problems.

Prevention

There is no known way to prevent achondroplasia because the gene

responsible for the condition can undergo mutation in families with no

history of the disorder, and 75

mutations.

–80 percent of cases result from new

The Future

Although new mutations of the gene associated with achondroplasia

cannot always be foreseen, people who have the condition should seek

genetic counseling before marriage. If the partner does not have the

mutation, there is a 50 percent chance with each pregnancy that the child

will have achondroplasia. If both spouses have the mutation, they have a

25 percent chance of a normal child with each pregnancy, a 50 percent

chance that the child will have achondroplasia, and a 25 percent chance

that the child will die before or shortly after birth.

SEE ALSO

Childhood obesity; Ear infection; Gigantism; Hydrocephalus’s bonesBack and leg pain in adult life.–80 percent of cases involve new

Panic Disorder

2011-03-03T03:09:00.001+03:00

Definition

Panic disorder is an anxiety disorder characterized by recurrent and unexpected

panic attacks that are not caused by drugs, alcohol, or certain

medical conditions like asthma. It can be a disabling condition, causing

people to quit jobs or social activities, avoid going outside their home,

or give up exercising. It also commonly leads to frequent and unnecessary

visits to hospital emergency rooms.

Description

The most noticeable symptom of panic disorder is a panic attack, which

is defined as a period of intense fear that comes on suddenly and builds

to a peak within a few minutes (usually about ten minutes). The attack

is often accompanied by a general feeling of doom and an urge to leave

or escape from the setting in which the attack occurs. There may or may

not be a pattern to a person

or two a week over a period of time, while others may have several attacks

close together and then go for months or years before another attack.

Although panic attacks are a symptom of panic disorder, the two are

not the same thing. It is possible for a person to have panic attacks without

being diagnosed with panic disorder. To meet the official criteria for a

diagnosis of panic disorder, a person must have recurrent and unexpected

panic attacks followed by at least one month of

worry about having another panic attack. In addition,

the official criteria specify that a person

must have at least four of the following thirteen

symptoms that characterize panic attacks:

•

Heart palpitations or fast heartbeat

•

Sweating

•

Trembling or shaking

•

Shortness of breath

•

Choking sensations

•

Chest pain

•

Nausea or pain in the abdomen

•

Dizziness or lightheadedness

•

Tingling sensations

•

Chills or hot flushes

•

unreal) or derealization (a feeling that the

external environment is unreal)

Depersonalization (a feeling that the self is

•

Fear of losing control (“going crazy”)

•

There are two subtypes of panic disorder: panic disorder with agoraphobia

and panic disorder without agoraphobia. Agoraphobia is an unrealistic

fear of going outside the safety of the home, particularly to use

public transportation or visit large public places (shopping malls, sports

arenas, or even parks or recreational facilities). About a third of Americans

diagnosed with panic disorder have panic disorder with agoraphobia.

Panic disorder with agoraphobia develops when the person

panic attacks takes the form of avoiding places from which a quick

exit or escape might be difficult or embarrassing (such as airplanes, trains,

or buses; crowded stores; worship or other group activities, etc.). This

form of panic disorder can interfere significantly with people

complete their education, go to work, or meet friends outside the home.

Fear of dying’s fear of recurrent’s ability to

Demographics

According to the National Institute of Mental Health (NIMH), between

1 and 4 percent of the American population suffers from panic disorder,

most of them adolescents or young adults. About 6 percent of the population

will have a panic attack at some point in their lives. The average

age of patients with panic disorder is twenty-four. It is unusual for people

over forty-five to develop panic disorder for the first time.

Women are between two and three times more likely than men to

develop panic disorder. With regard to race and ethnicity, researchers disagree.

Some studies suggest that African Americans have a slightly higher

rate of panic disorder than either Caucasian or Asian Americans, while

other researchers think that these findings point to problems in the

screening interviews used to detect panic disorder rather than the actual

rates of occurrence.

People with certain medical conditions, such as hypertension (high

blood pressure), migraine headaches, and irritable bowel syndrome,

appear to have an increased risk of developing panic disorder.

Causes and Symptoms

The causes of panic disorder are not completely understood. Some possible

causes that researchers are studying include:

•

a person with panic disorder is eight times as likely to develop it as

a person in the general population.

Genetic factors. A first-degree relative (parent, child, or sibling) of

•

think that differences in body chemistry cause some people to

overreact to noises, lights, or other stimuli in the environment.

Biochemical imbalances in the central nervous system. Some doctors

•

appear to trigger panic attacks in some people.

Consuming large amounts of coffee, tea, or alcohol. These substances

•

A tendency to convert anxious thoughts into physical symptoms.

•

symptoms of a full-blown panic attack. For example, a man whose

heartbeat speeds up when he is angry may worry when he notices

the change in heart rate. He then experiences the resulting anxiety

as the chest pain of a panic attack.

A tendency to intensify minor physical sensations into the physical

Diagnosis

The diagnosis of panic disorder is usually a diagnosis of exclusion, which

means that the doctor arrives at the diagnosis by ruling out other possibilities

rather than by positively identifying the disorder on the basis of

tests. There are no laboratory tests or imaging studies for panic disorder.

The doctor will examine the patient for such medical conditions as disorders

of the thyroid gland; asthma or other breathing disorders; or substance

abuse. Men in particular are likely to drink alcohol in order to

cope with panic attacks. The doctor will want to make sure that the

patient is not abusing alcohol or prescription drugs.

If people go to the emergency room complaining of chest pain, the

doctors there will commonly ask two simple questions to screen for panic

disorder: 1) Have they had a spell or attack in the past six months when

all of a sudden they felt anxious, frightened, or very uneasy? 2) In the past

six months, have they ever had a spell in which they felt their heart race,

could not catch their breath, or felt faint? A

is considered a positive screen for panic disorder.

“yes” answer to either question

Treatment

Panic disorder is highly treatable. Most patients are given a combination

of medications and psychotherapy. The two forms of psychotherapy that

are most useful in treating people with panic disorder are exposure

therapy (for those with agoraphobia) and cognitive behavioral therapy.

In exposure therapy, patients are introduced to their feared situation in

gradual stages until they feel comfortable with it. For example, someone

who is afraid to go shopping for groceries might start by just opening the

front door, then walking down the front path to the sidewalk. Next, the

person walks a few blocks, then goes to the store itself and purchases only

one item, and so on. Some people recovering from agoraphobia refer to

exposure therapy as the

recover, and repeat.

In cognitive behavioral therapy (CBT), patients are given some education

about anxiety and are taught to recognize and control their reactions

to panic attacks. In CBT sessions, people learn to recognize

things that trigger panic attacks or make them worse, such as specific

thoughts or situations. They also learn to modify behavior so that it is

more useful than simply avoiding the feared place or situation.

Doctors may prescribe medications in addition to psychotherapy,

particularly if the patients

The medications prescribed for adults are usually antidepressants

or tranquilizers. It may take several weeks for the medications to take

effect. The doctor may need to try more than one medication before

finding the drug that works best for the specific patient, but most

patients with panic disorder are helped by these drugs.

Complementary and alternative therapies that are effective in

treating panic disorder include yoga, meditation, relaxation techniques,

guided imagery, and hypnosis.

Prognosis

Most people do very well when treated for panic disorder provided they

stick with their treatment plan. In addition, people who have been

treated with psychotherapy can usually make arrangements for

sessions

groups and online communities for people with panic disorder.

“booster” if they feel the need for further help. There are also many support

Prevention

There is no known way to prevent panic disorder because its causes are

not yet fully understood. People can, however, lower their risk of panic

attacks by avoiding the use of recreational drugs and learning stress management

or relaxation techniques.

The Future

Panic disorder is likely to continue to be a disabling condition for many

people, particularly those who do not know that it is treatable. It is

possible that further research will help doctors learn more about the

causes of the disorder and develop even more effective treatments.

SEE ALSO

Alcoholism; Hypertension; Irritable bowel syndrome

For more information

BOOKS

Campbell, Nancy M.

National Institute of Mental Health (NIMH).

No. 06-3879. Bethesda, MD: NIMH, 2006.

Panic Disorder. Mankato, MN: LifeMatters, 2002.Anxiety Disorders. NIH Publication

WEB SITES

Anxiety Disorders Association of America (ADAA).

Available online in PDF format at http://www.adaa.org/bookstore/

Brochures/panic_adaa.pdf (accessed May 5, 2008). This four-page brochure

includes a self-test for panic disorder.

National Alliance on Mental Illness (NAMI).

Available online at http://www.nami.org/Template.cfm?Section=

By_Illness&Template=/TaggedPage/TaggedPageDisplay.cfm&TPLID=

54&ContentID=23050 (updated May 2003; accessed May 5, 2008).

National Institute of Mental Health (NIMH).

Available in PDF format at http://www.nimh.nih.gov/health/publications/

panic-disorder-a-real-illness/complete.pdf (updated October 2005; accessed

May 5, 2008).

WORDS TO KNOW
Agoraphobia: An irrational fear of venturing outside
the home or into open spaces, so strong
that a large number of activities outside the
home are limited or avoided altogether. Agoraphobia
is often associated with panic attacks.
Cognitive: Pertaining to thinking, learning, or
memory.
Diagnosis of exclusion: A diagnosis that the
doctor arrives at by ruling out other diseases one
by one rather than making the diagnosis on the
basis of laboratory tests or imaging studies, or
other test results.
Panic attack: An episode of intense fear that lasts
for several minutes and is accompanied by
physical symptoms or temporary disturbances of
thinking.
Phobia: An unfounded or morbid dread of a specific
object or situation that arouses feelings of
panic.Panic Disorder.About Mental Illness: Panic Disorder.Panic Disorder—A Real Illness.“five Rs,” which stand for react, retreat, relax,’ panic attacks are keeping them virtually housebound.’s panic attacks. Some people may have one

Panic Disorder

Obesity

2011-03-03T01:37:00.000+03:00

Obesity

Definition

Obesity is defined as a condition in which a person has accumulated so

much adipose (fatty) tissue that his or her health is impaired. It is also

defined by a person

BMI is an indirect measurement of body fat. To calculate an adult

in English measurements, multiply a person

703.1, and divide that number by the person

A personwith a BMI above 25 is considered overweight; a BMI over 30 is considered

obese; and a BMI above 40 is considered morbid obesity. In terms of

waistmeasurement, women with a waistline greater than 35 inches (88.9 centimeters)

and men with a waistline greater than 40 inches (101.6 centimeters)

are considered obese.

Some doctors think that obesity itself should be defined as a disease,

while others maintain that it should be considered more broadly as an

unhealthy condition that increases a person

diseases.

’s body mass index (BMI) or waist measurement. The’s BMI’s weight in pounds by’s height in inches squared.’s risk of diabetes and other

Description

Obesity is a condition that develops when a person takes in more food calories

than his or her body burns up in the course of one

The body turns those excess calories into fat. Overweight refers to an

excess of body weight compared to set standards. The extra weight may

come from muscle, bone, fat, or body water. Obesity refers specifically

to having an abnormally high proportion of body fat. Thus it is possible

for an athlete to be overweight without being obese if his or her extra

weight consists of muscle rather than fat tissue.

Obesity is a concern to doctors because it is associated with a number of

diseases and disorders that can shorten a person

lower one

include:

’s life expectancy as well as’s quality of life. Some of these diseases and other health problems

•

Type 2 (adult-onset) diabetes

•

High blood cholesterol levels

•

Heart disease

•

Stroke

•

High blood pressure

•

Osteoarthritis

•

Sleep apnea

•

Gallbladder disease

•

Complications of pregnancy

•

Depression

•

Increased risk of breast, colorectal, or kidney cancer•

Demographics

Obesity is a growing health problem in all countries in the developed

world. The World Health Organization (WHO) estimated in 2005 that

10 percent of the world

with another 760 million overweight. In the United States, about twothirds

of adults are overweight compared to the ideal weight for their sex,

age, and height; one-third of American adults are obese. The proportion

of obese adults in the general American population has more than

doubled since 1960. Obesity costs the United States about $100 billion

each year, $52 billion for direct health care costs and $33 billion for

weight-loss products or programs.

Obesity is equally likely to affect men and women. There are, however,

racial and ethnic differences within the American population.

Groups that have a higher than average risk of obesity include the Pima

Indians of Arizona and several other Native American tribes; Hispanics;

African Americans; and Pacific Islanders.

Obesity is often associated with eating disorders in adults; about

30 percent of obese adults have a history of bulimia or binge eating.

’s population, or 400 million people, were obese,

Causes and Symptoms

Obesity is thought to be the end result of a combination of factors rather

than having a single cause. Although obesity can be briefly described as an

imbalance between food energy taken in and energy used up in exercise,

eating and exercise are intertwined with other factors in complicated ways.

•

of the variations in human body size. Genetic factors affect

how efficiently a person

the excess fat is stored. People whose fat is stored around the

abdomen have a higher risk of health problems than those whose

extra weight is carried on the hips.

Genetic factors. Researchers think that these account for 40–70 percent’s body burns food and where on the body

•

foods is likely to adopt their eating habits.

Family environment. A person whose parents eat a lot of highcalorie

•

their calorie requirements drop; thus people who may not have been

obese as young adults may become obese as they grow older.

Age. People’s bodies lose muscle tissue and gain fat as they age, and

•

their calorie requirements for maintaining their body weight are

higher than women

the same height and weight to gain weight if they consume the

same number of calories as the men.

•

the thyroid gland, or depression are at increased risk of obesity.

Medical conditions. People with Cushing’s syndrome, disorders of

•

drugs, antiseizure medications, or antidepressants may gain weight

on these drugs.

Medication side effects. People who must take corticosteroid

•

when they are sad, angry, bored, or upset.

Emotional factors. Some people use food to soothe their feelings

•

because food tastes better after they quit. In addition, the nicotine

in tobacco raises the rate at which the body burns calories, so the

former smoker

Quitting smoking. People who quit smoking often gain weight’s body needs fewer calories to maintain its weight.

•

after each pregnancy; over time, these weight gains can lead

to obesity.

Pregnancy. Most women retain 4 to 6 pounds (1.8 to 2.7 kilograms)

Diagnosis

The diagnosis of obesity in adults may be based on the CDC body mass

index tables, or it may be based on other measurements. One common

test involves measuring the thickness of the skin fold over the triceps

muscle on the upper arm, although this measurement may not be accurate

unless performed by a trained technician. Another test involves measuring

the person

just below the belly button.

’s waist circumference at its widest point, usually at or

Treatment

Treatment of obesity is usually more complicated than simply placing

people on a calorie-restricted diet or telling them to get more exercise.

The doctor must take into account other health conditions that may

affect the patients, their medications, occupation, and other lifestyle factors.

For example, a person who lives alone can control food purchases or

daily workouts more easily than someone who has to take the eating

habits and time schedules of other family members into consideration.

Similarly, someone with osteoarthritis may need to find forms of exercise

that will not damage sore joints. In some cases the doctor and patient can

work out a diet and exercise plan with the help of a registered dietitian or

physical therapist, so that the patient can eat a nutritious diet that

includes one

likes as well. One of the keys to sticking with a weight-loss program is

satisfaction; people who feel deprived of the foods they like or bored

by their physical exercise program are likely to quit.

It helps to remember that losing even a small amount of weight can be

beneficial. Some doctors call this approach the

is, losing just 10 percent of one

disease and diabetes. If the person is able to keep that 10 percent weight

loss for six months or longer, he or she can consider losing more weight.

People who have been unable to lose weight by a combination of

exercise and food intake, or who are morbidly obese, may be treated by

medications or weight-loss surgery. The two major medications that have

been approved by the Food and Drug Administration (FDA) for weight

loss are Meridia, which works by making the person feel full more

quickly during a meal, and Xenical, which works by lowering the amount

of fat that the body absorbs from the intestines. Both drugs have side

effects, and weight loss tends to be modest, about 13 pounds (5.9 kilograms)

in a year.

Weight-loss surgery, known as bariatric surgery, is usually limited to

people with a BMI over 40 or those with a BMI over 35 combined with

type 2 diabetes, sleep apnea, or heart disease. There are two basic types of

surgery for weight loss, restrictive and malabsorptive. Restrictive procedures

work by closing off part of the stomach so that the person cannot

eat as much without feeling full. In malabsorptive procedures, the surgeon

creates a bypass around the part of the small intestine where most of the

calories in the food are absorbed. This type of surgery lowers the amount

of calories that the body absorbs as well as lowering the patient

intake. Bariatric surgery is not for everyone; it can produce serious complications

that include bloating, nausea, and diarrhea. In addition, the

patient will need to see the doctor periodically for the rest of his or her life.

’s favorite foods and find a form of exercise that he or she“10 percent solution”—that’s excess weight can lower the risk of heart’s food

Prognosis

According to the Centers for Disease Control and Prevention (CDC), obese

adults have a 10

compared to people whose weight is normal or only slightly overweight.

Obesity shortens a person

and accounts for 112,000 excess deaths each year in the United States compared

to people of normal weight. Men with a BMI over 40 have their life

expectancy shortened by twenty years, and women by five years.

Prevention

Preventing weight gain or maintaining weight loss can be difficult in a

society where inexpensive high-calorie snacks make it easy to overeat and

television or video games make it easy to avoid physical activity. The following

tips, however, can help a person stay committed to a weight-loss

or weight-maintenance program:

•

swimming, or other forms of moderate exercise.

Make time each day—thirty to sixty minutes—for fast walking,

•

foods rather than sweets or snacks that are high in fat.

Build a daily menu around fruits, vegetables, and whole-grain

•

One way to spot these patterns is to keep a food diary.

Learn to recognize the situations or triggers that lead to overeating.

•

related to overeating.

If necessary, get help for depression or other psychological problems

•

Keep track of weight and waist size on a regular basis.

The Future

It is likely that obesity will increase in the future, not just in the United

States but worldwide. The World Health Organization (WHO) reported

in 2006 that the only part of the world where obesity is still unusual is

sub-Saharan Africa. Obesity is rising in all age groups, including the

elderly, as well as in almost all countries.

Since the discovery in 1994 of leptin, a hormone that regulates the

brain

studying it in hopes of learning more about the biological factors that

influence appetite and food intake in humans. Other researchers are

looking at the emotional and social factors that encourage people to

overeat, and to test the effectiveness of psychotherapy as well as medications

in weight-loss programs.

SEE ALSO

Hypertension; Sleep apnea

Bulimia; Childhood obesity; Diabetes; Hypercholesterolemia;

For more information

BOOKS

Freedman, Jeri.

Obesity

Hensrud, Donald D., ed.

MN: Mayo Clinic Health Information, 2005.

Hicks, Terry Allen.

Malvasi, Meg Greene.

Understanding Obesity: The Mental and Physical Effects of. New York: Rosen Publishing, 2009.Mayo Clinic Healthy Weight for Everybody. Rochester,Obesity. New York: Marshall Cavendish Benchmark, 2009.Obesity. Philadelphia: Mason Crest, 2007.

PERIODICALS

Kolata, Gina.

Times

ref/health/healthguide/esn-obesity-ess.html (accessed on September 16,

2008).

“For the Overweight, Bad Advice by the Spoonful.” New York, March 16, 2008. Available online at http://health.nytimes.com/

WEB SITES

Mayo Clinic.

obesity/DS00314 (updated May 9, 2007; accessed on September 16, 2008).

National Heart, Lung, and Blood Institute (NHLBI).

Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/obe/obe_

whatare.html (updated May 2008; accessed on September 16, 2008).

Obesity Society.

information/what_is_obesity.asp (cited September 16, 2008).

TeensHealth.

http://kidshealth.org/teen/nutrition/weight/obesity.html (updated May

2007; accessed on September 16, 2008).

Weight-Control Information Network (WIN).

and Obesity

(updated May 2007; accessed on September 16, 2008).

WORDS TO KNOW
Adipose tissue: Fatty tissue.
Binge: An episode of eating in which a person
consumes a larger amount of food within a limited
period of time than most people would eat
in similar circumstances.
Body mass index: BMI. An indirect measurement
of the amount of body fat. The BMI of adults
is calculated in English measurements by
multiplying a person’s weight in pounds by
703.1, and dividing that number by the person’s
height in inches squared.
Cushing syndrome: A disorder caused by the
excess secretion of cortisol by the pituitary gland.
Ideal weight: Weight corresponding to the lowest
death rate for individualsObesity. Available online at http://www.mayoclinic.com/health/Overweight and Obesity.What Is Obesity? Available online at http://www.obesity.org/When Being Overweight Is a Health Problem. Available online atStatistics Related to Overweight. Available online at http://win.niddk.nih.gov/statistics/index.htm’s sense that the body has had enough to eat, researchers are–50 percent increase in their risk of dying from any cause,’s life expectancy by six to seven years on average,Sex. Men have more muscle tissue and less fat than women, and’s. Thus women are more likely than men ofIncreased risk of complications following surgery’s daily activities.

Narcolepsy

2011-01-17T00:38:00.000+03:00

Narcolepsy

Definition

Narcolepsy is a sleep disorder caused by the brain

normal sleep/wake cycles. People with narcolepsy have sleep episodes in

the daytime, hallucinations when falling asleep or awaking, and often

awaken at night.

’s inability to regulate

Description

Narcolepsy can affect people in any age group but may not be diagnosed

for as long as ten years after onset. It can be a disabling condition.

Because people with narcolepsy can fall asleep in the daytime in the

middle of other activities

equipment

with narcolepsy can fall behind in school or be judged as lazy students

even though they are of normal intelligence.

Having narcolepsy does not mean that people with the disorder sleep

more than other people. The disorder is better understood as a disturbance

of the normal boundaries between sleeping and waking rather than simply

sleeping too much. A normal adult who sleeps for about eight hours has

between four and six sleep cycles during that time. A sleep cycle is a period

of a type of sleep called non-rapid eye movement (NREM) sleep followed

by a period of rapid eye movement (REM) sleep. REM sleep is

characterized by increased brain activity, rapid movement of the eyes

below the lids, and sleep paralysis. People who say that they were having

a dream when they woke up have been awakened from REM sleep. In

normal adults, a sleep cycle is about 100

minutes of NREM sleep followed by 10

In narcolepsy, however, the patient

normal pattern. Instead, the person falls into REM sleep very shortly after

falling asleep. In addition, the short periods of sleep that the patient has

during the daytime are REM sleep. This abnormal occurrence of REM

sleep helps to explain such symptoms of narcolepsy as sleep paralysis and

cataplexy.

–110 minutes long, 80–100–20 minutes of REM sleep.’s sleep cycles do not follow this

Demographics

It is possible that narcolepsy affects more people than is presently known.

The rate of narcolepsy in the general population varies widely around the

world. In Israel, for example, only about one person per 500,000 is diagnosed

with narcolepsy whereas the rate in Japan is one person in every

600. In the United States, narcolepsy affects about one person in every

2,000. It is slightly more common in African Americans than in members

of other races.

Narcolepsy affects men and women equally. It is not thought to be

inherited. However, about 10 percent of Americans with narcolepsy have

a relative with the condition, but this percentage is low compared to

other disorders that are known to be purely genetic in origin.

Most cases of narcolepsy first appear in people between the ages of

ten and twenty-five years, but the disorder has been diagnosed in children

as young as three and in adults over fifty.

Causes and Symptoms

The basic cause of narcolepsy remains unknown. Progress has been made

since the late 1990s in identifying two pieces of the puzzle. The first is a

connection between narcolepsy and changes in a set of genes on chromosome

6 called the HLA complex. It is thought that changes in these genes

may be linked to the loss of cells in the brain that secrete hypocretin, a

protein that regulates the sleep/wake cycle. Researchers do not know

exactly what causes the loss of the brain cells that make hypocretin.

Because the HLA complex has been linked to other autoimmune disorders,

however, some doctors think that narcolepsy may be an autoimmune

disease. No one has been able to prove this theory as of late

2008, however. Other researchers think that the hypocretin-producing

cells may be damaged by some type of infection, but this theory has yet

to be proved.

Narcolepsy has four primary symptoms:

•

form of

drowsiness, or daytime episodes of sleep lasting half an hour or

longer.

Excessive daytime sleepiness (EDS). This symptom may take the“microsleeps” of a few seconds, a long-lasting feeling of

•

may result in slurred speech, sagging of the facial muscles, general

muscle weakness, inability to hold up one

knees, or loss of strength in the arms. Cataplexy is often triggered

by strong emotions, whether positive feelings like laughter or pleasant

surprise or negative emotions like fear, shock, or anger. Cataplexy

can last from a few seconds to as long as thirty minutes. The

person is awake and alert during an episode of cataplexy even

though he or she may appear unconscious to others.

Cataplexy. Cataplexy refers to a sudden loss of muscle tone that’s head, buckling of the

•

partial alertness that people have when they are waking up or

falling asleep. People with narcolepsy experience very vivid and

sometimes frightening dreams when they are half awake, and they

may mistake these dreams for reality.

•

move or speak while falling asleep or waking up. These episodes

last only one or two minutes and do not affect everyone with

narcolepsy, but they can be frightening to patients who do have

them.

Other symptoms experienced by some people with narcolepsy

include automatic behavior, in which the person performs a routine task

like sorting laundry or making a cup of coffee without conscious awareness

or later memory of the action. People with narcolepsy may also

thrash about in bed at night or act out their dreams by screaming or

waving their arms.

Sleep paralysis. Sleep paralysis refers to a temporary inability to

Diagnosis

The diagnosis of narcolepsy is often delayed because its symptoms

resemble those of such other disorders as depression, seizure disorders,

simple lack of sleep, or even illegal drug use. Early diagnosis is important

because the impact of the disorder on a person

relationships, and self-esteem can be severe. According to one study, 24

percent of adults with narcolepsy had to quit working and 18 percent

had been fired from their jobs because of the disease.

The diagnosis of narcolepsy is based on a combination of the

patient

testing in a sleep laboratory. The screening questionnaire that is used

most commonly is the Epworth Sleepiness Scale, or ESS, which was

developed in Australia in the early 1990s. The patient may also be asked

to keep a sleep diary for one or two weeks and wear a device called an

actigraph. The actigraph resembles a wrist watch and measures the person

sleep.

The patient will usually be tested overnight in a medical center

equipped with a polysomnograph. The polysomnograph is a machine

that measures the electrical activity of the heart and brain, breathing, and

eye movement while the patient is sleeping. Another sleep test is called

the multiple sleep latency test or MSLT. The patient is given a chance

to sleep every two hours during normal waking time. Observations are

made of the time taken to reach various stages of sleep. The MSLT

measures the degree of the patient

how soon REM sleep begins.

’s daytime sleepiness and also detects

Treatment

Treatment of narcolepsy involves a combination of medications, lifestyle

changes, and psychotherapy. The most common medications given are

stimulants that resemble amphetamine. It is important for persons taking

stimulants to notify their employer, because the drugs may show up

during pre-employment urine tests. Another type of drug that may be

prescribed is a drug called Xyrem, which controls cataplexy and helps

patients sleep better at night.

Lifestyle changes that are recommended for patients with narcolepsy

include:

•

and get up at the same time every day rather than changing their

sleeping schedule frequently.

Getting enough sleep at night. Patients are advised to go to bed

•

This practice helps to reduce daytime sleepiness.

Taking scheduled short naps at intervals during waking hours.

•

make it harder to sleep at night.

Avoiding the use of alcohol and tobacco. These substances can

•

bedtime helps many people with narcolepsy sleep better.

Getting regular exercise. Physical exercise four to five hours before

•

Being careful to avoid driving when tired or sleepy.

•

support from others with the same disorder is particularly helpful

to patients who may have waited years to be diagnosed and suffered

the loss of jobs, relationships, or educational opportunities

in the meantime.

Joining a narcolepsy support group. Finding understanding and

Prognosis

Narcolepsy cannot be cured but it is not a fatal disease. People with narcolepsy

can expect to live normal life spans (barring accidents). They can

also expect to lead normally productive and meaningful lives with proper

care and periodic consultations with a sleep specialist.

Prevention

There is no way known to prevent narcolepsy.

The Future

New drugs that will help narcoleptic patients remain awake were at the

clinical trial stage in late 2008. Some researchers in Germany were

experimenting with a nasal spray containing hypocretin that might be

beneficial to people with narcolepsy. Another possibility is the use of

stem cell transplants to restore the cells in the brain that make hypocretin,

but that approach will likely take several decades to be successful.

SEE ALSO

Restless legs syndrome; Sleep apnea

For more information

BOOKS

Sutton, Amy L., ed.

about Sleep and Sleep Disorders

Sleep Disorders Sourcebook: Basic Consumer Health Information. Detroit, MI: Omnigraphics, 2005.

PERIODICALS

Chen, Ingfei.

Times

health/healthguide/esn-narcolepsy-ess.html (accessed May 21, 2008).

“A Leap Forward, But Hurdles Remain in Narcolepsy.” New York, May 10, 2008. Available online at http://health.nytimes.com/ref/

WEB SITES

American Academy of Sleep Medicine (AASM).

online in PDF format at http://www.aasmnet.org/Resources/FactSheets/

Narcolepsy.pdf (updated 2006; accessed May 21, 2008).

Epworth Sleepiness Scale (ESS)

org/do2.php (accessed May 21, 2008). This is the screening

questionnaire that has been used since 1991 to evaluate people for

narcolepsy.

Narcolepsy Network.

http://www.narcolepsynetwork.org/faq.php (updated 2003; accessed May

21, 2008).

National Institute of Neurological Disorders and Stroke (NINDS).

Fact Sheet

narcolepsy/detail_narcolepsy.htm (updated January 11, 2008; accessed

May 21, 2008).

WORDS TO KNOW
Automatic behavior: Activity that a person with
narcolepsy can carry out while partially awake
but is not conscious of at the time and cannot
recall afterward.
Cataplexy: Sudden loss of tone in the voluntary
muscles.
Hypnagogic: Referring to the period of partial
alertness on the boundary between sleeping and
waking.
Hypocretin: A protein produced by certain brain
cells that promotes wakefulness and helps to
regulate the sleep/wake cycle. It is also known as
orexin.
Non-rapid eye movement (NREM) sleep: The first
phase of a sleep cycle, in which there is little or
no eye movement.
Rapid eye movement (REM) sleep: The phase of a
sleep cycle in which dreaming occurs; it is characterized
by rapid eye movements.
Sleep cycle: A period of NREM sleep followed by a
shorter phase of REM sleep. Most adults have
four to six sleep cycles per night.. Available online at http://www.narcolepsynetwork.Narcolepsy: Frequently Asked Questions. Available online atNarcolepsy. Available online at http://www.ninds.nih.gov/disorders/Fact Sheet: Narcolepsy. Available’s education, employment,’s history, the results of a screening questionnaire, and overnight’sHypnagogic hallucinations. Hypnagogic refers to the period of—including eating, driving, or operating heavy—they can be involved in serious accidents. Children or adolescents

Malaria

2011-01-17T00:16:00.000+03:00

Malaria

Definition

Malaria is an infectious disease caused by a parasite that spends part of its

life cycle in humans and part in mosquitoes.

Description

Malaria is a potentially fatal disease that has infected humans as far back

as 50,000

Egypt in 2700

from the same period describe the symptoms of the disease. The English

name of the disease comes from an eighteenth-century Italian doctor

who wrote a textbook about it and attributed it to bad air, or

BCE. There are records of mosquito netting being used inBCE to protect against malaria. Chinese medical recordsmal’aria

in Italian.

Humans develop malaria when they are infected with a protozoan

called

the bloodstream and are carried to the liver, where they infect liver cells

and multiply. The mature parasites are released back into the bloodstream,

where they infect red blood cells. The red cells burst in two to

three days, releasing more parasites that, in turn, invade more red blood

cells. Most of the symptoms of malaria (fever,

chills, generally sick or flu-like feeling) are

related to the destruction of red blood cells. The

reason why the fever associated with malaria

comes in two- or three-day cycles in some people

is that the bursting of infected red blood cells

and the infection of new red blood cells occurs

every two to three days.

There are four different species of

Plasmodium

that infect people. One of these,

falciparum

other three. It can cause failure of the lungs, kidneys, and central nervous

system within a few hours or days. The different species also take different

lengths of time to produce the first symptoms of malaria in

humans. Some remain in the liver for long periods of time, thus causing

flare-ups of the disease months or even years later. These variations are

one reason why doctors try to identify the particular

when they test a person

be infected with more than one species of the parasite at the same time.

People cannot get malaria from sharing a household with an infected

person since it takes more than a week before a mosquito is able to

transmit the disease. It is possible for a pregnant woman to transmit the

disease to her unborn baby, however. It is also possible to get malaria

through a transfusion of infected blood, but this form of transmission

is rare in developed countries. In the United States, people who have traveled

in an area with endemic malaria cannot donate blood for a full year

after returning to the United States. They are forbidden to donate blood

for three years if they have been treated for malaria.

Plasmodium, is much deadlier than thePlasmodium species’s blood for malaria. It is possible for a person to

Demographics

Malaria is one of the most common infectious diseases in tropical and

subtropical parts of the world. These countries account for 41 percent

of the world

900 million cases of malaria around the world each year and 1 million to

3 million deaths, most of them African children under age five. In some

parts of Africa, it is estimated that one person dies of malaria every thirty

seconds. The disease is endemic in parts of Africa, southern Asia, and

portions of South America.

Malaria has not been endemic in the United States since 1951, when

a four-year program was started in 1947 to spray areas in the southeastern

part of the country that were known to harbor the mosquitoes

that transmit malaria. By 1952 the Centers for Disease Control and Prevention

(CDC) reported that malaria had been eradicated from the

United States. Cases of malaria since that time were either acquired by

people traveling to countries where malaria is endemic or were small local

outbreaks caused by local mosquitoes biting infected travelers and then

transmitting the malaria parasites to others nearby. In 2002 the CDC

reported 1,337 cases of malaria in the United States, including eight

deaths. All but five cases were acquired abroad.

People who are at greatest risk for malaria are those who have never

been exposed to the disease, pregnant women, and young children. Some

researchers also think that genetic factors may increase some people

of getting the disease.

’s risk

Causes and Symptoms

The cause of malaria is a protozoan of the genus

deadly of the four species that can cause malaria in humans is

falciparum

of chills and shaking followed by fever and sweating lasting four to six

hours. People infected by

as well. In some cases, the early symptoms of malaria may be mistaken

for the flu.

Children infected by

on the brain and suffer permanent brain damage even if they survive.

Adults infected by

dehydration, an enlarged liver and spleen, rupture of the spleen, severe

headache, loss of blood supply to the brain, and coma. Some die. The

destruction of red blood cells by the parasite may cause the urine to look

brown or black, which is why the disease got the name

fever.

Plasmodium. The mostPlasmodium. The classical symptom of malaria is a repeated cycleP. falciparum may feel a tingling in the skinP. falciparum may develop increased fluid pressureP. falciparum may develop kidney failure,“blackwater”

Diagnosis

Diagnosis of malaria is based on a combination of the patient

and the results of blood tests. The patient

the dates of any trips abroad, because two of the four species of

the malaria parasite can remain dormant in the liver for months or

even years.

The basic blood test involves looking at blood smears made by

pricking the patient

technique is called a thick smear, which is used to estimate the number of

parasites in the blood. The other is called a thin smear and is used to

determine the species. A rapid test called OptiMAL has been developed

to distinguish

time than the smear method and can be used by doctors in areas without

hospital laboratories.

’s finger at twelve- to twenty-four-hour intervals. OneP. falciparum from the other species. It gives results in less

Treatment

Malaria is treated with various combinations of drugs, which may be

given by mouth or intravenously. Patients infected by

be taken to a hospital for treatment because of the possibility of major

organ damage. The oldest drugs used to prevent or treat malaria are quinine

and chloroquine. Relatively inexpensive, they are not always effective

because the malaria parasites have developed resistance to them in

some countries. Newer drugs have been developed that are more effective

for resistant strains. People who are traveling to parts of the world where

malaria is endemic need to take these drugs while they are abroad.

The specific drug that is given to a patient and the length of treatment

depend on the type of malaria, the source of the infection, the

patient

People often feel weak and tired for a few weeks when taking these

medications.

P. falciparum may’s age, and the severity of the symptoms when treatment began.

Prognosis

Malaria caused by

of the first symptoms. In some areas, the death rate from this type of

malaria is as high as 20 percent. People infected by the other three species

months until all the parasites have been cleared from their livers.

P. falciparum is the most deadly; it can kill within daysPlasmodium usually recover, but some may have bouts of malaria for

Prevention

There is no vaccine effective against the malaria parasite, although scientists

are working on several possibilities. For the time being, prevention is

the most effective way to lower one

three basic strategies recommended by the CDC:

’s risk of getting malaria. There are

•

draining swampy areas. This approach is called vector control.

Controlling the mosquito population by using insecticides and

•

other sleeping areas. These nets have cut the number of deaths

from malaria in parts of Africa by 20 percent.

Using mosquito netting treated with insecticide to cover beds and

•

where malaria is endemic. The CDC has general advice for travelers

and a list of countries where travelers are at risk for malaria at

http://www.cdc.gov/malaria/travel/index.htm.

Taking medications to prevent the disease when visiting countries

The Future

It is unlikely that the mosquitoes that carry malaria will ever be completely

wiped out. At present, efforts to relieve the impact of malaria in Africa

are aimed at preventing the disease. Methods include spraying insecticides,

providing people with insecticide-treated mosquito netting, and

supplying poor countries with antimalarial drugs. In 2005 the President

Malaria Initiative (PMI)

the National Institutes of Health, the World Health Organization, and

the World Bank as well as the White House

to cut deaths from malaria by 50 percent in fifteen African countries.

The most promising area of malaria research as of 2008 was the development

of vaccines against the disease. Scientists have identified the

genetic sequence of the malaria parasite, which may help researchers target

a particular stage in the life cycle of the parasite or prevent it from developing

inside the mosquito. One possibility is developing a vaccine that

would stop the parasite inside the human body before it gets to the point

of infecting the red blood cells. Another group of researchers is experimenting

with cultivating

parasite with radiation in order to make a vaccine. This approach is

described in the video listed below.

’s—a cooperative program that involves the CDC,—began a five-year programP. falciparum inside mosquitoes and treating the

SEE ALSO

Influenza; Syphilis; West Nile virus infection

For more information

BOOKS

Abramovitz, Melissa. Malaria. Detroit, MI: Lucent Books, 2006.

Lynette, Rachel.

Marcus, Bernard A.

Malaria. Farmington Hills, MI: KidHaven Press, 2006.Malaria. Philadelphia: Chelsea House Publishers, 2004.

PERIODICALS

Appleton, Samantha.

2005. Available online at http://www.newyorker.com/archive/2005/10/24/

slideshow_051024?slide=1#showHeader (accessed April 24, 2008). This is a

slide show of fifteen photographs of the 2005 malaria epidemic in Africa.

McNeil, Donald G., Jr.

December 11, 2007. Video available online at http://video.on.nytimes.com/

index.jsp?fr_story=6e4647e2867283dce5b8cb2cf46003e7fdcd6267

(accessed April 25, 2008). This is a four-minute video about ongoing efforts

to develop a vaccine against malaria.

“Slide Show: Healing Africa.” New Yorker, October 24,“Searching for a Cure for Malaria.” New York Times,

WEB SITES

Centers for Disease Control and Prevention (CDC).

Available online at http://www.cdc.gov/malaria/ (updated April 18, 2008;

accessed April 24, 2008). Contains links to news items as well as basic

information about malaria and its treatment.

Mayo Clinic.

malaria/DS00475 (updated February 8, 2008; accessed April 25, 2008).

President

fightingmalaria.gov/resources/pmi_fastfacts.pdf (posted January 2008;

accessed April 26, 2008).

Sumanas, Inc.

online at http://www.sumanasinc.com/scienceinfocus/sif_malaria.html

(accessed April 5, 2008). This is an animation of the life cycle of the malaria

parasite with voiceover. It takes three minutes to play.

WGBH Educational Foundation.

www.pbs.org/wgbh/rxforsurvival/series/diseases/malaria.html (posted 2005;

accessed April 24, 2008). The right-hand side of the page includes links to

three videos on malaria, each about five minutes in length.

WORDS TO KNOW
Dementia: Loss of memory and other mental
functions related to thinking or problem-solving.
Endemic: A term applied to a disease that
maintains itself in a particular area without
reinforcement from outside sources of infection.
Protozoan (plural, protozoa): A one-celled animallike
organism with a central nucleus enclosed by
a membrane. Many protozoa are parasites that
can cause disease in humans.
Spleen: An organ located behind the stomach that
cleans old blood cells out of the blood and holds
a reserve of red blood cells.
Vector: An insect or other animal that carries a
disease from one host to another.

Malaria Research and the Nobel Prize

One indication of the importance

complexity

prizes in medicine that have been awarded to

doctors who studied the disease. Charles Louis

Alphonse Laveran (1845

doctor working in a military hospital in Algeria in

1880 when he discovered that malaria is caused by

a protozoan (a type of one-celled organism). This

was the first time that a protozoan had been

shown to cause any disease in humans. Laveran

was awarded the Nobel Prize in Physiology or

Medicine in 1907.

In 1898, Sir Ronald Ross (1857

doctor working in India, was able to show that

mosquitoes are the vectors that carry malaria to

humans. Ross even demonstrated that the parasites

are present in the mosquito

He was awarded the Nobel Prize in Physiology or

Medicine in 1902. Austrian doctor Julius Wagner-

Jauregg (1857

He showed that malaria could actually be used to

treat patients suffering from late-stage syphilis, a

common cause of dementia in the early twentieth

century. The reason this treatment was thought to

work was that the fever caused by the malaria

parasite was high enough to kill the bacteria that

cause syphilis.

The fourth Nobel Prize in Physiology or Medicine

related to malaria research was given in 1948 to

Paul Hermann Müller (1899

chemist who discovered dichloro-diphenyltrichloroethane

(DDT) in 1939. DDT was the first

insecticide that was effective in controlling the

mosquitoes that spread malaria.

—and the—of malaria is the number of Nobel–1922) was a French–1932), a British’s salivary glands.–1940) won a Nobel prize in 1927.–1965), a Swiss

Malaria: Topic Home.Malaria. Available online at http://www.mayoclinic.com/health/’s Malaria Initiative (PMI). Fast Facts. Available online at http://www.Malaria: Cooperation among Parasite, Vector, and Host. AvailableRx for Survival: Malaria. Available at http://’s history’s history is critical, particularly’s population. It is estimated that there are between 400 andPlasmodium through the bite of a mosquito. The parasites enter