What is it?

Retinitis pigmentosa is a group of eye disorders leading to vision loss and difficulty with

night vision.

Who gets it?

In the United States it occurs in about 1:4000 people (although in Navajo Indians it happens to 1 in 1878 people). Worldwide it’s reported that retinitis pigmentosa happens to about 1 in 5000 people.

Retinitis pigmentosa is an inherited disease, meaning it’s in your genes, and having a relative with the disease may raise your chance of having it. In 50% of cases, though, there are no known affected relatives.

It can happen to men, as well as women, and is usually found in young adults (although it can be found almost at any age).

What causes it?

The eye, as can be seen in the drawing above, has many parts. The layer that lines it from the inside is the retina, which is a layer of nerve cells responsible for interpreting the light that enters the eye into a signal which the brain understands and converts to an image.

The cells that do this translation are called photoreceptors. To make things (a little) more complicated – there are two types of photoreceptors -

1. Rods - Are responsible for seeing in low light situations (for example – at night). They aren’t responsible for seeing sharp.
2. Cones – These are the cells responsible for colors perception, and for our sharper vision.

Retinitis pigmentosa most commonly affects the rods. For an unknown reason, these cells die in the disease.

How does it feel?

There are a few things that people with retinitis pigmentosa can feel -

1. Night blindness(called nyctalopia) – This is the symptom that happens the earliest. People have trouble walking outside at night or in dark surroundings (like movie theaters, or while driving). It may also take them more time to adapt to light after leaving a dark area.
2. Visual loss – Vision is usually lost in the periphery and not in the center of the visual field. This causes a “tunnel vision” effect, in which you can only see what’s ahead of you, but not to the sides. This can lead to bumping into things you can’t see, such as furniture or doorframes.

Tunnel vision – you only see what’s in the center of the picture and miss out on the rest. Photo by Скампецкий

How is it discovered?

There are a few things which can help in the diagnosis of retinitis pigmentosa:

1. Examination of the eye– We won’t go into details of how this is done, since it’s way beyond the scope of this article. However, there are some things that are characteristic of this disease – one example, as you can see in the picture below, are pigment deposits in the retina that look like bone spicules (the black strings in the periphery of the photo).
2. ERG (electroretinogram)– This is a test which measures the electrical response of various cell types in the retina and can show if there’s a problem.
3. Genetic testing – This can help with reaching the diagnosis, as well as with preventing the disease in future generations.

Photo by Christian Hamel

These are just some of the tests used to discover retinitis pigmentosa. Others are beyond the scope of this article.

How is it treated?

Unfortunately, no cure for retinitis pigmentosa exists. Over the years there have been attempts at treating the condition by various means (for example consuming high levels of vitamin A). Future therapies may include genetic therapy (replacing the defective genes) or stem cell transplantation, but these don’t exist today.

The bottom line – How do I avoid it?

Sadly, there is currently no known way to prevent retinitis pigmentosa.

The following video is an interview with a retinitis pigmentosa patient, Gordon Anthony:

Watch this video on YouTube.

Related posts:

1. Refsum Disease–Losing Your Vision and Sense of Smell, All Because of Your Diet (As Seen on House MD)

That’s right – from now on we’ll be having on board a new team of physicians writing

on the site, each about their own field of specialty. You can see them here. The list will grow in the upcoming days, but we’re still looking for new writers. If you’re a physician or know of someone who will be interested, feel free to contact us.

What else is new?

• A new layout – You can now find diseases easily through the new top menu. Diseases are sorted by organ, by severity, and by age.
• Access diseases you saw on TV episodes more easily – There’s now a menu item especially for that.
• Less is more – We took down some of the less relevant areas of the site to give you more of the core content.
• And of course, a flashy new design – Hope it’s easy on your eyes.

As always, you can keep up with what’s new by following us on Facebook, Twitter, and now also on Google+. We even have a whole new newsletter you can sign up to by entering your email address on the top right.

Have fun, and be sure to let us know what you think.

Related posts:

1. The New A Disease A Day Health Forums
2. New on A Disease A Day – The Meebo Bar
3. A Disease A Day – Now on the Amazon Kindle

. Meredith thinks differently and tries to change the course of Mary’s disease.

Danger Level: High

What is it?

Astrocytoma is a type of brain tumor which tends to spread inside the brain ignoring anatomical borders. That causes it to be present on both sides of the brain (and sometimes look life a butterfly – hence the name).

Who gets it?

Astrocytomas are rare – in the United States, every year there are 5.4 new cases per 100,000 people. They are a little more common in men, and most cases appear around ages 20-45.

What causes it?

Astrocytes are star-shaped brain cells located between nerve cells (astro=star, cyte=cell). They are actually part of a larger group of cells in the brain called glia cells – which support the nerve cells and glue them together.

Photo by Neurorocker

When astrocytes start dividing without control, they create a tumor called astrocytoma. These tumors come in different grades (1 to 4) – low grade tumors are slow-growing while high-grade tumors can be very aggressive (on the Grey’s Anatomy episode, Mary had a grade-4 tumor which is the most aggressive type).

The reason for astrocytoma is unknown, but scientists have found that it can be related to radiation to the head at young age, and there are several genes that are also related to this tumor.

How does it feel?

The symptoms of astrocytoma are related to its location – almost any neurological symptom is possible, including changes in mental status, seizures, and movement or sensory problems. These symptoms appear because the tumor puts pressure on brain tissue or ruins it while growing. Symptoms like these are called focal neurological symptoms.

Besides that, astrocytoma (and any other brain tumor) can increase the pressure inside the skull (called intra-cranial pressure) – this causes symptoms like headaches, nausea and vomiting as well as decreased alertness.

How is it discovered?

When someone comes to the doctor with the symptoms described above, the doctor will order a scan – a CT or an MRI (MRI is the best option). Sometimes doctors can guess the type of the tumor according to the way it looks on MRI – but final diagnosis can be made only when checking the tumor under a microscope after it’s removed in surgery.

This is a part of a brain with a grade 4 astrocytoma which spread to both sides of the brain.

How is it treated?

Aggressive astyrocytomas are treated with surgery to remove the tumor, radiation and chemotherapy. Steroids sometimes help with the symptoms, and so do anti-epileptic drugs (for patients with seizures).

What happens after treatment?

Even with treatment, astrocytoma can be deadly. Patients with low-grade tumors can survive for an average of 6-8 years, but with high-grade aggressive disease, average survival is less that 1 year.

The story of Jodi Fenton who recovered from grade-3 astrocytoma

The bottom line – how do I avoid it

Unfortunately, there is no known way to avoid astrocytoma.

Related posts:

1. As Seen on Grey's Anatomy – Tay-Sachs Disease – Fat Accumulating in The Brain
2. Nesidioblastoma – A Tumor of the Pancreas That Can Secrete Hormones (As Seen on House MD)
3. Carcinoid Tumors – A Rare Tumor Often Not Found On Time

On episode 3 of season 8 (named “Charity Case”), altruist millionaire Benjamin Byrd collapses in the street ri

ght after he donated a large sum of money to another foundation. The team argues wether his altruism is a symptom or not, and meanwhile he develops tachycardia (fast heartbeat) and his hands are shaking. When he offers to donate both his kidneys the presence of mental symptoms is obvious, and when understanding that his symptoms got worse after he received contrast media containing iodine, he is diagnosed with Plummer’s Disease.

Danger level: Low

What is it?

In Plummer’s Disease (also known as Toxic Nodular Goiter), an area in the thyroid gland works with no control, and causes a state called hyperthyroidism – too much thyroid hormone in the blood.

Who gets it?

The disease is responsible for 15-30% of the hyperthyroidism cases. It usually develops in adults older than 50, and is more common in women. The disease is also more common in areas of the world where iodine deficiency is common.

What causes it?

As explained before about another disease which causes hyperthyroidism (Graves Disease), the thyroid gland normally produces thyroid hormone in response to a molecule called TSH that comes from the brain. In Plummer’s disease, an area in the thyroid gland (a nodule) starts producing thyroid hormone independently – without TSH. Such nodules are called toxic nodules – there is also such thing as non-toxic nodules, which don’t produce thyroid hormone or any other substance.

The disease is related to exposure to iodine (which is an important factor in the function of the thyroid gland).

How does it feel?

Plummer’s disease can cause symptoms that are related to hyperthyroidism and symptoms that are related to the presence of the nodules themselves.

• Hyperthyroidism can cause weight loss with increased appetite, frequent bowel movements, tremor, intolerance to heat, heart palpitations and a fast heart beat (tachycardia), hyperactivity and irritability and muscle weakness.
• If the nodule is large enough, you can see an enlargement of the gland called goiter, that looks like this:

This is a very large goiter (very rare today).

• Also, when the nodule is very large, it may compress other organs in the neck and cause problems with breathing and swallowing, and sometimes also hoarseness or voice changes.

How is it discovered?

First, the doctor will want to check if the level of thyroid hormone in the blood is high. This can be done by testing the levels of the hormone itself and also by checking the levels of TSH (which will be low).

Ultrasound of the thyroid gland can help recognize nodules in the thyroid (which look like balls in different sizes), and another test called thyroid scan can differentiate between toxic and non-toxic nodules. Sometimes the doctor will want to take a biopsy from the nodule to make sure that it’s not cancer.

How is it treated?

There are two ways to treat Plummer’s disease – the first one is to remove the toxic nodule in surgery (like on the House episode), and the second is to use radioactive iodine that is injected to the bloodstream, concentrates in the nodule and destroys it.

What happens after treatment?

Treatment usually cures the disease, but even when untreated the disease is usually not life threatening (though it’s not very pleasant to live with).

The bottom line – how do I avoid it?

Most of the time there is no specific way to prevent the disease. People with low levels of iodine in their blood are at risk for the disease, so it’s important to consume enough iodine in the diet. In the United States iodine is added to table salt and other foods so iodine deficiency in the diet is very rare.

Related posts:

1. Appendicitis – A Small Part of The Intestine That Can Cause Big Trouble
2. Graves Disease – Why Some People Are Hyperactive For A Reason
3. Kawasaki Disease – A Childhood Disease That Can Endanger The Heart

On episode 2 of season 8 (named “Transplant”), House treats the lungs of an 18-years old man who died in a motorcycle accident. The lungs were donated and planned to be transplanted in one of Wilson’s patients, but went bad just before the transplant, and House’s job was to find out what’s wrong with them. After ruling out cocaine abuse, a tumor in another organ (which affected the lungs) and even peanut allergy and heavy metal poisoning, House and his new and only team member find white blood cells in the lungs, and then diagnose the lungs with eosinophylic pneumonia

Photo by fox

Photo by FOX

Danger level: Medium

What is it?

Eosinophilic pneumonia is a group of diseases in which eosinophils (a type of white blood cells that are responsible for the body’s response in allergies and infections by parasites) accumulate in the lungs and interfere with their function.

Who gets it?

The disease isn’t common, but exactly how rare it is isn’t known. Different diseases in this group can be more common in men or women, and most of them develop in adults (usually not in elderly people).

What causes it?
Eosinophils are cells in our immune system that are active during allergic reactions and parasitic infections. When activated, eosinophils secrete chemicals that can cause inflammation. In people with eosinophilic pneumonia, eosinophils accumulate in the lung, are activated and secrete the chemicals – this causes the symptoms of the disease.
There are many causes for eosinophilic pneumonia. Some cases develop after the person is exposed to something outside the body – certain foods, drugs or even smoke (like in the House episode). Infections by parasites can also cause eosinophilic pneumonia. In other cases, the disease is related to changes inside the body – for example, it can be associated with another disease process. In some cases the reason for the disease is unknown.

An eosinophil, as seen under a microscope. Photo by Akay Miller

How does it feel?

The symptoms can be mild or severe, and include cough, wheezing and shortness of breath. When the disease is severe, it can cause the rate of oxygen in the blood to decrease and sometimes respiratory failure develops.

How is it discovered?

The doctor will suspect eosinophilic pneumonia if symptoms appeared shortly after exposure to foods or drugs that can cause the disease. Tests are performed to approve the diagnosis: blood tests to search for an elevated number of eosinophils in the blood; chest x-ray to see signs of pneumonia, and microscopic examination of lung secretions to search for eosinophils there as well.

How is it treated?

Usually, eosinophilic pneumonia is treated with steroids. If the disease appeared after exposure to foods or drugs – avoiding them will help with recovery, and if the disease is due to a parasitic infection – antibiotics are required.

What happens after treatment?

Most cases respond to medications (or even get better without treatment at all), but sometimes there’s severe lung failure which can be life threatening.

The bottom line – how do I avoid it?

If the disease appeared after exposure to a certain food or drug, avoiding them may prevent the disease from recurring. Also, people who had an attack of the disease should seek medical help right away if symptoms come back.

Related posts:

1. Pleural Mesothelioma – Cancer of The Lungs Caused by Exposure to Asbestos
2. Your Questions Answered – Asbestosis – What Work Exposure Can Do To Your Lungs
3. Deep Vein Thrombosis – Clots in Your Veins Which Can Travel To Your Heart and Lungs

You can read about this horrible cancer in our Cialis online store

-ne

ws-pancreatic-cancer-the-4th-leading-cause-of-death” target=”_blank”>original post.

Here are some updated statistics you should know about -

• Each year, more than 43,000 people are diagnosed with this cancer in the United States alone.
• 37,660 people have died of pancreatic cancer since the beginning of the year.
• Smoking is the most important risk factor for pancreatic cancer. Smokers are more likely to develop this cancer, while heavy smokers are at an even higher risk.
• Jaundice (yellowing of the skin, dark urine and pale stools) may be a sign of pancreatic cancer. Also abdominal pain may be one of the first signs.
• It’s usually discovered too late, which is one of the reasons so many people die of it
• If the cancer can’t be removed by surgery, survival may last for only 4-6 months.

Haiku by Andrew Forgrave

The Lustgarten foundation was established to advance the scientific and medical research related to the diagnosis, treatment, cure and prevention of pancreatic cancer. You can make a donation to help prevent further deaths from this disease.

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1. In The News – Pancreatic Cancer – The 4th Leading Cause of Death
2. Swine Flu – 7 New Facts
3. Preparing For The Summer – New Sunscreen Regulations [News]

probably start spending more time at home. We expect the winter to be allergy-free, but those of us who are prone to allergies might continue sneezing and itching during the winter.

AllergyBeGone.com have created an infographic about the things indoors that can cause annoying allergy symptoms to continue during the winter, and how we can avoid them. For example:

It also explains in general about allergies:

You can see the entire infographic here:

Allergy Be Gone – 7 Allergens In Your Home That You Didn’t Know About

No related posts.

On the first episode of season 8 (named “Twenty Vicodin”, and featuring an interesting guest in the cast!), Ho

use is in prison after crashing his car into Cuddy’s living room. One of the prisoners has a fever, joint pain and a rash on his thigh, and House convinces the prison’s doctor that he has lupus. Later, after the prisoner breaks his arm from a minor hit and doesn’t stop bleeding from a small cut, House listens to his chest and discovers an “acoustic shadow”, meaning there is a mass in his lungs. After drinking some coffee the prisoner develops a severe allergic reaction (anaphylaxis) which causes his airway to swell up and almost kills him. House then realizes that the reason for the reaction was the high temperature of the coffee and diagnoses him with mastocytosis

Photo by fox

Danger level: Medium

What is it?

Our immune system is composed of many types of cells and partןcles. Mast cells belong to the immune system and are involved mostly in allergic reactions. These cells produce substances that cause some of the allergy symptoms, the most famous of them is histamine. In systemic mastocytosis the amount of these mast cells increases significantly, causing the disease.

This is how a mast cell looks. Photo by Ed Uthman

Who gets it?

Systemic mastocytosis is an extremely rare disease – so rare that it’s frequency in the population is not known. It’s a bit more common in men than women, and appears mostly in children, though it may happen to adults (and then the most common age is 55).

What causes it?

The disease develops when a mast cell starts dividing uncontrollably (like in cancer). Since the mast cells keep dividing, there are too many of them – and they can form a tumor, circulate in the blood or accumulate in organs. Also, substances that mast cells produce like histamine are released in larger amounts than usually. All these processes can cause symptoms.

How does it feel?

Symptoms can appear in any organ where mast cells accumulate. This can cause skin rashes, bone pain and problems with the liver, spleen or bone marrow.

Substances that are produced in mast cells and released in large amounts (like histamine) can cause itching, flushing and symptoms in the digestive system (for example: abdominal pain, diarrhea, peptic ulcers and problems with the absorption of food).

Another important symptom is severe allergic reactions (also called anaphylaxis) which can be dangerous and cause difficulty breathing or a very low blood pressure. The most severe allergic reaction in mastocytosis is to bee stings.

In some cases flushing and low blood pressure can develop in response to certain drugs against inflammation (like in the “aspirin test” at the end of the episode), and any symptom can be worsened by these drugs, alcohol or narcotics.

Mastocytosis in toddlers

How is it discovered?

The doctor can suspect mastocytosis based on the symptoms and blood work, but the only definitive test is a bone marrow biopsy, in which a bone sample is taken from the lower back. An important test which can support the diagnosis before performing the biopsy is measuring the levels of histamine in the blood or urine.

How is it treated?

There is no cure for mastocytosis. Treatment is aimed at reducing symptoms, and this is done mostly by different types of pills (for example, anti-histamines which are usually used for allergies).

What happens after treatment?

There are different types of mastocytosis which are dangerous in different levels. In some cases patients have the same life expectancy as the normal population, but in the more violent types (which are, luckily, more rare) patients survive for several months only.

The bottom line – how do I avoid it?

Unfortunately, there is no known way to avoid mastocytosis.

Related posts:

1. Astrocytoma (Butterfly Tumor)–A Brain Tumor That Spreads To Both Sides (As Seen On Grey’s Anatomy)
2. Nesidioblastoma – A Tumor of the Pancreas That Can Secrete Hormones (As Seen on House MD)
3. Pheochromocytoma – A Rare Tumor That Can Cause Hypertension (As Seen on House MD)

rough various machines. One of those is the MRI machine.

Almost anyone has at least heard the name of the machine. Some of you may have even been scanned by it. But knowing how it works? That’s a completely different story.

A new infographic was published that explains just that. For example, it explains what MRI can be used for:

For the more technical-minded, it also explains the inner workings of the machine:

You can see the entire infographic here:

Visualization in Medicine – How MRI Scans Work

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3. 7 Allergens In Your Home That You Didn’t Know About [Infographic]

On episode 3 of season 7 (named “Unwritten”), famous writer Alice Tanner has a seizure while trying to shoot her

self. She is admitted to the hospital, and the team notices she sweats too much. Later, she has a sudden episode of severe headache and dangerously high blood pressure, after which she develops a pericardial effusion (fluids around the heart). After reading her yet-to-be-published book, House deduces that she also has joint pains, fatigue, depression and light-sensitivity. Finally, he diagnoses her with syringomyelia caused by a car accident she had in the past.
Photo by Fox

Photo by Fox

Danger level: Medium

What is it

Syringomyelia is damage to the spinal cord caused by a fluid-filled area (a cyst, which is called a syrinx). The syrinx usually appears first in the neck, and later extends upwards or downwards – putting pressure on other areas of the spinal cord.

Who gets it

Syringomyelia is not common – the frequency in the US is 8.4 cases per 100,000 people. The disease usually appears around the ages of 20-40, and men get it more than women.

What causes it

The fluid inside the syrinx is called Cerebro-Spinal Fluid (CSF) – this fluid can be found normally around and inside the brain and spinal cord. A syrinx is formed when there is a problem with the circulation of this fluid so there’s too much of it in a specific area inside the spinal cord. This might happen for several reasons, including birth defects (which are the most common reason), trauma to the spinal cord (like in the House episode), a tumor in the spine or inflammation of the spine.

How does it feel

The symptoms usually develop slowly and appear gradually:

• Muscle problems, including muscle weakness in the arms and legs, loss of muscle mass and contractions or muscle-spasm in the legs.
• Sensory problems – decreased sensations (of pain, temperature and touch), numbness or pain. These problems are more common in the neck, shoulders, arms and trunk (a “cape-like” pattern).
• Headaches.
• Problems with bowel and bladder function.

How is it discovered

If you have symptoms of syringomyelia, the doctors will start with a neurological exam (checking muscle strength and sensation) which will help them to estimate where the problem which causes the symptoms is located. In order to prove that there is a syrinx and show it, the doctor will perform an MRI of the spinal cord.

An MRI of syringomyelia. The syrinx is the white area inside the gray spinal cord. Photo by Cyborg Ninja

How is it treated

When there are symptoms, the treatment is surgery to drain the fluid from the syrinx. Sometimes a tube is inserted for continuous draining. After surgery, physiotherapy can help restoring function in the damaged muscles. If there are no symptoms, treatment is not necessary.

What happens after treatment

The surgery stops the progression of the syrinx so new symptoms will not appear. Also, about half of the patients report significant improvement in the symptoms they had.

Without treatment the disease gets worse and worse and eventually causes severe disabilities.

The bottom line – how do I avoid it

There is no way to prevent syringomyelia – the most important thing is to catch it on time before the symptoms cause disabilities.

Related posts:

1. As Seen on Grey’s Anatomy – Tethered Spinal Cord Syndrome
2. Teratoma–When You Can Find Teeth and Hair Inside Your Body (As Seen on House MD)
3. As Seen on Grey’s Anatomy – Normal Pressure Hydrocephalus (NPH)