2007-02-13T17:25:00.000+07:00

Anemia

Summary
Anemia is a lack of red blood cells and/or the iron-rich molecule (hemoglobin) in red blood cells. Hemoglobin carries oxygen throughout the body and gives blood its red color. There are more than 100 different types of anemia, including sickle cell anemia. Many forms of anemia can be successfully treated, depending on the underlying cause. If left untreated, certain forms of anemia may be debilitating or even life-threatening. In many cases, anemia is one of the the signs of another illness and is not the primary problem.
Anemia means the body's tissue is not getting sufficient oxygen. As a result, an anemic person may experience fatigue, headaches, weakness, rapid pulse and shortness of breath. Occasionally, the individual may have jaundice causing a yellowing of the skin or the whites of their eyes.The most common initial method for diagnosing anemia is a blood test known as a complete blood count (CBC).
Severe anemia has been associated with various forms of cancer, including cancers of the digestive system and bone marrow. The condition can occur due to bleeding or because the cancer interferes with the body’s ability to make red blood cells. Some leukemias, lymphomas and metastatic cancers may cause anemia when cancer cells crowd out healthy blood cells.
Anemia is more often a side effect of chemotherapy and radiation therapy, which can destroy red blood cells as well as cancer cells. Certain medications can be prescribed to help increase the body’s production of red blood cells. In some cases, blood transfusions or a bone marrow transplant may be necessary.
Preventing anemia that is caused by an iron or vitamin deficiency may be as simple as a change of diet or adding supplements. But this may not be the case for individuals who are undergoing chemotherapy or radiation treatments. Their anemia may last as long as their treatments continue. Some degree of anemia may be present for many weeks or even months after cancer treatment has been completed
Other forms of anemia, such as sickle cell anemia, are genetic. These types of anemia cannot be prevented and remain with a person for life. Medications or iron supplements do not improve the quality or quantity of the red blood cells in individuals with genetic anemias.

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About anemia
Anemia occurs when the number of red blood cells in the body drops below normal levels. The function of red blood cells is to carry oxygen throughout the body and to remove carbon dioxide. Hemoglobin is the protein molecule in red blood cells that carries the oxygen and gives blood its red color. If the body does not have enough oxygen, the muscles and organs cannot function properly, which can lead to fatigue and other symptoms of anemia.
Red blood cells are produced in the bone marrow, which is the soft, inner part of the bones. Besides red blood cells, the bone marrow produces white blood cells, which are part of the immune system, and platelets, which help repair damaged blood vessels.
The average normal blood hemoglobin level for adults for men is 14 to 17 grams/deciliter (g/dL) and 12 to 15 g/dL for women. Anemia may be defined as a blood hemoglobin level under 12 grams/deciliter. However, many individuals do not experience symptoms of anemia until their hemoglobin level drops below 10 g/dL especially if the decline has been gradual over weeks to months.
Anemia is not always a primary disease but can be a sign of another disease process. It can be either chronic (developing over a long period of time) or acute (rapid onset). While anemia can be linked to more than 100 causes, the three basic reasons for the condition are:
• The body is losing red blood cells (bleeding)
• The body is not producing enough red blood cells
• The body’s red blood cells are being destroyed (e.g. antibodies, chemicals)
Anemia can affect individuals at any point in their lives. Hereditary forms of anemia may affect infants at birth and continue through life. It is not uncommon for teenagers to develop anemia due to their rapid growth spurts, which are accompanied by an increased demand for all types of nutrients, including iron. Women in their childbearing years have an increased risk of anemia due to increased demands for iron during pregnancy and as a result of monthly menstruation (blood loss), both of which can lead to iron-deficiency anemia.
Anemia can be caused by several different types of cancer for a number of reasons. For example, anemia can be the result of blood loss due to internal bleeding, a common problem associated with digestive system cancers. Also, most forms of leukemia affect the bone marrow, as do cancers that metastasize to the bone marrow. When this happens, the blood-producing marrow is compromised and the number of blood cells drops.
Moreover, anemia can arise when cancer interferes with the organs involved in maintaining proper blood levels, such as the kidneys or spleen. In addition, people who have active cancer for some time tend to develop what is known as “anemia of chronic disease.” This is due to decreased production of red blood cells.

While anemia can be caused directly or indirectly by cancer, often it is the result of cancer treatments. At times, cancer treatment can require major surgery. With any type of major surgery, there is always a risk for significant blood loss, resulting in anemia. In severe cases, blood transfusions may be recommended.
In addition to surgery, treatments such as chemotherapy can also lead to anemia. Chemotherapy drugs target rapidly producing cells, including those in the bone marrow that are responsible for making new blood cells. The use of chemotherapy can lead to a low number of blood cells. Anemia in these cases may develop over time and will be closely monitored by healthcare professionals.
For some advanced forms of cancer, more aggressive treatments are used, including bone marrow transplants (BMT) or peripheral blood stem cell transplants (PBSCT). In these cases, patients are given high doses of chemotherapy, possibly in combination with radiation therapy. The treatment effectively destroys nearly all of the bone marrow and halts blood cell production. Some patients undergoing BMT or PBSCT may need blood transfusions.
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Types and differences of anemia
There are many types of anemia and each type has its own cause and degree of severity. Some of the most common types include:
• Anemia of chronic disease. Several chronic diseases, and sometimes their treatments, can lead to anemia. These chronic conditions include cancer, kidney failure, rheumatoid arthritis and Crohn’s disease, all of which hinder the production of red blood cells.
• Cancer treatments. Radiation therapy and certain types of chemotherapy can affect a patient's bone marrow, which is where red blood cells are made. This can cause the production of these cells to slow or even stop temporarily. Other cancer treatments, such as immunotherapy or bone marrow transplants are also associated with anemia.
• Iron deficiency anemia. This form of anemia is by far the most common. Iron is necessary for the bone marrow to produce hemoglobin. Without this essential mineral, the body fails to produce enough hemoglobin for red blood cells. In addition to food, the usual way for the body to obtain iron is to recycle the iron from blood cells that have died and use it to create new blood cells. Thus, when blood is lost, so is the iron. This process explains why an iron-poor diet, heavy menstrual periods or a growing fetus in a pregnant woman can cause iron deficiency anemia. In men, iron deficiency anemia means that bleeding has occurred somewhere in his body.

• Aplastic anemia. This rare form of anemia occurs in one to two people for every million residents of the United States, according to the American Cancer Society (ACS). It is seen more often in developing countries where there is greater exposure to toxic chemicals. In this form of anemia, the bone marrow does not make blood cells. While aplastic anemia can be a sign of certain cancers that affect bone marrow (such as leukemias), it is not a type of cancer itself. Exposure to chemicals, such as benzene, as well as chemotherapy drugs and radiation treatment, can cause this type of anemia. It can also be a primary immune disease.
• Anemias associated with bone marrow disease. The production of blood in the bone marrow can be affected by a variety of diseases, including leukemia, myelodysplasia (MDS, a pre-leukemia condition), multiple myeloma, myeloproliferative disorders, lymphoma and metastatic cancer. The severity of these types of anemias can range from a mild alteration to a potentially fatal shutdown in the production of blood.
• Vitamin deficiency anemia. In order to produce red blood cells, the body requires vitamin B12, folic acid and other key nutrients. A diet that is lacking in these essential nutrients can lead to decreased production of red blood cells. Intestinal disorders that reduce the amount of nutrients the body can absorb are a common cause of this type of anemia. The category for all vitamin deficiency anemias is megaloblastic anemias. With this group, the bone marrow of affected individuals produces large, irregular red blood cells (megablasts).
• Hemolytic anemias. This group of anemias develops when red blood cells are abnormally destroyed within the body. Autoimmune diseases and certain blood disorders can cause hemolytic anemias. Some medications, including antibiotics, can also break down red blood cells causing this condition.
• Sickle cell anemia. More than 70,000 Americans have sickle cell anemia, making it the most common inherited blood disorder in the United States, according to the National Institutes of Health (NIH). This condition disproportionately affects African Americans at a rate of one out of every 500. Sickle cell anemia is an inherited disease marked by a chronic shortage of red blood cells due to a defective form of hemoglobin.
• Idiopathic anemia. Despite their best efforts, physicians are sometimes unable to determine the cause of anemia in a patient. These cases are labeled idiopathic anemias. These patients should be followed at regular intervals for delayed manifestations of a cancer or other cause of anemia.
There are many other types of anemia which affect a smaller number of people and have an abnormal forn of hemoglobin. Thalassemia is one example of an inherited blood disorder that causes mild to severe anemia. This blood disorder is found among individuals of Mediterranean descent, such as Italians and Greeks. These hereditary anemias are called hemoglobinopathics.
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Diagnosis methods for anemia
Anemia is a condition caused by a shortage of hemoglobin in the blood. Hemoglobin is the part of a red blood cell that transfers oxygen from the lungs to the bodily tissues. Anemia is defined as a blood hemoglobin level under 12 grams/deciliter (g/dL). However, many individuals do not experience symptoms of anemia until their hemoglobin level drops below 10 g/dL. The slower the drop in hemoglobin, the more delayed is the onset of the symptoms. Anemia can be caused by the cancer itself because of the immune system’s response to the cancer cells. It also may be caused by cancer treatments that can deplete the body’s oxygen supply.
Anemia can be diagnosed with a complete blood count (CBC). A CBC is a test that measures the levels of red blood cells, white blood cells and platelets in a person’s blood. Patients undergoing chemotherapy or radiation therapy will have their blood sampled on a regular basis to monitor the effects on the blood cells. Bone marrow samples may also be taken to monitor blood cell production.
Treatment methods for anemia
Treatment for anemia is directed at the underlying cause. If the anemia is caused by a specific deficiency, it may be treated with supplements, injections of specific vitamins and/or increased intake of nutrient-rich foods. In iron deficiency anemia, all efforts should be made to find the source of the blood loss.
Anemia that is the result of cancer treatment is common and usually temporary. However, some types of treatments may be necessary until the body is able to produce sufficient levels of its own blood cells.
A physician may prescribe certain drugs that can help the patient’s body increase its red blood counts, which may in turn improve energy levels. The medication, which can take several weeks to work, mimics certain biochemicals that signal the bone marrow to produce blood cells. They may not be prescribed when the anemia is not severe. For instance, chemotherapy affects the production of blood cells gradually and the body has some time to adjust. Good medical practice and cost considerations reserve these drugs for lower hemoglobin levels.
Blood transfusions may be necessary in more urgent cases, such as due to sudden loss of blood (which can occur with certain cancers) or due to leukemia. In addition, transfusions may be given when a patient has other conditions that make a person more sensitive to anemia (e.g., heart disease), or if anemia symptoms are more severe.
A transfusion carries some risks, such as possible infections or reactions. A physician will consider the severity of the anemia as well as the overall health of the patient when considering a blood transfusion.
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Prevention methods for anemia
Prevention methods for anemia depend on the type and cause of the condition. For those who are undergoing chemotherapy or radiation treatments, the anemia may last as long as the treatments continue. Some cancer patients report anemia-related fatigue lasting for several weeks or possibly months after the completion of their treatments.
If anemia is caused by a vitamin or mineral deficiency, prevention can be as simple as eating a well-balanced diet that includes a wide variety of nutritious vegetables, including:
• Green leafy and cruciferous vegetables
• Fresh and dried fruits (e.g., raisins)
• Grains (e.g., iron-fortified cereals)
• Lean red meats
• Eggs
• Dried beans
For those who require an iron supplement, it is best to take it with vitamin C (as a supplement or a glass of orange juice) since vitamin C can help boost iron absorption. When taking iron supplements, it is best to avoid drinking tea with the supplement since this popular drink contains tannin. Tannin has been shown to reduce the body’s ability to absorb iron from the supplement or from food. Milk and antacids are also implicated in reducing the body’s absorption of iron. It may be best to not drink milk at the same time as iron-rich foods or supplements.
Patients who are anemic should not attempt to self-treat with iron supplements. In many cases, people are told they cannot donate blood because they are anemic, and there is a popular misconception that they should start taking iron. This misconception is dangerous because too much iron can damage vital organs such as the heart.
In addition, iron supplements do not treat all types of anemias and in some cases may cause damage as with certain genetic anemias. In some people, taking supplements can mask the signs of more dangerous underlying conditions. People who think they are anemic should consult with their healthcare provider before taking any iron supplements. The exact cause of anemia should be determined before a treatment plan is established.

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Questions for your doctor about anemia
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about anemia:
1. What could be causing my anemia?
2. What type of anemia do I have?
3. How severe is my anemia?
4. What is the best treatment for my condition?
5. Can I use iron supplements?
6. How often will I need blood tests to monitor my condition?
7. Am I likely to become anemic during my cancer treatments?
8. How will I know if my anemia requires immediate attention?
9. Is there a point where I may need blood transfusions?
10. Is there any way to prevent anemia during my treatments?
11. How long can I expect to be anemic?
12. If my anemia is inherited, what are the chances that I will pass it on to my children?
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