Anemia

Anemia refers to a condition that the blood is deficient in red blood cells or hemoglobin. The major function of red blood cells is to transport oxygen to various organs, providing the necessary energy. The hemoglobin is an oxygen-carrying protein in the red blood cell to execute this function. Therefore, without sufficient amount of red blood cells and hemoglobin, the organs would not have enough energy to operate properly.

Symptoms and Diagnosis

The most common symptom for anemia is a feeling of weakness or fatigue. Some patients may also have rapid heart beat, shortness of breath, dizziness or pale skin. Anemia can be diagnosed by complete blood count, particularly the following parameters:

• The number of red blood cells (RBCs).
• The amount of hemoglobin in the blood.
• Mean corpuscular volume (MCV) - the average volume of RBCs.
• Mean corpuscular hemoglobin (MCH) - the average amount of hemoglobin per RBC.
• Red cell distribution width (RDW) - a measure of the variation in RBC sizes.

Causes

There are many types of anemia, with different causes. A few of them are described below.

Iron deficiency anemia. This is the most common type of anemia, affecting about 20% of women and 3% of men in the United States. Its cause is a shortage of iron in the body, because iron is necessary for the production of hemoglobin.

Vitamin deficiency anemia. Folic acid and vitamin B-12 are also required to make sufficient numbers of healthy red blood cells.  Deficiency in these nutrients can reduce red blood cell production, resulting in anemia. This type of anemia is also called megaloblastic anemia.

Anemia of chronic disease. Certain chronic diseases can reduce the body's ability to produce red blood cells. For example, kidneys make a hormone called erythropoietin, which is involved in the production of red blood cells. Kidney failure can then result in deficiency of red blood cells.

Aplastic anemia. This is a rare but life-threatening anemia because the production of all three types of blood cells (red, white and platelets) is reduced. The underlying mechanism is unknown, but it could arise from autoimmune disorder, where the white blood cells attack the bone marrow (the place where new blood cells are produced).

Sickle cell anemia. This is the most common inherited blood disorder in the United States, affecting about 1 in 500 African Americans. It is caused by a defective form of hemoglobin, distorting red blood cells into sickle shapes. The abnormal red blood cells may become trapped within small blood vessels and block them, producing pain and eventually damaging organs.

Treatment

Iron deficiency anemia. This type of anemia can be treated with iron supplements, or eating foods that are rich in iron, such as red meat, fish and liver.

Vitamin deficiency anemia. Deficiency in vitamin B-12 usually happens to someone with pernicious anemia - a type of autoimmune disease. This is treated with B-12 pills or injections. Deficiency in folic acid is treated with its supplements.

Anemia of chronic disease. Treatment for this type of anemia is focused on the underlying disease.

Aplastic anemia. This type of anemia may be treated with blood transfusions to increase red blood cells, bone marrow transplant to make new blood cells, or immune-suppressing drugs to reduce the immune system's response.

Sickle cell anemia. At present, there is no cure for sickle cell anemia. However, pain-relieving drugs, fluids, antibiotics and blood transfusions may be used to treat symptoms and prevent complications. Hydroxyurea, an antitumor drug, has been shown to be effective in preventing pain, since it can prevent sickling.