Aplastic anemia is a blood disorder in which the body’s bone marrow doesn’t make enough new blood cells to replenish older blood cells. Typically, anemia refers to low red blood cell counts, but aplastic anemia patients have lower counts of all three blood cell types: red blood cells, white blood cells and platelets (pancytopenia). Aplastic anemia is also called bone marrow failure, because bone marrow is the source of blood cell production. Aplastic anemia can be moderate, severe or very severe. People with severe or very severe aplastic anemia are at risk for life-threatening infections or bleeding.
Although aplastic anemia can appear at any age and in any race or gender, it is diagnosed more often in children and young adults and is more likely to strike Asian-Americans. Each year, between 600 and 900 people in the U.S. are diagnosed with aplastic anemia.
It is generally considered to have no known cause, but is sometimes the result of an autoimmune disorder in which white blood cells attach the bone marrow. Rare risk factors may include exposure to chemicals such as benzene or drugs such as chlorampenicol, carbamazepine, felbamate, phenytoin, quinine and pheynylbutazone. Exposure to ionizing radiation from radioactive materials is also associated with the development of aplastic anemia. Marie Curie, famous for her pioneering work in the field of radioactivity, died of aplastic anemia after working unprotected with radioactive materials over a long period of time; damaging effects of ionizing radiation were not then known. Aplastic anemia is also present in up to 2% of patients with acute viral hepatitis.
Diagnosis can only be confirmed by bone marrow biopsy.
Although very mild cases of the disease may resolve on their own (relapses are common), untreated aplastic anemia generally leads to rapid death, typically within six months. When it is diagnosed correctly and treatment begun promptly, survival rate for the next five to ten years is substantially improved, with many patients living well beyond that time.
Treatments for aplastic anemia may include blood transfusions, suppression of the immune system through multiple daily medications, mild chemotherapy, antibody therapy and, in more severe cases, bone marrow transplants. A bone marrow stem cell transplant will replace failing bone marrow stem cells with healthy donor cells capable of producing all three blood cell lines, giving the patient a constant source of new blood cells and a new immune system.