Idiopathic aplastic anemia

Alternative names:

anemia - idiopathic aplastic

Definition:

A failure of the bone marrow to properly form all types of blood cells.

Causes, incidence, and risk factors:

Idiopathic aplastic anemia is a condition that results from injury to the stem cell, a cell that gives rise to other cell types when it divides. Consequently, there is a reduction in all cell types--red blood cells, white blood cells and platelets--with this type of anemia, which is called pancytopenia. The cause of idiopathic aplastic anemia is unknown, but is thought to be an autoimmune process (when the body reacts against its own cells). Causes of other types of aplastic anemia may be chemotherapy, radiation therapy, toxins, drugs, pregnancy, congenital disorder, or systemic lupus erythematosus.

Symptoms arise as the consequence of bone marrow failure. Anemia (low red blood cell count) leads to fatigue and weakness. Low white blood cell counts, or neutropenia, causes an increased risk of infection. Low platelet counts, or thrombocytopenia, results in bleeding of mucus membranes and skin. The disease may be acute or chronic, and is always progressive. Risk factors are unknown. The incidence is 2 out of 1 million people.