Secondary aplastic anemia

Alternative names:

acquired aplastic anemia; anemia - secondary aplastic

Definition:

A failure of the blood-cell forming capacity of the bone marrow that affects all blood-cell types

Causes, incidence, and risk factors:

Secondary aplastic anemia is a condition that is a result of injury to the stem cell, a cell that gives rise to other blood cell types when it differentiates. Consequently, there is a reduction in all types of blood cells with this anemia: red blood cells, white blood cells, and platelets (which is called pancytopenia).

Causes of secondary aplastic anemia include chemotherapy, drug therapy to suppress the immune system, radiation therapy, toxins such as benzene or arsenic, drugs, pregnancy, congenital disorders, infectious hepatitis, and systemic lupus erythematosus. The cause may be unknown, and is then referred to as idiopathic aplastic anemia.

Symptoms arise as a consequence of bone-marrow failure. Anemia (a low red blood cell count) leads to fatigue and weakness. A low white blood cell count (neutropenia) causes an increased risk of infection. A low platelet count (thrombocytopenia) results in bleeding of the mucus membranes, internal organs, and skin. The disease may be acute or chronic and is always progressive. The risk factors are unknown. The incidence is 4 out of 100,000 people.