You are in Medical Library . 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. 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.
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. A physical examination may reveal enlarged spleen , tenderness of the sternum, and an irregular heart rate . A CBC shows low hematocrit and hemoglobin levels.