Secondary aplastic anemia results from injury to stem cells. Normal stem cells divide and differentiate into all blood cell types. Thus, when stem cells are injured, there is a reduction in red blood cells, white blood cells, and platelets. This condition can be caused by chemotherapy, drug therapy to suppress the immune system, radiation therapy, toxins such as benzene or arsenic, drugs, pregnancy, and congenital disorders. When the cause is unknown, it is then referred to as idiopathic aplastic anemia. The disease may be acute or chronic and is usually gets worse unless the cause is removed.
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