Aplastic anemia

Aplastic anemia is clinical syndrome, characterized by a hypoplastic bone marrow in the setting of pancytopenia. The pathogenesis of aplastic anemia is damage to the pluripotent stem cell reserves of the bone marrow, which leads to profound low white blood cell, red blood cell, and platelet counts.

Patterns of aplastic anemia include:

• Hereditary
• Drug-induced
• Radiation
• Infection
• Idiopathic

Hereditary forms of aplastic anemia

Fanconi's anemia is the most common hereditary aplastic anemia. Genes involved in DNA mismatch repair have been implicated in Fanconi's anemia, and aplastic anemia usually takes place before adulthood.

Drugs and aplastic anemia

Clinicians will avoid drugs associated with aplastic anemia unless there is no better choice, which is indeed the case. Not all drugs carry the same risk, and thus are more likely to be used. In the list below, for example, there are usually alternatives to chloramphenicol, but most anticonvulsants are on the list:

• Phenylbutazone
• Chloramphenicol
• Gold
• Sulfonamides
• Sulfonylureas, such as glipizide
• Felbamate
• Carbamazepine
• Valproic acid
• Phenytoin
• Nifedipine
• Ticlopidine
• Clopidogrel
• Penicillin
• Allopurinol
• Furosemide

Radiation-induced aplastic anemia

Acute radiation syndrome with a single exposure to 5 Gy of radiation energy will kill 50 percent of recipients, due to irreversible injury to hematopoeitic stem cells.