Neutropenia: causes and consequences

Neutrophils play a critical role in the acute inflammatory response and host-defenses against bacterial infections. Neutropenia, a deficiency of these cells, predisposes to infection, chiefly by organisms resident on body surfaces. The risk of infection is greatest with severe neutropenia, defined by an absolute blood neutrophil count (ANC) less than 0.5 x 10(9)/L. Severe chronic neutropenia, lasting for more than a few weeks, can be caused by congenital marrow defects, as well as intrinsic and acquired disorders. Evaluation of patients begins with confirmation of neutropenia and examination of a blood smear. A careful review of the patient's medical history, family history, and physical examination is extremely important. Most severely neutropenic patients have a history of oral ulcers and inflammation and recurrent skin infections. Examination of a bone marrow aspirate and/or biopsy and cytogenetic testing are primary for diagnostic evaluation.