Investigating neutropenia

Neutropenia is a reduction in the absolute number of neutrophils in the peripheral blood compared with a healthy subject matched for age, sex, physiological status and ethnic origin. Appropriate reference ranges are necessary to avoid misdiagnosis, as infants and children have lower counts than adults; certain races, particularly Africans, have lower counts than Caucasians. Neutropenia may be an isolated finding or associated with other significant pathology. In its severest forms, it predisposes to recurrent bacterial infection, which may be life-threatening or even fatal. Investigation to determine the cause of neutropenia is important for the identification and treatment of any primary pathology and also for prognosis and appropriate management of any underlying syndrome. Rapid identification of an idiosyncratic drug reaction is essential, as this is a serious disorder with significant mortality. The mainstay of treatment for persistent neutropenia is antibiotics, which should be given promptly at early signs of infection but may also be needed prophylactically. Granulocyte colony-stimulating factor has been used to increase the neutrophil count in a wide variety of neutropenic conditions.