agranulocytos

Agranulocytosis is a severe form of neutropenia characterized by an extremely low number of neutrophils, a key type of white blood cell that helps defend against bacterial infections. It is commonly defined by an absolute neutrophil count (ANC) below 500 cells per microliter of blood, though some definitions use an ANC below 1000 cells/µL with infection risk.

The condition may be drug-induced, autoimmune, infectious, or due to bone marrow disorders. Many cases are linked to medications such as clozapine, carbamazepine, methimazole or propylthiouracil, dapsone, and certain antibiotics or chemotherapy. The underlying mechanisms include direct suppression of myeloid precursors in the bone marrow or immune-mediated destruction of neutrophils. Other causes include radiation, nutritional deficiencies, congenitally inherited disorders, and severe infections.

Clinical features typically include fever and signs of infection, such as a sore throat, mouth ulcers, or pneumonia, with rapid progression because neutrophil-mediated defenses are compromised. Diagnosis relies on a blood count showing a markedly reduced ANC, often alongside a recent exposure to a potential offending drug.

Management requires prompt action: stop the suspected offending agent and, in febrile patients or those with suspected infection, initiate broad-spectrum antibiotics without delay. Supportive care may include isolation and, in some cases, administration of granulocyte colony-stimulating factors to shorten the neutropenic period. Prevention hinges on careful monitoring in high-risk therapies (for example, regular blood counts during clozapine treatment) and avoiding re-exposure after an agranulocytosis event. Prognosis improves with rapid recognition and treatment.