Incidence, etiology and bone marrow characteristics of non-chemotherapy-induced agranulocytosis

Agranulocytosis is a rare but fatal condition. The majority of cases are associated with drugs. However, in-patient incidences and the relationship between clinical outcomes and bone marrow characteristics have not been established.

We conducted a retrospective study in a university hospital. A total of 38 in-patients diagnosed with agranulocytosis were analyzed.

The average incidence of agranulocytosis in Songklanagarind Hospital between 1993 and 2007 was 0·98 cases per 10 000 admissions per year. Antimicrobial agents were the most common etiology (63% of patients) and antithyroid agents were the second most common (13·6%). Two patterns of bone marrow were noted: type I was characterized by a left-shifted granulopoiesis and type II was recognized as having hypocellular bone marrow with markedly reduced granulocyte precursors. A significantly higher mortality was associated with type II.

Antimicrobial agents are the most common cause and the rare granulocyte precursors in bone marrow are associated with higher mortality rates.