Idiosyncratic Drug-Induced Severe Neutropenia and Agranulocytosis: State of the Art

In this chapter, we report and discuss the diagnosis and management of idiosyncratic drug-induced, or drug-associated, severe neutropenia, and agranulocytosis (neutrophil count of <0.5 × 10 9 /L). In this setting, neutropenia remains a potentially serious adverse event due to the frequency of severe sepsis, with severe deep tissue infections (e.g., pneumonia), life-threatening infections, septicemia, and septic shock in two-thirds of all hospitalized patients. Recently, several poor prognostic factors, impacting the hemato- logical recovery, the duration of hospitalization, and the outcome have been identified that may be helpful when identifying “frailty” patients. These factors include: old age, poor performance status, septicemia or shock, comorbidities such as renal failure, and a neutrophil count below 0.1 × 10 9 /L. recovery. In this situation, modern management, with broad-spectrum antibiotics in case of any sepsis sign and hematopoietic growth factors (HGF) (particularly G-CSF), is likely to improve the prognosis, with a current mortality rate around 5%.