Agranulocytosis: causes, symptoms, diagnosis and treatment

Characteristics and diagnosis

Routine blood tests show a reduced total white blood cell count and, specifically, a low absolute neutrophil count (ANC). Mild neutropenia is usually defined at ANC below 1,500 cells/µL and severe neutropenia at ANC below 500 cells/µL. Diagnosis combines the laboratory count with clinical features such as fever and signs of infection. Basic anatomic terms: granulocytes contain cytoplasmic granules that enable microbial killing and are distinguished from other leukocytes by their appearance under the microscope (cytoplasm).

Causes

• Drug-induced toxicity is a leading cause; many medicines — for example some antithyroid drugs, certain antibiotics, antipsychotics and chemotherapy agents — can suppress granulocyte production.
• Autoimmune disorders and bone marrow failure syndromes can destroy granulocyte precursors or impair their development.
• Severe infections, viral illnesses, radiation exposure and rare congenital forms are other recognized causes.

Symptoms, complications and management

Common early symptoms include fever, sore throat, mouth ulcers and rapidly spreading or unusual infections. Because signs may be muted, any fever in a person with known neutropenia is an emergency. Management priorities are immediate evaluation, stopping any suspected causative drug, prompt empirical broad‑spectrum antibiotics for fever, protective isolation when indicated, and supportive care. In many cases hematopoietic growth factors such as G‑CSF are used to accelerate neutrophil recovery.

Prognosis and public health importance

The outlook depends on cause, speed of recognition, and underlying health. Drug‑related cases often recover after discontinuation of the offending agent, while marrow failure or chemotherapy‑related agranulocytosis can require prolonged support. Because of the risk of fatal infection, clinicians treat agranulocytosis as a potentially life‑threatening condition needing urgent care.

History, terminology and further reading

The name agranulocytosis derives from Greek roots: a‑ (without), granulocyte (cells with cytoplasmic granules), and -osis (condition). For concise overviews and clinical guidelines see authoritative resources: general overview, white cell physiology, and specialist summaries at hematology references diagnosis, cell biology and neutrophil function.