Neutropenie

Neutropenia is a condition defined by an abnormally low number of neutrophils, a white blood cell type essential for fighting bacterial and fungal infections. It is typically defined by an absolute neutrophil count (ANC) below 1.5 × 10^9/L, with severe neutropenia often below 0.5 × 10^9/L.

Causes are diverse and include congenital conditions such as Kostmann syndrome and cyclic neutropenia, as well as acquired factors like chemotherapy, infections, autoimmune diseases, nutritional deficiencies, hypersplenism, bone marrow failure, and marrow infiltration by malignancy.

Pathophysiology involves reduced production in the bone marrow, increased destruction or sequestration in the spleen, or abnormal distribution of neutrophils. Because neutrophils have a short circulating life, disturbances in production or consumption can markedly lower the ANC.

Clinical features vary. Many patients are asymptomatic, but the major concern is infection. Febrile neutropenia is a medical emergency and requires prompt evaluation and empiric broad-spectrum antibiotics. Common infection sites include skin, oropharynx, lungs, and indwelling lines.

Diagnosis relies on a CBC with differential to confirm ANC and monitor changes. Evaluation for underlying causes includes review of medications, infections, nutritional status, and autoimmune disease; bone marrow examination is considered if marrow failure or malignancy is suspected.

Management depends on severity and risk. Mild neutropenia without infection may be observed and the underlying cause treated. In high-risk cases, growth factors such as G-CSF can shorten neutropenia. Antimicrobial prophylaxis may be used in selected patients, and infections are treated promptly with appropriate antibiotics.

Prognosis depends on etiology and comorbidity. In cancer patients, prevention of infection through hygiene, vaccination where appropriate, and timely treatment of infections is important for outcomes.