Febrile Neutropenia

Definition

Febrile neutropenia is a potentially life-threatening condition characterized by fever in a patient with an abnormally low neutrophil count, commonly occurring in patients undergoing chemotherapy or with hematologic malignancies.

Epidemiology

• Common complication in patients receiving cytotoxic chemotherapy (10–50% depending on regimen)
• Higher risk in hematologic malignancies than solid tumors
• Incidence increases with advanced age and comorbidities
• Associated with increased morbidity, prolonged hospitalization, and mortality (5–20%)
• More frequent in patients with prolonged or profound neutropenia (<500/µL)

Etiology

• Chemotherapy-induced myelosuppression is the most common cause
• Hematologic malignancies causing marrow suppression
• Bone marrow transplant recipients
• Immunosuppressive therapy (corticosteroids, biologics)
• Infections by bacteria, viruses, fungi, or rarely parasites; often bacterial in origin (Gram-negative rods, Gram-positive cocci)

Pathophysiology

• Cytotoxic therapy or disease suppresses bone marrow, reducing neutrophil production
• Neutropenia impairs innate immune response, decreasing ability to control infections
• Even minor infections can rapidly progress due to impaired host defense
• Fever may be the only sign of infection due to blunted inflammatory response
• Rapid escalation of infection can lead to sepsis, multi-organ failure, and death if untreated