Neutropenic Sepsis
An oncological emergency requiring antibiotics within one hour — recognition, risk stratification and management
Neutropenic sepsis is a medical emergency occurring in patients with cancer whose neutrophil count has fallen below 0.5 x10⁹/L following chemotherapy. It carries a mortality exceeding 50% without prompt treatment. NICE NG51 mandates that empirical intravenous antibiotics must be given within one hour of presentation — this standard saves lives.
What is Neutropenic Sepsis?
Neutropenic sepsis occurs when the bone marrow suppression caused by chemotherapy leaves the body unable to mount a normal immune response to infection. Neutrophils are the primary defence against bacterial and fungal pathogens, and their depletion creates a window of extreme vulnerability. The condition is defined as a temperature of 38°C or above, or other signs consistent with clinically significant sepsis, in a patient whose absolute neutrophil count is at or below 0.5 x10⁹/L. Even mild symptoms should be treated as a potential emergency in this context. Gram-negative bacteraemia (particularly Escherichia coli, Klebsiella, and Pseudomonas aeruginosa) remains the most common cause, though gram-positive organisms from central line infections and fungal infections in prolonged neutropenia are increasingly recognised.
Recognition and Risk Stratification
Any patient undergoing or recently having completed chemotherapy who presents with fever or feeling unwell should be assessed for neutropenic sepsis immediately. Full blood count, blood cultures (from peripheral vein and from each lumen of any central line), and a clinical assessment of the infection source must be completed without delay. Risk stratification using the MASCC (Multinational Association for Supportive Care in Cancer) score or CISNE score guides whether patients can be safely managed as outpatients with oral antibiotics (MASCC ≥21, clinically stable, reliable follow-up) or require hospital admission with IV antibiotics. High-risk features include hypotension, active bleeding, altered mental state, respiratory compromise, dehydration, and neutrophil count below 0.1 x10⁹/L.
Emergency Management Principles
The single most important intervention is the administration of empirical broad-spectrum intravenous antibiotics within one hour of presentation. NICE NG51 is explicit on this standard and trusts must have clear pathways to achieve it. Piperacillin/tazobactam is the first-line empirical agent in most UK centres. Delay in antibiotic administration is directly associated with increased mortality. Blood cultures should be taken before antibiotics but must never delay the antibiotic dose. Patients with haemodynamic instability require immediate IV fluid resuscitation and ITU referral. At 48 to 72 hours, a careful evaluation of clinical response, culture results, and microbiological sensitivities allows rationalisation or escalation of the antibiotic regimen according to antimicrobial stewardship principles.
Prevention and Patient Education
NICE NG51 mandates that all patients starting chemotherapy with a significant risk of neutropenic sepsis must receive written information, verbal explanation, and an alert card before treatment begins. They must know: the temperature threshold (38°C) that requires immediate action, to call 999 or attend A&E immediately without waiting, and never to take paracetamol or antipyretics first (which mask fever and delay diagnosis). G-CSF (granulocyte colony-stimulating factor) prophylaxis is recommended as primary prevention for chemotherapy regimens carrying a greater than 20% risk of febrile neutropenia. Secondary prophylaxis is indicated after a prior episode. Avoiding crowded environments, raw foods, and contact with people with active infections reduces, but does not eliminate, risk during neutropenic periods.