Neutropenic Sepsis

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Neutropenic sepsis is a life-threatening complication of neutropenia, characterised by fever and systemic infection in patients with an absolute neutrophil count (ANC) <0.5 x 10⁹/L.

Aetiology

  • Chemotherapy-induced: most common cause due to myelosuppression.
  • Haematological malignancies: leukaemia, lymphoma.
  • Bone marrow disorders: aplastic anaemia, myelodysplastic syndromes.
  • Autoimmune conditions: lupus, Felty’s syndrome.
  • Congenital neutropenia: Kostmann syndrome, cyclic neutropenia.

Pathophysiology

  • Neutrophils play a key role in immune defence against bacterial and fungal infections.
  • Neutropenia impairs the body's ability to contain infections, leading to systemic spread.
  • Inflammatory response may be blunted, leading to atypical presentations of sepsis.

Risk Factors

  • Recent chemotherapy or radiotherapy.
  • Prolonged hospitalisation or central venous catheters.
  • Use of immunosuppressants (steroids, biologics).
  • History of recurrent infections.
  • Severe malnutrition.

Signs and Symptoms

  • Fever (≥38°C) or hypothermia.
  • Tachycardia and hypotension.
  • Respiratory distress.
  • Altered mental state in severe cases.
  • Signs of focal infection may be absent due to neutropenia.

Investigations

  • Full blood count (FBC): confirms neutropenia.
  • Blood cultures: at least two sets prior to antibiotics.
  • Lactate: assesses severity of sepsis.
  • CRP/procalcitonin: markers of infection and inflammation.
  • Urinalysis and urine culture: screens for urinary infection.
  • Chest X-ray: identifies pulmonary sources of infection.

Management

1. Immediate Management:

  • Administer broad-spectrum IV antibiotics within 1 hour (e.g., piperacillin-tazobactam or meropenem in high-risk cases).
  • Fluid resuscitation if hypotensive.
  • Monitor vital signs closely (consider ICU if haemodynamically unstable).

2. Further Management:

  • Granulocyte colony-stimulating factor (G-CSF) in select high-risk patients.
  • Antifungal therapy if persistent fever despite antibiotics.
  • Review antimicrobial therapy based on cultures.

3. Referral:

  • Haematology: for chemotherapy-related neutropenia or bone marrow disorders.
  • Infectious diseases: if antibiotic-resistant or atypical infections are suspected.
  • Intensive care: if septic shock develops.
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