Fever in a critically ill patient

Etiologies

• Non-infectious
  • Acalculous cholecystitis
  • Acute myocardial infarction
  • Adrenal insufficiency
  • Atelectasis
  • Blood product transfusion
  • Cytokine release syndrome
  • Dressler syndrome
  • Drug fever
  • Fat emboli
  • Fibroproliferative phase of acute respiratory distress syndrome
  • Gout
  • Heterotopic ossification
  • Immune reconstitution inflammatory syndrome
  • Intracranial hemorrhage
  • Jarisch-Herxheimer reaction
  • Malignant hyperthermia
  • Neuroleptic malignant syndrome
  • Nonconvulsive status epilepticus
  • Pancreatitis
  • Pulmonary embolism
  • Pneumonitis without infection
  • Serotonin syndrome
  • Stroke
  • Thyroid storm
  • Transplant rejection
  • Tumour lysis syndrome
  • Venous thrombosis
  • Withdrawal from certain substances including alcohol, opiates, barbiturates, benzodiazepines

Investigations

• Invasive central temperature measurement, if possible, or else oral or rectal preferred over axillary or tympanic
• Routine chest x-ray
  • If abnormal, bedside chest ultrasound for pleural effusion, parenchymal disease, or interstitial lung disease
• Routine COVID testing, when transmission is high
• If recent abdominal, pelvic, or thoracic surgery, CT of surgical site
• If recent abdominal surgery or if localizing abdominal signs or symptoms, ultrasound of the abdomen
• If still undiagnosed after routine investigations, consider PET/CT if stable enough
• If central line, simultaneous CVC (at least 2 lumens) and peripheral blood cultures
• If suspected respiratory source, multiplex PCR for respiratory pathogens
• If pyuria and suspected UTI, replace catheter and get fresh urine culture
• If low suspicion of bacterial infection and no clear focus of infection, consider procalcitonin and C-reactive protein

Management

• Avoid routine use of antipyretics for temperature alone (can continue to use for comfort)

Further Reading

• SCCM and IDSA Guidelines for Evaluating New Fever in Adult Patients in the ICU. Crit Care Med. 2023;51(11):1570-1586. doi 10.1097/CCM.0000000000006022