Postoperative Fever Quiz

Postoperative Fever: Causes, Timing, and Differential Diagnosis

• Postoperative fever is common and can pose a diagnostic challenge for the care team.
• Fever is defined as 38°C (100.4°F) or higher, but this can vary between hospitals and units.
• Most early postoperative fever is caused by the inflammatory stimulus of tissue damage and exposure to foreign materials that occurs during surgery.
• Infections related to the surgical procedure are more common starting on postoperative day 4, but the differential diagnosis also includes noninfectious conditions.
• It is important to consider a broad differential and not to assume that fever is due to infection.
• Fever as a manifestation of infection may be reduced or absent in immunocompromised patients.
• The timing of fever after surgery is one of the most important factors to consider in generating a differential diagnosis.
• The differential diagnoses of infectious and noninfectious causes of fever are categorized into immediate postoperative, early postoperative, late postoperative, and delayed.
• Immediate postoperative fever has its onset in the operating suite or within hours after surgery and can be caused by inflammation, trauma or burn-induced inflammation, immune-mediated reactions to medications or blood products, malignant hyperthermia, or infections predating the operation.
• Self-limited "physiologic" fever is common following most major surgeries and is caused by inflammatory pyrogenic cytokine mediators.
• The magnitude of tissue trauma correlates with the degree of the fever response, and laparoscopic cholecystectomy is associated with less trauma and fewer episodes of postoperative fever compared with open cholecystectomy.
• Bacterial endotoxins and exotoxins can also stimulate cytokine release and cause postoperative fever, and elevated levels of bacterial DNA have been demonstrated with polymerase chain reaction testing.