What is the management approach for post-operative fever occurring less than 7 days after surgery?

Management of Postoperative Fever Within 7 Days

For postoperative fever, timing is critical - fever within 48-72 hours is typically benign and self-limiting, while fever after 96 hours warrants thorough investigation for infectious causes. 1

Timing-Based Approach

Early Postoperative Fever (0-72 hours)

• Most fevers occurring within the first 48-72 hours are due to the normal systemic inflammatory response to surgical trauma and are benign 1
• Limited workup is recommended for isolated fever during this period without additional symptoms 1
• The following are NOT routinely indicated if fever is the only symptom:
  • Chest radiograph 2, 1
  • Urinalysis and urine culture 2, 1
  • Wound cultures (without signs of infection) 2, 1
• Daily wound inspection is essential but cultures should only be obtained if signs of infection are present 2, 1

Late Postoperative Fever (72 hours - 7 days)

• Fever persisting beyond 72-96 hours is more likely to represent infection and requires thorough evaluation 1, 3
• By postoperative day 4, fever is equally likely to be caused by a surgical site infection or another infection 1
• Focused evaluation using the "four Ws" mnemonic is recommended:
  • Wind (pulmonary causes: pneumonia, aspiration, pulmonary embolism) 3
  • Water (urinary tract infection, especially with indwelling catheters) 2, 3
  • Wound (surgical site infection) 2, 3
  • What did we do? (iatrogenic causes: drug fever, blood product reaction, IV line infections) 3

Specific Evaluation by Cause

Surgical Site Infections

• Inspect wounds daily for:
  • Purulent drainage
  • Erythema or warmth
  • Tenderness
  • Swelling 2, 1
• Early surgical site infections (1-3 days) are rare but can occur with group A streptococcal or clostridial infections 2, 1
• Surgical site infections account for approximately 25% of costs associated with surgical procedures 2

Urinary Tract Infections

• Common after surgery due to urinary catheterization 2
• Duration of catheterization is the most important risk factor 2
• Urinalysis and culture are indicated for:
  • Patients with indwelling catheters for >72 hours 2
  • Patients with urinary symptoms 2, 1

Pulmonary Causes

• Consider pneumonia, aspiration, or pulmonary embolism 3
• Maintain high suspicion for pulmonary embolism in patients with:
  • Sedentary status
  • Lower limb immobility
  • Malignancy
  • Oral contraceptive use 2, 1
• Atelectasis has traditionally been considered a cause of postoperative fever but should be a diagnosis of exclusion 2, 4

Other Considerations

• Hematoma formation can cause fever 2
• Many emergency abdominal operations are performed for control of infection (e.g., peritonitis) and may take up to 72 hours to defervesce even with appropriate treatment 2
• Drug fever and reactions to blood products should be considered in the differential diagnosis 3

Common Pitfalls to Avoid

• Overinvestigating early postoperative fever (within 48 hours) when it's likely a normal inflammatory response 1, 3
• Attributing fever to atelectasis without excluding other causes 2, 4
• Failing to inspect surgical wounds daily 2, 1
• Delaying evaluation of fever that persists beyond 96 hours 1
• Unnecessary antibiotic use for non-infectious causes of fever 5, 6

Evidence Limitations

• Studies show that fever, even up to the seventh postoperative day, may not reliably distinguish between infection and general inflammation in clean orthopedic surgery 5
• Some patients may have postoperative infections without fever as a clinical sign 6