Immediate Management: Examine the Surgical Wound (Answer C)
On postoperative day 4 following sigmoid resection, the immediate next step is to examine the surgical wound, as fever at this timepoint is equally likely to be caused by a surgical site infection as any other source, and wound inspection is the most critical initial diagnostic maneuver. 1, 2
Rationale for Wound Examination First
Fever occurring after 96 hours (day 4) post-surgery shifts the probability significantly toward infectious causes rather than benign inflammatory response, with surgical site infections becoming equally likely as other infection sources at this timepoint 1, 2
The Infectious Diseases Society of America mandates removing surgical dressings to inspect wounds when new or persistent fever occurs days after surgery 2
For sigmoid resection specifically, wound examination is the priority because gastrointestinal tract operations carry higher risk for polymicrobial surgical site infections involving both aerobic and anaerobic bacteria 2
What to Look for During Wound Examination
The Infectious Diseases Society of America recommends inspecting the surgical incision thoroughly for the following signs 1, 2:
- Purulent drainage (obtain Gram stain and culture immediately if present)
- Spreading erythema (measure extent from incision)
- Induration, warmth, tenderness, or swelling
- Any necrosis (requires immediate intervention)
If erythema extends >5 cm from the incision with induration, or if any necrosis is present, immediate intervention is required with opening of the suture line, empiric antibiotics, and dressing changes 1, 2
When to Obtain Blood Cultures
Blood cultures should be obtained when temperature ≥38°C is accompanied by systemic signs of infection beyond isolated fever, such as hemodynamic instability, altered mental status, or signs of bacteremia/sepsis 1, 2
The yield of blood cultures increases significantly only if there are signs of bacteremia or sepsis beyond isolated fever 3
Blood cultures are not the immediate first step unless the patient shows systemic signs of severe infection 1
When to Order Chest X-Ray
Chest X-ray is not mandatory on day 4 if fever is the only indication 2
Chest radiograph becomes indicated only if respiratory symptoms develop 1, 2
Within the first 72 hours post-surgery, chest X-ray is generally unnecessary for isolated fever, and this principle extends to day 4 unless respiratory symptoms are present 1
Empiric Antibiotic Selection (If Wound Infection Confirmed)
For sigmoid resection with confirmed surgical site infection, the Infectious Diseases Society of America recommends empiric coverage for both aerobic and anaerobic bacteria 1, 2:
- Cephalosporin + metronidazole
- Levofloxacin + metronidazole
- Carbapenem
Common Pitfalls to Avoid
Assuming atelectasis without investigation - atelectasis should be a diagnosis of exclusion and is vastly overdiagnosed as a cause of postoperative fever 3, 4
Starting empiric antibiotics before obtaining appropriate cultures - this compromises diagnostic accuracy 3
Delaying wound inspection because other findings are unremarkable - isolated fever on day 4-5 after gastrointestinal surgery mandates wound examination 3
Ordering extensive fever workup (chest X-ray, blood cultures, urine cultures) before examining the wound - this wastes resources and delays diagnosis 1, 5
Red Flags Requiring Immediate Escalation
Immediate escalation of care is required if the patient develops 2, 3:
- Hemodynamic instability
- Signs of severe infection or sepsis
- Respiratory compromise
- Altered mental status
- Persistent fever beyond 48-72 hours despite appropriate therapy