What is the most likely diagnosis for a post-laparoscopic cholecystectomy patient with fever, tachycardia, leukocytosis, slight wound erythema, and hypotension?

Most Likely Diagnosis: SIRS (Systemic Inflammatory Response Syndrome)

This patient meets criteria for SIRS, which is the most appropriate diagnosis given the constellation of fever (38.6°C), tachycardia (HR 116), leukocytosis, and hypotension (BP 90/60) in the early post-operative period after laparoscopic cholecystectomy. 1

Clinical Reasoning

Why SIRS is the Primary Diagnosis

The patient demonstrates at least 3 of 4 SIRS criteria present within the early post-operative period:

• Fever >38°C (patient has 38.6°C) 2
• Tachycardia >90 bpm (patient has HR 116) 2, 1
• Leukocytosis (documented in presentation) 2
• Hypotension with MAP likely <65 mmHg (BP 90/60 suggests MAP ~70 mmHg, borderline) 1

SIRS is extremely common after laparoscopic cholecystectomy, occurring in approximately 63% of post-surgical patients, and is associated with the inflammatory response to surgery itself rather than necessarily indicating infection. 3

Why NOT Surgical Site Infection (SSI)

SSIs rarely occur within the first 48 hours post-operatively, and fever during this early period usually arises from non-infectious causes. 2 The key distinguishing features against SSI include:

• Minimal wound findings: Only "slight erythema" with no pus formation 2
• Timing is wrong: SSIs typically manifest after 48 hours, and fever before this timeframe is usually non-infectious 2
• Insufficient local criteria: SSI requires purulent drainage, positive culture, or significant local signs requiring surgical opening of the wound 2

If temperature >38.5°C or heart rate >110 bpm with erythema extending >5 cm beyond wound margins, then SSI becomes more likely and would require wound opening plus short-course antibiotics (24-48 hours). 2 This patient's "slight erythema" does not meet this threshold.

Why NOT UTI

No urinary symptoms are mentioned (dysuria, frequency, urgency, suprapubic pain), and UTI would not typically cause hypotension and this degree of systemic response in the immediate post-operative period without other localizing signs. 2

Why NOT Thrombophilia

Thrombophilia is a hypercoagulable state, not an acute clinical syndrome. Pulmonary embolism should be excluded in post-operative patients with respiratory distress and hypoxia, but this patient's presentation with fever and leukocytosis points toward inflammatory response rather than thromboembolic disease. 2

Critical Differential Considerations

Rule Out Life-Threatening Early Complications

In the first 24-48 hours post-cholecystectomy with fever and hypotension, you must aggressively investigate for:

1. Toxic Shock Syndrome (TSS): Rare but critical diagnosis occurring 1-2 days post-operatively with fever, hypotension, and erythroderma caused by toxin-producing Staphylococcus aureus. 4 The "slight erythema" could represent early TSS, though typically TSS presents with more dramatic sunburn-like rash. 2, 4

2. Bile Duct Injury (BDI) with bile leak/peritonitis: The combination of fever, tachycardia, and tachypnea are significant predictors of anastomotic/staple line leak after laparoscopic surgery. 2 Alarm symptoms include persistent abdominal pain, distention, and fever. 2

3. Septic shock: If hypotension persists despite adequate fluid resuscitation with MAP <65 mmHg, this becomes septic shock requiring immediate ICU admission and vasopressor support. 1

Immediate Management Algorithm

Step 1: Assess for progression to septic shock

• Measure MAP precisely (if truly <65 mmHg = septic shock) 1
• Initiate aggressive fluid resuscitation
• Prepare for vasopressor support if hypotension persists 1

Step 2: Investigate for surgical complications

• Obtain abdominal CT to detect fluid collections, biloma, or ductal dilation 2
• Check liver function tests (bilirubin, AST, ALT, ALP), CRP, procalcitonin, lactate 2
• Blood cultures if septic shock suspected 2

Step 3: Examine wound thoroughly

• Look for purulent drainage, extensive erythema (>5 cm), or signs suggesting TSS 2, 4
• If TSS suspected: open wound, culture, begin anti-staphylococcal therapy (vancomycin + clindamycin or linezolid to suppress toxin production) 2

Step 4: Monitor SIRS burden

• Track number of SIRS variables daily over first 4 days 3
• Higher SIRS burden associates with poor outcomes even without infection 3

Common Pitfalls

• Do not dismiss early fever as "normal post-operative" when accompanied by hypotension and tachycardia—this demands investigation 2
• Do not assume SSI based solely on slight erythema in the first 48 hours without purulent drainage 2
• Do not delay imaging if clinical deterioration occurs—bile leaks can rapidly progress to peritonitis and septic shock 2
• Remember that leukocytosis may be diluted by aggressive fluid resuscitation, potentially masking severity 2