What is the most appropriate initial management for a 64‑year‑old man with severe left lower quadrant abdominal pain, bloody diarrhea, anorexia, guarding, and a 2 cm × 2 cm pericolic collection in the sigmoid colon on CT?

Management of Perforated Sigmoid Diverticulitis with Small Pericolic Abscess

This patient requires urgent laparotomy with sigmoidectomy (Option A) given the clinical presentation of severe abdominal pain, bloody diarrhea, significant tenderness with guarding, and a CT-confirmed pericolic collection—findings that indicate complicated diverticulitis with likely perforation and peritoneal contamination. 1

Clinical Assessment and Severity Classification

This 64-year-old man presents with:

• Severe abdominal pain with guarding (indicating peritoneal irritation) 1
• Bloody diarrhea (suggesting mucosal compromise or ischemia) 2
• Left lower quadrant tenderness with anorexia (classic for sigmoid pathology) 1
• 2×2 cm pericolic collection on CT (WSES stage 1b-2a complicated diverticulitis) 3

The presence of guarding is the critical finding that distinguishes this from uncomplicated disease and mandates surgical intervention. 1

Why Surgery is Mandatory in This Case

Peritoneal Signs Preclude Conservative Management

• Guarding indicates peritoneal irritation and likely ongoing contamination, which is an absolute contraindication to non-operative management 1
• The WSES guidelines explicitly state that patients with diffuse peritonitis or signs of peritoneal irritation require prompt surgical source control 1
• Non-operative management is only appropriate for hemodynamically stable patients WITHOUT peritoneal signs 1, 3

The Small Abscess Size Does Not Change the Surgical Indication

• While abscesses <3-4 cm can sometimes be managed with antibiotics alone or percutaneous drainage in asymptomatic or minimally symptomatic patients, this patient has severe pain with guarding 1
• Percutaneous drainage (Option D without resection) is contraindicated when peritoneal signs are present 1
• The presence of bloody diarrhea suggests mucosal compromise that will not resolve with drainage alone 2

Surgical Approach: Sigmoidectomy vs. Washout Alone

Sigmoidectomy with resection of the diseased segment (Option A) is superior to washout alone (Option D):

• Source control requires removal of the perforated/diseased bowel segment, not just drainage of the collection 1
• Washout without resection leaves the source of contamination in place and has high failure rates 1
• The WSES guidelines recommend sigmoid resection as definitive source control for perforated diverticulitis 1, 3

Hartmann Procedure vs. Primary Anastomosis

• In this emergency setting with peritoneal contamination, Hartmann procedure (sigmoidectomy with end colostomy) is often the safest option 4
• Primary anastomosis may be considered if the patient is hemodynamically stable, has minimal contamination, and good bowel preparation—but guarding suggests significant contamination 1, 4
• The surgeon should be prepared to perform a Hartmann procedure given the clinical severity 1, 4

Why Other Options Are Incorrect

Option C (Observation and IV Antibiotics) is Dangerous

• Guarding is an absolute contraindication to conservative management 1
• Non-operative treatment in the presence of peritoneal signs has failure rates of 40-60% and risks progression to septic shock 1, 5
• Even in patients with pericolic air but NO peritoneal signs, conservative management has a 6-38% failure rate requiring emergency surgery 5
• This patient's severe symptoms and guarding place him at the highest risk for failure of medical management 1

Option D (Laparotomy with Washout Only) is Inadequate

• Washout without resection fails to achieve adequate source control 1
• The perforated sigmoid segment will continue to leak and contaminate the peritoneum 1
• This approach has been abandoned in modern surgical practice for perforated diverticulitis 1

Critical Timing Considerations

• Surgery should be performed within 24 hours of diagnosis 1
• Delays beyond 24 hours are associated with increased mortality and need for relaparotomy 1
• Early surgical intervention (within 24h) significantly improves outcomes compared to delayed surgery 1

Common Pitfalls to Avoid

1. Do not be falsely reassured by the small abscess size (2×2 cm)—the clinical examination (guarding) trumps imaging findings 1
2. Do not attempt percutaneous drainage in patients with peritoneal signs—this delays definitive treatment and worsens outcomes 1
3. Do not confuse this with uncomplicated diverticulitis—bloody diarrhea and guarding indicate complicated disease requiring surgery 3
4. Do not delay surgery for "optimization"—prompt source control is the priority in perforated diverticulitis 1