In a hemodynamically stable patient with diverticulosis presenting with severe left iliac fossa pain, constipation, localized tenderness, and CT showing a large intra‑abdominal collection without free intraperitoneal air, what is the most appropriate next management: colonoscopy, exploratory laparotomy, or percutaneous drainage?

Management of Complicated Diverticulitis with Large Abscess and Intraperitoneal Air

In this hemodynamically stable patient with a large intra-abdominal collection and intraperitoneal air, the most appropriate next step is percutaneous drainage (Option C) combined with broad-spectrum antibiotics. 1, 2

Why Percutaneous Drainage is the Correct Choice

For abscesses larger than 4 cm in stable patients without diffuse peritonitis, percutaneous drainage combined with antibiotic therapy is the recommended first-line treatment. 1, 2 This patient meets all criteria for non-operative management:

• Hemodynamic stability (BP 110/80, HR 92) 1, 2
• Localized tenderness (left iliac fossa only, not diffuse peritonitis) 1, 2
• Large collection amenable to drainage 1, 2

The World Society of Emergency Surgery classifies this presentation as WSES Stage 2a–2b complicated diverticulitis, which specifically calls for image-guided drainage rather than immediate surgery in stable patients. 2 Abscesses >4 cm treated with antibiotics alone have an 18.7% failure rate, making source control via drainage essential. 1, 2

Why NOT Colonoscopy (Option A)

Colonoscopy is absolutely contraindicated during acute diverticulitis. 2 Performing endoscopy during the acute inflammatory phase can convert a contained perforation into free perforation, dramatically worsening the clinical situation. 2 Colonoscopy should be deferred 4–6 weeks after complete symptom resolution to exclude underlying malignancy (present in ~11% of diverticular abscess cases). 2

Why NOT Immediate Exploratory Laparotomy (Option B)

Immediate laparotomy is NOT indicated in hemodynamically stable patients without diffuse peritonitis. 1, 2 Surgery is reserved for:

• Hemodynamic instability (hypotension, shock, tachycardia >100 bpm) 2
• Diffuse peritonitis on examination 1, 2
• Diffuse intra-abdominal fluid with distant free gas (WSES Stage 3–4) 1, 2
• Clinical deterioration despite resuscitation 2

This patient has localized tenderness only and stable vital signs, making surgery unnecessarily aggressive. 1, 2

Critical Nuance: The Intraperitoneal Air

The presence of intraperitoneal free air does not automatically mandate surgery in stable patients. 1, 2 The 2022 WSES guidelines specifically state that selected stable patients with distant intraperitoneal gas can be managed non-operatively, though this carries a 57–60% failure rate and requires close monitoring. 1, 2 The key differentiator is whether there is diffuse fluid and diffuse peritonitis—this patient has neither based on the localized examination findings. 1, 2

Immediate Management Protocol

1. Initiate broad-spectrum IV antibiotics covering anaerobes and gram-negatives (e.g., piperacillin-tazobactam or ceftriaxone plus metronidazole) 1, 3

2. Perform CT-guided or ultrasound-guided percutaneous catheter drainage of the large collection 1, 2

3. Obtain drainage fluid cultures to tailor antibiotic therapy 1, 2

4. Close monitoring with vital signs every 3–6 hours, serial labs (WBC, CRP, lactate), and catheter output assessment 2

When to Convert to Surgery

Proceed to exploratory laparotomy if any of the following develop: 1, 2

• Clinical deterioration within 48–72 hours (worsening fever, leukocytosis, abdominal exam) 2
• Development of hemodynamic instability 2
• Persistent tachycardia beyond 24 hours despite adequate drainage 2
• Inability to place drainage catheter or failure to achieve sepsis control 2

Common Pitfalls to Avoid

• Do not perform colonoscopy acutely—this can cause free perforation 2
• Do not rush to surgery in stable patients—percutaneous drainage achieves comparable success with lower morbidity 1
• Do not ignore the need for source control—antibiotics alone fail in nearly 1 in 5 cases with large abscesses 1, 2
• Do not assume all free air requires surgery—localized peritonitis without diffuse fluid can be managed conservatively with drainage 1, 2

Expected Outcomes

When appropriately selected, percutaneous drainage combined with antibiotics achieves success rates of 70–90% for diverticular abscesses, with significantly lower complication rates and shorter hospital stays compared to immediate operative management. 1 If this approach fails, the patient can still undergo elective surgery under more controlled conditions rather than emergent operation. 1, 2