What is the most appropriate initial management for an elderly patient with a known case of diverticulosis (diverticula of the colon), presenting with mild intermittent left lower abdominal pain, no fever, normal white blood cell (WBC) count, and no signs of peritonitis?

Initial Management: CT Abdomen with IV Contrast

For an elderly patient with known diverticulosis presenting with mild intermittent left lower abdominal pain, normal WBC count, no fever, and no peritonitis, the most appropriate initial management is CT abdomen/pelvis with IV contrast (Option A) to confirm the diagnosis and distinguish between uncomplicated and complicated diverticulitis before initiating any treatment. 1

Rationale for Imaging First

The 2022 World Society of Emergency Surgery (WSES) guidelines specifically recommend against basing the diagnosis of acute diverticulitis in elderly patients on clinical signs, symptoms, and laboratory tests alone 1. Even with normal inflammatory markers, elderly patients presenting with left lower abdominal pain should undergo appropriate imaging 1.

CT scan with IV contrast is the gold standard diagnostic test, with 98-99% sensitivity and 99-100% specificity for acute diverticulitis 1, 2. This imaging is essential to:

• Confirm whether this represents acute diverticulitis versus simple diverticulosis 1
• Distinguish uncomplicated from complicated disease (abscess, perforation, fistula) 1
• Guide appropriate treatment decisions 1

Why Other Options Are Incorrect

Option B (IV Antibiotics and Bowel Rest) - Premature

Antibiotics are NOT routinely indicated for uncomplicated diverticulitis in immunocompetent elderly patients without sepsis-related organ failures 1, 3. The WSES guidelines specifically state that antibiotic therapy should be avoided in this population (WSES stage 0) 1.

Multiple high-quality randomized trials, including the DIABOLO trial with 528 patients, demonstrated that antibiotics neither accelerate recovery nor prevent complications or recurrence in uncomplicated cases 4, 3, 2. Starting antibiotics before confirming the diagnosis and severity would represent overtreatment 3.

Option C (Increase Fiber and Fluid Intake) - Wrong Clinical Context

This patient has active symptoms (mild intermittent left lower abdominal pain), not asymptomatic diverticulosis 3. Fiber and fluid intake are appropriate for:

• Long-term prevention after resolution of acute diverticulitis 3
• Management of asymptomatic diverticulosis 3

However, this recommendation does not address the current acute presentation requiring diagnostic evaluation 1.

Option D (Laparotomy) - Grossly Inappropriate

Laparotomy is reserved for patients with diffuse peritonitis (WSES stage 3-4) or distant free intraperitoneal air 1, 5. This patient has no signs of peritonitis, making emergency surgery completely unwarranted 1.

Clinical Algorithm After CT Results

If CT Shows Uncomplicated Diverticulitis (WSES Stage 0):

• Observation with supportive care (clear liquid diet, acetaminophen for pain) 3, 2
• No antibiotics for immunocompetent patients without systemic symptoms 1, 3
• Outpatient management with re-evaluation within 7 days 1

If CT Shows Complicated Diverticulitis:

• WSES Stage 1a (pericolic air/fluid): Consider antibiotics 1
• WSES Stage 1b-2a (abscess <4cm): IV antibiotics 1
• WSES Stage 2a (abscess ≥4cm): Percutaneous drainage + antibiotics 1
• WSES Stage 2b-4 (free air, peritonitis): Surgical consultation 1, 5

Critical Pitfalls to Avoid

• Never assume the diagnosis without imaging in elderly patients, even with classic symptoms and normal labs 1
• Never start antibiotics empirically before confirming diagnosis and severity, as this represents unnecessary antibiotic exposure 1, 3
• Never apply dietary management to acute symptomatic presentations without first ruling out complications 3
• If IV contrast is contraindicated (renal disease, contrast allergy), use ultrasound, MRI, or non-contrast CT as alternatives 1