An elderly man with known diverticulosis presents with mild intermittent left lower quadrant abdominal pain, no fever, normal white blood cell count, and no peritoneal signs. What is the most appropriate initial management?

Management of Elderly Man with Known Diverticulosis and Mild Intermittent Left Lower Quadrant Pain

The most appropriate initial management is CT abdomen and pelvis with IV contrast (Option A) to confirm the diagnosis and distinguish between uncomplicated and complicated diverticulitis before initiating any treatment. 1, 2

Why CT Imaging is Essential First

In elderly patients, empirical treatment without imaging is explicitly not recommended by the World Society of Emergency Surgery (WSES) guidelines, as it may lead to missing serious pathology with high mortality. 1 The clinical presentation described—mild intermittent pain without fever, normal WBCs, and no peritoneal signs—does not reliably exclude complicated disease or alternative diagnoses in this age group.

Key Evidence Supporting CT First:

• CT demonstrates 98-99% sensitivity and 99-100% specificity for acute diverticulitis, making it the gold standard diagnostic test 2, 3
• Diagnostic difficulty in elderly patients is high, with 43% of cases having a clinically unsuspected diagnosis prior to CT 1
• CT results influence treatment decisions in 65% of elderly patients, determining whether medical management (52%) or surgical management (48%) is required 1
• Clinical diagnosis alone has poor accuracy, with positive predictive value of only 0.65 compared to 0.95 with CT imaging 4

Critical Differential Diagnoses That Must Be Excluded:

The CT scan is essential to exclude other conditions common in elderly patients that present similarly but require different management 4, 1:

• Colorectal malignancy (can mimic diverticulitis)
• Ischemic colitis (common in elderly with vascular disease)
• Inflammatory bowel disease
• Bowel obstruction
• Perforated viscus with small amounts of free air

Why Other Options Are Inappropriate at This Stage

Option B (IV Antibiotics and Bowel Rest) - Incorrect

Starting antibiotics before imaging confirmation represents unnecessary antibiotic exposure and is explicitly discouraged by WSES guidelines. 2 Furthermore:

• For uncomplicated diverticulitis (WSES stage 0), antibiotics should be avoided in immunocompetent elderly patients 4, 2
• The American College of Gastroenterology and WSES suggest antibiotics may not be necessary in mild-moderate uncomplicated cases, but this decision can only be made after CT confirmation 1
• Antibiotics are reserved for patients with systemic symptoms (persistent fever, increasing leukocytosis), age >80 years, immunocompromise, or complicated disease 3

Option C (Increase Fiber and Fluid Intake) - Premature

While dietary modification is appropriate for confirmed uncomplicated diverticulitis or chronic diverticulosis management, it is premature without:

• Confirming the diagnosis (this could be cancer, ischemia, or other pathology)
• Excluding complications (abscess, perforation, fistula)
• Ruling out acute diverticulitis requiring different initial management

Option D (Laparotomy) - Grossly Inappropriate

Surgery is only indicated for:

• Generalized peritonitis with organ dysfunction (WSES stage 3-4) 4
• Free intraperitoneal air with diffuse peritonitis 4
• Failed medical management of complicated disease 4

This patient has no peritoneal signs, making laparotomy completely unjustified.

Algorithmic Approach After CT Imaging

Once CT confirms the diagnosis, management proceeds based on WSES classification 4:

If Uncomplicated Diverticulitis (WSES Stage 0):

• Observation with supportive care 2
• Clear liquid diet and acetaminophen for pain 2, 3
• No antibiotics for immunocompetent patients without systemic symptoms 4, 2

If Complicated Diverticulitis:

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

Common Pitfalls to Avoid

• Never assume the diagnosis without imaging in elderly patients, even with classic symptoms and normal labs 2
• Never start antibiotics empirically before confirming diagnosis and severity 2
• Do not rely on normal WBC count to exclude complicated disease—elderly patients may not mount typical inflammatory responses 4
• If IV contrast is contraindicated (renal disease, allergy), use ultrasound, MRI, or non-contrast CT as alternatives 4, 5

Answer: A - CT abdomen (with pelvis and IV contrast)