What is the recommended treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis without signs of systemic inflammation, antibiotics are not recommended—observation with supportive care is the first-line approach. 1, 2

Classification and Initial Assessment

The treatment strategy depends critically on whether diverticulitis is complicated or uncomplicated:

• Uncomplicated diverticulitis is defined as localized diverticular inflammation without abscess, perforation, fistula, obstruction, or bleeding—CT findings show diverticula, wall thickening, and increased pericolic fat density 1, 2
• Complicated diverticulitis involves abscess formation, perforation, peritonitis, fistula, obstruction, or bleeding 3, 4
• CT scan with IV contrast is the gold standard diagnostic test with 98-99% sensitivity and 99-100% specificity 4, 5

Treatment of Uncomplicated Diverticulitis

Observation Without Antibiotics (First-Line for Most Patients)

The paradigm has shifted away from routine antibiotic use. Multiple high-quality randomized trials, including the DIABOLO trial with 528 patients, demonstrate that antibiotics neither accelerate recovery nor prevent complications or recurrence in immunocompetent patients with uncomplicated disease 1, 2

Management consists of:

• Clear liquid diet during acute phase, advancing as symptoms improve 2
• Pain control with acetaminophen (avoid NSAIDs and opioids) 2, 4
• Outpatient management for clinically stable, afebrile patients who can tolerate oral intake 3, 5
• Re-evaluation within 7 days, or sooner if clinical deterioration occurs 1

When to Use Antibiotics Selectively

Reserve antibiotics for patients with specific high-risk features:

Absolute indications:

• Immunocompromised status (chemotherapy, organ transplant, chronic corticosteroids) 1, 2
• Systemic inflammatory response or sepsis 2, 4
• Persistent fever or chills 2, 4

Relative indications:

• Age >80 years 2, 4
• Pregnancy 2, 4
• WBC count >15 × 10⁹ cells/L 2
• CRP >140 mg/L 2
• Presence of fluid collection or longer segment of inflammation on CT 2
• Symptoms >5 days duration 2
• ASA score III or IV 2
• Persistent vomiting or inability to maintain hydration 2

Antibiotic Regimens When Indicated

Outpatient oral regimens (4-7 days for immunocompetent patients):

• First-line: Amoxicillin-clavulanate 875/125 mg orally twice daily 2, 4
• Alternative: Ciprofloxacin 500 mg orally twice daily PLUS metronidazole 500 mg orally three times daily 2, 4

Inpatient IV regimens (transition to oral as soon as tolerated):

• Ceftriaxone PLUS metronidazole 2, 4
• Piperacillin-tazobactam 4g/0.5g every 6 hours 6, 4
• Ampicillin-sulbactam 4

Duration:

• 4-7 days for immunocompetent patients 2
• 10-14 days for immunocompromised patients 2

Treatment of Complicated Diverticulitis

Small Abscesses (<4-5 cm)

• Initial trial of IV antibiotics alone with pooled failure rate of 20% and mortality rate of 0.6% 3
• Hospitalization with bowel rest and IV antibiotics 3, 5

Large Abscesses (≥4-5 cm)

• Percutaneous drainage combined with IV antibiotics is the recommended approach 3, 6, 5
• If drainage not feasible in non-critically ill, immunocompetent patients, antibiotics alone may be attempted with close monitoring 6
• In critically ill or immunocompromised patients where drainage is not feasible, surgical intervention should be considered 6
• Antibiotic duration: 4 days post-drainage if adequate source control in immunocompetent patients; up to 7 days in immunocompromised or critically ill patients 3, 6

Microperforation with Pericolic Gas

• For hemodynamically stable patients with small amounts of pericolic extraluminal gas without diffuse peritonitis, non-operative treatment with antibiotics is appropriate 3, 6
• Patients with distant free gas without diffuse fluid may be treated non-operatively only with close follow-up, though failure rate is 57-60% 6

Diffuse Peritonitis

This is a surgical emergency requiring:

• Prompt fluid resuscitation 3
• Immediate IV antibiotic administration 3
• Urgent surgical intervention 3, 4
• Surgical options include primary resection with anastomosis (with or without diverting stoma) or Hartmann's procedure 3, 6
• Laparoscopic peritoneal lavage should NOT be considered the treatment of choice 3

Special Populations

Immunocompromised Patients

These patients are at significantly higher risk for treatment failure and complications:

• Emergency surgery rate of 39.3%, highest in those on chronic corticosteroids 1
• Postoperative mortality of 31.6% 1
• Lower threshold for CT imaging, antibiotic treatment, and surgical consultation 2
• Require longer antibiotic duration (10-14 days) 2

Surgical Considerations

Elective Resection

The traditional "two-episode rule" is no longer accepted. 3

Decision should be based on:

• Impact on quality of life 3
• Frequency of recurrence 3
• Risk factors for complicated disease 3
• Patient comorbidities and ongoing symptoms 3
• The DIRECT trial demonstrated significantly better quality of life at 6 months with elective sigmoidectomy versus conservative management in patients with recurrent/persistent symptoms 3

Surgical Mortality

• Elective colon resection: 0.5% mortality 4
• Emergent colon resection: 10.6% mortality 4

Prevention of Recurrence

Evidence-based lifestyle modifications:

• High-quality diet: High in fiber from fruits, vegetables, whole grains, legumes; low in red meat and sweets (>22.1 g fiber/day shows protective effect) 2
• Regular vigorous physical activity 2
• Achieve or maintain normal BMI 2
• Smoking cessation 2
• Avoid regular use of NSAIDs and opioids when possible 2

What NOT to restrict:

• Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—these are not associated with increased diverticulitis risk 2

Follow-up and Monitoring

• Colonoscopy is recommended 4-6 weeks after resolution for patients with complicated diverticulitis or first episode of uncomplicated diverticulitis to exclude colorectal cancer (risk 1.16%) 5
• Re-evaluation within 7 days for all patients, earlier if deterioration 1

Critical Pitfalls to Avoid

• Overusing antibiotics in uncomplicated cases without risk factors—this contributes to antibiotic resistance without clinical benefit 1, 2
• Applying the "no antibiotics" approach to complicated diverticulitis or immunocompromised patients—these populations were specifically excluded from trials supporting observation 1
• Assuming all patients require hospitalization—outpatient management is safe and cost-effective (35-83% cost savings) for appropriate candidates 3
• Stopping antibiotics early when indicated—complete the full course even if symptoms improve 2
• Unnecessarily restricting diet (nuts, seeds, popcorn)—not evidence-based 2
• Delaying surgical consultation in patients with frequent recurrences affecting quality of life 3