What is the recommended treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, observation with supportive care (pain control and clear liquid diet) without antibiotics is the recommended first-line treatment, as antibiotics do not accelerate recovery, prevent complications, or reduce recurrence rates. 1, 2, 3

Classification and Initial Diagnostic Approach

Uncomplicated diverticulitis is defined as localized diverticular inflammation without abscess, perforation, fistula, obstruction, or bleeding. 1, 3 Complicated diverticulitis involves inflammation with abscess, phlegmon, fistula, obstruction, bleeding, or perforation. 4, 5

• CT scan with IV contrast is the gold standard diagnostic test, with sensitivity of 98-99% and specificity of 99-100%. 1, 4
• CT findings in uncomplicated disease include diverticula, bowel wall thickening, and increased pericolic fat density. 1
• CT findings suggesting complicated disease include extraluminal gas, intra-abdominal fluid, abscess formation, or longer segments of inflamed colon. 2, 3

Treatment Algorithm for Uncomplicated Diverticulitis

When to Withhold Antibiotics (Most Patients)

Antibiotics are NOT recommended for immunocompetent patients with uncomplicated diverticulitis who lack systemic inflammatory signs. 1, 3 This strong recommendation is based on high-quality evidence from multiple randomized controlled trials, including the DIABOLO trial with 528 patients, which demonstrated no difference in recovery time, recurrence rates, or progression to complicated disease between antibiotic and observation groups. 3

When Antibiotics ARE Indicated

Reserve antibiotics for patients with ANY of the following high-risk features: 3, 4

• Immunocompromised status (chemotherapy, organ transplant, chronic corticosteroids) 1, 3
• Persistent fever (>101°F) or chills 3, 4
• Increasing leukocytosis or WBC >15 × 10⁹ cells/L 3, 4
• Elevated CRP >140 mg/L 3
• Age >80 years 3, 4
• Pregnancy 3, 4
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 4
• Vomiting or inability to maintain oral hydration 3
• CT findings of pericolic extraluminal gas, fluid collection, or longer inflamed colon segment 3
• Symptoms lasting >5 days 3
• Pain score ≥8/10 at presentation 3

Outpatient vs. Inpatient Management

Outpatient management is appropriate when patients meet ALL of the following criteria: 2, 3

• Afebrile or temperature <100.4°F 2, 3
• Able to tolerate oral fluids and medications 2, 3
• No significant comorbidities or frailty 2, 3
• Adequate home support and ability to maintain self-care 2, 3
• Pain controlled with acetaminophen alone (pain score <4/10) 3

Hospitalization is required for: 2, 3

• Complicated diverticulitis 2, 3
• Inability to tolerate oral intake 2, 3
• Systemic inflammatory response or sepsis 2, 3
• Significant comorbidities or frailty 2, 3
• Immunocompromised status 2, 3

Antibiotic Regimens

Outpatient oral regimens (4-7 days for immunocompetent patients): 3, 4

• First-line: Amoxicillin-clavulanate 875/125 mg orally twice daily 3, 4
• Alternative: Ciprofloxacin 500 mg orally twice daily PLUS metronidazole 500 mg orally three times daily 3, 4

Inpatient IV regimens (transition to oral as soon as tolerated): 2, 3, 4

• Ceftriaxone PLUS metronidazole 2, 3, 4
• Piperacillin-tazobactam 4g/0.5g every 6 hours 2, 6, 4
• Ampicillin-sulbactam 4

Duration of antibiotic therapy: 3

• Immunocompetent patients: 4-7 days 3
• Immunocompromised patients: 10-14 days 3
• Post-operative with adequate source control: 4 days (based on STOP IT trial) 2, 3

Treatment of Complicated Diverticulitis

Small Abscesses (<4 cm)

Antibiotics alone for 7 days is appropriate initial management, with a pooled failure rate of 20% and mortality rate of 0.6%. 2, 6

Large Abscesses (≥4-5 cm)

Percutaneous drainage combined with antibiotic therapy is recommended. 2, 6 If percutaneous drainage is not feasible in non-critically ill, immunocompetent patients, antibiotics alone may be considered. 6 In critically ill or immunocompromised patients where drainage is not feasible, surgical intervention should be pursued. 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 recommended. 6 However, patients with distant free gas have a significant failure rate (57-60%) and require close monitoring. 6

Diffuse Peritonitis

Patients with diffuse peritonitis require: 2, 6

• Prompt fluid resuscitation 2
• Immediate IV antibiotic administration 2
• Urgent surgical intervention (emergent laparotomy with colonic resection) 2, 4

Special Populations

Immunocompromised Patients

Immunocompromised patients are at high risk for failure of standard non-operative treatment (weak recommendation based on very low-quality evidence). 1 These patients have a 39.3% rate of emergency surgery, 31.6% postoperative mortality, and 27.8% recurrence rate after successful non-operative management. 1 Patients on chronic corticosteroid therapy (Group I) require emergency surgery most frequently. 1

Lower thresholds for CT imaging, antibiotic treatment, and surgical consultation are warranted. 3 Antibiotic duration should be extended to 10-14 days. 3

Follow-up and Prevention

Re-evaluation within 7 days is mandatory, with earlier assessment if symptoms worsen. 2, 3 For patients with uncomplicated diverticulitis, colonoscopy is recommended 4-6 weeks after resolution of symptoms if they have complicated disease or meet age-appropriate screening criteria. 5, 7

Preventive strategies to reduce recurrence: 3

• High-quality diet (high in fiber from fruits, vegetables, whole grains, legumes; low in red meat and sweets) 3
• Regular physical activity, particularly vigorous exercise 3
• Achieving or maintaining normal BMI 3
• Smoking cessation 3
• Avoiding regular use of NSAIDs and opiates when possible 3

Do NOT restrict consumption of nuts, corn, popcorn, or small-seeded fruits, as these are not associated with increased risk of diverticulitis. 3

Surgical Considerations

The traditional recommendation for colectomy after 2 episodes of diverticulitis is no longer accepted. 2 The decision for elective resection should be made case-by-case, considering risk factors for recurrence, morbidity of surgery, ongoing symptoms, complexity of disease, and patient comorbidities. 2 The DIRECT trial demonstrated that elective sigmoidectomy resulted in significantly better quality of life at 6 months compared to continued conservative management in patients with recurrent/persistent symptoms. 3

Postoperative mortality: 4

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

Critical Pitfalls to Avoid

• Do not routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients without risk factors, as this contributes to antibiotic resistance without clinical benefit. 1, 3
• Do not apply the "no antibiotics" approach to patients with abscesses, pericolic gas, or higher Hinchey stages, as the evidence supporting observation specifically excluded these patients. 3
• Do not stop antibiotics early even if symptoms improve, as this may lead to incomplete treatment and recurrence. 3
• Do not overlook immunocompromised status or chronic corticosteroid use, as these patients have significantly higher rates of perforation and mortality. 1, 3
• Do not delay surgical consultation in patients with frequent recurrence affecting quality of life. 3