What is the recommended treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis without systemic inflammation, antibiotics are not recommended—observation with pain control and dietary modification is the appropriate first-line treatment. 1, 2

Classification and Initial Assessment

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

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

Treatment of Uncomplicated Diverticulitis

Outpatient Management

Clinically stable, afebrile patients with uncomplicated diverticulitis should be managed as outpatients, with only a 4.3% failure rate and significant cost savings compared to hospitalization 2:

• No antibiotics are needed for immunocompetent patients without systemic signs of inflammation—this is a strong recommendation based on high-quality evidence showing antimicrobial treatment is not superior to observation 1
• Pain management with acetaminophen (avoid NSAIDs) 3
• Clear liquid diet initially, advancing as tolerated 3, 5

When Antibiotics ARE Indicated for Uncomplicated Disease

Reserve antibiotics for specific high-risk situations 3:

• Persistent fever or chills
• Increasing leukocytosis
• Age >80 years
• Pregnancy
• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant)
• Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes)

First-line oral antibiotics: amoxicillin/clavulanic acid OR cefalexin plus metronidazole 3

If oral intake not tolerated: IV cefuroxime or ceftriaxone plus metronidazole, or ampicillin/sulbactam 3

Special Consideration: Pericolic Extraluminal Gas

For isolated pericolic gas without diffuse peritonitis, attempt non-operative treatment with antibiotics, though elevated CRP may predict failure 2, 6

Treatment of Complicated Diverticulitis

Small Abscesses (<4 cm)

Initial trial of antibiotics alone is recommended, with a pooled failure rate of 20% and mortality of 0.6% 2, 6

Large Abscesses (≥4 cm)

Percutaneous drainage combined with antibiotic therapy is the preferred approach 2, 6:

• If percutaneous drainage is not feasible in non-critically ill, immunocompetent patients, antibiotics alone may be attempted 6
• In critically ill or immunocompromised patients where drainage is not feasible, proceed directly to surgical intervention 6

Antibiotic Selection for Complicated Disease

Empiric regimen should be based on clinical condition, presumed pathogens, and antimicrobial resistance risk 6:

For non-critically ill, immunocompetent patients with adequate source control:

• Piperacillin/tazobactam 4g/0.5g q6h OR
• Eravacycline 1 mg/kg q12h 6

For inadequate source control or high ESBL risk:

• Ertapenem 1g q24h OR
• Eravacycline 1 mg/kg q12h 6

Alternative regimens: Ceftriaxone plus metronidazole 3, 4

Duration of Antibiotic Therapy

A fixed 4-day course is recommended if source control is adequate in immunocompetent, non-critically ill patients—the STOP IT trial demonstrated this is equivalent to longer courses 2, 6

For immunocompromised or critically ill patients with adequate source control: up to 7 days based on clinical condition and inflammatory markers 6

Surgical Management

Emergent Surgery Indications

Patients with diffuse peritonitis require immediate fluid resuscitation, rapid antibiotic administration, and urgent surgical intervention 2, 6, 4:

• Hartmann procedure OR
• Primary resection and anastomosis with or without diverting loop ileostomy 6, 4
• Mortality: 0.5% for elective resection vs. 10.6% for emergent resection 3

Elective Surgery Considerations

The decision for elective resection should be individualized—the traditional recommendation for colectomy after 2 episodes is no longer accepted 2:

• Consider risk factors for recurrence, ongoing symptoms, disease complexity, and patient comorbidities 2
• Laparoscopic approach results in shorter hospital stay, fewer complications, and lower mortality compared to open surgery 5, 4

Special Populations

Immunocompromised Patients

Immunocompromised patients are at high risk for failure of standard non-operative treatment and should be monitored closely 1:

• Emergency surgery rate of 39.3%, highest in those on chronic corticosteroids 1
• Postoperative mortality of 31.6% 1
• Recurrence rate after successful non-operative management of 27.8% 1

Follow-up and Prevention

• Colonoscopy is recommended 4-6 weeks after resolution for all patients with complicated disease or those meeting screening criteria 5, 4
• Monitor for treatment failure: persistent fever, increasing leukocytosis, worsening clinical condition 6
• Prevention strategies: high-fiber diet, regular exercise, smoking cessation, weight loss if BMI ≥30 5

Common Pitfalls to Avoid

• Do not routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients—this represents outdated practice not supported by current evidence 1
• Do not delay surgical consultation in patients with peritonitis or hemodynamic instability—mortality increases significantly with delayed intervention 3
• Do not continue antibiotics beyond 4 days if source control is adequate—longer courses provide no additional benefit 2, 6