What is the recommended treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis without systemic inflammation, antibiotics should NOT be prescribed—observation with pain control and dietary modification is the recommended approach. 1, 2

Initial Diagnostic Approach

CT scan with IV contrast is the gold standard diagnostic test, with sensitivity of 98-99% and specificity of 99-100%. 3, 4 This imaging confirms diagnosis, distinguishes complicated from uncomplicated disease, and identifies abscesses or perforation. 5

Classification-Based Treatment Algorithm

Uncomplicated Diverticulitis (85% of cases)

Uncomplicated disease is defined as localized inflammation without abscess, perforation, stricture, or fistula. 1, 3

Outpatient Management (Preferred for Stable Patients)

• Clinically stable, afebrile patients should be managed as outpatients with only 4.3% failure rate and significant cost savings. 2
• Pain control with acetaminophen (avoid NSAIDs as they are risk factors for disease). 3
• Clear liquid diet initially, advancing as tolerated. 3
• No antibiotics are needed for immunocompetent patients without systemic signs. 1

When to Prescribe Antibiotics in Uncomplicated Disease

Reserve antibiotics for high-risk patients only: 3

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

First-line oral antibiotics: 3

• Amoxicillin/clavulanic acid, OR
• Cefalexin plus metronidazole

If oral intake not tolerated, use IV antibiotics: 3

• Ceftriaxone plus metronidazole, OR
• Cefuroxime plus metronidazole, OR
• Ampicillin/sulbactam

When oral antibiotics are used, prefer oral route over IV as early switch facilitates shorter hospital stays. 1

Special Case: Pericolic Extraluminal Gas

For isolated pericolic gas without diffuse peritonitis, attempt non-operative treatment with antibiotics. 2, 5 However, if distant free gas is present without diffuse fluid, non-operative management carries 57-60% failure rate and requires close monitoring. 5

Complicated Diverticulitis (15% of cases)

Small Abscesses (<4 cm)

Treat with antibiotics alone for 7 days, with pooled failure rate of 20% and mortality of 0.6%. 2, 5

Large Abscesses (≥4 cm)

Percutaneous drainage combined with antibiotics is recommended. 2, 5

• If drainage not feasible in non-critically ill, immunocompetent patients, antibiotics alone may be attempted. 5
• If drainage not feasible in critically ill or immunocompromised patients, proceed to surgery. 5

Empiric IV antibiotic regimens for complicated disease: 5, 3

• Non-critically ill, immunocompetent patients: Piperacillin/tazobactam 4g/0.5g q6h OR eravacycline 1 mg/kg q12h
• High risk for ESBL organisms or inadequate source control: Ertapenem 1g q24h OR eravacycline 1 mg/kg q12h
• Alternative regimens: Ceftriaxone plus metronidazole

Antibiotic duration: 5

• 4 days if adequate source control in immunocompetent, non-critically ill patients
• Up to 7 days for immunocompromised or critically ill patients based on clinical response and inflammatory markers

Diffuse Peritonitis or Hemodynamic Instability

Immediate surgical intervention is mandatory. 2, 3, 4

• Prompt fluid resuscitation
• Immediate IV antibiotics
• Urgent laparotomy with colonic resection

Surgical options include: 5

• Hartmann's procedure
• Primary resection and anastomosis with or without diverting stoma
• Laparoscopic peritoneal lavage (in select cases)

Mortality rates: 3

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

Special Populations

Immunocompromised Patients

Consider immunocompromised patients at high risk for treatment failure. 1 Emergency surgery rate is 39.3%, with postoperative mortality of 31.6%. 1 Patients on chronic corticosteroids have the highest surgery rates. 1 Lower threshold for antibiotics and surgical intervention in this population.

Critical Pitfalls to Avoid

• Do not routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients—this represents outdated practice contradicted by high-quality evidence. 1
• Do not assume pericolic gas always requires surgery—stable patients can be trialed on non-operative management with close monitoring. 2, 5
• Do not continue antibiotics beyond 4 days if source control is adequate in non-critically ill patients. 5
• Do not delay surgery in patients with diffuse peritonitis—mortality increases significantly with delayed intervention. 3

Follow-up Considerations

Colonoscopy is recommended: 4

• For all patients with complicated diverticulitis 6 weeks after resolution
• For uncomplicated diverticulitis with suspicious CT features or meeting bowel cancer screening criteria

Elective resection decisions should be individualized rather than following the outdated "two-episode rule," considering recurrence risk factors, ongoing symptoms, disease complexity, and patient comorbidities. 2