What is the treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, observation without antibiotics is the recommended first-line treatment, as antibiotics do not accelerate recovery, prevent complications, or reduce recurrence rates. 1

Initial Assessment and Risk Stratification

When evaluating a patient with suspected diverticulitis, obtain a CT scan with contrast to confirm the diagnosis (sensitivity 98-99%, specificity 99-100%) and classify the disease as uncomplicated versus complicated. 2 Uncomplicated diverticulitis is defined as localized inflammation without abscess, perforation, fistula, obstruction, or bleeding. 1

Check for high-risk features that mandate antibiotic therapy:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 1, 2
• Age >80 years 1
• Pregnancy 1
• Systemic inflammatory response or sepsis 1
• White blood cell count >15 × 10⁹ cells/L 1
• C-reactive protein >140 mg/L 1
• Presence of fluid collection or longer segment of inflammation on CT 1
• Persistent vomiting or inability to tolerate oral intake 1
• Symptoms lasting >5 days 1
• ASA score III or IV 1

Treatment Algorithm for Uncomplicated Diverticulitis

For Immunocompetent Patients WITHOUT High-Risk Features:

Outpatient management with observation alone: 1, 3

• Clear liquid diet during acute phase, advancing as symptoms improve 1
• Pain control with acetaminophen 1 g three times daily 2, 4
• No antibiotics required 1, 3
• Mandatory re-evaluation within 7 days, or sooner if symptoms worsen 1

This approach is supported by the DIABOLO trial (528 patients), which demonstrated no difference in recovery time, complications, or recurrence rates between antibiotic and non-antibiotic groups, with actually shorter hospital stays in the observation group (2 vs 3 days). 1

For Patients WITH High-Risk Features:

Outpatient antibiotic regimens (4-7 days): 1, 5

• First-line: Amoxicillin-clavulanate 875/125 mg orally twice daily 1, 2
• Alternative: Ciprofloxacin 500 mg orally twice daily PLUS metronidazole 500 mg orally three times daily 1, 5

Criteria for outpatient treatment: 1

• Able to tolerate oral fluids and medications
• Temperature <100.4°F
• Pain score <4/10 (controlled with acetaminophen)
• No significant comorbidities or frailty
• Adequate home support

For Patients Requiring Hospitalization:

Inpatient IV antibiotic regimens: 1, 2

• Ceftriaxone PLUS metronidazole 1, 2
• Piperacillin-tazobactam 1, 2
• Cefuroxime PLUS metronidazole 5

Transition to oral antibiotics as soon as the patient tolerates oral intake to facilitate earlier discharge. 1 Total antibiotic duration remains 4-7 days for immunocompetent patients. 1, 5

For immunocompromised patients, extend antibiotic duration to 10-14 days. 1

Treatment of Complicated Diverticulitis

Small Abscesses (<4-5 cm):

• IV antibiotics alone for 7 days 1, 3
• Hospitalization required 3

Large Abscesses (≥4-5 cm):

• Percutaneous drainage PLUS IV antibiotics for 4 days 1, 3
• Antibiotics: piperacillin-tazobactam, ceftriaxone plus metronidazole, or meropenem for critically ill patients 1, 2

Generalized Peritonitis:

• Emergent laparotomy with colonic resection 3, 2
• IV antibiotics with broad-spectrum coverage 3

Prevention of Recurrence

Dietary and lifestyle modifications significantly reduce recurrence risk: 1

• High-quality diet: high in fiber from fruits, vegetables, whole grains, legumes; low in red meat and sweets (>22.1 g fiber/day) 1
• Regular vigorous physical activity 1
• Achieve or maintain normal BMI 1
• Smoking cessation 1
• Avoid regular use of NSAIDs and opioids when possible 1

Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—these are not associated with increased diverticulitis risk. 1

Critical Pitfalls to Avoid

• Do not routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients without risk factors—this contributes to antibiotic resistance without clinical benefit. 1
• Do not apply the "no antibiotics" approach to complicated diverticulitis (Hinchey 1b or higher)—these patients were specifically excluded from trials supporting observation alone. 1
• Do not assume all patients require hospitalization—outpatient management is safe in appropriately selected patients and results in 35-83% cost savings per episode. 1
• Do not stop antibiotics early if they are indicated, even if symptoms improve—complete the full 4-7 day course. 1
• Do not delay surgical consultation in patients with frequent recurrences affecting quality of life—the traditional "two-episode rule" is no longer accepted, and decisions should be individualized based on quality of life impact. 1