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 (bowel rest, clear liquid diet, and acetaminophen for pain) is the first-line treatment. 1, 2

Initial Diagnostic Confirmation

CT scan with IV contrast is the gold standard diagnostic test, with sensitivity of 98-99% and specificity of 99-100% for confirming diverticulitis and assessing for complications such as abscess, perforation, or peritonitis. 3, 4

Classification-Based Treatment Algorithm

Uncomplicated Diverticulitis (85% of cases)

Uncomplicated diverticulitis is defined as localized inflammation without abscess, perforation, fistula, obstruction, or bleeding. 1, 2

Outpatient Management (Most Patients)

Outpatient treatment is appropriate for clinically stable, afebrile patients who can tolerate oral fluids, have no significant comorbidities, and have adequate home support. 5, 2

• Observation without antibiotics for immunocompetent patients without systemic symptoms 1, 2
• Clear liquid diet during acute phase, advancing as symptoms improve 2
• Acetaminophen for pain control (avoid NSAIDs and opioids) 2, 4
• Mandatory re-evaluation within 7 days, or sooner if clinical deterioration occurs 5, 2

When to Prescribe Antibiotics for Uncomplicated Disease

Reserve antibiotics for patients with specific high-risk features: 2, 4

• Immunocompromised status (chemotherapy, organ transplant, chronic corticosteroids) 1, 2
• Age >80 years 2, 4
• Pregnancy 2, 4
• Persistent fever or chills 2, 4
• Increasing leukocytosis (WBC >15 × 10⁹ cells/L) 2
• Elevated CRP >140 mg/L 2
• Symptoms lasting >5 days 2
• Presence of vomiting or inability to maintain hydration 2
• CT findings of fluid collection or longer segment of inflammation 2
• Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 4

Outpatient antibiotic regimens (4-7 days for immunocompetent patients): 2

• 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

For immunocompromised patients, extend duration to 10-14 days. 2

Inpatient Management Criteria

Hospitalize patients with: 5, 2

• Inability to tolerate oral intake 5, 2
• Systemic inflammatory response or sepsis 2
• Significant comorbidities or frailty 5, 2
• Immunocompromised status 2
• Signs of peritonitis 5

Inpatient treatment includes: 2, 4

• IV fluid resuscitation 5
• IV antibiotics: Ceftriaxone PLUS metronidazole OR piperacillin-tazobactam 4g/0.5g q6h 2, 3, 4
• Transition to oral antibiotics as soon as patient tolerates oral intake to facilitate earlier discharge 1, 2
• Total antibiotic duration: 4-7 days for immunocompetent patients 2

Complicated Diverticulitis (15% of cases)

Small Abscesses (<4-5 cm)

Initial trial of IV antibiotics alone is appropriate, with a pooled failure rate of 20%. 5, 3

• Antibiotic duration: 7 days for small abscesses 3
• Close monitoring for treatment failure (persistent fever, increasing leukocytosis, worsening clinical condition) 3

Large Abscesses (≥4-5 cm)

Percutaneous drainage combined with IV antibiotics is the recommended approach. 5, 3

• Antibiotic duration after drainage: 4 days in immunocompetent patients with adequate source control 5, 3
• Up to 7 days for immunocompromised or critically ill patients 5, 3
• If percutaneous drainage is not feasible in non-critically ill patients, antibiotics alone can be attempted with close monitoring 3
• In critically ill or immunocompromised patients where drainage is not feasible, surgical intervention should be considered 3

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

• However, patients with distant free gas have a significant failure rate (57-60%) and require close follow-up 3

Diffuse Peritonitis

Patients with diffuse peritonitis require: 5, 3

• Prompt fluid resuscitation 5
• Immediate IV antibiotic administration 5
• Urgent surgical intervention 5, 3

Surgical options include: 3

• Primary resection with anastomosis (with or without diverting stoma) for stable patients 3
• Hartmann's procedure for critically ill patients 3
• Laparoscopic peritoneal lavage should NOT be considered the treatment of choice 3

Special Population: Immunocompromised Patients

Immunocompromised patients are at high risk for failure of standard non-operative treatment and require urgent surgical intervention more frequently (39.3% emergency surgery rate), with significantly higher mortality (31.6%). 1

• Chronic corticosteroid therapy carries the highest risk for emergency surgery 1
• Lower threshold for CT imaging, antibiotic treatment, and surgical consultation 2
• Longer antibiotic duration (10-14 days) 2

Prevention of Recurrence

High-quality diet is the cornerstone of prevention: 2

• High in fiber from fruits, vegetables, whole grains, and legumes (>22.1 g/day) 2
• Low in red meat and sweets 2
• Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—these are NOT associated with increased risk 2

Additional preventive measures: 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

Elective Surgery Considerations

The traditional "two-episode rule" for elective colectomy is no longer accepted. 5

The decision for elective resection should be based on: 5

• Impact on quality of life 5
• Frequency of recurrence 5
• Risk of complicated disease 5
• Patient comorbidities and surgical risk 5

The DIRECT trial demonstrated that elective sigmoidectomy results in significantly better quality of life at 6 months compared to continued conservative management in patients with recurrent/persistent symptoms. 5

Follow-up Colonoscopy

Colonoscopy is recommended 4-6 weeks after resolution of symptoms for: 5, 6

• All patients with complicated diverticulitis 6
• Patients with uncomplicated diverticulitis who have suspicious features on CT or meet age-appropriate screening criteria 6

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, 2
• Do NOT apply the "no antibiotics" approach to patients with abscesses (Hinchey 1b/2 or higher)—the evidence specifically excluded these patients 2
• Do NOT stop antibiotics early even if symptoms improve—complete the full prescribed course 2
• Do NOT extend antibiotics beyond 4 days post-operatively in complicated cases with adequate source control unless the patient is immunocompromised or critically ill 5
• Do NOT delay surgical consultation in patients with frequent recurrences affecting quality of life 5
• Do NOT assume all patients require hospitalization—most can be safely managed as outpatients with appropriate follow-up, resulting in 35-83% cost savings 5, 2