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 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 2, 3
• 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 for Most Patients

• Antibiotics are NOT recommended for immunocompetent patients without systemic inflammation (strong recommendation based on high-quality evidence) 1
• Management consists of observation, pain control with acetaminophen, and clear liquid diet 3
• This represents a paradigm shift from traditional practice, as multiple studies demonstrate antimicrobial treatment is not superior to withholding antibiotics for clinical resolution 1

When to Use Antibiotics in Uncomplicated Disease

Reserve antibiotics for patients with:

• Persistent fever or chills 3
• Increasing leukocytosis 3
• Age >80 years 3
• Pregnancy 3
• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 3
• Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 3

Antibiotic Selection for Uncomplicated Disease

• First-line oral antibiotics: amoxicillin/clavulanic acid OR cefalexin plus metronidazole 3
• If unable to tolerate oral intake: IV cefuroxime or ceftriaxone plus metronidazole, OR ampicillin/sulbactam 3
• When oral antibiotics are used, prefer oral administration as early switch from IV to oral facilitates shorter hospital stays 1

Microperforation with Pericolic Gas

• For isolated pericolic extraluminal gas without diffuse peritonitis, attempt non-operative treatment with antibiotics in hemodynamically stable patients 2, 5
• However, patients with distant free gas have a 57-60% failure rate and require close monitoring 5

Treatment of Complicated Diverticulitis

Small Abscesses (<4 cm)

Initial trial of antibiotics alone is recommended with a pooled failure rate of 20% and mortality rate of 0.6% 2, 5

Large Abscesses (≥4 cm)

Percutaneous drainage combined with antibiotic therapy is the recommended approach 2, 5

• If percutaneous drainage is not feasible in non-critically ill, immunocompetent patients, antibiotics alone may be considered 5
• In critically ill or immunocompromised patients where drainage is not feasible, proceed to surgical intervention 5

Antibiotic Selection for Complicated Disease

Empiric regimen should be based on clinical condition, presumed pathogens, and antimicrobial resistance risk factors 2, 5

• For non-critically ill, immunocompetent patients: piperacillin/tazobactam 4g/0.5g q6h OR eravacycline 1 mg/kg q12h 5
• For inadequate source control or high ESBL risk: ertapenem 1g q24h OR eravacycline 1 mg/kg q12h 5
• Alternative regimens: ceftriaxone plus metronidazole 3, 4

Duration of Antibiotic Therapy

A 4-day postoperative antibiotic course is recommended if source control is adequate (based on the STOP IT trial showing similar outcomes to longer courses) 2, 5

• For immunocompromised or critically ill patients with adequate source control, extend up to 7 days based on clinical condition and inflammatory markers 5

Diffuse Peritonitis

Patients with diffuse peritonitis require:

• Prompt fluid resuscitation 2, 4
• Immediate IV antibiotic administration 2, 4
• Urgent surgical intervention 2, 3

Surgical Options

• Primary resection and anastomosis with or without diverting stoma 5
• Hartmann's procedure 5, 4
• Laparoscopic peritoneal lavage and drainage 5
• Laparoscopic surgery results in shorter hospital stays, fewer complications, and lower mortality compared to open colectomy 6

Special Populations

Immunocompromised Patients

Immunocompromised patients should be considered 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% emergency surgery rate, 31.6% postoperative mortality, and 27.8% recurrence rate after successful non-operative management 1
• Patients on chronic corticosteroid therapy have the highest need for emergency surgery 1

Monitoring and Follow-up

Monitor for treatment failure including:

• Persistent fever 5
• Increasing leukocytosis 5
• Worsening clinical condition 5
• Track white blood cell count, C-reactive protein, and procalcitonin 5

Colonoscopy is recommended:

• 4-6 weeks after resolution for patients with complicated disease 6, 4
• For patients with suspicious CT features or who meet bowel cancer screening criteria 4

Elective Surgery Considerations

The decision for elective resection should be individualized rather than following the outdated "two-episode rule" 2

Consider:

• Risk factors for recurrence 2
• Morbidity of surgery (0.5% mortality for elective vs. 10.6% for emergent resection) 3
• Ongoing symptoms 2
• Disease complexity 2
• Patient comorbidities 2

Common Pitfalls

• Do not reflexively prescribe antibiotics for all uncomplicated diverticulitis—this outdated practice is not supported by current evidence 1
• Do not delay surgical consultation in immunocompromised patients—they have significantly higher failure rates with conservative management 1
• Do not extend antibiotic courses beyond 4 days if source control is adequate—longer courses provide no additional benefit 2, 5