What is the treatment for diverticulitis?

Treatment of Diverticulitis

Antibiotic treatment should be used selectively rather than routinely in patients with uncomplicated diverticulitis, while antibiotics are necessary for complicated diverticulitis or for high-risk patients with uncomplicated disease. 1

Classification and Diagnosis

Diverticulitis is classified into two main categories:

1. Uncomplicated diverticulitis:

   • Inflammation of diverticula without perforation, abscess, or peritonitis
   • Typically shows colonic wall thickening and pericolic inflammatory changes on CT scan

2. Complicated diverticulitis:

   • Includes abscess, perforation, peritonitis, obstruction, stricture, or fistula
   • Approximately 12% of patients present with complicated disease 1

Diagnosis typically requires CT imaging to confirm the presence and severity of diverticulitis.

Treatment Algorithm

1. Uncomplicated Diverticulitis

A. Low-risk patients (immunocompetent with mild symptoms):

• Diet: Clear liquid diet during acute phase, advancing as symptoms improve 1
• Antibiotics: Can be withheld in immunocompetent patients with mild disease 1
• Setting: Outpatient management for patients who can take fluids orally and have no significant comorbidities 1
• Follow-up: Re-evaluation within 7 days; earlier if clinical condition deteriorates 1

B. High-risk patients with uncomplicated diverticulitis:

Antibiotics are advised for patients with any of the following 1:

• Comorbidities or frailty
• Refractory symptoms or vomiting
• CRP >140 mg/L
• White blood cell count >15 × 10⁹ cells per liter
• Fluid collection or longer segment of inflammation on CT scan
• Immunocompromised status

2. Complicated Diverticulitis

A. Small abscess (<4 cm):

• Antibiotics alone may be sufficient 1
• Close clinical monitoring required

B. Large abscess (>4 cm):

• Percutaneous drainage plus intravenous antibiotics 1
• If drainage not feasible, antibiotics alone with careful monitoring 1

C. Diffuse peritonitis:

• Surgical intervention
• Antibiotic therapy covering Gram-negative bacilli and anaerobes 1
• Duration: 4 days of postoperative antibiotic therapy if source control has been adequate 1

Antibiotic Regimens

When antibiotics are indicated:

Outpatient setting:

• Oral fluoroquinolone (e.g., ciprofloxacin) plus metronidazole, OR
• Amoxicillin-clavulanate monotherapy 1
• Duration: 4-7 days (can be longer based on clinical response) 1

Inpatient setting:

• IV antibiotics with coverage for gram-negative and anaerobic bacteria
• Oral antibiotics may be equally effective as IV administration 1
• Consider early switch from IV to oral antibiotics to facilitate discharge 1

Special Considerations

1. Outpatient vs. Inpatient Management:

   • Outpatient treatment is safe and effective for selected patients with uncomplicated diverticulitis 1, 2
   • Hospitalization criteria: significant comorbidities, inability to take oral fluids, severe pain, or signs of systemic inflammation 1

2. Duration of Antibiotic Therapy:

   • Short-course IV antibiotic treatment (≤5 days) does not increase recurrence rates compared to longer courses 3
   • For complicated diverticulitis with adequate source control, 4 days of antibiotics is sufficient 1

3. Colonoscopy:

   • Should be performed after resolution of acute episode (6-8 weeks later) to exclude malignancy
   • May be deferred if high-quality colonoscopy was performed within the past year 1

4. Chronic Symptoms:

   • About 45% of patients report periodic abdominal pain at 1-year follow-up
   • Exclude ongoing inflammation with imaging and colonoscopy
   • Consider visceral hypersensitivity and treat with low-dose tricyclic antidepressants if appropriate 1

Pitfalls to Avoid

1. Overuse of antibiotics in mild uncomplicated cases where they may not be necessary
2. Failure to identify high-risk patients who require antibiotics despite having uncomplicated disease
3. Delayed recognition of treatment failure - patients should be re-evaluated if symptoms worsen or fail to improve
4. Inadequate follow-up - patients should be monitored for resolution and potential complications
5. Missing underlying malignancy - colonoscopy should be performed after resolution to exclude cancer

The treatment approach to diverticulitis has evolved significantly in recent years, with a trend toward more conservative management for uncomplicated cases while maintaining aggressive treatment for complicated disease or high-risk patients.