What is the treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, observation with supportive care (clear liquid diet and pain control with acetaminophen) is the recommended first-line approach, reserving antibiotics only for those with specific high-risk features. 1, 2

Classification and Initial Assessment

Uncomplicated diverticulitis is defined as localized inflammation without abscess, perforation, fistula, obstruction, or bleeding, typically confirmed by CT scan showing diverticula, wall thickening, and increased density of pericolic fat. 2, 3 This represents approximately 85-88% of acute diverticulitis cases. 4, 2

Complicated diverticulitis involves abscess formation, perforation, fistula, or obstruction and always requires antibiotics and potentially invasive intervention. 3, 2

CT scan with oral and intravenous contrast is the gold standard diagnostic test, with 98-99% sensitivity and 99-100% specificity. 1, 4

Treatment Algorithm for Uncomplicated Diverticulitis

Supportive Care (First-Line for Most Patients)

Multiple high-quality randomized controlled trials, including the DIABOLO trial with 528 patients, demonstrate that antibiotics neither accelerate recovery nor prevent complications or recurrence in immunocompetent patients with mild uncomplicated diverticulitis. 2, 3

Initial management consists of:

• Clear liquid diet during the acute phase, advancing as symptoms improve 1, 2
• Pain control with acetaminophen (avoid NSAIDs and opioids as they increase diverticulitis risk) 2, 4
• Observation without antibiotics for immunocompetent patients with mild disease 1, 2
• Re-evaluation within 7 days; earlier if clinical condition deteriorates 1, 2

When Antibiotics ARE Indicated in Uncomplicated Diverticulitis

Reserve antibiotics for patients with ANY of the following high-risk features: 1, 2

Systemic/Clinical Indicators:

• Persistent fever or chills despite supportive care 2
• Increasing leukocytosis (WBC >15 × 10⁹ cells/L) 1, 2
• Elevated CRP >140 mg/L 1, 2
• Refractory symptoms or vomiting 1, 2
• Inability to maintain oral hydration 2
• Symptoms lasting >5 days prior to presentation 1, 2

Patient-Specific Risk Factors:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 1, 2, 4
• Age >80 years 2, 4
• Pregnancy 2, 4
• Significant comorbidities or frailty (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 2, 4
• ASA score III or IV 1, 2

CT Imaging Findings:

• Fluid collection or abscess 1, 2
• Longer segment of inflammation 1, 2
• Pericolic extraluminal air 2

Antibiotic Regimens When Indicated

Outpatient Oral Therapy (4-7 days for immunocompetent patients)

First-line options: 1, 2, 5

• Ciprofloxacin 500 mg orally twice daily PLUS Metronidazole 500 mg orally three times daily
• Amoxicillin-clavulanate 875/125 mg orally twice daily (alternative, provides comprehensive coverage)

Inpatient IV Therapy

For patients unable to tolerate oral intake or with severe disease: 1, 2, 4

• Ceftriaxone PLUS Metronidazole
• Piperacillin-tazobactam
• Cefuroxime PLUS Metronidazole

Transition to oral antibiotics as soon as the patient tolerates oral intake to facilitate earlier discharge. Hospital stays are actually shorter in observation groups (2 vs 3 days). 2, 5

Duration of Antibiotic Therapy

• Immunocompetent patients: 4-7 days 1, 2, 5
• Immunocompromised patients: 10-14 days 1, 2
• Post-drainage for complicated disease with adequate source control: 4 days 1, 2

Treatment of Complicated Diverticulitis

Small Abscesses (<4-5 cm)

• IV antibiotics alone for 7 days 2, 3
• Close clinical monitoring for progression 2

Large Abscesses (≥4-5 cm)

• Percutaneous CT-guided drainage PLUS IV antibiotics for 4 days 2, 5, 3
• Cultures from drainage guide antibiotic selection 5

Generalized Peritonitis or Sepsis

• Emergent surgical consultation 2, 3
• IV antibiotics with broad-spectrum coverage 2, 4
• Surgical options include primary resection with anastomosis or Hartmann's procedure 2

Outpatient vs. Inpatient Management

Criteria for Outpatient Management

Patients appropriate for outpatient treatment must meet ALL of the following: 2, 6

• Ability to tolerate oral fluids and medications
• No significant comorbidities or frailty
• Adequate home and social support
• Temperature <100.4°F (38°C)
• Pain score <4/10 (controlled with acetaminophen alone)
• Ability to maintain self-care at pre-illness level

Outpatient management results in 35-83% cost savings per episode compared to hospitalization. 2

Indications for Hospitalization

• Complicated diverticulitis 2, 3
• Inability to tolerate oral intake 2, 3
• Severe pain or systemic symptoms 2
• Significant comorbidities or frailty 2
• Immunocompromised status 1, 2
• Systemic inflammatory response or sepsis 2

Post-Acute Management and Prevention

Follow-up Colonoscopy

Perform colonoscopy 4-6 weeks after symptom resolution for: 2

• Complicated diverticulitis (7.9% risk of colon cancer)
• First episode of uncomplicated diverticulitis in patients >50 years requiring routine screening
• Patients who haven't had high-quality colonoscopy in the past year

Lifestyle Modifications to Prevent Recurrence

Strongly recommend: 1, 2

• High-quality diet: High in fiber from fruits, vegetables, whole grains, legumes (>22.1 g/day); low in red meat and sweets
• Regular vigorous physical activity
• Achieve or maintain normal BMI (18-25 kg/m²)
• Smoking cessation
• Avoid nonaspirin NSAIDs when possible (aspirin use does not need to be routinely avoided)

Do NOT restrict: Nuts, corn, popcorn, or small-seeded fruits—these are NOT associated with increased diverticulitis risk. 1, 2

Do NOT prescribe: Mesalamine or rifaximin for prevention—strong evidence shows no benefit. 2

Special Populations

Immunocompromised Patients

• Require lower threshold for CT imaging, antibiotic treatment, and surgical consultation 1, 2
• May present with milder signs despite more severe disease 2
• Corticosteroid use specifically increases risk of perforation and death 1, 2
• Require longer antibiotic duration (10-14 days) 1, 2

Elderly Patients (>80 years)

• Higher risk for complications and progression 2, 5
• Lower threshold for antibiotic therapy 2, 4
• Surgery carries higher mortality (10.6% for emergent vs 0.5% for elective resection) 4

Critical Pitfalls to Avoid

• Overusing antibiotics in uncomplicated diverticulitis without risk factors contributes to antibiotic resistance without clinical benefit 2, 3
• Failing to recognize high-risk features that predict progression to complicated disease (CRP >140 mg/L, WBC >15 × 10⁹/L, symptoms >5 days, vomiting, fluid collection on CT) 1, 2
• Applying the "no antibiotics" approach to Hinchey 1b/2 or higher disease—the evidence specifically excluded these patients 2
• Stopping antibiotics early even if symptoms improve—complete the full course when indicated 2
• Unnecessarily restricting diet (avoiding nuts, seeds, popcorn) is not evidence-based and may reduce overall fiber intake 1, 2
• Assuming all patients require hospitalization when most can be safely managed as outpatients with appropriate follow-up 2, 6
• Delaying surgical consultation in patients with frequent recurrence affecting quality of life 2

Surgical Considerations

Elective surgery should NOT be based on number of episodes alone, but rather on: 2

• Quality of life impact
• Frequency of recurrence
• Patient preferences
• Operative risks and benefits

The traditional "two-episode rule" is no longer accepted. 2 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. 2