What is the treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, observation without antibiotics is the recommended first-line treatment—antibiotics should be reserved only for those with specific high-risk features such as immunocompromised status, persistent fever, increasing leukocytosis, or systemic symptoms. 1, 2

Initial Assessment and Classification

Your first step is determining whether the diverticulitis is uncomplicated (localized inflammation without abscess, perforation, fistula, or obstruction) or complicated (presence of any of these features). 1, 3

• CT scan with IV contrast is the gold standard for diagnosis, with 98-99% sensitivity and 99-100% specificity. 1, 3
• Laboratory workup should include complete blood count, C-reactive protein, and basic metabolic panel. 4
• High-risk features predicting progression include: CRP >140 mg/L, WBC >15 × 10⁹ cells/L, symptoms >5 days, ASA score III or IV, presence of fluid collection or longer segment of inflammation on CT, and pericolic extraluminal air. 1

Treatment Algorithm for Uncomplicated Diverticulitis

Step 1: Determine if Antibiotics Are Needed

Most immunocompetent patients do NOT need antibiotics. The DIABOLO trial with 528 patients demonstrated no difference in recovery time, recurrence rates, or complications between antibiotic and observation groups. 1, 2

Reserve antibiotics ONLY for patients with:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 1, 3
• Persistent fever or chills despite supportive care 1
• Increasing leukocytosis or CRP >140 mg/L 1
• Age >80 years 1, 3
• Pregnancy 1, 3
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 1, 3
• Refractory symptoms, vomiting, or inability to maintain oral hydration 1
• Fluid collection or longer segment of inflammation on CT 1

Step 2: Choose Outpatient vs. Inpatient Management

Outpatient management is appropriate when ALL of the following are met: 1, 2

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

Hospitalization is required for: 1, 2

• Complicated diverticulitis
• Inability to tolerate oral intake
• Severe pain or systemic symptoms (sepsis)
• Immunocompromised status
• Significant comorbidities or frailty

Step 3: Supportive Care (For All Patients)

• Clear liquid diet during acute phase, advancing as symptoms improve 1
• Acetaminophen for pain control (avoid NSAIDs and opioids as they increase diverticulitis risk) 1
• Adequate hydration 1

Step 4: Antibiotic Regimens (If Indicated)

Outpatient oral regimens (4-7 days for immunocompetent patients): 1, 3

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

Inpatient IV regimens: 1, 3

• Ceftriaxone PLUS metronidazole
• Piperacillin-tazobactam
• Transition to oral antibiotics as soon as patient tolerates oral intake to facilitate earlier discharge 1

Duration of therapy: 1

• 4-7 days for immunocompetent patients
• 10-14 days for immunocompromised patients

Treatment of Complicated Diverticulitis

Small Abscesses (<4-5 cm)

• IV antibiotics alone for 7 days may be sufficient, with a pooled failure rate of 20%. 2, 5

Large Abscesses (≥4-5 cm)

• Percutaneous CT-guided drainage PLUS IV antibiotics is the recommended approach. 1, 5
• Antibiotic duration: 4 days in immunocompetent patients with adequate source control, up to 7 days in immunocompromised or critically ill patients. 5

Generalized Peritonitis or Sepsis

• Emergent surgical consultation with IV antibiotics (ceftriaxone plus metronidazole or piperacillin-tazobactam). 1, 3
• Surgical options include primary resection with anastomosis or Hartmann procedure. 1

Follow-Up and Monitoring

• Re-evaluation within 7 days is mandatory, with earlier assessment if clinical condition deteriorates. 1, 2
• Monitor for decreased abdominal pain, resolution of fever, and normalization of bowel movements. 1
• Warning signs requiring immediate attention: fever >101°F, severe uncontrolled pain, persistent nausea/vomiting, inability to eat or drink, signs of dehydration. 1

Post-Acute Management

Colonoscopy Timing

• Perform colonoscopy 4-6 weeks after resolution for complicated diverticulitis or first episode in patients >50 years to exclude malignancy (1.16% risk of colorectal cancer in uncomplicated cases, 7.9% in complicated cases). 1

Prevention of Recurrence

Lifestyle modifications significantly reduce recurrence risk: 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 BMI 18-25 kg/m²
• Smoking cessation
• Avoid regular use of NSAIDs and opioids

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—there is strong evidence against their efficacy. 1

Surgical Considerations

Elective surgery should NOT be based on number of episodes alone. The traditional "two-episode rule" is no longer accepted. 1, 2

Base the decision on: 1, 2

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

The DIRECT trial showed significantly better quality of life at 6 months with elective sigmoidectomy versus continued conservative management in patients with recurrent/persistent symptoms. 2

Common Pitfalls to Avoid

• Overusing antibiotics in uncomplicated cases without risk factors contributes to antibiotic resistance without clinical benefit. 1
• Assuming all patients require hospitalization when most can be safely managed as outpatients with appropriate follow-up (outpatient management has only 4.3% failure rate and results in 35-83% cost savings). 1, 2
• Unnecessarily restricting diet (avoiding nuts, seeds, popcorn) is not evidence-based and may reduce overall fiber intake. 1
• Stopping antibiotics early if they are indicated, even if symptoms improve. 1
• Applying the "no antibiotics" approach to complicated diverticulitis—the evidence specifically excluded these patients. 1
• Delaying surgical consultation in patients with frequent recurrence affecting quality of life. 1