What is the treatment for diverticulitis?

Treatment of Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, observation without antibiotics is the recommended first-line treatment, as antibiotics do not accelerate recovery, prevent complications, or reduce recurrence rates. 1

Classification and Initial Assessment

Diverticulitis is classified into two categories that determine treatment approach:

• Uncomplicated diverticulitis: Localized inflammation without abscess, perforation, fistula, obstruction, or bleeding 1
• Complicated diverticulitis: Inflammation with abscess, perforation, fistula, obstruction, or bleeding requiring more aggressive intervention 1

CT scan is the gold standard for diagnosis, with 98-99% sensitivity and 99-100% specificity 2

Treatment Algorithm for Uncomplicated Diverticulitis

Step 1: Determine if Antibiotics Are Needed

Most patients do NOT need antibiotics. Reserve antibiotics only for patients with these specific risk factors 1, 3:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant)
• Age >80 years
• Pregnancy
• Persistent fever or chills
• Increasing leukocytosis (WBC >15 × 10⁹ cells/L)
• Elevated CRP >140 mg/L
• Vomiting or inability to maintain hydration
• Symptoms lasting >5 days
• CT findings showing pericolic extraluminal air, fluid collection, or longer inflamed colon segment
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes)

Step 2: Outpatient vs Inpatient Management

Outpatient management is appropriate for most patients who meet these criteria 1, 4:

• Can 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
• Significant comorbidities or frailty
• Immunocompromised status
• Generalized peritonitis

Step 3: Supportive Care (All Patients)

• Clear liquid diet during acute phase, advancing as symptoms improve 1
• Pain control with acetaminophen (avoid NSAIDs and opioids as they increase diverticulitis risk) 1, 2
• Adequate hydration 1

Antibiotic Regimens When Indicated

Outpatient Oral Antibiotics (4-7 days for immunocompetent patients) 1, 2

First-line options:

• Amoxicillin-clavulanate 875/125 mg orally twice daily 1, 2
• Ciprofloxacin 500 mg orally twice daily PLUS metronidazole 500 mg orally three times daily 1

Duration:

• 4-7 days for immunocompetent patients 1
• 10-14 days for immunocompromised patients 1

Inpatient IV Antibiotics 1, 2

Options with gram-negative and anaerobic coverage:

• Ceftriaxone plus metronidazole 1, 2
• Piperacillin-tazobactam 1, 2
• Cefuroxime plus metronidazole 2
• Ampicillin-sulbactam 2

Transition strategy: Switch to oral antibiotics as soon as patient tolerates oral intake to facilitate earlier discharge 1

Treatment of Complicated Diverticulitis

All patients with complicated diverticulitis require 1, 2:

• Hospitalization with IV fluid resuscitation
• IV antibiotics with gram-negative and anaerobic coverage (ceftriaxone plus metronidazole or piperacillin-tazobactam)
• Surgical consultation

Specific interventions based on complication:

• Abscess ≥4-5 cm: Percutaneous drainage when feasible 1
• Generalized peritonitis: Emergent laparotomy with colonic resection 2
• Adequate surgical source control: Limit antibiotics to 4 days postoperatively 1

Follow-up and Monitoring

• Re-evaluation within 7 days from diagnosis; earlier if clinical condition deteriorates 1, 3
• Monitor for warning signs requiring immediate attention: fever >101°F, severe uncontrolled pain, persistent nausea/vomiting, inability to eat or drink 1
• Colonoscopy should be performed 4-8 weeks after symptom resolution to exclude malignancy or inflammatory bowel disease 5

Prevention of Recurrence

Lifestyle modifications to reduce recurrence risk 1:

• High-quality diet: high in fiber from fruits, vegetables, whole grains, legumes; low in red meat and sweets
• Regular physical activity, particularly vigorous exercise
• Achieve or maintain normal body mass index
• Avoid smoking
• Avoid regular use of NSAIDs and opioids when possible

Important dietary guidance:

• Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—these are not associated with increased diverticulitis risk 1
• Fiber supplementation can be beneficial but is not a replacement for a high-quality diet 1

Critical Pitfalls to Avoid

• Do not automatically prescribe antibiotics for all diverticulitis cases—multiple high-quality randomized controlled trials (including the DIABOLO trial with 528 patients) demonstrate no benefit in uncomplicated cases without risk factors 1, 3
• Do not miss immunocompromised status—these patients ALWAYS require antibiotics and have lower threshold for hospitalization 1, 3
• Do not extend antibiotics beyond 4-7 days for immunocompetent patients—longer duration (10-14 days) is specifically for immunocompromised patients only 1
• Do not perform colonoscopy during acute episode—wait 4-8 weeks after symptom resolution 5
• Do not assume all patients require hospitalization—outpatient management results in 35-83% cost savings per episode and reduced hospital-acquired infections 1

Special Populations

Immunocompromised patients require 1:

• Lower threshold for CT imaging, antibiotic treatment, and surgical consultation
• Longer antibiotic duration (10-14 days)
• Higher likelihood of hospitalization

Patients on corticosteroids are at higher risk for perforation and death 1