What is the recommended treatment for diverticulitis?

Treatment of Acute Diverticulitis

For immunocompetent patients with uncomplicated diverticulitis, antibiotics are not recommended—observation with supportive care (clear liquid diet and pain control with acetaminophen) is the first-line treatment. 1

Classification: Uncomplicated vs Complicated Disease

Uncomplicated diverticulitis is defined as localized diverticular inflammation without abscess or perforation, confirmed by CT scan showing diverticula, colonic wall thickening, and increased density of pericolic fat. 1, 2

Complicated diverticulitis involves abscess formation, perforation, fistula, obstruction, or generalized peritonitis. 2, 3

Treatment Algorithm for Uncomplicated Diverticulitis

Step 1: Determine if Antibiotics Are Needed

Most immunocompetent patients do NOT require antibiotics. Multiple high-quality randomized trials, including the landmark Chabok trial with 623 patients, demonstrated that antibiotics neither accelerate recovery nor prevent complications or recurrence in uncomplicated cases. 1

Reserve antibiotics ONLY for patients with:

• Immunocompromised status (chronic corticosteroids, transplant recipients, chemotherapy, chronic renal failure) 1, 3
• Systemic symptoms (persistent fever >101°F, chills, sepsis) 2, 3
• Age >80 years 2, 3
• Pregnancy 3
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 3
• Laboratory markers: CRP >140 mg/L or WBC >15 × 10^9/L 2, 4
• CT findings: fluid collection or longer segment of inflammation 2, 4
• Symptoms >5 days or presence of vomiting 2, 4

Step 2: Outpatient vs Inpatient Management

Outpatient management is appropriate for uncomplicated diverticulitis when patients:

• Can tolerate oral fluids and medications 4, 5
• Have no significant comorbidities or frailty 4, 6
• Have adequate home support 4
• Have pain controlled with acetaminophen alone 4

Hospitalization is required for:

• Complicated diverticulitis 2, 6
• Inability to tolerate oral intake 2, 6
• Severe pain or systemic symptoms 2, 6
• Significant comorbidities or immunocompromised status 2, 6

Step 3: Antibiotic Selection (When Indicated)

Oral regimens for outpatient treatment (4-7 days for immunocompetent patients): 2, 4

• First-line: Ciprofloxacin 500 mg PO twice daily PLUS metronidazole 500 mg PO three times daily 4, 3
• Alternative: Amoxicillin-clavulanate 875/125 mg PO twice daily 4, 3

IV regimens for inpatient treatment: 3

• Ceftriaxone PLUS metronidazole 3
• Piperacillin-tazobactam 3
• Cefuroxime PLUS metronidazole 3

Duration of antibiotic therapy:

• Immunocompetent patients: 4-7 days 2, 4
• Immunocompromised patients: 10-14 days 2, 4

Transition from IV to oral antibiotics as soon as the patient can tolerate oral intake to facilitate earlier discharge. 1, 4

Treatment of Complicated Diverticulitis

For abscesses <4 cm: Antibiotic therapy alone for 7 days 2, 6

For abscesses ≥4-5 cm: Percutaneous drainage combined with antibiotic therapy for 4 days 1, 2, 6

For generalized peritonitis: Emergent laparotomy with colonic resection PLUS IV antibiotics (piperacillin-tazobactam, meropenem, or ceftriaxone plus metronidazole) 6, 3

Postoperative antibiotic duration: 4 days for immunocompetent patients with adequate source control; up to 7 days for immunocompromised or critically ill patients 4

Special Populations: Immunocompromised Patients

Immunocompromised patients are at high risk for failure of standard non-operative treatment. 1 The rate of emergency surgery in this population is 39.3%, with postoperative mortality of 31.6%. 1 Patients on chronic corticosteroid therapy have the highest risk and most frequently require emergency surgery. 1

These patients require:

• Lower threshold for CT imaging, antibiotic treatment, and surgical consultation 4
• Longer antibiotic duration (10-14 days) 2, 4
• Close monitoring for progression to complicated disease 4

Follow-Up and Monitoring

Re-evaluation within 7 days is recommended; earlier if clinical condition deteriorates. 2, 4

Warning signs requiring immediate medical attention:

• Fever >101°F 4
• Severe uncontrolled pain 4
• Persistent nausea or vomiting 4
• Inability to eat or drink 4
• Signs of dehydration 4

Common Pitfalls to Avoid

Do not routinely prescribe antibiotics for all patients with uncomplicated diverticulitis. This provides no benefit in immunocompetent patients and contributes to antibiotic resistance. 1, 2

Do not fail to recognize high-risk patients who need antibiotics despite having uncomplicated disease. Immunocompromised status, advanced age, significant comorbidities, and elevated inflammatory markers are critical risk factors for progression. 2

Do not stop antibiotics early, even if symptoms improve. Complete the full prescribed course to prevent incomplete treatment and recurrence. 4

Do not assume all patients require hospitalization. Outpatient management is safe and cost-effective for appropriately selected patients, reducing costs by 35-83% per episode and avoiding hospital-acquired infections. 5

Do not overlook young patients (<50 years) or those with high pain scores (≥8/10). These patients have increased risk for complicated or recurrent diverticulitis and require closer monitoring. 2