What is the treatment for diverticulitis?

Treatment of Diverticulitis

Initial Classification and Risk Stratification

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, 2, 3

Uncomplicated diverticulitis is defined as localized diverticular inflammation without abscess or perforation, confirmed by CT scan showing diverticula, wall thickening, and increased pericolic fat density. 1, 4

Treatment Algorithm for Uncomplicated Diverticulitis

Low-Risk Patients (No Antibiotics Needed)

For immunocompetent patients without risk factors, management consists of:

• Clear liquid diet during acute phase, advancing as symptoms improve 2, 3
• Pain control with acetaminophen (avoid NSAIDs and opioids) 3, 5
• Outpatient management if able to tolerate oral intake and has adequate home support 1, 2
• Mandatory re-evaluation within 7 days; earlier if clinical deterioration occurs 2, 4

High-Risk Patients (Antibiotics Indicated)

Reserve antibiotics for patients with ANY of the following risk factors:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 2, 3, 5
• Age >80 years 2, 4, 5
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 2, 5
• Systemic symptoms (persistent fever >101°F, chills, sepsis) 2, 4, 5
• Increasing leukocytosis or WBC >15 × 10^9/L 2, 3
• CRP >140 mg/L 2, 4
• Pregnancy 4, 5
• Refractory symptoms or vomiting 2, 3
• CT findings of fluid collection or longer segment of inflammation 2, 3, 4
• ASA score III or IV 3
• Symptoms >5 days duration 3

Antibiotic Regimens When Indicated

Outpatient Oral Regimens (Preferred)

• First-line: Amoxicillin-clavulanate (Augmentin) 625 mg three times daily for 4-7 days 1, 2, 5
• Alternative: Ciprofloxacin 500 mg twice daily PLUS metronidazole 500 mg three times daily for 4-7 days 2, 3, 5
• Alternative: Cefalexin plus metronidazole 5

Inpatient IV Regimens

For patients unable to tolerate oral intake or with severe symptoms:

• Ceftriaxone plus metronidazole 3, 5
• Cefuroxime plus metronidazole 2, 5
• Piperacillin-tazobactam 2, 3, 5
• Ampicillin-sulbactam 2, 5

Transition from IV to oral antibiotics as soon as possible to facilitate earlier discharge 2, 4

Duration of Antibiotic Therapy

• Immunocompetent patients: 4-7 days 2, 4
• Immunocompromised or critically ill patients: 7-14 days 2, 4
• Complicated diverticulitis with abscess drainage: 4 days after adequate drainage 2

Treatment of Complicated Diverticulitis

Small Abscesses (<4-5 cm)

• Antibiotic therapy alone for 7 days 2, 4
• IV antibiotics: ceftriaxone plus metronidazole or piperacillin-tazobactam 3, 5

Large Abscesses (≥4-5 cm)

• Percutaneous drainage combined with antibiotic therapy for 4 days 2, 3, 4
• Surgical consultation for failed drainage or clinical deterioration 3, 4

Generalized Peritonitis

• Emergent laparotomy with colonic resection 5
• Postoperative mortality: 0.5% for elective resection vs 10.6% for emergent resection 5

Inpatient vs Outpatient Decision

Criteria for Outpatient Management

• Able to tolerate oral intake 1, 2
• No significant comorbidities or frailty 2, 3
• Adequate home support 1, 2
• No systemic inflammatory response or sepsis 3
• Immunocompetent status 2, 3

Criteria for Inpatient Management

• Complicated diverticulitis 3, 4
• Inability to tolerate oral intake 2, 3
• Severe pain or systemic symptoms 3, 4
• Significant comorbidities or frailty 2, 3
• Immunocompromised status 2, 3

Outpatient management reduces costs by 35-83% per episode and decreases risk of hospital-acquired infections 3

Critical Pitfalls to Avoid

• Failing to recognize high-risk patients who need antibiotics despite having uncomplicated disease can lead to progression to complicated diverticulitis 2, 4
• Overusing antibiotics in low-risk immunocompetent patients provides no benefit and contributes to antibiotic resistance 1, 4
• Stopping antibiotics early, even if symptoms improve, may lead to incomplete treatment and recurrence 3
• Overlooking corticosteroid use as a risk factor for perforation 3
• Failing to establish reliable follow-up mechanisms for outpatient management 3
• Assuming all patients require inpatient management 3

Post-Discharge Management

• Complete full antibiotic course as prescribed 3
• Avoid alcohol until 48 hours after completing metronidazole 3
• Monitor for warning signs: fever >101°F, severe uncontrolled pain, persistent vomiting, inability to eat/drink, signs of dehydration 3
• Follow-up with primary care within 2 weeks 3
• Consider colonoscopy for diverticular abscesses to rule out underlying malignancy 4

Prevention of Recurrence

• High-quality diet: high in fiber from fruits, vegetables, whole grains, legumes; low in red meat and sweets 3
• Regular vigorous physical activity 3
• Achieve or maintain normal BMI 3
• Avoid smoking 3
• Avoid regular use of NSAIDs and opioids when possible 3
• Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—these are not associated with increased risk 2, 3