What is the appropriate outpatient treatment for an adult with uncomplicated diverticulitis flare‑up who is hemodynamically stable, afebrile or mildly febrile, tolerating oral intake, and without perforation, abscess, obstruction, or severe comorbidities?

Outpatient Treatment of Uncomplicated Diverticulitis

For hemodynamically stable, immunocompetent adults with uncomplicated diverticulitis who can tolerate oral intake, observation with supportive care alone—without routine antibiotics—is the first-line approach. 1

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Patient Selection for Outpatient Management

All of the following criteria must be met to safely manage a patient at home:

• CT-confirmed uncomplicated disease (no abscess, perforation, fistula, or obstruction) 1
• Ability to tolerate oral fluids and medications 1, 2
• Temperature < 100.4°F (38°C) 1, 2
• Pain controlled with acetaminophen alone (pain score < 4/10) 1
• No significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 1, 2
• Immunocompetent status (no chemotherapy, high-dose steroids, or organ transplant) 1
• Adequate home and social support 1, 2

Cost-effectiveness: Outpatient management saves 35–83% per episode compared to hospitalization, with only a 3–5% failure rate requiring subsequent admission. 1, 3, 4

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Supportive Care Protocol (No Antibiotics)

The DIABOLO trial (528 patients) demonstrated that antibiotics do not accelerate recovery, prevent complications, or reduce recurrence in uncomplicated diverticulitis; hospital stays were actually shorter without antibiotics (2 vs 3 days). 1, 2

Supportive measures include:

• Clear liquid diet for 2–3 days during the acute phase, then advance as tolerated 1, 2, 3
• Adequate oral hydration 1
• Acetaminophen 1 g three times daily for pain (avoid NSAIDs) 1, 3
• Bowel rest while symptoms persist 1

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High-Risk Features Requiring Antibiotics

Reserve antibiotics ONLY for patients with any of the following:

Clinical Indicators

• Persistent fever > 100.4°F or chills despite supportive care 1, 2
• Refractory symptoms or vomiting 1, 2
• Inability to maintain oral hydration 1, 2
• Symptom duration > 5 days before presentation 1, 2

Laboratory Markers

• C-reactive protein > 140 mg/L 1, 2
• White blood cell count > 15 × 10⁹/L or rising leukocytosis 1, 2

CT Findings

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

Patient Factors

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant) 1, 2
• Age > 80 years 1, 2
• Pregnancy 1, 2
• ASA physical status III–IV 1, 2
• Significant comorbidities or frailty 1, 2

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Antibiotic Regimens When Indicated

First-Line Oral Therapy (4–7 days for immunocompetent patients)

Amoxicillin-clavulanate 875/125 mg orally twice daily (validated in the DIABOLO trial) 1, 5, 3, 4

Alternative: Ciprofloxacin 500 mg orally twice daily PLUS Metronidazole 500 mg orally three times daily (for penicillin allergy) 1, 5, 3, 4

Duration

• Immunocompetent patients: 4–7 days 1, 5, 2
• Immunocompromised patients: 10–14 days 1, 5, 2

Complete the full antibiotic course even if symptoms improve early. 1

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Follow-Up and Monitoring

Mandatory re-evaluation within 7 days of diagnosis (earlier if symptoms worsen). 1, 2, 4

Instruct patients to return immediately for:

• Fever > 101°F (38.3°C) 1, 2
• Severe uncontrolled pain (score ≥ 8/10) 1, 2
• Persistent vomiting 1, 2
• Inability to eat or drink 1, 2
• Signs of dehydration 1

If symptoms persist beyond 5–7 days despite appropriate management, obtain repeat CT imaging to rule out complications. 1

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Indications for Hospital Admission

Admit patients with any of the following:

• Complicated diverticulitis on CT (abscess ≥ 4–5 cm, perforation, fistula, obstruction) 1, 2
• Inability to tolerate oral intake 1, 2
• Signs of systemic inflammatory response or sepsis 1, 2
• Immunocompromised status 1, 2
• Significant comorbidities or frailty preventing safe home management 1, 2

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Post-Acute Management

Schedule colonoscopy 6–8 weeks after symptom resolution for first episode of uncomplicated diverticulitis (if no recent high-quality colonoscopy), complicated disease, or patients ≥ 50 years needing routine screening. 1

Recurrence prevention measures:

• High-fiber diet (≥ 22 g/day from fruits, vegetables, whole grains, legumes) 1
• Regular vigorous physical activity 1
• Maintain BMI 18–25 kg/m² 1
• Smoking cessation 1
• Avoid NSAIDs when possible 1

Do NOT restrict nuts, corn, popcorn, or small-seeded fruits—they are not associated with increased diverticulitis risk. 1

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Common Pitfalls to Avoid

• Do NOT prescribe routine antibiotics for uncomplicated diverticulitis without high-risk features—this adds antimicrobial resistance without clinical benefit. 1, 2
• Do NOT assume all diverticulitis patients need hospitalization—most immunocompetent patients with uncomplicated disease can be safely managed outpatient. 1, 2
• Do NOT discharge patients without CT confirmation of uncomplicated disease. 1
• Do NOT overlook immunocompromised patients—they require immediate antibiotics (10–14 days), lower threshold for repeat imaging, and early surgical consultation. 1, 2

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Special Populations

Immunocompromised patients: Require immediate antibiotic therapy for 10–14 days, lower threshold for CT imaging, and early surgical consultation regardless of other factors. 1, 2

Elderly patients (> 65 years): Lower threshold for antibiotic treatment and closer monitoring, even when outpatient criteria are otherwise met. 1, 5