In a hemodynamically stable older adult with imaging showing diverticula throughout the colon, pericolonic fat stranding in the mid‑sigmoid, trace pericolic fluid, and no abscess or free intraperitoneal air (Hinchey stage 0), what is the recommended outpatient management?

Outpatient Management of Uncomplicated Acute Diverticulitis (Hinchey Stage 0)

In a hemodynamically stable older adult with uncomplicated diverticulitis (Hinchey stage 0), antibiotics should be avoided; outpatient management consists of a clear-liquid diet, acetaminophen for pain control, and close follow-up within 48–72 hours. 1

Confirming Eligibility for Outpatient Management

Your imaging findings—diverticula throughout the colon, pericolonic fat stranding in the mid-sigmoid, trace pericolic fluid, and no abscess or free air—define uncomplicated diverticulitis (WSES Stage 0). 2, 3 This patient can be managed as an outpatient only if all of the following criteria are met:

• Immunocompetent status (no active immunosuppression, chemotherapy, or HIV with CD4 < 200). 2, 3
• Ability to tolerate oral intake without persistent vomiting. 2
• Absence of systemic inflammatory response syndrome (SIRS) or sepsis-related organ failures—specifically, no persistent fever > 38°C, heart rate > 90 bpm, respiratory rate > 20/min, or WBC > 12,000 or < 4,000 cells/μL. 1
• Access to reliable follow-up within 48–72 hours for clinical reassessment. 2, 3
• No significant comorbidities that would impair recovery (e.g., poorly controlled diabetes, chronic kidney disease stage 4–5, or severe cardiac disease). 3

Antibiotic Decision: When to Omit

Routine antibiotics are not required for immunocompetent elderly patients with uncomplicated diverticulitis (WSES stage 0) without sepsis-related organ failures. 1 The 2022 WSES guidelines for elderly patients explicitly state that antibiotic therapy should be avoided in this population when the above criteria are met. 1

The AVOD and DIABOLO trials demonstrated that antibiotics neither accelerate recovery nor prevent complications or recurrences in uncomplicated disease. 1 However, antibiotics are indicated if any of the following red flags are present:

• Age > 80 years. 3
• Immunocompromised status (including pregnancy). 3
• Persistent fever or chills despite initial management. 3
• Rising leukocytosis (WBC > 15 × 10⁹ cells/L). 3
• C-reactive protein > 140 mg/L. 3
• Inability to tolerate oral intake or worsening pain. 3

Outpatient Treatment Protocol

• Diet: Start with a clear-liquid diet (broth, gelatin, clear juices) for 2–3 days until symptoms improve, then advance to low-residue foods as tolerated. 2, 3
• Pain control: Use acetaminophen (650–1000 mg every 6 hours as needed); avoid NSAIDs and opioids when possible, as NSAIDs may worsen inflammation and opioids can cause ileus. 2, 3
• Activity: Encourage light activity as tolerated; bed rest is not required. 3
• Follow-up: Schedule a clinic visit or telephone check-in within 48–72 hours to assess symptom resolution, ability to advance diet, and absence of fever or worsening pain. 2, 3

When to Escalate to Antibiotics or Hospitalization

Admit the patient and initiate intravenous broad-spectrum antibiotics (covering gram-negative and anaerobic organisms, such as ciprofloxacin 400 mg IV every 12 hours plus metronidazole 500 mg IV every 8 hours, or piperacillin-tazobactam 3.375 g IV every 6 hours) if any of the following develop during outpatient management:

• Persistent or worsening abdominal pain after 48–72 hours. 3
• New fever (≥ 38°C) or rising inflammatory markers. 3
• Inability to tolerate oral intake or signs of dehydration. 3
• Development of complications on repeat imaging (abscess, perforation, or distant free air). 2, 3

Predictors of Progression to Complicated Disease

Although your patient has uncomplicated disease, be aware that fluid collections on initial CT (even trace pericolic fluid) and a longer inflamed colon segment (> 8 cm) are associated with progression to complicated diverticulitis within 90 days. 4 Other red flags include:

• Symptoms lasting > 5 days before presentation. 2
• Pain score ≥ 8 on a visual analog scale. 2
• Vomiting. 2
• CRP > 140 mg/L. 2, 3

If any of these are present, consider a lower threshold for hospitalization and closer follow-up (e.g., 24–48 hours instead of 72 hours). 2, 3

Common Pitfalls to Avoid

• Do not routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients; this contributes to antimicrobial resistance without improving outcomes. 1, 3
• Do not order routine colonoscopy after CT-confirmed uncomplicated diverticulitis unless the patient is due for age-appropriate screening or imaging reveals complications (abscess, perforation, fistula, abnormal lymph nodes > 1 cm, or a mass). 2
• Do not discharge patients who cannot tolerate oral intake or who have unreliable follow-up; these patients require hospitalization. 2, 3
• Do not use NSAIDs for pain control; they may worsen inflammation and increase the risk of perforation. 3

Long-Term Prevention of Recurrence

After resolution of the acute episode, counsel the patient on the following evidence-based strategies to reduce recurrence risk:

• High-fiber diet (> 22 g/day from fruits, vegetables, whole grains, and legumes). 3
• Regular vigorous exercise (≥ 150 minutes per week of moderate-intensity activity). 3
• Maintain a normal BMI (18–25 kg/m²). 3
• Smoking cessation. 3
• Avoid non-aspirin NSAIDs when possible. 3