How to manage an older adult patient with a known case of diverticulosis (diverticulosis) presenting with mild and intermittent left lower quadrant pain, without fever or signs of peritonitis?

Management of Mild Uncomplicated Diverticulitis in Known Diverticulosis

This patient with known diverticulosis presenting with mild, intermittent left lower quadrant pain without fever or peritonitis should be managed conservatively without antibiotics, using observation, pain control with acetaminophen, and dietary modification with a clear liquid diet. 1, 2

Immediate Diagnostic Confirmation

While the clinical presentation suggests uncomplicated diverticulitis, obtain a CT scan with IV contrast to confirm the diagnosis and classify disease severity using the WSES staging system, as clinical signs alone are insufficient, particularly in older adults. 3 This imaging has 98-99% sensitivity and 99-100% specificity for diagnosing acute diverticulitis. 2

• If the patient has contrast allergy or severe kidney disease, use ultrasound, MRI, or CT without contrast as alternatives. 1, 3

Treatment Based on WSES Classification

For WSES Stage 0 (Uncomplicated Diverticulitis)

Antibiotics should be avoided in immunocompetent patients without sepsis-related organ failures. 1, 3 This represents a significant shift from traditional management, as multiple recent studies demonstrate that antibiotics do not accelerate recovery or prevent complications in mild uncomplicated disease. 2, 4

Outpatient management is appropriate with the following components:

• Pain control with acetaminophen (avoid NSAIDs as they are a risk factor for diverticular disease progression). 2
• Clear liquid diet initially, advancing as tolerated. 2
• Close outpatient follow-up to monitor for clinical deterioration. 2

Indications for Antibiotic Therapy

Reserve antibiotics for patients with any of the following high-risk features, even if imaging shows uncomplicated disease: 2

• Persistent fever or chills
• Increasing leukocytosis
• Age older than 80 years
• Pregnancy
• Immunocompromised state (chemotherapy, high-dose steroids, organ transplant)
• Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes)

First-line oral antibiotics: amoxicillin/clavulanic acid OR cefalexin plus metronidazole. 2

Indications for Hospitalization

Admit the patient if any of the following are present: 5, 4

• Immunosuppression
• Intolerance to oral intake
• Signs of severe sepsis or hemodynamic instability
• Lack of social support for outpatient monitoring
• Significant comorbidities
• Suspicion of complicated disease on imaging

Critical Pitfalls to Avoid

• Do not prescribe antibiotics reflexively in immunocompetent patients with uncomplicated disease, as this represents outdated practice not supported by current evidence. 1, 2
• Do not advise dietary restrictions such as avoiding nuts, corn, popcorn, or seeds—this myth has been debunked and these foods do not increase diverticulitis risk. 5
• Do not perform colonoscopy during the acute episode, as this increases perforation risk. 5

Follow-Up Management

Colonoscopy Timing

Plan colonoscopy 4-6 weeks after symptom resolution to exclude colorectal cancer or alternative diagnoses (ischemic colitis, inflammatory bowel disease). 1, 3, 4 This is particularly important given the patient's age and if they are not up-to-date with colorectal cancer screening. 5

Prevention of Recurrence

Recommend the following lifestyle modifications to reduce future episodes: 5, 4

• High-fiber diet (whole grains, fruits, vegetables)—this appears to decrease the likelihood of symptomatic diverticulitis
• Regular exercise
• Smoking cessation if applicable
• Weight loss if BMI ≥30 kg/m²
• Avoid chronic NSAID, opioid, and corticosteroid use when possible

Elective Surgery Considerations

Do not recommend elective sigmoid resection after this first episode if the patient becomes asymptomatic after conservative treatment. 1, 3 Surgery should only be considered if: 1

• Stenosis, fistulae, or recurrent diverticular bleeding develops
• Very symptomatic disease significantly compromises quality of life
• Patient is immunocompromised and experiences recurrent episodes

When to Escalate Care

Instruct the patient to return immediately or call if they develop: 2, 4

• Worsening or severe abdominal pain
• Fever (temperature >38°C/100.4°F)
• Inability to tolerate oral intake
• Vomiting
• Signs of peritonitis (rigid abdomen, rebound tenderness)
• Urinary symptoms suggesting fistula formation