What is the treatment for suspected diverticulitis?

Workup for Suspected Diverticulitis

The initial diagnostic workup for suspected diverticulitis should include CT scan with IV contrast, which has 98-99% sensitivity and 99% specificity for confirming the diagnosis and distinguishing complicated from uncomplicated diverticulitis. 1

Diagnostic Approach

Imaging

• First-line imaging: CT scan with IV contrast 2, 1
• Alternative imaging options (for patients who cannot undergo CT with IV contrast due to kidney disease or contrast allergy):
  • Ultrasound
  • MRI
  • CT scan without IV contrast 2, 1

Important Clinical Considerations

• Diagnosis should not be based solely on clinical signs, symptoms, and laboratory tests, especially in elderly patients 2
• Patients with abdominal guarding or pain in the lower left abdomen should undergo appropriate imaging regardless of leukocyte count or C-reactive protein (CRP) levels 2

Management Based on Disease Classification

Uncomplicated Diverticulitis (WSES stage 0)

• Observation with pain management (typically acetaminophen)
• Clear liquid diet during acute phase with advancement as symptoms improve 1, 3
• Antibiotics should be avoided in immunocompetent patients without sepsis-related organ failures 2, 3

Indications for Antibiotic Therapy

Antibiotics should be reserved for:

• Patients with systemic symptoms (persistent fever/chills)
• Increasing leukocytosis
• Age >80 years
• Pregnant patients
• Immunocompromised patients
• Patients with chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 3
• Localized complicated diverticulitis with pericolic air bubbles or little pericolic fluid (WSES stage 1a) 2

Complicated Diverticulitis with Abscess (WSES stage 1b-2a)

• Broad-spectrum antibiotic therapy covering gram-negative bacilli and anaerobes 2, 1
• Percutaneous drainage for abscesses larger than 4 cm, when skills and facilities are available 2
• Cultures from percutaneous drainage should guide antibiotic therapy 2

Complicated Diverticulitis with Peritonitis (WSES stage 2b-4)

• Surgical intervention is recommended for patients with:
  • Distant intraperitoneal free air 2
  • Diffuse peritonitis 2
  • Generalized peritonitis (emergent laparotomy with colonic resection) 3

Antibiotic Selection

Oral Options (for patients who can tolerate oral intake)

• Amoxicillin/clavulanic acid
• Cefalexin with metronidazole 3
• Ciprofloxacin with metronidazole 4

Intravenous Options

• Ceftriaxone plus metronidazole
• Piperacillin-tazobactam
• Ampicillin/sulbactam
• Cefuroxime plus metronidazole
• Ampicillin plus gentamicin plus metronidazole 1, 3

Duration of Antibiotic Therapy

• For complicated diverticulitis: 3-5 days after adequate source control 2
• If signs of peritonitis or systemic illness persist beyond 5-7 days, further diagnostic investigation is indicated 2

Follow-up Care

• Colonoscopy should be performed 4-8 weeks after acute episode to rule out malignancy 1
• High-fiber diet is recommended for prevention of recurrence 1

Risk Factors for Disease Progression

• Symptoms lasting >5 days before presentation
• Vomiting
• Systemic comorbidity
• High C-reactive protein levels
• CT findings of pericolic extraluminal air, fluid collection, or longer inflamed colon segment 1
• Large amounts of distant intraperitoneal air or distant retroperitoneal air (associated with 57-60% failure rates of non-operative management) 1

Common Pitfalls to Avoid

1. Relying solely on clinical presentation for diagnosis, especially in elderly patients
2. Routine use of antibiotics for uncomplicated diverticulitis
3. Delaying surgical intervention when indicated (delay >60 hours increases mortality)
4. Failing to arrange follow-up colonoscopy to exclude malignancy
5. Not considering outpatient management for uncomplicated cases (which has been shown to be safe and cost-effective in selected patients) 4