What is the next step in managing a patient with focal diverticulitis (inflammation of the diverticula) and leukocytosis (elevated white blood cell count) seen on computed tomography (CT) scan?

Management of Focal Diverticulitis with Leukocytosis

For a patient with focal diverticulitis seen on CT scan and elevated white blood cell count, selective antibiotic therapy is recommended along with supportive care, with hospitalization considered for patients with concerning features such as significant leukocytosis (WBC >15 × 10^9/L) or systemic symptoms. 1, 2

Initial Assessment and Risk Stratification

Classification of Diverticulitis

• Uncomplicated diverticulitis: Localized inflammation without abscess, perforation, fistula, or obstruction
• Complicated diverticulitis: Inflammation with abscess, phlegmon, fistula, obstruction, bleeding, or perforation

Risk Assessment

Factors indicating higher risk that warrant more aggressive management:

• WBC count > 15 × 10^9/L
• C-reactive protein > 140 mg/L
• Symptoms lasting > 5 days
• Presence of vomiting
• Systemic inflammatory response
• Immunocompromised status
• Age > 80 years
• Significant comorbidities
• CT findings of pericolic extraluminal air, fluid collection, or longer inflamed colon segment 2, 1

Management Approach

For Uncomplicated Diverticulitis with Mild Symptoms

1. Diet: Clear liquid diet during acute phase, advancing as symptoms improve 2
2. Antibiotics: Can be used selectively rather than routinely in immunocompetent patients 2, 1
3. Outpatient Management: Appropriate for stable patients without concerning features 1
4. Pain Control: Acetaminophen is preferred for pain management 3

For Patients with Leukocytosis or Concerning Features

1. Antibiotic Therapy: Indicated for patients with:

   • WBC count > 15 × 10^9/L
   • Systemic symptoms (fever, chills)
   • Immunocompromised status
   • Significant comorbidities
   • CT findings of pericolic air or fluid 2, 1

2. Antibiotic Options:

   • Outpatient: Amoxicillin/clavulanic acid or cephalexin with metronidazole 3
   • Inpatient: Piperacillin-tazobactam, ceftriaxone plus metronidazole, or ampicillin/sulbactam 1, 4, 3

3. Hospitalization: Consider for patients with:

   • Inability to tolerate oral intake
   • Severe pain
   • Significant leukocytosis
   • Systemic symptoms
   • Failed outpatient management 1, 3

For Complicated Diverticulitis

1. Small Abscess (< 3-6 cm): May be treated with antibiotics alone 2
2. Large Abscess (> 3-6 cm): Percutaneous drainage plus IV antibiotics 2
3. Peritonitis or Perforation: Surgical consultation and possible emergency operation 1

Monitoring and Follow-up

1. Clinical Monitoring: Assess for resolution of inflammatory process within 2-3 days 2, 5
2. Repeat Imaging: If no clinical improvement within 2-3 days, repeat CT scan to assess for complications 5
3. Colonoscopy: Recommended 6-8 weeks after resolution to exclude colonic neoplasm if not recently performed 1, 6

Special Considerations

• Antibiotic Duration: Typically 7-10 days, but may be longer if complications occur 5
• Fluid Resuscitation: Important component of management, especially with significant inflammation 3
• Surgical Consultation: Consider early if signs of perforation, peritonitis, or failure to improve with medical management 1

Pitfalls to Avoid

1. Overuse of Antibiotics: Recent evidence suggests antibiotics may not be necessary for all cases of uncomplicated diverticulitis 2
2. Delayed Recognition of Complications: Failure to recognize progression to complicated diverticulitis can lead to increased morbidity and mortality 2
3. Inadequate Follow-up: Patients require close monitoring, especially in the first 48-72 hours of treatment 5
4. Missing Alternative Diagnoses: Conditions like ischemic colitis or inflammatory bowel disease can mimic diverticulitis 2

This approach balances the recent trend toward more selective use of antibiotics in uncomplicated diverticulitis with the recognition that patients with leukocytosis and other concerning features benefit from more aggressive management including antibiotic therapy.