What is the recommended diagnostic approach and treatment for diverticulitis?

Diagnostic Approach and Treatment for Diverticulitis

CT scan of the abdomen and pelvis with IV contrast is the diagnostic test of choice for suspected acute diverticulitis, with 94-99% sensitivity and 96-99% specificity. 1

Diagnostic Approach

Clinical Presentation

• Left lower quadrant abdominal pain
• Fever
• Nausea/vomiting
• Leukocytosis
• Note: Elderly patients often present atypically, with only 50% presenting with lower quadrant pain and 17% with fever 1

Imaging

1. First-line: CT scan with IV contrast

   • Gold standard with 94-99% sensitivity and 96-99% specificity 1, 2
   • Excellent for identifying complications (abscess, fistula, obstruction, perforation)
   • Low-dose techniques can reduce radiation exposure by 75-90% while maintaining diagnostic accuracy 1

2. Alternative: Ultrasound

   • Good alternative when CT is contraindicated
   • Sensitivity and specificity around 90%
   • Limitations: less reliable in obese patients and for distal sigmoid diverticulitis 1
   • Diagnostic criteria: colonic wall thickening >5mm, inflamed diverticulum, hyperechoic pericolic tissue 1

3. MRI

   • Sensitivity 94%, specificity 88%
   • Less sensitive than CT for detecting extraluminal gas 1

Important caveat: Clinical assessment alone is unreliable for diagnosis, with misdiagnosis rates of 34-68% 1

Treatment Approach

1. Uncomplicated Diverticulitis (85% of cases)

• First-line: Observation with pain management (typically acetaminophen) and dietary modification with clear liquid diet 2

• Antibiotics should be reserved for patients with:

  • Systemic symptoms (persistent fever/chills)
  • Increasing leukocytosis
  • Age >80 years
  • Pregnancy
  • Immunocompromised status
  • Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 1, 2

• Antibiotic options for uncomplicated cases:

  • Oral: amoxicillin/clavulanic acid or cefalexin with metronidazole 2
  • IV (if unable to tolerate oral): cefuroxime or ceftriaxone plus metronidazole or ampicillin/sulbactam 2

2. Complicated Diverticulitis

• Intravenous antibiotics:

  • Ceftriaxone plus metronidazole or piperacillin-tazobactam 2

• Management of complications:

  • Abscesses ≥3cm: Percutaneous drainage recommended 1
  • Free perforation and peritonitis: Surgical intervention necessary 1
  • Generalized peritonitis: Emergent laparotomy with colonic resection 2

Treatment Setting

• Outpatient management is appropriate for patients who can tolerate oral intake, have adequate social support, and no significant comorbidities 1
• Inpatient management for severe cases, significant comorbidities, inability to tolerate oral intake, or inadequate home support

Special Considerations

• Immunocompromised patients are at high risk for failure of standard non-operative treatment and require close monitoring 1
• Mortality rates differ significantly between elective (0.5%) and emergent (10.6%) colon resection 2
• Recurrent diverticulitis may benefit from mesalazine (alone or with antibiotics) to prevent symptomatic recurrence 3

Clinical pearl: Barium enema is contraindicated in acute diverticulitis due to risk of barium peritonitis if perforation is present 1