Definition

Diverticulitis is a common digestive disease, particularly found in the large intestine. Diverticulitis develops from diverticulosis, which involves the formation of pouches (diverticula) on the outside of the colon. Diverticulitis results if one of these diverticula becomes inflamed, which occurs in 4% of patients with diverticulosis.

Classification:

• Uncomplicated Diverticulitis: Localized inflammation without complications.
• Complicated Diverticulitis: Associated with abscess, phlegmon, fistula, obstruction, bleeding or perforation.

Key History

Key Physical Exam

Risk Factors for Diverticulitis

• History of diverticulosis
• Age > 40
• Poor fiber intake
• Lack of exercise

Differential Diagnosis

Diagnostic Testing

The evaluation process for diverticulitis involves a combination of clinical assessment, laboratory tests, and imaging studies to confirm the diagnosis and assess the severity of the disease.

Laboratory Tests:

• Complete Blood Count (CBC): To check for leukocytosis, which indicates infection or inflammation.
• Basic Metabolic Panel: To assess renal function and electrolyte imbalances.
• C-Reactive Protein (CRP): Elevated levels can indicate inflammation.
• Urinalysis: To rule out urinary tract infections that can mimic diverticulitis.

Imaging Studies:

• Computed Tomography (CT) Scan: The preferred imaging modality for diagnosing diverticulitis. It helps confirm the diagnosis, assess the extent and severity of the disease, and identify complications such as abscesses, fistulas or perforation. CT with intravenous contrast is particularly useful.
• Ultrasound: Can be used as an alternative in certain settings, but it is less sensitive and specific compared to CT.
• MRI: May be considered in patients who cannot undergo CT, though it is less commonly used.

Follow-Up:

• Colonoscopy: Recommended 6-8 weeks after resolution of symptoms to rule out malignancy, especially in patients with complicated diverticulitis or those who have not had a recent high-quality colonoscopy.
• The American College of Radiology (ACR) guidelines emphasize the importance of CT imaging in the evaluation of suspected diverticulitis to guide appropriate management decisions.

Clinical Risk and Safety Pearls

• Left-sided diverticulitis is common in Western countries. Right-sided diverticulitis is common in Asian countries.
• Diverticulitis can occur in patients under 40.
• Approximately 15% of patients with diverticulitis will have a complication such as abscess, perforation, fistula or colonic obstruction.
• Most patients with acute uncomplicated diverticulitis can be treated with conservative therapy, including antibiotics (selectively) and bowel rest.

Treatment

The treatment of diverticulitis is stratified based on whether the condition is uncomplicated or complicated.

Uncomplicated Diverticulitis:

• Outpatient Management: Selected patients with mild, uncomplicated diverticulitis can be managed on an outpatient basis. This includes a clear liquid diet initially, advancing as tolerated, and oral antibiotics if deemed necessary. Recent evidence suggests that antibiotics may not be required in all cases of uncomplicated diverticulitis.
• Antibiotics: If used, common regimens include ciprofloxacin (500 mg twice daily) plus metronidazole (500 mg three times daily), or amoxicillin-clavulanate (875/125 mg twice daily) for 7-10 days.

Complicated Diverticulitis:

• Hospitalization: Patients with complicated diverticulitis—characterized by abscess, perforation, fistula or obstruction—require hospitalization.
• Intravenous Antibiotics: Broad-spectrum antibiotics covering Gram-negative and anaerobic bacteria are recommended. Options include piperacillin-tazobactam, ceftriaxone plus metronidazole, or ertapenem.
• Percutaneous Drainage: Abscesses larger than 3 cm should be managed with percutaneous drainage.
• Surgery: Emergent surgery is indicated for patients with generalized peritonitis, failure of percutaneous drainage, or clinical deterioration despite adequate medical therapy. Surgical options include primary resection with anastomosis or Hartmann's procedure, depending on the patient's stability and the extent of contamination.

1. Surgical consult
2. IV antibiotics – Broad spectrum to cover gram-negative aerobes and anaerobes—Ampicillin/sulbactam OR imipenem OR Metronidazole AND Cipro
3. IV hydration
4. NPO
5. Type and crossmatch if GI bleeding
6. Bowel rest
7. Mild cases may be treated with outpatient oral antibiotics—Cipro and flagyl or amoxicillin-clavulanate and a clear liquid diet. Patients sent home should be advised to call or come back with increasing pain, fever, or inability to tolerate fluids or no clinical improvement after 2 to 3 days.