What is the recommended treatment for diverticulitis?

Treatment of Diverticulitis

The treatment of diverticulitis depends critically on disease severity: immunocompetent patients with uncomplicated diverticulitis should be managed with observation, pain control, and dietary modification WITHOUT antibiotics, while antibiotics are reserved for those with risk factors, and complicated diverticulitis requires intravenous antibiotics with consideration for drainage or surgery. 1, 2

Classification and Initial Assessment

Diverticulitis must first be categorized as uncomplicated versus complicated to guide management:

• Uncomplicated diverticulitis is localized inflammation without abscess, perforation, fistula, obstruction, or bleeding 1, 2
• Complicated diverticulitis involves abscess formation, perforation with peritonitis, fistula, obstruction, or bleeding 1, 2
• CT scan with IV contrast is the gold standard for diagnosis with 98-99% sensitivity and 99-100% specificity, and should be obtained to confirm diagnosis and assess for complications 2, 3

Management of Uncomplicated Diverticulitis

First-Line Treatment (No Risk Factors)

For immunocompetent patients without risk factors, antibiotics are NOT recommended:

• Observation with supportive care is the primary treatment, including pain management with acetaminophen (avoid NSAIDs) and bowel rest 1, 2
• Clear liquid diet during the acute phase, advancing as symptoms improve over 3-5 days 4, 1
• Outpatient management is appropriate for patients who can tolerate oral intake and have adequate home support 1, 2
• Re-evaluation within 7 days is mandatory, with earlier follow-up if symptoms worsen 1

This approach is based on high-quality evidence showing antibiotics do not accelerate recovery, prevent complications, or reduce recurrence rates in low-risk patients 1, 5.

When to Add Antibiotics

Antibiotics should be prescribed for patients with ANY of the following risk factors:

• Immunocompromised status (chemotherapy, high-dose steroids, organ transplant recipients) 1, 2
• Age >80 years 1, 2
• Pregnancy 1, 2
• Systemic symptoms (persistent fever >101°F, chills, signs of sepsis) 1, 2
• Increasing leukocytosis or WBC >15 × 10^9 cells/L 1
• Elevated CRP >140 mg/L 1
• CT findings of pericolic fluid collection or longer segment of inflammation 1
• ASA score III or IV 1
• Symptoms >5 days duration 1
• Presence of vomiting or inability to tolerate oral intake 1
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 2

Antibiotic Regimens for Uncomplicated Disease

Outpatient oral regimens (4-7 days for immunocompetent patients):

• First-line: Amoxicillin-clavulanate OR ciprofloxacin 500 mg twice daily plus metronidazole 500 mg three times daily 1, 2
• Alternative: Cephalexin plus metronidazole 2
• Duration: 10-14 days for immunocompromised patients 1

Inpatient IV regimens (for those unable to tolerate oral intake):

• Ceftriaxone or cefuroxime plus metronidazole 1, 2
• Ampicillin-sulbactam 2
• Transition to oral antibiotics as soon as tolerated to facilitate earlier discharge 1

Management of Complicated Diverticulitis

Abscess Management

• Abscesses <3 cm: IV antibiotics alone may be sufficient 3
• Abscesses ≥3 cm: CT-guided percutaneous drainage PLUS IV antibiotics 3
• IV antibiotic options: Ceftriaxone plus metronidazole OR piperacillin-tazobactam 1, 2
• Duration: 4 days for immunocompetent patients with adequate source control; up to 7 days for immunocompromised or critically ill patients 1

Indications for Hospitalization

Admit patients with:

• Complicated diverticulitis (abscess, perforation, obstruction) 1
• Inability to tolerate oral intake 1
• Severe pain or systemic symptoms 1
• Significant comorbidities or frailty 1
• Immunocompromised status 1
• Failed outpatient management 1

Surgical Management

Emergent surgery is indicated for:

• Diffuse peritonitis with hemodynamic instability 6
• Failed percutaneous drainage 3
• Clinical deterioration despite adequate medical therapy 6

Surgical approach:

• Hartmann's procedure (resection with end colostomy) for unstable patients or those with multiple comorbidities 6
• Resection with primary anastomosis (with or without diverting stoma) for stable patients without significant comorbidities 6
• Laparoscopic lavage is NOT first-line treatment for generalized peritonitis due to disappointing results in recent trials (SCANDIV, DILALA, Ladies), though it may be considered in highly selected patients 6

Mortality rates:

• Elective colon resection: 0.5% 2
• Emergent colon resection: 10.6% 2

Special Considerations for Free Air on CT

• Distant free gas WITHOUT diffuse peritonitis or fluid: Non-operative management may be attempted in highly selected, hemodynamically stable patients with close monitoring 6
• Large amount of distant intraperitoneal gas or distant retroperitoneal gas: Associated with 57-60% failure rate of non-operative management; surgical intervention should be strongly considered 6
• Pericolic gas only: Non-operative management is more likely to succeed 6

Prevention of Recurrence

After resolution of acute diverticulitis:

• High-quality diet: High in fiber from fruits, vegetables, whole grains, and legumes; low in red meat and sweets 4, 1
• Regular physical activity, particularly vigorous exercise 4, 1
• Achieve or maintain normal BMI (18-25 kg/m²) 4, 3
• Avoid smoking 4, 1
• Limit NSAIDs and opioids when possible 4, 2
• DO NOT restrict nuts, corn, popcorn, or small-seeded fruits - these are NOT associated with increased diverticulitis risk 4, 1

Follow-Up and Colonoscopy

• Colonoscopy is NOT routinely required after uncomplicated diverticulitis in patients without other CRC risk factors, as cancer risk is only 0.01% 6
• Colonoscopy should be performed 4-6 weeks after resolution in patients with complicated diverticulitis or those who haven't had age-appropriate screening 3, 5
• Never perform colonoscopy during acute flare 3

Common Pitfalls to Avoid

• Overusing antibiotics in uncomplicated cases without risk factors - this provides no benefit and contributes to resistance 1
• Unnecessarily restricting nuts, seeds, and popcorn - current evidence does not support this outdated recommendation 4, 1
• Stopping antibiotics early when they are indicated, even if symptoms improve 1
• Failing to recognize risk factors for progression to complicated disease (immunosuppression, corticosteroid use, advanced age) 1
• Delaying surgical consultation in patients with peritonitis or hemodynamic instability 6
• Assuming all patients need hospitalization - most uncomplicated cases can be managed outpatient with appropriate selection 1
• Using laparoscopic lavage as first-line treatment for generalized peritonitis - recent high-quality trials show inferior outcomes compared to resection 6