Management of Diverticulitis

Diagnosis and Initial Assessment

CT scan with IV contrast is the gold standard for diagnosing diverticulitis and must be obtained to confirm uncomplicated disease before withholding antibiotics. 1, 2 The test has 98-99% sensitivity and 99-100% specificity. 1, 2

Key Diagnostic Features to Identify on CT:

Uncomplicated diverticulitis: Bowel wall thickening, pericolic fat stranding, diverticula—no abscess, perforation, fistula, obstruction, or extraluminal contrast 1, 3
Complicated diverticulitis: Presence of abscess (measure size), extraluminal gas >5 cm from inflamed segment, distant free fluid, or diffuse peritonitis 1, 3

Risk Stratification—High-Risk Features Predicting Progression:

Clinical: Symptoms >5 days, vomiting, pain score ≥8/10, temperature >100.4°F 1, 3, 4
Laboratory: CRP >140 mg/L, WBC >15 × 10⁹/L or rising leukocytosis 1, 3
CT findings: Fluid collection, abscess, pericolic extraluminal air, longer segment of inflammation 1, 3
Patient factors: Age >80 years, ASA score III-IV, immunocompromised status, significant comorbidities (cirrhosis, CKD, heart failure, poorly controlled diabetes) 1, 3, 2

Management of Uncomplicated Diverticulitis

For immunocompetent patients with CT-confirmed uncomplicated diverticulitis, observation with supportive care alone is first-line therapy—antibiotics are reserved only for high-risk patients. 1, 3, 2 Multiple high-quality RCTs, including the DIABOLO trial (n=528), demonstrated that antibiotics neither accelerate recovery nor prevent complications or recurrence in uncomplicated cases. 1, 3, 5

Supportive Care Protocol:

Diet: Clear liquid diet during acute phase, advance as tolerated; if unable to advance diet after 3-5 days, immediate reassessment required 1, 3
Pain control: Acetaminophen only (avoid NSAIDs and opioids) 3, 2, 6
Hydration: Oral fluids; if unable to tolerate, hospitalization indicated 1, 3

When to Add Antibiotics—Any ONE of These Criteria:

Clinical indicators:

Persistent fever >100.4°F or chills despite 48 hours supportive care 1, 3
Refractory symptoms or vomiting 1, 3
Inability to maintain oral hydration 1, 3
Symptoms >5 days before presentation 1, 3

Laboratory indicators:

CRP >140 mg/L 1, 3
WBC >15 × 10⁹/L or rising leukocytosis 1, 3

CT findings:

Fluid collection or small abscess <4 cm 1, 3
Pericolic extraluminal air 1, 3
Extensive segment of inflammation 1, 3

Patient factors (absolute indications for antibiotics):

Immunocompromised (chemotherapy, high-dose steroids, organ transplant) 1, 3, 2
Age >80 years 1, 3
Pregnancy 1, 3
Significant comorbidities: cirrhosis, CKD, heart failure, poorly controlled diabetes 1, 3, 2
ASA score III-IV 1, 3

Antibiotic Regimens When Indicated:

Outpatient oral therapy (4-7 days for immunocompetent):

First-line: Amoxicillin-clavulanate 875/125 mg PO twice daily 1, 3, 2
Alternative: Ciprofloxacin 500 mg PO twice daily PLUS metronidazole 500 mg PO three times daily 1, 3, 2

Inpatient IV therapy (transition to oral within 48 hours when tolerating):

Ceftriaxone PLUS metronidazole 1, 3, 2
Piperacillin-tazobactam 1, 3, 2
Amoxicillin-clavulanate 1.2 g IV q6h 1, 3

Duration:

Immunocompetent: 4-7 days total 1, 3, 2
Immunocompromised: 10-14 days total 1, 3

Outpatient vs. Inpatient Decision—Hospitalize if ANY:

Unable to tolerate oral fluids or medications 1, 3, 4
Severe systemic symptoms or signs of sepsis 1, 3
Significant comorbidities or frailty 1, 3, 4
Immunocompromised status 1, 3
Pain score ≥4/10 despite acetaminophen 1, 3
Temperature ≥100.4°F 1, 3
Inadequate home/social support 1, 3, 4

Outpatient management results in 35-83% cost savings and shorter hospital stays (2 vs. 3 days) compared to routine hospitalization. 1, 3, 4

Management of Complicated Diverticulitis

All complicated diverticulitis requires hospitalization, IV antibiotics, and surgical consultation. 1, 3, 2

Small Abscess (<4-5 cm):

IV antibiotics alone for 7 days 1, 3
Regimens: Ceftriaxone + metronidazole OR piperacillin-tazobactam 1, 3, 2

Large Abscess (≥4-5 cm):

CT-guided percutaneous drainage PLUS IV antibiotics 1, 3, 2
Continue antibiotics for 4 days after adequate source control in immunocompetent patients 1, 3
Continue antibiotics for up to 7 days in immunocompromised or critically ill patients 1, 3
Send drainage fluid for culture to guide antibiotic selection 1, 3

Generalized Peritonitis or Sepsis:

Emergent surgical consultation for source control surgery 1, 3, 2
Immediate broad-spectrum IV antibiotics 1, 3, 2
Surgical options: Hartmann's procedure or primary resection with anastomosis (if hemodynamically stable, no feculent peritonitis, no severe malnutrition) 1, 3, 7

Follow-Up and Monitoring

Mandatory re-evaluation within 7 days of diagnosis (earlier if symptoms worsen). 1, 3 If symptoms persist after 5-7 days of appropriate therapy, obtain repeat CT to assess for complications requiring drainage or surgery. 1, 3

Colonoscopy Timing:

Perform colonoscopy 6-8 weeks after symptom resolution in these scenarios:

First episode of uncomplicated diverticulitis AND no high-quality colonoscopy within past year 1, 3
Any complicated diverticulitis (7.9% risk of colon cancer vs. 1.3% in uncomplicated) 1, 3
Age >50 years requiring routine screening 1, 3, 6
Alarm symptoms: change in stool caliber, iron-deficiency anemia, rectal bleeding, weight loss 1, 3

Defer colonoscopy if: Recent (<1 year) high-quality colonoscopy with no findings warranting short-interval follow-up AND uncomplicated diverticulitis. 1, 3

Prevention of Recurrence

Approximately 20% of patients experience recurrence within 5 years; 50% of risk is genetic. 1, 3

Evidence-Based Lifestyle Modifications:

High-fiber diet: ≥22.1 g/day from fruits, vegetables, whole grains, legumes (low in red meat and sweets) 1, 3, 8
Regular vigorous physical activity 1, 3, 8
Achieve/maintain normal BMI (18-25 kg/m²) 3, 8
Smoking cessation 3, 8, 6
Avoid nonaspirin NSAIDs when possible 1, 3, 8
Aspirin use does NOT need to be avoided 1, 8

What NOT to Restrict:

Do NOT advise patients to avoid nuts, corn, popcorn, or small-seeded fruits—no evidence these increase diverticulitis risk. 1, 3, 8, 7, 6

Medications to AVOID for Prevention:

Strong recommendation AGAINST mesalamine (no benefit, increased adverse events) 1, 3, 8
Conditional recommendation AGAINST rifaximin 1, 3, 8
Conditional recommendation AGAINST probiotics 1, 8

Elective Surgery Considerations

Do NOT recommend elective colectomy based solely on number of episodes. 1, 3 The traditional "two-episode rule" is obsolete. 1, 3

Individualized Surgical Decision—Consider Surgery When:

≥3 CT-confirmed episodes within 2 years 3
Persistent symptoms >3 months between episodes (smoldering diverticulitis) 1, 3
Significant quality-of-life impairment despite conservative management 1, 3
History of complicated diverticulitis 3
Immunocompromised status 3

The DIRECT trial demonstrated significantly better quality of life at 6 months and 5 years after elective sigmoidectomy vs. continued conservative management in patients with recurrent/persistent symptoms. 1, 3 However, elective surgery carries 10% short-term complication rate and 25% long-term complications. 1, 3

Management of Chronic Post-Diverticulitis Pain

Approximately 45% of patients report ongoing abdominal pain at 1-year follow-up, usually due to visceral hypersensitivity rather than ongoing inflammation. 1, 3

Evaluation Protocol:

CT imaging to exclude persistent inflammation, stricture, fistula 1, 3
Lower endoscopy to exclude alternative diagnoses (ischemic colitis, IBD, malignancy) 1, 3

Treatment if No Active Inflammation:

Low-to-moderate dose tricyclic antidepressants for visceral hypersensitivity 1, 3
Reassurance that ongoing symptoms are common and not indicative of recurrent diverticulitis 1, 3

Special Populations

Immunocompromised Patients:

Require immediate antibiotic therapy (10-14 days), lower threshold for CT imaging, and early surgical consultation regardless of other factors. 1, 3, 2 Corticosteroid use specifically increases risk of perforation and death. 1, 3, 2

Elderly Patients (>65 years):

Require antibiotic therapy even for localized complicated diverticulitis; lower threshold for hospitalization. 1, 3 Mortality for emergent surgery is 10.6% vs. 0.5% for elective surgery. 2

Critical Pitfalls to Avoid

Overusing antibiotics in uncomplicated diverticulitis without high-risk features contributes to resistance without clinical benefit 1, 3
Applying the "no antibiotics" approach to Hinchey 1b or higher disease—the evidence specifically excluded patients with abscesses 1, 3
Failing to obtain CT confirmation before withholding antibiotics—all studies supporting observation required imaging to rule out complications 1, 3
Assuming all patients require hospitalization—most can be safely managed outpatient with appropriate follow-up 1, 3, 4
Stopping antibiotics early even if symptoms improve—complete the full course 1, 3
Unnecessarily restricting nuts, seeds, popcorn—outdated recommendation lacking evidence 1, 3, 8, 7, 6
Prescribing mesalamine, rifaximin, or probiotics for prevention—no evidence of benefit 1, 3, 8
Delaying surgical consultation in patients with frequent recurrence affecting quality of life 1, 3
Extending antibiotics beyond 7 days in immunocompetent patients with uncomplicated disease—does not improve outcomes 1, 3

What is the recommended management for an otherwise healthy adult with uncomplicated diverticulitis, and how does it differ for complicated diverticulitis?

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