Initial Treatment for Acute Diverticulitis
For select patients with acute uncomplicated left-sided colonic diverticulitis, initial management without antibiotics is recommended, focusing on supportive care with bowel rest and hydration. 1
Classification and Initial Assessment
- Uncomplicated diverticulitis refers to localized inflammation without abscess, phlegmon, fistula, obstruction, bleeding, or perforation 1
- Complicated diverticulitis involves inflammation associated with abscess, phlegmon, fistula, obstruction, bleeding, or perforation 1
- CT scan is the recommended diagnostic test with 98-99% sensitivity and 99-100% specificity for confirming diverticulitis 2
Treatment Algorithm for Uncomplicated Diverticulitis
Outpatient Management
- Outpatient management is appropriate for most patients with uncomplicated diverticulitis who can tolerate oral intake and have adequate home support 1
- Clear liquid diet during the acute phase, advancing as symptoms improve 3, 4
- Observation with supportive care (bowel rest and hydration) without antibiotics for immunocompetent patients 1
- Pain management with acetaminophen 2
- Re-evaluation within 7 days; earlier if clinical condition deteriorates 1, 4
When Antibiotics Are Indicated for Uncomplicated Diverticulitis
Antibiotics should be reserved for patients with:
- Immunocompromised status 1, 3
- Systemic inflammatory response or signs of sepsis 1, 3
- Advanced age (>80 years) 3, 2
- Significant comorbidities 3, 4
- Symptoms lasting longer than 5 days 1
- Vomiting 1
- High C-reactive protein levels (>140 mg/L) 1
- Elevated white blood cell count (>15 × 10^9 cells/L) 3, 2
- CT findings of pericolic extraluminal air, fluid collection, or longer inflamed colon segment 1
Antibiotic Selection When Indicated
- Oral regimens: amoxicillin-clavulanate or ciprofloxacin plus metronidazole for 4-7 days 3, 5
- For patients unable to tolerate oral intake: IV antibiotics with gram-negative and anaerobic coverage (ceftriaxone plus metronidazole or piperacillin-tazobactam) 3, 2
- Duration: 4-7 days for immunocompetent patients; 10-14 days for immunocompromised patients 3, 4
Treatment of Complicated Diverticulitis
- For small abscesses (<4-5 cm): antibiotic therapy alone for 7 days 4
- For large abscesses (>4-5 cm): percutaneous drainage combined with antibiotic therapy 4
- Surgical intervention if clinical deterioration occurs 1
Inpatient vs. Outpatient Management
Criteria for Inpatient Management
- Complicated diverticulitis 1
- Inability to tolerate oral intake 1, 5
- Severe pain or systemic symptoms 1
- Significant comorbidities or frailty 1, 4
- Immunocompromised status 1, 3
Benefits of Outpatient Management
- Similar safety and efficacy to inpatient management 5, 6
- Cost savings of 35-83% per episode compared to inpatient management 1
- Reduced risk of hospital-acquired infections 1
Common Pitfalls to Avoid
- Overuse of antibiotics in uncomplicated cases without risk factors, which contributes to antibiotic resistance without providing benefit 1, 4
- Failing to recognize high-risk patients who need antibiotics despite having uncomplicated disease 3, 4
- Unnecessarily restricting consumption of nuts, corn, popcorn, or small-seeded fruits, which is not supported by evidence 1, 3
- Prolonging antibiotic therapy beyond recommended duration, which increases risk of C. difficile infection and antimicrobial resistance 7
- Failing to monitor for signs of progression to complicated diverticulitis, which occurs in approximately 5% of cases 3