Acute Diverticulitis
These materials are intended for general clinical education and guidance. They are not a substitute for a clinician’s knowledge, skill or judgment in treating patients.
Background
- Diverticulitis is an inflammatory process of colonic diverticula, with infection typically arising as a complication in more severe or advanced cases
- Uncomplicated: Characterized by colonic wall thickening and pericolic inflammatory changes without signs of complicated diverticulitis
- Complicated: Includes the presence of abscess, perforation/peritonitis, obstruction, stricture and/or fistula
- High risk for complications: Immunocompromised patients, pregnancy, symptom duration >5 days, vomiting, and laboratory/radiologic evidence of severe or complicated disease (e.g., CRP >140 mg/L, WBC >15 × 10⁹/L, fluid collection or extensive inflammation on CT)
Common pathogens
- Enterobacterales (e.g,. E. coli, K. pneumoniae, Proteus spp.)
- Anaerobes (e.g., Bacteroides spp.)
Empiric therapy
Syndrome | 1st line | Alternative for allergy to 1st line* | Duration of treatment (after surgery) |
|---|---|---|---|
Uncomplicated diverticulitis (immunocompetent patients, clinically stable) | Watchful waiting | ||
Complicated diverticulitis or high risk for complications Stable, not perforated or contained perforation | Ceftriaxone 1 g IV q24h AND Metronidazole 500 mg IV q12h OR Amoxicillin/clavulanate 875 mg/125 mg PO BID | Ciprofloxacin 500 mg PO or 400 mg IV q12h AND Metronidazole 500 mg PO/IV q12h | No abscess: 5 days With abscess, undrained: 7 to 14 days dependent upon imaging and/or symptom resolution |
Complicated diverticulitis or high risk for complications Unstable, intra-abdominal sepsis, uncontained perforation | Piperacillin-tazobactam 4.5 g IV q6h (extended infusion) | If beta-lactam possible: Meropenem 1 g IV q8h (extended infusion) If beta-lactam not possible: Tobramycin 7 mg/kg IV q24h AND Metronidazole 500 mg IV q12h | With adequate surgical source control: 4 days post-operatively – extend to 7 days if bacteremia is present |
*Patients with a history of intolerance, non-specific rash to beta-lactams, or type I hypersensitivity to penicillin or amoxicillin can generally receive ceftriaxone safely. Patients with SJS/TEN, DRESS, AGEP or any other severe type II–IV hypersensitivity reaction should avoid ceftriaxone. See Beta-lactam Allergy Assessment and Management clinical summary.
- Peery AF, Shaukat A, Strate LL. AGA clinical practice update on medical management of colonic diverticulitis: expert review. Gastroenterology. 2021;160(3):906–911.
- Hall J, Hardiman K, Lee S, et al. The American Society of Colon and Rectal Surgeons clinical practice guidelines for the treatment of left-sided colonic diverticulitis. Dis Colon Rectum. 2020;63(6):728–747.
- Qaseem A, Wilt TJ, McLean RM, et al. Diagnosis and management of acute left-sided colonic diverticulitis: a clinical guideline from the American College of Physicians. Ann Intern Med. 2022;175(3):388–397.
- Mazuski JE, Tessier JM, May AK, et al. The Surgical Infection Society revised guidelines on the management of intra-abdominal infection. Surg Infect (Larchmt). 2017;18(1):1–76. doi:10.1089/sur.2016.261
- Huston JM, Barie PS, Dellinger EP, Forrester JD, Duane TM, Tessier JM, Sawyer RG, Cainzos MA, Rasa K, Chipman JG, Kao LS, Pieracci FM, Colling KP, Heffernan DS, Lester J; Therapeutics and Guidelines Committee. The Surgical Infection Society Guidelines on the Management of Intra-Abdominal Infection: 2024 Update. Surg Infect (Larchmt). 2024 Aug;25(6):419-435. doi: 10.1089/sur.2024.137. Epub 2024 Jul 11. PMID: 38990709