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    Acute Diverticulitis

    Gastrointestinal, Infections

    Last Updated Feb 07, 2024
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    By Tarinder Grewal, Jessica ter Wolbeek

    First 5 Minutes

    • Assess for sepsis and peritonitis.
    • Resuscitate accordingly.
    • Consider other diagnoses such mesenteric ischemia and abdominal aortic aneurysm.
    • Consider other complications such as abscess or obstruction.


    • The prevalence of diverticulosis increases with age.
    • Diverticula occur primarily in the sigmoid colon. However, in some Asian populations, the ascending colon is more likely to be affected.
    • Diverticulitis is the inflammation of one or more diverticula. This occurs in less than 5% of patients with diverticulosis.
    • Risk factors for developing diverticulitis include consumption of red meat, low fibre intake, obesity, smoking, significant alcohol intake, physical inactivity, corticosteroids, NSAIDs, and a family history of diverticulitis.
    • Diverticulitis is the most common non-cancerous disease of the colon, and its incidence is increasing, both overall and in younger age groups.
    • Acute diverticulitis may be simple (about 90% of cases) or complicated, i.e., involving abscess, obstruction, perforation or fistula formation.

    Diagnostic Process

    • The most common symptom is persistent pain that may be relieved with defecation and may worsen with movement. Pain is usually in the lower left quadrant but may be right-sided in some patients.
    • Patients may also present with constipation or diarrhea, nausea, vomiting, loss of appetite, and/or fever. Urinary symptoms may occur due to irritation of the bladder.
    • Physical exam should focus on differentiating between localized and diffuse pain and assessing for peritoneal signs.
    • A digital rectal exam may reveal occult blood but is not specific enough to be useful
    • Appropriate laboratory investigations include a complete blood count, electrolytes, creatinine, urea, C-reactive protein, and urinalysis.
    • Abdominal CT with IV contrast is the imaging test of choice to confirm a diagnosis of diverticulitis and to assess for complications/other diagnoses. Findings may include evidence of localized inflammation or microperforation, abscesses, or free air.
    • Colonoscopy should be avoided in the acute setting but can be performed in follow-up of complicated diverticulitis approximately 6 weeks after symptom resolution.
    • Other diagnoses to consider include IBS, IBD, infectious or ischemic colitis, appendicitis, epiploic appendigitis, hernia, GI perforation due to malignancy or ulcer, post-surgical anastomotic leak, gynecologic pathologies including ectopic pregnancy, and urologic pathologies including renal stones.

    Recommended Treatment

    • Acute uncomplicated diverticulitis
      • Treatment includes pain control with oral analgesics such as acetaminophen and ibuprofen and some degree of bowel rest.
      • Opioid analgesia should be avoided due to its effect on intestinal motility.
      • Bowel rest may involve a liquid diet for 2-3 days, followed by gradual advancement to a soft diet with eventual return to a regular diet.
      • There is increasing evidence that antibiotics should not be used routinely for mild uncomplicated diverticulitis.
      • Clinical judgement and consideration of risk factors (e.g., significant comorbidities, vomiting, symptoms ongoing for more than 5 days, substantially elevated WBC and/or CRP) can direct decisions regarding antibiotics.
      • If antibiotics are used, coverage should include both gram negative and anaerobic species. Suitable therapies include:
        • TMP/SMX 1DS tablet PO BID and metronidazole 500 mg PO BID for 4-7d, or
        • amoxicillin-clavulanate 875 mg/125 mg PO BID for 4-7 days, or
        • ciprofloxacin 500 mg PO BID and metronidazole 500 mg PO BID for 4-7 days.
    • Complicated diverticulitis
      • should be treated with IV antibiotics:
        • ceftriaxone 1-2g IV daily and metronidazole 500mg IV BID, or
        • ciprofloxacin 400 mg IV BID and metronidazole 500 mg IV BID, or
        • piperacillin/tazobactam 4.5g IV q8h or 3.375g IV q6h.
      • Patients admitted with complicated diverticulitis should initially be kept on full bowel rest with IV hydration.
      • Pain control with IV/IM analgesics should also be provided.
      • Percutaneous drainage should be considered for abscesses larger than 4cm.

    Criteria For Hospital Admission

    • Any patient with complicated diverticulitis should be admitted for in-hospital treatment.
    • Inpatient management may also be considered for patients:
      • not tolerating oral intake.
      • whose pain is not sufficiently controlled in the ED.
      • with multiple and/or significant comorbidities.
      • who are immune suppressed.

    Criteria For Transfer To Another Facility

    • Dependent on local resources.

    Criteria For Close Observation And/or Consult

    • A surgical consult is appropriate for abscesses larger than 3cm or if there is evidence of perforation, bowel obstruction, or fistula formation.

    Criteria For Safe Discharge Home

    • Uncomplicated diverticulitis can almost always be treated on an outpatient basis. Patients should be reassessed if their symptoms worsen or if there is no subjective improvement within 2-3 days.

    Quality Of Evidence?


    The recommendation for selective use of antibiotics in patients with uncomplicated diverticulitis is supported by randomized controlled trials and several observational studies. Treating with antibiotics does not shorten recovery time or reduce development of complications.


    Related Information


    Reference List

    1. Thomas N, Wu AW. Large Intestine. In: Walls RM, Hockberger RS, Gausche-Hill M, Erickson TB, Wilcox SR, editors. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia (US): Elsevier; 2023. p. 1132-1150.

    2. Bailey J, Dattani S, Jennings A. Diverticular Disease: Rapid Evidence Review. Am Fam Physician. 2022 Aug;106(2):150-156.

    3. Hanna MH, Kaiser AM. Update on the management of sigmoid diverticulitis. World J Gastroenterol 2021; 27(9): 760-781. https://www.wjgnet.com/1007-9327/full/v27/i9/760.htm

    4. Pemberton JH, Peery, A. 2023. Clinical manifestations and diagnosis of acute colonic diverticulitis in adults. UpToDate. Retrieved January 2024 from https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-acute-colonic-diverticulitis-in-adults

    5. Pemberton, JH. 2023. Acute colonic diverticulitis: Medical management. UpToDate. Retrieved January 2024 from https://www.uptodate.com/contents/acute-colonic-diverticulitis-medical-management


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