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Acute Diverticulitis

Michael Koenig


  • Inflammation and/or infection of a diverticulum, a small out-pouching along wall of colon
  • Presence of colonic flora on urine culture or pneumaturia suggests colovesical fistula
  • Most pts with uncomplicated diverticulitis have significant improvement 2-3 days after antibiotics


  • Lower abdominal pain (85% LLQ), tenderness to palpation on exam, N/V, low-grade fever, change in bowel habits (constipation or diarrhea)


  • CBC w/diff, CMP, Lipase, U/A, β - hCG
  • Imaging: CT abdomen/pelvis with oral and IV contrast
  • CT findings: localized bowel wall thickening (>4mm), paracolic fat stranding, presence of colonic diverticula


  • Bowel rest vs. clear liquids (advance diet as tolerated)
  • PO or IV antibiotics: should cover GNRs and anaerobic organisms
  • Zosyn, cefepime + metronidazole, or meropenem (if high risk for organisms w/ESBL)
  • Cipro/flagyl if PO
  • If low risk and mild disease, may not need antibiotics
  • Continue IV abx until abdominal pain/tenderness is resolved (usually 3-5 days), then transition to oral: cipro + metronidazole or Augmentin to complete 10-14 d course
  • Colonoscopy after complete resolution of symptoms (6 – 8 weeks) to definitively rule out presence of underlying colorectal cancer (unless performed in last year)


  • Pts who fail to improve or deteriorate require repeat imaging
  • Abscess continue antibiotics & percutaneous drainage (if possible) for abscesses > 4 cm
  • Surgery if no improvement 2-3 days after drainage
  • Obstruction: radiographic differentiation between acute diverticulitis and colon cancer is difficult; thus surgical resection of bowel is needed to relieve obstruction and rule out cancer
  • Fistula: Rarely heal spontaneously, require surgical correction
  • Perforation:
    • Microperforation (contained perforation):
    • Presence of small amount of air bubbles, but no oral contrast outside of colon on CT
    • Most treated with IV abx and bowel rest like uncomplicated diverticulitis
    • Frank perforation:
      • Intraabdominal free air, diffuse peritonitis requires emergency surgery