Acute Diverticulitis

Emily Poellinger

Alex DeWeerd

Background

  • 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

Presentation

  • Lower abdominal pain (85% LLQ), tenderness to palpation on exam, decreased appetite, nausea/vomiting, low-grade fever, change in bowel habits (constipation or diarrhea), leukocytosis

Evaluation

  • 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

Management

  • Generally okay to treat in the outpatient setting (no differences in outcomes were found between outpatient and inpatient care in uncomplicated diverticulitis), but inpatient treatment recommended for the following:
  • Complicated diverticulitis (presence of abscess, perforation, obstruction, fistula)
  • Septic, uncontrollable abdominal pain, age >70, significant comorbidities, immunosuppressed, inability to tolerate PO intake
  • Diet: Bowel rest vs. clear liquids (advance diet as tolerated)
  • IVF: give IVF to correct volume deficits from decreased PO intake
  • Antibiotics: should cover GNRs and anaerobic organisms
  • In general, hospitalized patients should be empirically started on IV antibiotics and then transitioned to PO after resolution of abdominal pain/advancing diet for a total 10-14 day course
  • IV regimen: Zosyn, Cefepime + Metronidazole, or meropenem (if high risk for organisms w/ESBL)
  • PO regimen: Ciprofloxacin/Levofloxacin + Metronidazole OR Augmentin
  • If low risk and mild disease, may not need antibiotics
  • Colonoscopy after complete resolution of symptoms (6 – 8 weeks) to definitively rule out presence of underlying colorectal cancer (unless performed in last year)

Complications

  • Patients who fail to improve on IV antibiotics or deteriorate require repeat imaging
  • Abscesses: depends on size of abscess
    • < 4cm: IV antibiotics, if fail to improve percutaneous drainage vs surgery
    • > 4cm: IV antibiotics + percutaneous drainage (if possible) vs surgery
  • Obstruction/structuring: 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: most commonly involves the bladder, vagina, small bowel, or uterus. Rarely heal spontaneously, therefore will require surgical correction.
  • Bleeding: most common cause of overt lower GI bleeding in adults, typically resolves spontaneously.
    • If persistent, endoscopic intervention to locate and stop the bleeding; if hemodynamically unstable, angiography is the next step to locate and/or control the bleed. If bleeding persists and patient is unstable, segmental colectomy can be performed if the site of bleeding is clearly located with endoscopy/angiography; if no site is found, subtotal colectomy can be performed.
    • Surgical management for a diverticular bleed is rare and should be a last resort approach.
  • Perforation:
    • Microperforation (contained perforation): Presence of small amount of air bubbles, but no oral contrast outside of colon on CT Most treated with IV antibiotics and bowel rest like uncomplicated diverticulitis
    • Frank perforation (contained perforation): Intraabdominal free air, air under the diaphragm, and diffuse peritonitis requires emergency surgery so consult EG
  • Recurrent diverticulitis: elective surgery generally not recommended for patients with prior diverticulitis episodes if they were managed medically and uncomplicated.
    • Indications for elective surgery include patients who have had a prior episode of complicated diverticulitis or are immunosuppressed. Surgery typically performed 10-12 weeks after last acute diverticulitis episode

Segmental colitis associated with diverticulosis (SCAD)

  • Definition: chronic mucosal inflammation in a segment of colon with diverticula
  • Pathogenesis: currently unknown, leading hypotheses include fecal stasis, localized ischemia, and mucosal prolapse
  • Symptoms: chronic diarrhea, abdominal pain, intermittent hematochezia
  • Diagnosis: colonoscopy with chronic inflammatory changes on biopsy only in an area of the colon with diverticula (sigmoid colon>>descending colon) and absence of inflammation in the rectum (compared to ulcerative colitis, which always involves the rectum)
  • Rule out other causes: acute uncomplicated diverticulitis (increased paracolic fat stranding/mild colonic wall inflammation, endoscopy shows primary involvement of diverticular orifices and peri diverticular mucosa), infectious colitis (stool studies/tissue biopsy), NSAID-induced colitis (medication exposure), ischemic colitis (acute presentation), IBD (UC involves rectum, CD typically involves other sites in GI tract), radiation colitis (history of radiation, tissue biopsy showing eosinophils)
  • Management: Start with antibiotics (cipro or flagyl x 10-14 days), if unresponsive, add oral mesalamine x 7-10 days with dose escalation if persistent after 2 weeks. If symptoms remain, start prednisone 40 mg and gradually taper over 6 weeks.
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