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Toxic megacolon

Sunil G Sheth, MD
J Thomas Lamont, MD
Section Editors
Martin Weiser, MD
Paul Rutgeerts, MD, PhD, FRCP
Deputy Editor
Wenliang Chen, MD, PhD


Toxic megacolon is a potentially lethal complication of inflammatory bowel disease (IBD) or infectious colitis that is characterized by total or segmental nonobstructive colonic dilatation plus systemic toxicity [1-3]. Colonic dilatation is also observed in patients with congenital megacolon (Hirschsprung's disease), idiopathic or acquired megacolon occurring with chronic constipation of any etiology, and intestinal pseudoobstruction, a manifestation of diffuse gastrointestinal dysmotility of various causes. However, the lack of systemic toxicity distinguishes these presentations from true toxic megacolon. (See "Acute colonic pseudo-obstruction (Ogilvie's syndrome)".)


The precise incidence of toxic megacolon is unknown. The incidence in ulcerative colitis and Crohn's disease was approximately 1 to 5 percent three decades ago [4], but has gradually decreased because of earlier recognition and intensive management of severe colitis. Clinically symptomatic Clostridium difficile infection occurs in approximately 1 percent of all hospitalized patients; a few of these may develop severe colitis with toxic megacolon [5-7]. (See "Clostridium difficile infection in adults: Clinical manifestations and diagnosis".)


Although most commonly recognized as a complication of inflammatory bowel disease (IBD), toxic megacolon may also occur with infectious colitides of diverse etiology, ischemic colitis, volvulus, diverticulitis, and obstructive colon cancer (table 1).

Clinical features that suggest IBD as a cause of toxic megacolon include a preceding history of diarrhea, bloody stools, abdominal pain, perianal disease, or extraintestinal manifestations such as arthritis, iritis, skin disease, or liver disease. (See "Clinical manifestations, diagnosis, and prognosis of ulcerative colitis in adults" and "Clinical manifestations, diagnosis and prognosis of Crohn disease in adults".)

Risk factors for the development of severe colitis in patients with C. difficile infection include malignancy, chronic obstructive pulmonary disease, immunosuppressive therapy, renal failure, or exposure to antiperistaltic medications or clindamycin [5]. Toxic megacolon has been described in patients with recurrent C. difficile [8].

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Literature review current through: Nov 2017. | This topic last updated: Apr 06, 2017.
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