Toxic colitis with dilated colon is referred to as toxic megacolon; dilation may be segmental or generalised. Toxic colitis can develop without megacolon.
An acute presentation from inflammatory or infectious colitis with significant morbidity and mortality.
Symptoms and signs of systemic toxicity are always present.
Criteria for the diagnosis include radiographical evidence of acute colitis and three of the following four features: fever >38.6°C (101.5°F), heart rate >120 bpm, white blood cell count >10.5 x 10⁹/L, or anaemia. One of the following is also required: volume depletion, mental status changes, electrolyte abnormalities, or hypotension.
Operative treatment is indicated by the presence of complications (perforation, massive rectal bleeding) or lack of clinical improvement after appropriate medical therapy for approximately 72 hours.
Involvement of a multidisciplinary team (gastroenterologist, surgeon, critical care specialist) in treatment planning is warranted.
Toxic colitis with an associated megacolon (colonic distension above 6 cm) is often referred to as toxic megacolon or toxic colitis/toxic megacolon (TC/TM). It is a potentially lethal complication of acute colitis, and is defined as total or segmental non-obstructive colonic distension associated with systemic toxicity. Toxic megacolon differs from other causes of colonic distension (including Hirschsprung's disease, congenital megacolon, idiopathic megacolon, acquired megacolon due to chronic constipation, and colonic pseudo-obstruction) by the presence of acute colitis and systemic toxicity.
History and exam
Key diagnostic factors
- presence of risk factors
- mental status changes
- abdominal distension
Other diagnostic factors
- abdominal pain
- abdominal tenderness
- ulcerative colitis (UC)
- Crohn's colitis
- pseudomembranous colitis
- infectious colitis
- discontinuation of medications for inflammatory bowel disease
- antimotility agents
- chemotherapy/chemical immunosuppression
- electrolyte abnormalities
1st investigations to order
- serum electrolytes
- serum albumin levels
- serum lactic acid
- stool studies
- CT abdomen/pelvis
- abdominal x-ray
- chest x-ray
Investigations to consider
- erythrocyte sedimentation rate (ESR)
- blood cultures
- rectal biopsy
- surgical specimen
- Colonic pseudo-obstruction
- Acute mesenteric ischaemia
- Large bowel obstruction
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