What is it?

Megacolon is an abnormal dilation of the colon that is not caused by mechanical obstruction. It is usually accompanied by symptoms such as abdominal discomfort, but may result in serious complications (colonic perforation, peritonitis, and/or sepsis) if left untreated.

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Signs & symptoms

Common symptoms of megacolon include constipation, bloating, and abdominal pain or tenderness. In more severe cases, hard fecal masses called fecalomas may also be present.
Depending on the cause, megacolon may have additional symptoms. In toxic megacolon, usually caused by infection, additional symptoms include fever, tachycardia, and shock. In disease-related cases of megacolon, additional symptoms are those of the disease itself.


Megacolon can be diagnosed by observing the size of the colon on an abdominal x-ray scan. Most physicians agree that a colon diameter greater than 12 centimeters at the cecum should be classified as megacolon.
A contrast enhanced CT scan is used to confirm these findings, additionally showing the colon is free of mechanical obstruction.If a CT scan is not possible, colonoscopy can be performed to verify the colon is free of mechanical obstruction. However, in toxic megacolon, colonoscopy should not be performed due to high risk of perforating the colon.


Treatment for megacolon starts by addressing the underlying cause (such as the offending medication or disease), if known. In acute megacolon, all food and drink should be withheld and a nasogastric tube placed. If non-toxic, neostigmine should be administered, and if necessary, the colon itself should be decompressed by means of a colonoscopy. If toxic, steroids and broad spectrum antibiotics should be given.
In chronic megacolon, both dietary and pharmacological methods should be used to increase intestinal motility. Laxatives and enemas may also be used to prevent fecal impaction.
If the patient does not respond to these treatments within one to three days, it may be necessary to use surgery to remove all or part of the colon. Following colectomy, options include ileorectal anastomosis and ileostomy.

☝️ This is not a substitute for professional medical advice. Please consult with your physician before making any medical decision.

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