What is toxic megacolon, how is it recognised, and why is it dangerous?

Toxic megacolon is acute non-obstructive colonic dilatation with systemic toxicity, a complication of severe colitis. Recognised by colonic diameter increasing on plain film, mucosal islands, fever, tachycardia, and abdominal distension. It is dangerous because of the high risk of perforation, needing emergency surgery.

Clinical relevance. Early recognition of toxic megacolon and timely colectomy prevent fatal perforation.

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Toxic megacolon

Toxic megacolon is a life-threatening complication of severe (usually ulcerative) colitis.

What it is

• Acute, non-obstructive dilatation of the colon with systemic toxicity ('disintegrative colitis').
• Suspected in patients with fulminant colitis (more than 10 movements/day, fever, tachycardia, continuous bleeding, anaemia, hypoalbuminaemia, distension).

Recognition

• Plain abdominal radiograph: increasing colonic diameter, mucosal islands, intramural gas.
• Clinical deterioration: sudden rise in pulse and temperature, increasing distension.

Why dangerous and management

• High risk of colonic perforation and peritonitis.
• Intensive medical therapy (IV steroids, fluids, monitoring); emergency colectomy if no rapid improvement, to avoid perforation.