Toxic dilatation of the colon.

Toxic dilatation of the colon represents the most serious complication of colonic inflammatory diseases. It is an acute transmural extension of severe inflammation resulting in decreased tissue cohesion and an increased tendency for bowel perforation. The process is characterized by dilatation and apparent radiologic thickening and nodularity of the bowel wall. Cases of toxic megacolon without dilatation occur infrequently.