Toxic idiopathic megacolon: fatal outcome in a mentally retarded adolescent.

The case of an 18-year-old mentally retarded boy who had long standing idiopathic megacolon and pica is presented. Acute toxic dilatation of the colon complicating pseudomembranous colitis developed, with a rapidly fatal outcome. No similar case of relatively benign idiopathic megacolon complicated by pseudomembranous colitis and toxic megacolon has been reported. The pathophysiology of this rare combination is discussed.