Sensibility of the rectum to distension and the anorectal distension reflex in ulcerative colitis.

The maximum volume of air tolerated within a rectal balloon was less in colitic patients than in normal subjects (P less than 0.001). Smaller volumes were tolerated by patients with a spontaneously bleeding mucosa than by those with less severe inflammation (P less than 0.001). Severe urgency of defaecation with incontinence was experienced by about half those with spontaneous mucosal haemorrhage but was infrequent among other colitics. Those patients with inactive colitis and a reduced maximum tolerable volume tended to have a smaller rectal size than those who could tolerate a normal volume within the rectum. Reflex relaxation of the internal anal sphincter on distension of the rectum appeared normal in patients with colitis.