Effect of eating on motility of the pelvic colon in constipation or diarrhoea.

Pelvic colonic pressures were recorded before, during, as well as after a meal in patients with non-specific diarrhoea (12) or constipation (14), who were selected according to strict clinical criteria of bowel habit. In the basal state diarrhoeal patients as a group had significantly less colonic activity than constipated patients, but the overlap was considerable. During the meal colonic activity was strikingly increased in diarrhoea, but returned to basal levels immediately after the meal; no such response was observed in constipation. It is suggested that this brief segmental response of the pelvic diarrhoeal colon may be inadequate to prevent entry of faeces into the rectum and the desire to defaecate, following a meal.