Abstract

Background—Colonic motor function has not been studied in the ambulatory setting over a prolonged period in the unprepared state. Furthermore, the disturbance of this function in patients with faecal incontinence is unknown.

Aim—To study colonic function over two to three days in the ambulatory, unprepared state in health and in patients with idiopathic faecal incontinence.

Methods—Six healthy women and six women with faecal incontinence and a structurally intact anal sphincter ingested a dual radioisotope meal, and had a six sensor, solid state manometric probe colonoscopically inserted into the left colon. Scanning was performed until radioisotope left the gut and pressure was recorded for a median of 44 hours.

Results—Three of six patients showed abnormal gastric emptying. Patients showed no disturbance of colonic radioisotope transit. Controls had a median of 12, whereas patients had a median of 16, high amplitude propagated waves per 24 hours. In three patients urge incontinence was associated with high amplitude (up to 500 cm water) propagated waves which often reached the rectum. These high pressure waves were identical to those occuring in healthy subjects, the only difference being the lack of adequate sphincter response. Passive incontinence was not associated with colonic motor activity. Defaecation in all subjects was associated with identical propagated waves, and distal movement of 13% (median) of right colonic content and excretion of 32% from the left colon and rectum. The urge to defaecate was associated with either propagated waves (45%) or non-propagated contractions (55%). Rectal motor complexes were recorded in both groups of subjects, but similar rhythmic activity was also recorded in the sigmoid and descending colon.

Conclusions—Normal colonic function consists of frequent high pressure propagated waves. Rhythmic activity occurs both proximal to and in the rectum. Defaecation is characterised by high pressure propagated waves associated with coordinated anal sphincter relaxation. Patients with faecal incontinence may have a widespread disturbance of gut function. Urge incontinence, an urge to defaecate, and defaecation can all be associated with identical high amplitude propagated pressure waves.