Differences of Anorectal Manometry Between Diarrhea- and Constipation-predominant Irritable Bowel Syndrome

Abstract

Background/Aims : The aim of this study was to identify differences in anorectal

manometry between diarrhea-predominant cases and constipation-predominant cases in

patients with irritable bowel syndrome (IBS). Methods : For 62 patients with IBS (29

patients with diarrhea and 33 patients with constipation) and 23 healthy controls, we

measured maximum basal and squeeze pressure of anus, threshold of rectoanal inhibitory

reflex, rectal compliance and volumes to elicit first sensation, sense of defecation,

urgency and maximum toleration. The rectums of subjects were classified into a normal

type, a sensitive type, and an insensitive type according to the threshold of sensation

and expansion rate of rectum. Results : The volumes to elicit sense of defecation,

urgency and maximum tolerable discomfort of patients with diarrhea were significantly

lower than those of patients with constipation. Sixteen (55.2%) in the

diarrhea-predominant patients with IBS had sensitive rectum but 4 (12.1%) in th

constipation-predominant patients with IBS and sensitive rectum. There were no

significant differences in other parameters among the two patients groups and controls.

Conclusions : There were significant differences in the threshold of rectal sensation and

rectal sensitivity between diarrhea-predominant patients with IBS and

constipation-predominant patients with IBS.