Abnormal Perception of Urge to Defecate: An Important Pathophysiological Mechanism in Women With Chronic Constipation

Abstract

INTRODUCTION: Although the association of absent or attenuated "call to stool" with constipation is well-recognized, no studies have systematically evaluated the perception of urge to defecate in a well-defined cohort of patients with chronic constipation (CC). METHODS:A prospective study of 43 healthy adult women and 140 consecutive adult women attending a tertiary center for investigation of CC. All participants completed a 5-day viscerosensory questionnaire, and all women with CC also underwent anorectal physiologic investigations. Normal urge perception and abnormal urge perception were defined using a Naive Bayes model trained in healthy women (95% having normal urge). RESULTS:In total, 181 toilet visits in healthy women and 595 in women with CC were analyzed. Abnormal urge perception occurred in 70 (50.0%) women with CC. In this group, the urge to defecate was more often experienced as abdominal sensation (69.3% vs 41.4%; P < 0.0001), and the viscerosensory referral area was 81% larger (median pixels anterior: 1,849 vs 1,022; P < 0.0001) compared to women with CC and normal urge perception. Abnormal (vs normal) urge in women with CC was associated with more severe constipation (Cleveland Clinic constipation score: 19 vs 15 P < 0.0001), irritable bowel syndrome (45.7% vs 22.9% P < 0.0001), and a functional evacuation disorder on defecography (31.3% vs 14.3% P 5 0.023). A distinct pattern of abnormal urge was found in women with CC and rectal hyposensitivity.DISCUSSION:Abnormal urge perception was observed in 50% of women with CC and was frequently described as abdominal sensation, supporting the concept that sensory dysfunction makes an important contribution to the pathophysiology of constipation.

From the organ bath to the whole person: a review of human colonic motility

“…Rectal sensitivity can be tested with a balloon inflated in the rectum. 43 Tests of evacuation disorders commonly use the balloon expulsion test or defaecography. The former requires the patient to expel a fluid-filled balloon placed within the rectum.…”

“…In general terms, a low resting pressure can indicate a weak or damaged internal anal sphincter, while a low squeeze pressure can indicate damage to the external anal sphincter. Rectal sensitivity can be tested with a balloon inflated in the rectum 43 . Tests of evacuation disorders commonly use the balloon expulsion test or defaecography.…”