Impaired rectal sensation in idiopathic faecal incontinence

Abstract

In 15 patients suffering from idiopathic faecal incontinence and in 15 matched controls, manometric studies of anorectal pressure and studies of the rectoanal reflex and rectal sensitivity were carried out. Patients with idiopathic faecal incontinence had normal resting pressure but reduced squeeze and stress pressures; the anal sphincter relaxed before a sensation of rectal distension occurred. The conclusion is that both reduced voluntary muscle contraction and impairment of rectal sensation are conducive to soiling in idiopathic faecal incontinence.

Rectal Hyposensitivity

“…10,[14][15][16][17] Inclusion on the basis of an elevated desire-to-defecate volume (because this may reflect the normal physiologic process more accurately) or the use of an elevated volume of maximum toleration (because this reflects the perception of discomfort and therefore may be less influenced by patient interpretation) may be argued. Previous studies of rectal sensory impairment have used a variety of these thresholds.…”

Clinical and physiological findings, and possible aetiological factors of rectal hyposensitivity

“…This so-called 'sensory incontinence' was first described over 50 years ago 29 . Subsequently, impaired sensation has been noted to be the only apparent abnormality in certain patients with faecal incontinence 8,9 , in whom it has been postulated that reflex inhibition of the internal anal sphincter as a result of rectal distension occurs without perception of rectal fullness 8 .…”

“…The clinical significance of RH is unclear and therefore has largely been ignored in clinical management. It has previously been reported in patients with chronic constipation 6,7 and faecal incontinence 8,9 , although other coexisting pathophysiological abnormalities, such as delayed colonic transit or anal sphincter abnormalities, are often responsible. There is, however, some evidence to suggest that isolated RH may give rise to symptoms in certain patients, and may be the only demonstrable abnormality in some patients with anorectal disorders 8 .…”

“…It has previously been reported in patients with chronic constipation 6,7 and faecal incontinence 8,9 , although other coexisting pathophysiological abnormalities, such as delayed colonic transit or anal sphincter abnormalities, are often responsible. There is, however, some evidence to suggest that isolated RH may give rise to symptoms in certain patients, and may be the only demonstrable abnormality in some patients with anorectal disorders 8 . The cause, or causes, of RH are unknown, but direct injury to the pelvic nerves 10 , diabetes mellitus 11 , multiple sclerosis 11 and cerebrospinal disease 12 have been implicated.…”

The Physiology of Human Defecation

“…Impaired (blunted) perception of rectal distension, or rectal hyposensitivity, is often associated with an attenuated ''call to stool'' and constipation [16,[210][211][212][213], with or without overflow incontinence [201,[214][215][216][217]. Conversely, rectal hypersensitivity, reflecting increased perception of distension, is associated with a heightened sense of urge, allied to fecal urgency, with or without incontinence [218][219][220][221].…”