DISTURBANCES OF ANORECTAL FUNCTION IN MULTIPLE-SCLEROSIS

Thirty patients with multiple sclerosis (MS) [18 men and 12 women, mea n age 40 years (range 22-50), disease duration 12 years (range 0.5-34) , Kurtzke's Expanded Disability Status Score 6.0 (range 4.0-7.5)] were interviewed about bowel symptoms and studied using ano-rectal manomet ry. The results were compared with findings in healthy controls. Twent y-eight had bowel symptoms: 8 constipation, 10 constipation and infreq uent faecal urgency, 4 infrequent faecal incontinence and 6 frequent f aecal incontinence. Anal sphincter pressure at rest was significantly reduced in MS patients 69 (SD 17) cm H2O, compared with 92 (SD 15) cm H2O in controls, and the external sphincter contraction force was also significantly reduced. Rectal sensation and rectal compliance were re duced and the ano-rectal inhibition reflex (defaecation reflex) requir ed a higher rectal pressure to be elicited in the patients. Upon recta l filling, an early external sphincter excitation was seen. The presen ce of faecal incontinence correlated strongly with reduced rectal sens ation. The findings suggest that faecal incontinence can at least part ly be explained by low anal sphincter pressure and poor rectal sensati on. The findings of early sphincter excitation and increased threshold of ano-rectal inhibition reflex may be an important pathophysiologica l factor for constipation in MS patients.