Multiple sclerosis: assessment of colonic and anorectal function in the presence of faecal incontinence

Six females suffering from Multiple Sclerosis (MS) with symptoms of constipation and faecal incontinence were investigated using anal manometry, proctometrogram, proctography and large bowel transit time estimates (using inert markers). Results were compared to a control group (4 females, 2 males). Resting anal sphincter pressure (internal sphincter function) was reduced, but not significantly so, compared with controls (46 +/- 12.6 vs. 68 +/- 8.2 mm Hg: P < 0.1). Maximum squeeze increment pressure (external sphincter function) was significantly diminished in the patient group (13.5 +/- 4.5 vs. 82.5 +/- 12.3 mm Hg: P < 0.0001). Radiological imaging of the anorectum demonstrated an abnormal position of the pelvic floor at rest, with moderate descent in most cases during straining. Measurement of anorectal angles (puborectalis muscle function) indicated a normal angle at rest (76 +/- 10.4 degrees), but with little change on maximum contraction (74 +/- 3.5 degrees) and on straining (79 +/- 4.6 degrees). Rectal sensory parameters did not differ from controls either for minimum sensation, 44.5 +/- 5.2 vs. 30 +/- 5.8 ml (P < 0.1), or at maximum tolerable volume, 163 +/- 34.5 vs. 148 +/- 22 ml (P > 0.2). Four of six patients failed to empty 100% of simulated stool at proctography, at which the only anatomical defect was the presence of a rectocele in two patients. Large bowel transit studies revealed abnormally slow transit in 82% of patients, all of whom had delay in the distal colon. These physiological studies demonstrate that in patients with MS who had anorectal dysfunction, there is a marked impairment of external anal sphincter function with moderate changes in pelvic floor musculature.(ABSTRACT TRUNCATED AT 250 WORDS)