Anorectal function in Crohn's disease.

Anorectal function was assessed in 63 patients with Crohn's disease and in 10 controls. Eleven patients with Crohn's disease (17%) were partially and three (5%) totally incontinent. The results of anal sphincter function studies of continent patients with Crohn's disease were similar to those of partially incontinent patients and controls. Incontinent patients had significantly lower maximal basal pressure (P less than 0.01) and significantly lower maximal squeeze pressure (P less than 0.05) as compared to controls. There was no significant difference in rectal capacity between continent, partially incontinent and totally incontinent patients and controls. There were significantly more patients with symptoms of anal incontinence in the group of patients with anal Crohn's disease as compared to the Crohn's group with normal anorectum (P less than 0.001). Risk factors for total anal incontinence in Crohn's disease were severe anorectal stenosis and previous surgery for anal abscesses. The most important reason for partial incontinence was diarrhoea. In conclusion, Crohn's disease without macroscopic lesions in the anorectum and without diarrhoea does not affect anorectal function.