Barium evaluation of anal canal in patients with inflammatory bowel disease.

Radiographs of the anorectum were obtained during double-contrast enema examination on 74 patients with Crohn disease, 32 patients with ulcerative colitis, and 135 patients without inflammatory bowel disease. The radiographs of the 241 patients were read blindly by two observers. About half the patients with Crohn colitis were found to have radiographically abnormal anal canals (i.e., fissures, fistulae, or abscesses). Some 13% of patients with small bowel Crohn disease, 6% of patients with ulcerative colitis, and 3% of patients without inflammatory bowel disease were considered abnormal. Extensive perianal disease was demonstrated radiographically in two patients with Crohn disease a few days after normal physical examinations of the perianal skin and anal canal. It is suggested that a search for disease of the anal canal be undertaken during colon examination in patients with known Crohn disease or in patients with indeterminate inflammatory disease of the colon. The finding of an anal abnormality is considered highly suggestive of Crohn disease of the gastrointestinal tract. Early but extensive perianal disease may be seen radiographically before it is fully manifest clinically.