[Function tests of the lower small intestine with 75selenium-labeled homotaurocholic acid in Crohn disease and resections of the small intestine].

Unlabelled: Faecal excretion of bile acids was investigated using 75Se-homotaurocholic acid (75SeHCAT) in a total of 75 patients: 9 with irritable colon, 58 with Crohn's disease and 8 with small-bowel resection due to various indications but without Crohn's disease. Bile acid malabsorption, taken as a pathological bile acid retention of less than 19%, was found present in 43 patients with diseased terminal ileum or with more than 20 cm resection of this organ, except in one case (12 cm). On the other hand a normal bile acid retention (21 to 27%) was found in 29 of 72 patients (including 9 patients with irritable colon) who showed either no radiologically detectable lesion of the ileum (n = 21) or changes involving an extension of up to 30 cm (inflammation or resection) in the terminal ileum (n = 8), with the exception of one case (50 cm). Three patients had a raised bile acid excretion contrary to clinical expectation: they had colitis Crohn without radiologically detectable involvement of the small intestine. Thus using the 75SeHCAT-retention test it seems possible to recognize functional disorders in diseased segments of the bowel before the appearance of radiologically detectable changes.

Conclusion: 75SeHCAT is a suitable substance for investigations on the function of the lower small intestine.