Tests of Bile-acid and Vitamin B12 Metabolism in Ileal Crohn’s Disease

The bile-acid breath test, fecal analysis of labeled bile acids, and Schilling test were used to study bile-acid and vitamin B12 metabolism in 31 patients with ileal Crohn’s disease. Results of the bile-acid breath test were positive for 42% of the patients; Schilling test, 42%; fecal analysis of bile-acid labels, 19%. Combination of the tests increased the percentage of positive cases to 65. About 50% of the patients who had positive breath tests had evidence of normal bile-acid absorption, indicating increased bile-acid deconjugation by small-intestinal bacteria. The other 50% had evidence of various degrees of bile-acid malabsorption. Disease activity did not correlate with results of any test. Extent of ileal involvement correlated with results of the bile-acid tests, but not with those of the Schilling test. The study demonstrates that there is a wide spectrum of disturbances of bile-acid and vitamin B12 metabolism in ileitis, and that the tests should be useful in the diagnostic evaluation of patients with proven or questionable Crohn’s disease who have diarrhea and malabsorptive abnormalities that could be related to disturbances of bile-acid and vitamin B12 metabolism.