Bile acid malabsorption in cystic fibrosis with and without pancreatic insufficiency.

Serum conjugated cholic acid (CCA) and conjugated chenodeoxycholic acid (CCDCA) fasting levels were measured in 30 children with cystic fibrosis (CF) without liver involvement, and mean levels were not significantly different from control values. In seven children (four with partially corrected pancreatic insufficiency and three without pancreatic insufficiency) serum levels of both primary bile acids (BAs) were also measured after the ingestion of a standard liquid meal; the values were then compared with those for total and fractional fecal BA excretion. The CCA mean peak increase was significantly reduced in patients with pancreatic insufficiency (p less than 0.01), as well as in those without pancreatic insufficiency (p less than 0.05), as compared to controls. The CCDCA mean peak increase was reduced only in patients with pancreatic insufficiency (p less than 0.01). Fecal results confirmed serum data, showing a significantly increased excretion of cholic and deoxycholic acids in patients without pancreatic insufficiency as compared to controls (p less than 0.02), despite a similar total BA excretion. In patients with pancreatic insufficiency, total fecal BA levels were markedly increased compared to control values (p less than 0.001); the fecal percentage of chenodeoxycholic and lithocholic acids was greater than that recorded in patients without pancreatic insufficiency (p less than 0.05), in agreement with the different behaviour of serum CCDCA postprandial curves for the two groups of patients. The results are consistent with selective malabsorption of cholic acid in CF, independent of the presence of pancreatic insufficiency; they confirm the usefulness of serum BA postprandial determinations in measuring BA malabsorption.