EXCRETION OF BILE ACIDS IN EXTRAHEPATIC BILIARY ATRESIA AND INTRAHEPATIC CHOLESTASIS OF INFANCY

This series included 24 infants, 16 boys and 8 girls, who were admitted to hospital with the diagnosis of obstructive jaundice. Five of the infants were subsequently found to have extra-hepatic biliary atresia (BA) and the other 19 infants intrahepatic cholestasis of infancy (IHC). The infants were investigated given special attention to: the quantitative urinary excretion of cholic and chenodeoxycholic acids, the isotope excretion after intramuscular injection of cholic acid-24–¹⁴C, the nature of labelled urinary bile acids, the half-life and the pool size of cholic acid. At the first examination of the infants after admission the urinary excretion of cholic and chenodeoxycholic acids varied greatly between the patients. However, on comparing the values obtained in the two groups, it was found that there was virtually no difference between the mean daily values of cholic and chenodeoxycholic acids in urine, and the ratio cholic to chenodeoxycholic acid between the BA group and the IHC group. After the injection of isotopic cholic acid most of the isotope was recovered in the urine in all cases. In the infants with BA the faecal excretion of the isotope was low, being less than 3 per cent of the injected isotope. Out of the 19 infants with IHC the recovery of the injected isotope in faeces was also less than 3% in 11 infants. In 8 infants with IHC the faecal isotope excretion was significantly high to exclude extrahepatic biliary atresia. The first 24 hour urine specimen contained small amounts of unconjugated labelled cholic acid in all cases whereas in no case did the patients excrete unconjugated labelled cholic acid 48 hours after the injection of the isotope. No transformation of cholic acid was observed. There was no difference between the BA group and IHC group with regard to the percentage labelled glycine conjugates of total excreted urinary conjugates. Neither was there any difference between the two groups with regard to half-life and pool size of cholic acid. There was no difference with respect to the bile acid metabolism between infants with congenital CMV infection, decreased serum concentrations of alfal-antitrypsin and the other patients.