Studies in obstructive jaundice.

Acute obstruction of the extrahepatic ducts causes gross proximal duct dilatation, and elevated levels of ornithine carbamyl transferase, bilirubin, and alkaline phosphatase. Slow progressive obstruction causes variable proximal duct dilatation and in these cases bilirubin, alkaline phosphatase, and ornithine carbamyl transferase return to normal, despite the presence of severe though incomplete obstruction of the common duct and microscopic findings of biliary cirrhosis. In the early phases, ornithine carbamyl transferase is a slightly more sensitive indicator of biliary obstruction than alkaline phosphatase or bilirubin, but the values still return to normal in the face of a persistent stricture. If a patient who has previously had common duct surgery develops recurrent episodes of fever which suggest cholangitis, it should be assumed that he has a recurrent stricture, even though a cholangiogram and liver function may be normal or only slightly altered. A delay until the liver function studies show consistently raised levels may result in severe biliary cirrhosis and decreased hepatic reserve.