Biliary Obstruction

Excerpt

Biliary obstruction commonly refers to blockage of the bile duct system, leading to impaired bile flow from the liver into the intestinal tract. Bile is a substance that contains bile salts, bilirubin, and cholesterol and is continuously synthesized in the liver hepatocytes. Bile is then transported via the bile ducts into the second portion of the duodenum to assist with the metabolism of fats.

Bile formed in the liver flows through the right and left hepatic ducts into the common hepatic duct. The common hepatic duct then joins the cystic duct arising from the gallbladder to form the common bile duct. The common bile duct then joins the pancreatic duct through its course within the head of the pancreas before opening into the duodenum through the major papilla or ampulla. The majority of the bile flows into the gall bladder through the cystic duct, where it is concentrated and temporarily stored, while the rest of the bile flows through the common bile duct into the duodenum through the sphincter of Oddi. The flow of bile into the duodenum is regulated by the release of the hormone Cholecystokinin (CCK) from the duodenum, which controls the release of stored bile from the gallbladder and the relaxation of the sphincter of Oddi.

Biliary obstruction is generally referred to as blockage of the extrahepatic biliary system. Biliary obstruction can occur anywhere along this path and can lead to serious complications such as hepatic dysfunction, renal failure, nutritional deficiencies, bleeding problems, and infections. Disruption in the bile flow due to impairment of the intrahepatic biliary system is generally referred to as cholestasis. Cholestasis can present as abnormalities in serum hepatic enzymes, such as elevated bilirubin and alkaline phosphatase levels, and can lead to jaundice and pruritis.

Biliary obstruction is common and affects a large portion of the world population, causing significant morbidity and mortality. The most common etiology of biliary obstruction is choledocholithiasis or gallstones, causing extrahepatic bile duct blockage. The most serious manifestation of this is the development of infection in the bile ducts called cholangitis, which can be fatal if not treated promptly.