Biliary atresia

	Biliary atresia;
ICD-10	Q44.2
ICD-9	751.61
OMIM	210500
DiseasesDB	1400
MeSH	C06.130.120.123

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Biliary atresia is a rare condition in newborn infants in which the common bile duct between the liver and the small intestine is blocked or absent. If unrecognised, the condition leads to liver failure but not (as one might think) to kernicterus. This is because the liver is still able to conjugate bilirubin, and conjugated bilirubin is unable to cross the blood-brain barrier. The cause of the condition is unknown. The only effective treatments are certain surgeries, or liver transplantation.

Symptoms and diagnosis

Initially, the symptoms are indistinguishable from neonatal jaundice, a common phenomenon. Symptoms are usually evident between two and six weeks after birth. Besides jaundice, other symptoms include pale stools, dark urine, swollen abdominal region and large hardened liver (which may or may not be observable by the naked eye). Prolonged jaundice that is resistant to phototherapy and/or exchange transfusions should prompt a search for secondary causes. By this time, liver enzymes are generally measured, and these tend to be grossly deranged, hyperbilirubinaemia is conjugated and therefore does not lead to kernicterus. Ultrasound investigation or other forms of imaging can confirm the diagnosis. Further testing include radioactive scans of the liver and a liver biopsy.

Biliary atresia is a very rare disorder. About one in 10,000 to 20,000 babies in the U.S are affected every year. Biliary atresia seems to affect girls slightly more often than boys. Within the same family, it is common for only one child in a pair of twins or only one child within the same family to have it. Asians and African-Americans are affected more frequently than Caucasians. There does not appear to be any link to medications or immunizations given immediately before or during pregnancy.

Pathophysiology

There is no known cause of biliary atresia.

As the biliary tract cannot transport bile to the intestine, bile is retained in the liver (known as stasis) and results in cirrhosis of the liver.

Treatment

If the intrahepatic biliary tree is unaffected, surgical reconstruction of the extrahepatic biliary tract is possible. This surgery is called a Kasai procedure (after the Japanese surgeon who developed the surgery, Dr. Morio Kasai) or hepatoportoenterostomy.

If the atresia is complete, liver transplantation is the only option.