Biliary Atresia

Biliary Atresia

Biliary atresia is a congenital condition characterized by the obliteration or discontinuity in the tubes or ducts that carry the bile from the liver to the gallbladder, leading to the obstruction in the flow of bile.

Pathophysiology

Biliary atresia occurs because of a congenital malformation of the bile duct system.  Research suggests that infectious and/or toxic agents as the possible culprits in causing obliteration of the bile ducts during the development of the fetus.  Other possible causes are genetic abnormalities, such as the deletion of the jun gene and mutations of the homeobox transcripton factor genes, although no direct causative factor have been described yet.

The bile ducts are the pathways where the wastes are removed from the liver and the bile are carried to help the small intestine digest fat from the diet. 

In infants with this condition, there is blockage of the bile flow from the liver to the gallbladder which could lead to liver damage and cirrhosis.

Epidemiology

In the United States, it is estimated that incidence of biliary atresia occurs in every 10,000 to 15,000 live births.  Cases are more common in the Asian population, especially among the Chinese. 

Clinical Features

Newborns with biliary atresia usually appear normal at birth.  During the second or third week of life, a yellowish discoloration of the skin and mucous membranes (jaundice) develops.  Typical symptoms may include weight loss, dark urine, and enlarged spleen and liver.  The stools may appear pale and have a foul smell.

Diagnosis

Blood tests show elevated total bilirubin, alkaline phosphatase (AP), and gamma-glutamyl transpeptidase (GGTP) levels.  Ultrasonography is not reliable in the evaluation of biliary atresia, although it can exclude other anomalies in the biliary system.  Hepatobiliary imaging such as the technetium-labeled diisopropyl iminodiacetic acid (DISIDA) nuclear scintigraphy, is helpful in determining the function of the gallbladder and bile ducts.  Percutaneous liver biopsy is valuable in establishing the severity of the cirrhosis and in ruling out the other causes of jaundice.  A definitive diagnosis is through the procedure called intraoperative cholangiography, wherein the anatomy and patency of the biliary system is demonstrated.

Treatment

Once biliary atresia has been confirmed, surgical management is the only appropriate intervention.  A surgical procedure called the Kasai procedure is performed to connect the liver to the small intestine and is best done prior to 8 weeks of age.  A liver transplant may be able to improve the survival.

Prognosis

The success rate of the Kasai procedure is 60 to 80%. Early surgery can improve survival and liver transplant would be less likely required. 

Complications

Possible complications can include infection, irreversible cirrhosis, and liver failure.  Failure of the surgical procedure (ie, Kasai procedure) is also possible. 

Public Discussion