Congenital Anomalies of the Biliary Tract

What are congenital anomalies of the biliary tract?

The biliary tract includes all parts of the digestive system involved in the creation, transportation, and secretion of bile. That includes the liver, where bile is made; the gallbladder, where bile is stored between meals; and the bile ducts, through which bile passes on its way to the small intestine, where it finally goes to work breaking down fats and neutralizing acids from the stomach. Any abnormality in that system present from birth is considered a congenital anomaly of the biliary tract.

Such anomalies fall into two main categories: cystic and non-cystic. Cystic congenital anomalies involve cysts, saclike structures filled with pus or other fluid that can occur in—and block or otherwise impede different parts of—the biliary system. An example of a cystic anomaly is a choledochal cyst, which is a cyst in the bile duct.

Non-cystic congenital anomalies, on the other hand, are abnormalities of the biliary structures themselves. Aberrant biliary ducts—ducts that are malformed—are one example of a non-cystic congenital anomaly. Another is called an abnormal pancreaticobiliary junction, in which the pancreatic duct and bile duct join each other farther than usual from where they enter the duodenum and so they cannot be controlled by a muscle in the duodenum wall called the sphincter of Oddi, which normally regulates the flow of digestive juices from the gallbladder and pancreas into the small intestine.

Most congenital defects of the liver itself also occur in the bile ducts. These include biliary atresia, in which the bile ducts are blocked, obstructing the flow of bile; a backup of bile can then cause sclerosis of the liver itself.

What are common symptoms of congenital anomalies of the biliary tract?

  • Jaundice: a yellow tint to the eyes and skin
  • Abdominal pain in the upper-right quadrant
  • Pale or clay-colored stools
  • Excess of the pancreatic enzyme amylase in the blood: called hyperamylasemia
  • Dark yellow or brown urine, due to excessive bilirubin
  • An enlarged liver that feels harder than normal
  • An enlarged spleen
  • Difficulty gaining weight

How are congenital anomalies of the biliary tract diagnosed?

Doctors may order blood, urine, and stool tests seeking evidence of structural malformations blocking or inhibiting the flow of bile, or to check enzyme levels that may indicate liver malfunction and/or inflammation. Endoscopic retrograde cholangiopancreatography (ERCP) can be used to insert dye into the biliary ducts to enhance the clarity of x-rays and highlight abnormalities in the biliary tract. Computer tomography (CT), ultrasound, and MRI can all be used to help with diagnosis. Sometimes a liver biopsy is required, and this can be collected using endoscopic ultrasound fine needle aspiration (EUS-FNA).

How do we treat congenital anomalies of the biliary tract?

Treatment for congenital biliary anomalies may include endoscopic procedures that reconstruct or bypass the defective bile ducts or other biliary components. Sometimes, traditional surgery is required. In rare cases, a liver transplant may be necessary.