Biliary atresia is a rare liver condition that affects newborns and infants. It occurs when the bile ducts become inflamed and blocked or fail to form correctly. Bile ducts are slender tubes that carry the digestive fluid bile from the liver to the small intestine. When bile cannot flow out of the liver, it builds up and causes liver damage, scarring and, eventually, progressive and severe scarring known as cirrhosis.

Biliary atresia appears in about 1 in every 10,000 to 20,000 live births, making it the leading cause of liver transplants in children. Babies with biliary atresia usually appear healthy at birth. The first sign of illness is often yellowing of the eyes and skin, called jaundice, and pale stools that last beyond two weeks.

Babies with biliary atresia should undergo a surgery called Kasai surgery. It also is called hepatoportoenterostomy. This procedure helps relieve bile buildup and slow liver damage, but it does not cure the condition. The surgery works best when done early in life, ideally within the first 60 days. The earlier it is performed, the better the outcome.

Although many children eventually require a liver transplant, a successful Kasai surgery can delay this need for many years. Some individuals may reach adulthood without ever needing a liver transplant.

Types

Healthcare professionals sometimes describe biliary atresia as either syndromic or nonsyndromic, depending on whether other birth defects are present.

• Syndromic biliary atresia. In some babies, biliary atresia occurs along with other structural problems, such as heart defects, spleen problems or differences in how the intestines are arranged. These babies may need extra tests and specialized care for those conditions.
• Nonsyndromic biliary atresia. In most cases, biliary atresia occurs without other malformations.

Healthcare professionals classify biliary atresia using the Kasai classification, which describes where the bile ducts are blocked:

• Type 1. The main bile duct, also called the common bile duct, is blocked. But the ducts inside the liver are still open.
• Type 2. The blockage is higher up, where the right and left bile ducts come together. But the smaller ducts inside the liver are still open.
• Type 3. Blockage is at the duct where bile leaves the liver, called the porta hepatis, with complete blockage of the extrahepatic biliary tree. This is the most common and severe form.

Understanding the type of biliary atresia helps healthcare professionals decide what approach may offer the best outcome.