Biliary atresia is a rare condition that affects the bile ducts in infants. It can cause bile to build up in the liver, causing damage. It can be life threatening, but treatment may improve survivability.

Bile ducts are small channels that carry bile from the liver to the gallbladder. Bile is a liquid created in the liver. It aids digestion in the small intestine.

When an infant has biliary atresia, scarring blocks their bile ducts. This results in less bile flowing from the liver to the gallbladder, causing bile to build up within the liver. This may lead to liver damage.

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Biliary atresia is a condition that causes the bile ducts in infants to become blocked. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), it occurs in around 1 in 12,000 infants in the United States.

The American Liver Foundation notes there is currently no way to prevent biliary atresia from developing. Biliary atresia is fatal without treatment. According to the NIDDK, treatment allows most infants to reach adulthood.

According to the NIDDK, there are two main types of biliary atresia:

  • Isolated biliary atresia: This form is also known as biliary atresia perinatal or biliary atresia without congenital anomalies — commonly known as birth defects. It is the most common type of biliary atresia.
  • Fetal or embryonic biliary atresia: This form may also be known as biliary atresia with congenital anomalies. An infant with this type of biliary atresia may have major congenital anomalies alongside the condition. Information from the American Liver Foundation notes around 10% of babies with biliary atresia have congenital anomalies.

Experts do not currently know the exact cause of biliary atresia. Research indicates it develops while a baby is in the womb or just after they are born.

Researchers are investigating the possibility of the following affecting biliary atresia:

  • certain infections
  • contact with harmful chemicals
  • issues with the immune system
  • a problem with liver and bile duct development in the womb
  • gene mutations

Certain risk factors may increase an infant’s chances of developing biliary atresia. These include being female and having Asian or African American heritage.

The NIDDK notes jaundice is generally the first sign of biliary atresia. Jaundice is a condition that causes yellowing of the skin and eyes. It occurs when bilirubin — a substance found in bile — builds up in the body. As bile builds up in the liver, so does bilirubin.

Jaundice commonly occurs in infants in the first 2 weeks after birth. An infant may have biliary atresia if their jaundice continues after they are 3 weeks old. Jaundice due to biliary atresia generally develops between the ages of 3 to 6 weeks.

The National Organization for Rare Diseases (NORD) notes other symptoms of biliary atresia may include:

  • abnormally pale stools
  • dark urine
  • a swollen abdomen
  • an enlarged liver
  • poor weight gain
  • irritability
  • an increase in blood pressure between the veins that carry blood from the intestine to the liver

The NIDDK recommends a person should have an infant tested for biliary atresia if they have jaundice 3 weeks after birth.

A doctor may diagnose an infant with biliary atresia in the following ways:

  • Medical history: A doctor may ask a person about changes in the infant’s stool and other symptoms.
  • Physical examination: A doctor may check the infant for signs of biliary atresia. This may include checking for jaundice, congenital anomalies, or feeling for an enlarged spleen or liver.
  • Blood tests: A doctor may take a sample of the infant’s blood to check their bilirubin levels. They may also check for other signs of liver disease.
  • Hepatobiliary scan: This scan creates an image of the liver and bile ducts. A doctor may also use an ultrasound to rule out other health conditions.
  • Liver biopsy: This involves a doctor taking a tissue sample from the liver. A pathologist may then check this sample for signs of biliary atresia or other liver problems.
  • Diagnostic surgery: This surgery involves a surgeon cutting into an infant’s abdomen. They can then examine the liver and bile ducts. Alternatively, a surgeon may insert a laparoscope into a smaller cut on the abdomen. A laparoscope is a thin tube with a camera on the end.

The NIDDK states biliary atresia may cause the following complications:

  • failure to thrive
  • malnutrition
  • cirrhosis, which is scarring of the liver
  • liver failure

An infant who has biliary atresia will develop cirrhosis within 6 months if they do not receive treatment. Additionally, without treatment, they will develop liver failure within a year. An infant with untreated biliary atresia will need a liver transplant by 2 years old.

Early surgery may help slow the progress of liver damage due to biliary atresia. However, most children with biliary atresia will need a liver transplant during childhood.

A person should consult a doctor as soon as possible if they notice any signs of biliary atresia in an infant.

Biliary atresia is a rare condition that affects the bile ducts of infants. Without treatment, it is fatal. There are two main types of biliary atresia: isolated biliary atresia and fetal biliary atresia. The isolated form is the most common type and is not associated with congenital anomalies — better known as birth defects.

Experts do not yet know the cause of biliary atresia and are currently unable to prevent it from developing. Jaundice is generally the first sign of biliary atresia. A person should consult a doctor immediately if an infant has jaundice more than 3 weeks after birth.

Without treatment, biliary atresia may cause additional health complications. This may include malnutrition or liver failure. The majority of children with this condition will need a liver transplant during childhood.