What Is Biliary Atresia
Biliary atresia is a progressive inflammatory destructive process of the extrahepatic (originating or occurring outside the liver) bile ducts as well as abnormalities of the intrahepatic (originating or occurring in the liver) bile ducts.
It typically presents in the first few weeks of life. When an infant has biliary atresia, the bile is trapped inside the liver, causing damage and scarring to the liver. If biliary atresia is left untreated, the blocked bile flow will lead to further liver damage and eventually liver failure, such that few children with biliary atresia survive beyond the age of two.
On average, there is one case of biliary atresia out of every 20,000 live births1. Females are affected slightly more often than males.
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Causes Of Biliary Atresia
The cause of biliary atresia is unknown. Autoimmune mechanisms may be partly responsible for the progressive process that takes place. Research also suggests that a viral infection may be linked with biliary atresia. About 10% of cases have other associated defects in the heart, blood vessels, intenstine or spleen.
Although the cause is uncertain, it is known that biliary atresia affects only newborns. It is not hereditary, contagious or preventable. Parents can be assured that biliary atresia is not caused by anything the mother did during pregnancy.
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Signs And Symptoms Of Biliary Atresia
The usual history is a full term infant who appears normal at birth but develops jaundice after the age of 2 to 3 weeks.
The infant will have yellow eyes and skin, light-coloured stools and dark urine which is caused by the build up of bilirubin in the blood. The abdomen may be swollen with a firm and enlarged liver. Weight loss and irritability may develop as the level of jaundice increases.
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Diagnosis And Treatment Options For Biliary Atresia
Several tests are needed to make a diagnosis of biliary atresia or to detect any underlying cause for persistent jaundice in an infant. These may include:
- Blood tests to confirm conjugated hyperbilirubinaemia.
- Ultrasound scan of the liver and gall bladder to confirm an atretic gall bladder.
- HIDA scan (radioactive scan of the biliary system) to confirm obstruction to bile flow.
- Liver biospy to look for cirrhosis.
- A surgical procedure to examine the bile ducts and determine the feasibility of a bile drainage procedure to relieve obstruction.
Early diagnosis of this disease is very important. There is a higher chance of success if surgery is performed before the baby is 2 months old. The success rate of the operation is poor if the baby is older than 3 months old. For this reason, all infants who are diagnosed with jaundice after the age of 4 weeks should be evaluated for biliary atresia.
The treatment for biliary atresia is an operation called the Kasai Procedure. A paediatric surgeon will remove the blocked bile ducts outside the liver and connect a loop of small intestine directly to the liver. This allows bile to flow from the liver directly into the intestine. This segment of intestine that connects to the liver forms a Y connection and is called a Roux-en-Y hepatoportojejunostomy or also known as Kasai Procedure. If the Kasai Procedure is successful in draining bile from the liver with complete disappearance of the jaundice, the child may live for many years and grow normally. When bile flow is only partly restored by surgery, the complications of cirrhosis will gradually develop and the child will eventually need a liver transplant. Some children may never need a liver transplant but those who still experience no bile flow after undergoing the Kasai Procedure will require a liver transplant.
Adequate bile flow is needed for the digestion and absorption of dietary fats and fat-soluble vitamins such as vitamins A, B, E and K. When bile flow is reduced, the child might experience poor growth and have malnutrition. Special formulas containing medium-chain triglycerides (an easily-digested form of dietary fat) and water-soluble viatmin supplments are often prescribed to maximise the child's growth and development.
About 50% to 60% patients will achieve clearance of jaundice following Kasai Procedure2. It is possible for these patients to survive more than 20 years on their native liver after undergoing the Kasai operation during early infancy. However, 60.5% of them may suffer from progressive liver-related complications1.
Long-term complications following Kasai Procedure are cholangitis and portal hypertension.
Cholangitis occurs when bacteria normally found in the small intestine migrate up the Roux-ex-Y, causing an infection. Signs of cholangitis include fever, increased jaundice and lighter colouration of stools. Antibiotics are needed to treat cholangitis or prevent it from happening.
Formation of scar tissue within the liver may cause hardening of the liver and a condition known as portal hypertension. Portal hypertension refers to the increased pressure in the veins connecting the intestines and spleen to the liver. Complications of portal hypertension include problems with bleeding and clotting, enlarged weak veins in the oesophagus and stomach and accumulation of fluid in the abdominal cavity called ascites.
When these complications can no longer be treated effectively with medication, the child is referred for liver transplantation. Liver transplantation is highly successful in the long-term treatment of children with biliary atresia with an overall survival of more than 90%3.
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The paediatric liver transplantation unit in NUH provides a comprehensive lifelong management of children with biliary atresia. The care begins with the Kasai procedure in infancy.
Jaundice clearance following the Kasai procedure is predictive of the short-term need for liver transplant within 2 years or the long-term survival with the native liver without a liver transplant. In NUH, there is clearance of jaundice in more than 60% of our patients.
The child will be monitored and the follow-up continues until adulthood. Liver transplantation may be indicated for those cases who develop decompensated liver disease and its complications. Following liver transplantation, survival in these children is more than 85% at one year.
Information is correct as of September 2017.
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Source: 1PubMed, 2ISRN Surgery, 3PubMed
The information provided on this page is meant purely for educational purposes and may not be used as a substitute for medical diagnosis or treatment. You should seek the advice of your doctor or a qualified healthcare provider before starting any treatment or if you have any questions related to your child’s health, physical fitness or medical conditions.