Biliary Atresia; Diagnosis, Symptoms, Treatment & Kasai Procedure

Investigations

Lab investigations are usually the first ones ordered and they include:

• Serum bilirubin: Serum bilirubin is the main measure of jaundice. It is divided into direct and indirect bilirubin. Generally speaking, if the percentage of direct bilirubin is more than 20%, it is considered as a direct hyperbilirubinemia, which is the case is any obstructive jaundice including biliary atresia.
• Alkaline phosphatase and Gamma-Glutamyl transferase: Both enzymes are produced in cases of abnormalities in the biliary tree. They are elevated in cases of biliary atresia.
• Liver function tests: Any condition that affects the biliary tract is liable to damage the liver, and such damage has to be documented and assessed. The doctor will ask for liver function tests which include enzymes released when liver cells are destroyed (ALT, AST) and proteins produced by the liver including prothrombin and albumin, whose production is affected when the liver is diseased.
• Alpha-1 antitrypsin deficiency: This enzyme’s deficiency is one of the commonest causes of jaundice in the newborn, and the condition has to be excluded.
• Sweat chloride test: Sweat chloride test is the test used to diagnose cystic fibrosis. It is also one of the conditions causing neonatal jaundice and it has to be excluded.

Other routine lab tests may be done including a complete blood count and kidney function tests to assess the general condition of the infant. Regarding imaging studies, they are as important as lab studies and the following are the most commonly performed:

• Abdominal ultrasound: Abdominal ultrasound can diagnose the condition by detecting the absence of the gallbladder and liver enlargement. It is not specific to the condition, and many other conditions can cause the same appearance.
• DISIDA scanning: DISIDA scanning is a type of nuclear scanning which shows how much bile is flowing in the biliary tract. It can show obstruction in cases of gall bladder stones or lost segments of the biliary tract in biliary atresia.
• ERCP: ERCP is short for Endoscopic Retrograde Cholangiopancreatography. It is an imaging study through the insertion of a cannula into the opening of the biliary tract in the small intestines. It was previously not possible in neonates, but it has become present in many centers.

Other than imaging studies and lab tests, the most important investigation that is done is liver biopsy. Liver biopsy means that a small sample of the liver is taken using a special needle through the skin. The procedure is safe and is done under anesthesia. This investigation helps differentiate biliary atresia from other liver diseases which cause the same symptoms.

The role of investigations is not only to confirm the disease, but also to exclude other possible causes. Conditions that cause symptoms similar to biliary atresia include:

• Other causes of cholestasis including choledochal cysts and Allagile syndrome
• Viral infections of the newborn including hepatitis, cytomegalovirus, and toxoplasmosis.
• Galactosemia
• Alpha-1 antitrypsin deficiency