What is Biliary Atresia?
Biliary atresia is a rare liver disease that affects 1 in every 12,000 infants worldwide. Infants born with this condition have bile ducts that do not develop normally. The bile duct is a tube that allows bile to flow from the liver into the gallbladder and eventually to the small intestine. Bile plays an important role in carrying waste products from the liver and helps the body absorb fats and vitamins. In biliary atresia, the waste gets built up in the liver, which over time leads to permanent scarring of the liver (cirrhosis) and liver failure.
Biliary Atrisia is the most common cause of end-stage liver disease and liver transplants in children.
The cause of biliary atresia is unknown. Infants may appear normal at birth and may not display any symptoms until a few weeks to months later. Symptoms of biliary include persistent yellowing of eyes or skin beyond 2 weeks of age, dark urine, pale-colored stools, slow weight gain, and enlarged liver.
Types of Biliary Atresia
Fetal form - biliary atresia that develops during fetal life and jaundice present at birth. Some children may have other birth defects in the heart, spleen, or intestines.
Perinatal form - the more common form of biliary atresia. Symptoms do not become evident until the second to fourth week of age.
Symptoms of Biliary Atresia
Infants may appear normal at birth and may not display any symptoms until a few weeks to months later. Symptoms of biliary include persistent yellowing of eyes or skin beyond 2 weeks of age, dark urine, pale or clay-colored (acholic) stools, slow weight gain, and enlarged liver.
Diagnosis of Biliary Atresia
Liver enzymes (AST, ALT, GGT) and direct bilirubin will be elevated.
Albumin, total protein, and clotting studies (PT, PTT, INR) can be affected as they are made by the liver.
Other blood and urine tests are ordered to look for other causes of liver problems that can look similar to biliary atresia.
Abdominal ultrasound - provides an image of the liver and associated structures/anatomy
Hepatobiliary Iminodiacetic Acid (HIDA) scan - a diagnostic imaging technique that injects harmless radioactive dye to determine whether there is bile flow from the liver into the gallbladder and intestine. Cases of biliary atresia typically demonstrate an absence of tracer in the gastrointestinal tract.
Liver biopsy - a tiny sample of the liver tissue is removed with a needle while the child is put to sleep. The pathologist will then examine the tissue under a microscope to help determine whether findings of biliary atresia are present and help rule out other causes of jaundice.
Intraoperative Cholangiogram - a dye is injected into the gallbladder. If there is no flow of contrast into the extrahepatic biliary ducts, a diagnosis of biliary atresia is made and a Kasai procedure is performed at that time.
Causes of Biliary Atresia
The cause of biliary atresia is unknown. There are many theories out there but none has been proven yet.
The Kasai portoenterostomy procedure is the preferred surgical treatment for biliary atresia. This procedure removes the blocked bile ducts and connects the small intestine to the liver in place of the bile duct, therefore, allowing bile to leave the liver and improve liver function. The Kasai procedure should be performed as soon as possible for the best outcome. The indications of a successful procedure include normal stool color, disappearance of jaundice, good weight gain, and improved liver function in blood tests. However, some children may have some variable degrees of liver dysfunction. While the Kasai procedure is not a cure for biliary atresia, it allows the patient to grow and remain in good health for many years. This delays the need for a liver transplant.
It is crucial to start the transplant evaluation when the child is showing a decline in liver functions. With a liver transplant, the damaged liver gets replaced with a new liver. The child can receive the new liver from a deceased or live donor. A liver can be transplanted as a whole or be split into two segments to save two lives. The majority of livers that are transplanted come from deceased organ donors. However, deceased donor organs are not always readily available and waiting lists can be long. As a life-saving alternative, children can receive living-donor liver transplantation. This is possible because the liver can regenerate and grow to its normal size shortly after the surgical removal. The long-term survival after liver transplantation for biliary atresia is over 80%.
Vitamin and protein deficiencies may occur due to liver damage and poor functioning. Children with liver disease require more calories than a normal child because their body does not absorb nutrients well. Special infant formulas, MCT (medium-chain triglycerides) oil, and fat-soluble vitamins (ADEKs) may be recommended to optimize nutritional status. Children who have poor growth or poor appetite will need to have a feeding tube and/or special intravenous line placed for nutritional support called total parenteral nutrition (TPN).