Biliary atresia is a rare disease of the liver and bile ducts that occurs in infants.
Cells within the liver produce liquid called bile. Bile helps to digest fat. It also carries waste products from the liver to the intestines for excretion. This network of channels and ducts is called the biliary system. When the biliary system is working the way it should, it lets the bile drain from the liver into the intestines.
When a baby has biliary atresia, bile flow from the liver to the gallbladder is blocked. This causes the bile to be trapped inside the liver, quickly causing damage and scarring of the liver cells (cirrhosis), and finally liver failure.
About one in 15,000 to 20,000 babies do not have complete bile ducts. Biliary atresia seems to affect girls more than boys. Within the same family, it is common for only one child in a pair of twins or only one child within the same family to have it. Asians and African-Americans are affected more frequently than Caucasians. There does not appear to be any link to medications taken during pregnancy.
The causes of biliary atresia are not completely understood. For some children, biliary atresia may occur because the bile ducts did not form properly during pregnancy. For other children with biliary atresia, the bile ducts may be damaged by the body’s immune system in response to a viral infection acquired after birth.
Ten to 15 percent of infants with biliary atresia may be born with other problems in the:
- Spleen (polysplenia)
- Blood vessels (inferior vena caval anomalies, pre-duodenal portal vein)
- Intestine (situs-inversus or malrotation)
Babies with biliary atresia usually appear healthy when they are born. Symptoms of the disease typically appear or develop about two to eight weeks after birth. Those symptoms include:
- Jaundice — a yellow coloring of the skin and eyes due to a very high level of bilirubin (bile pigment) in the bloodstream. Jaundice caused by an immature liver is common in newborns. It usually goes away within the first week to 10 days of life. A baby with biliary atresia usually appears normal at birth, but develops jaundice at two or three weeks after birth.
- Dark urine — caused by the build-up of bilirubin (a breakdown product from hemoglobin) in the blood. The bilirubin is then filtered by the kidney and removed in the urine.
- Acholic stools (clay-colored stools) — because no bile or bilirubin coloring is being emptied into the intestine. Also, the abdomen may become swollen from a firm, enlarged liver.
- Weight loss and irritability — develop when the level of jaundice increases.
Jaundice may be present with other liver disorders, so several tests are needed to get the correct diagnosis.
Children with liver disease have a faster metabolism than healthy children. This means that children with biliary atresia may require more calories. A child with biliary atresia cannot properly digest fats. This is because not enough bile gets to the intestine. Due to liver damage, there may also be a loss of vitamins and protein. Guidelines from your doctor for your child’s nutrition may include:
- A well-balanced diet, consisting of three meals a day plus small snacks in between meals.
- Vitamin supplements.
- Adding medium-chain triglyceride (MCT) oil to foods and liquids or infant formulas. MCT adds extra calories that will help your child grow.
- High-calorie liquid feedings may be recommended if your child is too ill to eat normally. Feedings are given through a special tube (nasogastric tube) that is placed in the nose and guided down the esophagus and into the stomach.
Although digestion may return to normal after surgery, extra vitamins or MCT oil may be needed.
Biliary atresia cannot be treated with medication. A Kasai procedure or hepatoportoenterostomy is done. The Kasai procedure is an operation to create an open duct so bile can drain from the liver.
With an experienced surgeon, the Kasai procedure is successful in 60 to 85 percent of the patients. This means that bile drains from the liver and the jaundice goes down.
The Kasai procedure is not a cure for biliary atresia, but it does allow babies to grow and have fairly good health for several years. When this procedure does not work, it is usually because the blocked bile ducts are inside the liver (intrahepatic), as well as outside the liver (extrahepatic). If this is the case, liver transplantation can correct this problem.
Success with this procedure is related to:
- Age. Surgery is most successful in infants younger than two to three months of age.
- Extent of liver damage (cirrhosis) at the time of surgery.
- The number and size of microscopic ducts in the scarred tissue that can drain bile.
Complications right after surgery are low. Most problems that develop are because the biliary atresia is getting worse.
Long-term survival after the Kasai procedure is affected by the presence of progressive liver disease (cirrhosis) and the development of portal hypertension (high blood pressure in the portal vein that carries blood to the liver). Nearly one-half of all infants who have had a Kasai procedure require liver transplantation before age 5. Older children may continue to have good bile drainage and no jaundice.
Some children may develop portal hypertension and have gastrointestinal bleeding, accumulation of fluid in the abdomen (ascites) and overactivity of the spleen (hypersplenism).
Eighty-five percent of all children who have biliary atresia will need to have a liver transplant before they are 20 years old. The remaining 15 percent have some degree of liver disease. Their disease can be managed without having a transplant.
If there is still not enough bile flow with the Kasai procedure, liver transplantation is a final option. A liver transplant operation removes the damaged liver and replaces it with a new liver from a donor.
After transplant surgery, the child’s health may improve quite quickly. However, the child’s body might reject the new organ. To prevent rejection, a strict schedule of anti-rejection medications must be taken. After a transplant, ongoing lifelong care is required. Frequent contact with physicians and other members of the transplant team is also necessary.