What is biliary atresia?
Biliary atresia is a chronic, progressive liver problem that becomes evident shortly after birth. Tubes in the liver, called bile ducts, normally allow a liquid produced by the liver called bile to drain into the intestines and kidneys. Bile aids in digestion and carries waste products from the liver to the intestine and kidneys for excretion. In biliary atresia, bile ducts in the liver are blocked. When the bile is unable to leave the liver through the bile ducts, the liver becomes damaged and many vital body functions are affected.
What causes biliary atresia?
The cause of biliary atresia is unknown. Some experts believe that babies are born with biliary atresia, implying that the problem with the bile ducts occurred during pregnancy while the liver was developing. Others believe that the disease begins after birth, and may be caused by exposure to infections or toxic substances.
Biliary atresia does not seem to be linked to medications the mother took, illnesses the mother had, or anything else the mother did during her pregnancy. Currently, there is not a genetic link known for biliary atresia. The disease is unlikely to occur more than once in a family.
How often does biliary atresia occur and who is at risk?
- Biliary atresia is the most common cause of liver transplantation in children living in the U.S.
- Biliary atresia occurs once in every 18,000 births and is more common in girls than in boys.
- Asian populations, African-American, and premature infants are more frequently affected than Caucasian newborns.
Why is biliary atresia a concern?
Biliary atresia causes liver damage and affects numerous processes that allow the body to function normally. Biliary atresia is a life-threatening disease and is fatal without treatment.
What are the symptoms of biliary atresia?
Infants with biliary atresia usually appear healthy at birth. Most often, symptoms develop between two weeks and two months of life, and may include:
- Dark urine
- Light colored stools
- Distended abdomen
- Weight loss
Jaundice is a yellow discoloration of the skin and whites of the eyes due to an abnormally high level of bilirubin (bile pigment) in the bloodstream, which is then excreted through the kidneys. High levels of bilirubin may be attributed to inflammation or other abnormalities of the liver cells, or blockage of the bile ducts. Jaundice is usually the first sign, and sometimes the only sign, of liver disease.
Symptoms of biliary atresia may resemble other liver conditions or medical problems. Please consult your child's doctor for a diagnosis.
How is biliary atresia diagnosed?
A doctor or other health care provider will examine your child and take a medical history. Several procedures are done to help evaluate the problem and may include the following:
- Blood tests:
- Liver enzymes. Elevated levels of liver enzymes can alert health care providers to liver damage or injury, since the enzymes leak from the liver into the bloodstream under these circumstances.
- Bilirubin. Bilirubin is made by the liver and is excreted in the bile. Elevated levels of bilirubin often mean bile flow is blocked or there is a defect in the processing of bile by the liver.
- Albumin and total protein. Below-normal levels of proteins made by the liver are associated with many chronic liver disorders.
- Clotting studies, such as prothrombin time (PT) and partial thromboplastin time (PTT). Tests that measure the time it takes for blood to clot. Blood clotting requires vitamin K and proteins made by the liver. Liver cell damage and bile flow obstruction can both interfere with proper blood clotting.
- Viral studies, including hepatitis and HIV. Checking for viruses in the bloodstream can help determine the cause of the liver problems.
- Blood culture. Checking for bacterial infection in the bloodstream that can affect the liver may help diagnose biliary atresia.
- Imaging tests:
- Abdominal ultrasound. A diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view the liver, gallbladder, and bile ducts.
- Hepatobiliary (HIDA) scan. A low radioactive isotope (technetium) is injected into the child's vein. The liver and intestine are scanned by a nuclear medicine machine. If the isotope passes through the liver into the intestine, the bile ducts are open and the child does not have biliary atresia.
The test that gives the most definitive diagnosis is a liver biopsy. A tissue sample is taken from your child's liver and examined for abnormalities, allowing biliary atresia to be distinguished from other liver problems. Diagnostic surgery may also be done. The surgeon can see the liver and bile ducts by making a cut in the abdomen. If biliary atresia is diagnosed, the surgeon may treat it at the same time.
What is the treatment for biliary atresia?
Specific treatment for biliary atresia will be determined by your child's doctor based on the following:
- The extent of the problem
- Your child's age, overall health, and medical history
- Your child's tolerance for specific medications, procedures, or therapies
- Expectations for the course of the problem
- The opinion of the health care providers involved in the child's care
- Your opinion and preference
Biliary atresia is an irreversible problem. There are no medications that can be given to unblock the bile ducts or to encourage new bile ducts to grow where there were none before. Until that happens, biliary atresia will not be curable. However, two different operations can be done that will allow the child with biliary atresia to live longer and have a better quality of life. Your child's doctor can help determine whether either of these operations are an option:
- Kasai portoenterostomy. This operation connects the bile drainage from the liver directly to the intestinal tract. It is most successful when done before an infant is 3 months old. This procedure is helpful because it can allow a child to grow and remain in fairly good health for several years. Eventually, cholestasis (backup of bile in the liver) will occur, causing liver damage.
A liver transplant operation removes the damaged liver and replaces it with a new liver from a donor. The new liver can be either:
- A whole liver, received from a deceased donor.
- Part of a liver, received from a deceased donor.
- Part of a liver, received from a relative or other person whose tissue types match the child's tissue type.
After surgery, the new liver begins functioning and the child's health often improves quickly. After a liver transplant, children will need to take medications to prevent the body from rejecting the new organ. Rejection occurs due to one of the body's normal protective mechanisms that helps fight against invasion of viruses, tumors, and other foreign substances. Antirejection medications are taken in order to prevent this normal response of the body from fighting against the transplanted organ. Frequent contact with the doctors and other members of the transplant team is crucial after a liver transplant.
If my child has biliary atresia, is nutrition a problem?
Before your child has either one of these operations, nutrition may be a problem. With biliary atresia, not enough bile reaches the intestine to help digest fats in the diet. Protein deficiencies may occur due to liver damage. Vitamin deficiencies may also occur. Children with liver disease require more calories than a normal child because of a faster metabolism.
Your doctor may recommend that a pediatric nutritionist advise you on your child's diet. Nutritional guidelines may include the following:
- Provide your child with a good, well-balanced diet.
- Supplement your child's diet with vitamins, as directed by your child's doctor.
- Provide your child with high-calorie liquid feedings, as directed by your child's doctor. Some children with liver disease become too sick to eat normally. In this case, your doctor may recommend that your child have liquid feedings given to help meet his or her body's requirements. These feedings are given through a tube called a nasogastric tube (NG) that is guided into the nose, down the esophagus, and into the stomach. A high-calorie liquid can be given through the tube to supplement your child's diet if he or she is able to eat only small amounts of food, or to replace meals if your child is too sick to eat.
After surgery, your child's digestion may return to normal, or you may still need to give extra vitamins and/or work with your child's diet. Please consult your child's doctor for recommendations.
What is the long-term outlook for a child with biliary atresia?
Many factors affect the long-term outlook for these children. Some of them include:
- The extent of bile duct damage.
- The age at which either a Kasai portoenterostomy or liver transplant is done.
- The extent of liver damage that has occurred.
- The overall health of your child.
After liver transplant, the child's health will usually improve; however, a rigorous medical regimen must be followed.