Biliary atresia is a chronic, progressive liver problem that becomes evident shortly after birth. Tubes inside and outside 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 that are located inside or outside 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.
The cause of biliary atresia is not known. Some researchers and physicians believe that babies are born with biliary atresia, implying 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 exposures to 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.
- Biliary atresia is the most common cause of chronic liver disease in neonates.
- Biliary atresia occurs once in every 15,000 births.
- Asian populations are most frequently affected. African Americans are affected approximately twice as much as Caucasians.
Biliary atresia causes liver damage and affects numerous important processes that allow the body to function normally. It is a life-threatening disease and is fatal without treatment.
Infants with biliary atresia usually appear healthy at birth. Most often, symptoms develop between two weeks to 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 physician for a diagnosis.
A physician or healthcare provider will examine your child and obtain a medical history. Several diagnostic procedures are done to help evaluate the problem and may include the following:
- blood tests
- liver enzymes
Elevated levels of liver enzymes can alert physicians to liver damage or injury, since the enzymes leak from the liver into the bloodstream under these circumstances.
Bilirubin is produced by the liver and is excreted in the bile. Elevated levels of bilirubin often indicate an obstruction of bile flow or 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 be used to diagnose biliary atresia.
- imaging tests:
- abdominal ultrasound - a diagnostic imaging technique which 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.
Specific treatment for biliary atresia will be determined by your child's physician 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 physicians 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 physician 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 8 weeks old. The Kasai 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. Up to 80 percent of children who undergo the Kasai portoenterostomy will eventually need to have a liver transplant.
- liver transplant
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 child who has died.
- part of a liver, received from a child who has died.
- 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. Anti-rejection medications are taken in order to prevent this normal response of the body from fighting against the transplanted organ. Frequent contact with the physicians and other members of the transplant team is crucial after a liver transplant.
Before your child has either one of these operations, nutrition may be a problem. With biliary atresia, not enough bile reaches the intestine to assist with the digestion of 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 physician may recommend that a pediatric nutritionist make recommendations regarding 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 physician.
- MCT (medium-chain triglyceride) oil or infant formulas with MCT (Portagen® or Pregestimil®) may be recommended to add extra calories to help your child grow. Medium-chain triglycerides are more easily digested without bile than other types of fats. MCT oil can be added to foods and liquids that your child eats.
- Provide your child with high-calorie liquid feedings, as directed by your child's physician. Some children with liver disease become too sick to eat normally. In this case, your physician may recommend that your child have liquid feedings given to help meet his/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/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 physician for recommendations.
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.
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