What is biliary atresia?
Biliary atresia is a serious liver disorder that occurs before or shortly after birth when a baby's bile ducts (the tubes that carry bile from the liver) become blocked. The body needs bile to aid digestion and carry wastes from the liver out of the body. When blocked ducts prevent bile from being excreted, the liver becomes damaged.
Causes and forms
The cause of biliary atresia is a mystery. Two forms of biliary atresia are generally recognized, although more may exist.
Perinatal biliary atresia
The most common is the perinatal form which accounts for 65-90 percent of all cases. These children typically appear healthy at birth. As a newborn, these infants pass normal-colored stool and are of average weight. Jaundice develops in the first few weeks of life.
Embryonic/fetal biliary atresia
The less-common embryonic or fetal form occurs in 10-35 percent of biliary atresia cases. These children are frequently jaundiced as newborns and frequently there are associated birth defects such as abnormalities of the heart, major blood vessels, spleen and intestines.
Neither form is thought to be inherited. Many theories about the causes of biliary atresia have been proposed, but none have been proven.
About the liver
The liver, the largest organ in the body, is located on the right side of the abdomen, underneath the ribs and diaphragm and on top of the stomach, right kidney and intestines. It is reddish-brown, weighs about 1½ to 2 pounds in a child (depending on age), and holds about 13 percent of the body's blood supply at any given moment. It receives oxygenated blood from the hepatic artery and nutrient-rich blood from the hepatic portal vein.
The liver has two main lobes, both of which are made up of thousands of lobules. These lobules are connected to small ducts, which connect with larger ducts to ultimately form the hepatic duct. The hepatic duct transports bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine).
What does the liver do?
One of the liver's primary functions is to filter the blood of toxins and other harmful substances, which are then excreted into bile or blood. Bile byproducts enter the intestine and leave the body in the feces; the kidneys filter out the blood byproducts, which leave the body in urine.
The liver carries out many other important jobs, including:
- Converting food into chemicals necessary for life and growth.
- Making the proteins needed for normal blood clotting.
- Processing medications we take into forms the body can use.
- Manufacturing bile, which helps the body digest and absorb fat, vitamins A, D, E and K, and medications. Bile is stored in the gallbladder and released into the intestines as needed.
- Producing cholesterol and special proteins to help carry fats through the body.
- Converting excess glucose (sugar) into glycogen for storage; this glycogen can later be converted back to glucose for energy.
- Regulating the level of amino acids, which form the building blocks of proteins, in the blood.
- Resisting infections by producing immune factors and removing bacteria from the bloodstream.
Infants with biliary atresia usually appear healthy at birth. Most often, symptoms develop within the first two weeks to two months of life. The majority of children with jaundice undergo a series of tests to distinguish biliary atresia from other conditions.
Your doctor will perform a physical exam and will look for or ask questions about the following: jaundice; dark urine; light or pale colored stools; distended abdomen; poor weight gain.
A variety of blood tests can be used to assess liver function. They include:
- Liver enzyme tests (AST, ALT, GGT) — 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 — Bilirubin is produced by the liver and is excreted in the bile. Elevated levels of direct or conjugated bilirubin often indicate an obstruction of bile flow or a defect in the processing of bile by the liver.
- Albumin, total protein, and globulin — 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 may be used to diagnose biliary atresia. 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.
- Infectious, genetic and metabolic studies — Tests on sweat, blood and urine may be done to look for other causes of liver problems that sometimes look very similar to biliary atresia.
- 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 internal organs as they function, and to assess blood flow through various vessels.
- DISIDA or HIDA scan — a diagnostic imagining technique which uses an injected radioactive dye to determine whether there is bile flow from the liver into the gallbladder and intestines.
A tissue sample is taken from your child's liver and examined for abnormalities, allowing biliary atresia to be distinguished from other liver problems.
A cholangiogram is an X-ray imaging study performed by a surgeon in the operating room to determine if there is blockage of bile flow in the ducts leaving the liver. If this test suggests there is an obstruction, the surgeon will proceed with exploration to determine if the child has biliary atresia.
Surgery: Kasai procedure
The Kasai procedure is the preferred treatment for biliary atresia at The Children's Hospital of Philadelphia and has been performed here for more than 30 years. The operation connects the bile draining from the liver directly to the gastrointestinal (GI) tract. It is most successful when done early in the disease process.
The specific age to obtain the best results from the Kasai procedure is unknown because biliary atresia is a rare disease and manifests differently in every child. Researchers have reported varying results over the past three decades. Some suggest the Kasai procedure is best completed before the infant is four weeks old, while others say the best rest results are produced when the operation is completed by the time the baby is 8 weeks old.
While the Kasai procedure is not a cure for biliary atresia, it is the preferred treatment because it allows a child to grow and remain in good health for several years. A successful Kasai procedure delays the need for a liver transplant until later in childhood or even adulthood.
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 they do not absorb the same amount of calories and nutrition. 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. Sometimes special infant formulas are required.
- MCT (medium-chain triglyceride) oil may be recommended to add extra calories to the diet and 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.
- Supplement your child's diet with vitamins, as directed by your child's physician.
- 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 your child have liquid feedings 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. These special diets are especially important in the first year of life when the child’s growth is most rapid.
A liver transplant removes the damaged liver and replaces it with a new liver from a donor. The new liver can be:
- A whole liver, received from a donor who has died
- Part of a liver, received from a donor who has died
- Part of a liver, received from a living 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 an invasion of viruses, tumors or 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.
In general, the long-term outlook for patients with biliary atresia is excellent. Most biliary atresia patients can expect to live into adulthood with either their native liver or a transplanted liver.
From the 1960s to the present, numerous advances in the surgical approach to biliary atresia have been incorporated into routine care. Prior to the early 1960’s, biliary atresia was considered a uniformly fatal disease.
Today — with the Kasai hepatoportoenterostomy and improvements in liver transplantation — patients with biliary atresia are reaching adulthood.
The most recent reports from the U.S., Japan, France, Germany and England have provided insight into the general prognosis patients with biliary atresia.
Overall survival with a native liver (not transplanted) ranges from 30-55 percent at 5 years of age; and 30-40 percent at 10 years of age. It is thought that approximately 80 percent of patients with biliary atresia will require liver transplantation by the age of 20. But these statistics may change as we learn more about biliary atresia and modify our treatment approaches.
Those living with their native liver and reaching adulthood, can expect to go to school, have jobs and even families, if they desire. Both young adults living with their native liver and those who have undergone transplantation can have children.
Their children do not inherit biliary atresia.
Whether living with a native or transplanted liver, young adults with biliary atresia have been described as enjoying a normal quality of life.
Beyond young adults, no one knows exactly what to expect. It is the current group of patients who will tell us what the future holds.
Continuing research efforts
Since 2002, physicians and scientists from around the country and at CHOP have been dedicated to improving the lives of those with biliary atresia through The Childhood Liver Disease Research and Education Network. There are current studies that focus on school functioning, medical complications, timing of transplantation, fibrosis and inflammation.
Together, these studies give the best hope to the new generation of children growing up with biliary atresia.
Frequently asked questions about biliary atresia
Why did my child get biliary atresia?
No one knows what causes biliary atresia. About one in 8,000 to 20,000 get this rare disorder.
Trying to figure out what causes this problem or how we can improve life with biliary atresia is one of the highest priorities of the physicians caring for children with biliary atresia at The Children’s Hospital of Philadelphia.
As far as we know, you did not cause your child to get biliary atresia because of anything you did during pregnancy. Nor do you have a gene that gave your child this problem. Within the same family, it is common for only one child in a pair of identical twins to have this disorder.
What will happen after surgery?
The surgery for biliary atresia is called a Kasai operation or hepatoportoenterostomy. The purpose of surgery for children with biliary atresia is to restore bile flow.
In the first weeks and months after the surgery, your doctors will closely follow your child to make sure jaundice (yellowness of the eyes and skin) disappears and your child's stools darken.
Will my child need special medicines?
The most important aspect of care in the first year of life is nutrition. Reduced bile flow and irritation in the liver can sometimes interfere with proper absorption of nutrients and fat provided by standard formulas. To help your child grow, we often use a special type of formula that has easy-to-absorb fat and we also prescribe special vitamins.
Your child may also be prescribed other medicines such as antibiotics to prevent infection of the bile ducts and ursodeoxycholic acid to promote bile flow.
Is surgery a cure for biliary atresia?
Although the Kasai procedure provides bile drainage for many children, it does not usually cure the child of ongoing inflammation in the liver and bile ducts.
Your child will need close follow-up by a specialist for life. The purpose of these office visits is to watch and, if possible, prevent complications.
What are the complications associated with biliary atresia?
Different types of problems develop at different times during your child’s lifetime.
In the first year or two, the major complications are difficulty overcoming the nutritional problems related to the biliary atresia and cholangitis, which is an infection in the bile ducts.
As your child grows, hardening and scarring of the liver might develop. If that happens, there is an increase in the blood flow through certain blood vessels. Hardening of the liver leads to portal hypertension, which is an increased blood flow to vessels that bypass the liver.
In turn, this leads to a number of complications. Some patients develop intestinal or esophageal bleeding. When that happens, your child may vomit a large amount of blood. This is always an emergency. In some cases, a special procedure is performed to stop the bleeding.
Another complication is ascites, which is a collection of fluid in the belly. The treatment is medication to allow the body to eliminate the fluid.
Lastly, some children develop an enlarged spleen. When the spleen is large, your physician may prescribe a spleen guard to be worn during gym or during certain activities to protect the spleen from injury.
Will my child need a liver transplant?
Approximately half of all children born with biliary atresia will need a liver transplant by the time they are 2 years old. By the age of 20, upwards of 70 percent of patients with biliary atresia will need a liver transplant. Your doctor will consider the possibility of transplantation if there are complications that are not responding to other medical approaches.
Typical reasons to consider liver transplantation include:
- poor growth,
- persistent infection of the bile ducts,
- ascites that does not respond to medicines, and
- persistent jaundice.
Your doctor will refer you to the liver transplant team before these problems are life threatening. Life after liver transplantation is typically very good.
Will my child be normal?
Yes! Infants with biliary atresia grow up to be children who go to school, participate in school activities and have normal friendships. They will have a scar from their initial surgery, but otherwise look and act normal.
We now care for a group of young adults who were the first generation of patients who underwent a Kasai operation. These adults have jobs and attend college. Worldwide, there are reports of men and women with biliary atresia becoming parents to healthy children.