Biliary atresia (BIL-ee-ayr-ee . ah-TREE-zee-uh) is the congenital absence or closure of the ducts that drain bile from the liver. One of the functions of the liver is to produce bile (made up of cholesterol, bile salts, and waste products) that drains from the liver into the small intestine where it helps digest food. Absence of the bile drainage system (called the hepatic system) or its disappearance is called biliary atresia.
For an unknown reason, a progressive inflammatory process begins in the liver soon after birth, typically first affecting the ducts outside the liver. Swelling and scarring of the drainage system traps the bile within the liver and this back-up then damages the liver cells very rapidly, resulting in liver cirrhosis (scarring and decreased function). A possible cause may be a virus that sets up an autoimmune reaction where the body's own defenses begin to damage its own cells. Biliary atresia only affects newborns and is not hereditary, contagious or preventable.
Babies will appear normal at birth but develop jaundice (skin and sclera of eyes turn yellow), dark urine and light-colored stools in the first week of life. Every baby jaundiced after 1 month of age should be evaluated for biliary atresia by screening the blood (measuring the type of bilirubin, conjugated versus unconjugated bilirubin). As the baby's bilirubin increases due to lack of drainage, the abdomen becomes very firm and enlarged due to the increasing liver size. As this occurs, the baby will become irritable and lose weight (although fluid buildup may mask this).
This rare condition occurs in 1 of every 15,000 births, slightly more often in females. It is more common in Asian and black children. About 300 babies are born each year with biliary atresia in the US.
Common Associated Conditions
About 10% of cases have other associated congenital defects of the heart, blood vessels, intestine, or spleen.
Short-Term Treatment and Outcomes
Time plays a huge role in the success of treatment for biliary atresia, and all health care providers caring for babies must be alert to detecting this condition in the newborn period. Early diagnosis of this disease is very important. If surgery is performed before the baby is 2 months old, success is much more likely. After 3 months, surgical success is much less likely.
A liver biopsy will first be done, and typically exploratory surgery will be necessary to examine the condition of the biliary system and liver to confirm the diagnosis. The preferred treatment, called the Kasai procedure, is surgery to remove the damaged biliary ducts outside the liver and attach the small intestine directly to the liver at the spot where bile is found or is expected to drain. Surgery is not a cure but it typically produces good results and allows the child to grow and lead a fairly normal life for a number of years.
Bile flow is re-established in approximately 80% of infants who are operated on when younger than 3 months of age. Of these, about 50% will have some bile drainage and as many as 30% will have complete bile drainage with a return to normal bilirubin. About 20% of infants will not be helped by the Kasai procedure. In these cases, the only other treatment option is a liver transplant.
Long-Term Treatment and Outcomes
The most common complication after surgery is infection of the liver and drainage system with bacteria from the small intestine. About half of all children will have this complication to some degree. Long-term oral antibiotics are used to prevent and treat this serious infection.
Because this surgery may be only partially effective, each baby's situation is different, and liver function may be excellent or poor. If liver function is poor, nutrition will be affected because bile flow is needed to digest dietary fats and fat-soluble vitamins (vitamins A, D, E, K). Poor growth and malnutrition may result. Special formulas containing medium-chain triglycerides (an easily digested form of dietary fat) and water-soluble vitamin supplements are helpful to maximize the child's growth and development.
In the years following surgery, scar tissue in the liver and drainage system may cause portal hypertension in many children. Blood passes through the liver to remove toxic substances, and when the liver is damaged the blood cannot flow normally and pressure in the veins increases. This pressure backs up into the intestines, esophagus and spleen (called portal hypertension, and occurring in about half of all children eventually). The increased pressure decreases spleen function, where clotting factors are produced, decreasing the blood's ability to clot. Weakened veins from portal hypertension can cause leakage of fluid into the abdominal cavity (causing swelling of the abdomen or ascites). If the Kasai procedure is successful in draining the liver and returning the bilirubin back to normal, children may live many years with normal growth and activities. More often, despite successful surgery, there will be slow, progressive damage to the liver (called cirrhosis). The child will require a liver transplant if progressive cirrhosis occurs.
Because of the increasing success in recent years, liver transplantation is now typically part of the long-term treatment of biliary atresia and it offers significant hope for all children born with this very serious condition. Long-term survival following the Kasai surgery is 47-60% at 5 years and 25-35% at 10 years. Fifty percent of children will require liver transplantation in the first 5 years of life.
Because the bile and liver are so essential to proper digestion, having the best possible nutrition is essential for babies and children with biliary atresia long-term. Brain growth is so essential in the early years, so nutrition must be maximized. A dietician will often be very helpful in maximizing the calories and in choosing the foods that are best digested and that contribute to growth and energy production. These foods can be expensive and sometimes unpalatable (i.e. special formulas). Extra fats and vitamins are necessary.
Children will take many medications to enhance liver function and treat complications. After liver transplant they will take anti-rejection drugs for the rest of their lives and will require very close follow-up. However, liver cirrhosis progresses more slowly in older children than in babies so the outcomes of liver transplantation have improved greatly in recent years.
Complications include: progressive cirrhosis if bile flow is only partially established by surgery; problems with bleeding and clotting; life-threatening bleeding from the enlarged weak veins in the esophagus and stomach; and accumulation of fluid in the abdominal cavity called ascites. When these complications can no longer be treated effectively, the child is referred for liver transplantation. If left untreated, the result of blocked bile flow is rapidly-progressive liver damage, and children will not survive past two years of age, typically.
Implications for Children's Development
Biliary atresia is very serious and results in extensive hospitalizations, multiple surgeries and shortened life span for most children. However in recent years the outlook has improved with better surgery outcomes and transplantation successes. Each child's situation will differ, but early diagnosis is essential to prevent progressive liver damage. Babies with liver failure will have difficulty interacting due to irritability, will grow poorly and be inactive due to their lack of energy-producing nutrients, and will have developmental delays. Medications can help to treat liver failure but only surgery can produce anything like a cure for this condition. Cognitive function will be variable, depending on the timing of surgery, its success in establishing bile drainage, and the complication rate.
Families of babies with biliary atresia will be very challenged by dealing with the multiple specialists that will be needed (surgery, gastroenterology, general pediatrics) and the frequent clinic visits and hospitalizations. Blood tests will be needed frequently to monitor liver function and to detect any complications that might be developing. This will be especially difficult for families who do not live near a major pediatric medical center since few general practitioners will have experience caring for children with this rare condition.
Early intervention by developmental specialists in the hospital and community as the child's health permits will help the family provide as normal a life as possible for the child and family. The child may have poor general health at times and be prone to infections.
Families can have many expenses due to the health care needs, hospitalizations and surgeries, and the expensive special formulas and diet. Social services and parent-to-parent support groups can be very helpful (Ronald McDonald House, online support groups for post-transplant families, etc).
For more information, including resources for parents and general information about biliary atresia, visit the following websites:
- American Pediatric Surgical Association
- American Liver Foundation
- Children's Liver Disease Foundation
- Children's Liver Association for Support Services
- Biliary Atresia Network
- Medline Plus - biliary atresia