What Causes Biliary Atresia?
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.
Who Is at Risk for Biliary Atresia?
Biliary atresia is a rare disorder. 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 the disease. Asians and African-Americans are affected more frequently than Caucasians.
There does not appear to be any link to medications taken during pregnancy.
Do Children with Biliary Atresia Have Other Associated Abnormalities?
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, preduodenal portal vein)
- Intestine (situs inversus or malrotation)
What Are the Symptoms of Biliary Atresia?
Babies with biliary atresia usually appear healthy when they are born. Symptoms of the disease typically appear within the first two weeks to two months of life. 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 buildup 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 (white or clay-colored stools) − because no bile or bilirubin coloring is being emptied into the intestine. Bile gives stool its green or brown color, and without such, stool is without color (often white or gray).
- Weight loss and irritability − develop when the level of jaundice increases.
How Is Biliary Atresia Diagnosed?
Jaundice may be present with other liver disorders, so several tests are needed to get the correct diagnosis.
- Blood tests are done to tell if there are liver function abnormalities. They may also identify the cause (etiology) of jaundice.
- X-rays of the abdomen look for an enlarged liver and spleen.
- An abdominal ultrasound can tell if there is a small gall bladder or none at all. The gall bladder is the organ that stores bile. If this organ is missing or absent since birth, that often indicates biliary atresia.
- A liver biopsy tells if an infant is likely to have biliary atresia. In a liver biopsy, a tiny sample of the liver is removed with a needle. That sample is then looked at under a microscope. A liver biopsy is very reliable. If the biopsy shows that the infant probably has biliary atresia, further surgery will confirm the diagnosis and treat the condition.
- Diagnostic surgery confirms if an infant has biliary atresia. Surgery allows doctors to see if there is an injured piece of the bile ducts going from the liver to the intestine. This could prevent normal bile flow from the liver.
- An operative cholangiogram is done during the surgery to confirm the diagnosis of biliary atresia.
A cholangiogram is a procedure done at time of operation. This procedure involves a dye that is injected through the gall bladder and goes through the bile ducts. An X-ray is done to learn if the dye flows normally into the intestine and the liver. In infants with biliary atresia, the dye does not usually flow out of the gall bladder due to the blocked ducts.
If the ducts are normal or open (patent) and the dye flows the way it should, biliary atresia is ruled out. A bigger liver biopsy (tissue sample) is then done to find the cause of the liver disorder.
Biliary atresia is diagnosed when the cholangiogram shows that the bile ducts are not open. Then infants usually undergo an operation called the Kasai procedure.
How Is Biliary Atresia Treated?
Biliary atresia cannot be treated with medication. A Kasai procedure (also known as a or hepatoportoenterostomy) is done. The Kasai procedure is an operation to re-establish bile flow from the liver into the intestine. It is named after the surgeon who developed it.
The surgeon removes the damaged ducts outside of the liver (called extrahepatic ducts) and identifies smaller ducts that are still open and draining bile. The surgeon then attaches a loop of intestine to this portion of the liver, so that bile can flow directly from the remaining healthy bile ducts into the intestine.
After this procedure, infants are usually in the hospital for seven to 10 days to heal. Long-term antibiotic therapy is given to reduce the risk of infection, and additional medications may be used to promote bile flow and maximize the success of the operation
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 level 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, sometimes for many years. About 25% of patients who undergo a Kasai procedure do not go on to require a liver transplant.
In 15-40 percent of patients the Kasai procedure does not work. If this is the case, liver transplantation can correct this problem.
Success with the Kasai procedure is related to:
- Age. The younger an infant at the time of surgery, the more likely the surgery will be successful. By the time an infant is older than about 3 to 4 months old, surgery is unlikely to be helpful.
- Extent of cirrhosis (scarring and damage to liver tissue) at the time of surgery.
- The number and size of microscopic ducts in the scarred tissue that can drain bile.
- The nutritional status of the baby at time of transplant (sufficient vitamins, high calorie diet)
Nutrition and Biliary Atresia
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 and jaundice 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 (Specifically Vitamins A, D, E, and K as these are absorbed in fat, and children with biliary atresia cannot absorb these well)
- 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.
What Are the Complications of Biliary Atresia and What Can Be Done for Them?
Complications right after surgery are low. Most problems that develop are due to progression of the liver disease.
- After the Kasai procedure, it is common to get an infection in the bile ducts. This is usually treated using intravenous antibiotics. Treatment may continue with oral antibiotics.
- Jaundice or itching may occur. These can often be treated successfully with medications such as cholestyramine and ursodeoxycholic acid (for itching).
- Many patients with cirrhosis have changes in blood flow through the liver and intestines. These changes may produce problems such as easy bruising of the skin, nosebleeds, retention of body fluid and enlarged veins (varices) in the stomach and esophagus.
Increased pressure in these veins can cause a sudden and large amount of bleeding in the stomach and intestines. Although this can be a very serious complication, with prompt and experienced medical care, bleeding can usually be stopped. Sometimes that requires specialized procedures in which a hardening (sclerosing) agent is injected into the abnormal vessels.
- If retention of body fluid occurs, it can be treated with diuretics (medicine that helps remove excess water from the body).
As the disease gets worse, other complications of cirrhosis may also occur.
What Is the Long-Term Outlook?
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 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 enlargement 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, ultimately, liver transplantation will be considered. A liver transplant operation removes the damaged liver and replaces it with a new liver from a donor.
After a transplant, ongoing lifelong care is required. Frequent contact with physicians and other members of the transplant team is also necessary.