Biliary atresia overview: What you need to know
Biliary atresia is a rare liver disease affecting infants, in which the ducts that carry the digestive fluid bile from the liver to the small intestine are blocked. This leads to symptoms such as jaundice, a yellow discoloration of the skin and whites of the eyes, and pale stools that usually appear within the first few weeks after birth.
The condition can be life-threatening, but with appropriate management, most children born with biliary atresia will survive into adulthood.
A prompt diagnosis and early treatment are key for ensuring optimal clinical results and preventing potential liver damage.
Biliary atresia is characterized by problems with the bile ducts, a series of tubes that normally transport bile from the liver to the gallbladder (the organ where bile is stored) and to the intestine. Bile is a fluid made in the liver that helps to break down certain fatty molecules and proteins into smaller pieces during digestion.
In biliary atresia, the bile ducts outside the liver — known as the extrahepatic bile ducts — are blocked or entirely absent, causing bile flow from the liver to other organs to be halted or markedly reduced, a phenomenon called cholestasis.
The resulting buildup of bile can cause damage to the liver, which filters all of the blood in the body. That, together with problems with digestion because bile cannot reach the intestines, gives rise to most biliary atresia symptoms.
Biliary atresia typically is divided into two types, based on when obvious symptoms of the disease become evident:
- In fetal biliary atresia, also called congenital biliary atresia, babies exhibit jaundice or other signs of biliary atresia at birth. This form of the disease is observed in 10%-20% of cases, and as many as one-third of patients are also born with other health problems. Such problems often involve issues with the heart, spleen, or intestines.
- In perinatal biliary atresia, also called acquired biliary atresia, babies appear healthy at birth and develop bile duct changes and other symptoms that characterize the disease only in the first few weeks of life. This is by far the more common of the two types of biliary atresia, accounting for about 80%-90% of cases.
Biliary atresia also may be classified into one of four types based on which bile ducts outside the liver are affected. These consist of type 1, type 2, type 2b, and type 3.
Biliary atresia is defined by the absence or complete blockage of all or part of the bile ducts outside the liver, which are known as the extrahepatic bile ducts. The exact cause of biliary atresia remains unknown, but several hypotheses have been proposed.
As children with biliary atresia sometimes have other co-occurring birth defects, it’s thought that abnormalities during liver or bile duct development in the womb are likely to contribute in some cases, causing the condition to be present at birth.
One potential explanation for these development abnormalities are genetic mutations. To date, no specific genes or genetic mutations have been definitively shown to be biliary atresia causes, and the condition does not appear to be passed from parents to their biological children.
However, biliary atresia disproportionately affects certain populations relative to others: It occurs in about 1 of every 12,000 infants in the U.S. and in 1 of every 18,000 in Europe, but it’s much more common in parts of east Asia, occurring in as many as 1 of every 2,400 live births. This supports the belief that genetics may play a role in disease development. The condition also is more common in females.
Another hypothesis is that biliary atresia may develop as a result of viral infections or exposure to toxic substances, either during fetal development or in the first days after birth. While animal models have indicated that certain viruses — such as cytomegalovirus, rotavirus, and reovirus — can cause biliary atresia in specific situations, there is no definitive proof that these viruses are responsible for the condition in people.
Other proposed biliary atresia causes include an abnormal immune response and differences in development due to weather and seasonality. Again, however, none of these ideas has been proven.
The first biliary atresia symptoms usually appear about two to six weeks after a baby is born and include:
- dark urine
- pale stools.
These three symptoms all are caused by the abnormal clearance of bilirubin, a yellow-reddish waste product that normally gets disposed of by the liver through the bile. As bile doesn’t flow normally in biliary atresia patients, bilirubin is not excreted through the intestines and accumulates to excess levels in the blood.
Jaundice — a yellow color to the skin and whites of the eyes due to high bilirubin levels — is fairly common among infants in the first few days after birth, but it usually goes away within a baby’s first two weeks. If jaundice persists beyond two weeks, babies should be checked for liver diseases, including biliary atresia.
The buildup of bilirubin in the blood also leads to more of this substance reaching the kidneys and getting excreted in urine, which is why babies with biliary atresia frequently have dark pee.
In contrast, biliary atresia poop is often unusually pale because bilirubin — which becomes brownish once metabolized in the digestive tract and normally helps give stool its distinctive color — isn’t getting into the intestines to be excreted in feces.
By around 6 to 10 weeks of age, babies with biliary atresia commonly start developing additional symptoms, which often include:
- growth delay, also called “failure to thrive,” due to digestive problems that make it difficult for the body to absorb enough nutrients
- itchiness, due to excess bile acids getting into the bloodstream
- a swollen belly, resulting from a buildup of fluid in the abdomen.
In the long term, liver damage can lead to biliary atresia complications. Among such complications are:
- cirrhosis, or scarring of the liver
- portal hypertension, which is high blood pressure in the liver’s main blood vessel
- liver failure, where the liver is unable to support the body’s needs.
Variations in symptoms may occur, especially among patients with different forms of the disease. Any signs of biliary atresia should be reported to an infant’s healthcare team.
The gold standard test used to definitively diagnose biliary atresia is called a cholangiogram. This is a surgical procedure in which a special dye is injected into the gallbladder to provide detailed X-ray images of the bile ducts. A biliary atresia diagnosis is confirmed if the dye fails to move out through the bile ducts, indicating the ducts are blocked or absent.
If a cholangiogram confirms a diagnosis of biliary atresia, doctors typically will immediately begin surgical operation to treat the condition. As such, this procedure is only done after less invasive tests are conducted.
These tests, which may be noninvasive or minimally invasive, can help identify signs of biliary atresia, and also be used to rule out other liver conditions that can cause similar symptoms. A number of measures may be used to to aid in a biliary atresia diagnosis:
- Blood tests, including tests to measure bilirubin levels and other markers of liver function, can rule out liver diseases with similar symptoms, such as Alagille syndrome. Genetic testing of blood samples also can be done to help in the diagnosis.
- Urine tests can look for causes of jaundice.
- Ultrasound can be used to image the liver.
- Hepatobiliary scintigraphy, another imaging procedure, may be used to check if the bile ducts and gallbladder are working properly.
- A liver biopsy, in which a small piece of the liver is removed and taken to a lab for study, can be done to better determine the cause of symptoms.
Diagnosing the condition as early as possible can help in getting treatment started for patients found to have biliary atresia, which, in turn, may lead to greater treatment success and better long-term outcomes.
The main strategy used for biliary atresia treatment is a surgical procedure referred to as a Kasai portoenterostomy. In simple terms, this procedure involves creating a new tube that can carry bile out of the liver and into the intestines, effectively replacing the blocked or absent bile ducts. The procedure is named for Morio Kasai, a Japanese surgeon who pioneered the technique in the 1950s.
The Kasai portoenterostomy procedure can substantially improve near-term outcomes for babies with biliary atresia, especially if the diagnosis is made early and the surgery is performed before too much liver damage has occurred. However, even with this procedure, children with biliary atresia frequently experience progressive cirrhosis and liver disease that eventually leads to liver failure.
When the liver isn’t able to do its job, a liver transplant — in which the ailing organ is replaced with a healthy liver from a donor — is the only treatment option. More than half of children with biliary atresia will require a liver transplant by age 10, and about 80% will need it before age 20. Efforts toward long-term biliary atresia management, such as ensuring a diet rich in needed nutrients to stay healthy, may help to delay the need for a transplant.
There is no cure for biliary atresia, and people with the disease commonly need lifelong medical management to stay healthy. However, modern surgical techniques, including the Kasai portoenterostomy and liver transplant, have radically improved outcomes for children with the disease, increasing biliary atresia life expectancy.
In the past, when no treatments were available, biliary atresia was fatal in early childhood — estimates indicate that fewer than 5% of untreated babies with the condition would survive past the age of 2.
Nowadays, with modern medical care, biliary atresia life expectancy has increased, with more than 90% of babies with the disease surviving past early childhood, and most of them growing into adults with normal quality of life.
The first pediatric liver transplants were performed only about 50 years ago, and the procedure has improved immensely since then. As such, the oldest biliary atresia patients who have been treated with what’s considered a modern standard-of-care are only now reaching the first decades of adulthood. The longer term outcomes for these individuals are not yet known.
Living with biliary atresia usually requires lifetime medical care and support. Patients and their families are advised to work with their healthcare team to come up with an appropriate plan for getting proper biliary atresia treatment and regular monitoring. They also should discuss with their care team any potential lifestyle modifications that may help, such as avoiding substances that can stress the liver or receiving nutritional support.
Given that biliary atresia can lead to less bile reaching the intestines, and that bile is crucial to digest certain nutrients, biliary atresia management often involves special care to ensure patients are getting all the nutrients needed for them to grow and stay healthy. This may include:
- supplements of fat-soluble vitamins, such as vitamins A, D, E, and K
- supplements of medium-chain triglycerides, a specific type of fat that’s more easily digested with minimal bile
- use of a feeding tube or an intravenous line to provide needed nutrients directly to the stomach or into the bloodstream.
Beyond the medical realities of managing the condition itself, living with biliary atresia can lead to unique social and emotional challenges. To prevent individuals with biliary atresia from having to navigate life with the condition on their own, it’s recommended that patients and caregivers look for support groups or other resources. There are a few online support groups where those affected by this condition can gather, share their experiences, and offer assistance. Among them are:
- the Facebook-based Biliary Atresia Network, a support group associated with the Children’s Liver Association for Support Services, known as C.L.A.S.S.
- Life with Biliary Atresia & Beyond, a support group from the American Liver Foundation.
Other groups, such as the Canadian Liver Foundation, the Childhood Liver Disease Research Network, the Children’s Liver Disease Foundation, the Children’s Organ Transplant Association, and the National Organization for Rare Disorders, known as NORD, also may offer assistance for families affected by biliary atresia.
Liver Disease News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
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