Congenital Absence of Bile Ducts

Congenital absence of bile ducts is a rare liver condition affecting newborn babies, where the tubes that carry bile from the liver are blocked, damaged, or missing. Without proper treatment, this condition can quickly lead to serious liver damage and requires urgent medical attention.

Table of contents

• What is congenital absence of bile ducts?
• Other names for this condition
• Types of the condition
• How common is this condition?
• What causes congenital absence of bile ducts?
• Signs and symptoms
• When to seek medical help
• How is it diagnosed?
• Treatment options
• Possible complications
• Outlook and survival

What is congenital absence of bile ducts?

biliary atresia, extrahepatic ductopenia, progressive obliterative cholangiopathy, cholecystohepatic ducts, interposition of the gallbladder

Congenital absence of bile ducts is a serious condition affecting the liver in newborn babies. The condition involves tubes in the liver called bile ducts, which are passages that carry a digestive fluid called bile from the liver to the small intestine. In babies with this condition, these bile ducts are blocked, narrowed, or completely missing.^[1]

Bile is a fluid made by the liver that serves two important purposes. First, it helps the intestines digest food, especially fats. Second, it carries waste products from the liver out of the body. When the bile ducts are blocked or absent, bile cannot flow properly from the liver to the intestine. Instead, bile becomes trapped inside the liver, where it builds up and causes damage.^[1]

This backup of bile causes the liver to become scarred and prevents it from working normally. The intestines also cannot receive the bile they need to break down nutrients and support the baby’s growth. Without prompt treatment, this condition can quickly lead to severe liver damage and can be fatal.^[3]

• Liver
• Bile ducts
• Gallbladder
• Small intestine

Other names for this condition

The most common medical term for this condition is biliary atresia. Healthcare providers may also use other terms such as extrahepatic ductopenia or progressive obliterative cholangiopathy.^[7]

In rare cases where the common bile duct is specifically absent, doctors may refer to it as “cholecystohepatic ducts,” “transverse lie of the gallbladder,” or “interposition of the gallbladder.” In these unusual situations, the bile drains directly into the gallbladder instead of through the normal duct system.^[2]

Types of the condition

Healthcare providers recognize two main types of congenital absence of bile ducts based on when the condition develops.^[12]

Perinatal biliary atresia is the most common type, accounting for about 65 to 90 percent of all cases. Babies with this form usually appear healthy at birth. They pass normal-colored stool as newborns and are of average weight. The jaundice, or yellowing of the skin, typically develops in the first few weeks after birth, most often when the baby is about 2 to 4 weeks old.^[9]

Fetal biliary atresia, also called embryonic biliary atresia, is less common and occurs in 10 to 35 percent of cases. Babies with this type are frequently jaundiced as newborns right from birth. They also more often have other birth defects affecting the heart, major blood vessels, spleen, or intestines.^[9]

How common is this condition?

Congenital absence of bile ducts is a rare condition. In the United States, researchers estimate that it occurs in about 1 in 12,000 babies born. In the U.S., this means approximately 400 to 500 newborns are diagnosed with the condition each year.^[1][14]

The condition is more common in other parts of the world, particularly in Asia. For example, in Taiwan, biliary atresia occurs in 1 in 6,000 babies, and across Asia, the rate can be as high as 1 in 5,000 births. Researchers continue to study the reasons for these differences around the world.^[1][5]

The condition affects girls slightly more often than boys. It also occurs slightly more often in Asian and African American babies. Premature babies are at greater risk than full-term infants.^[4][12]

Congenital absence of bile ducts is the most common reason why babies and children need a liver transplant in the United States.^[1]

What causes congenital absence of bile ducts?

Doctors and researchers do not fully understand why this condition occurs. The exact cause remains unknown, and experts continue to investigate possible reasons.^[1]

Several theories suggest that multiple factors may play a role. Research indicates that the condition is likely not inherited, meaning it does not pass directly from parent to child. Only a few family cases have been described, and there is no increase in cases among twins.^[3]

Scientists are exploring several possible causes, including:^[12]

Viral or bacterial infections may trigger the condition. Several infectious organisms have been suggested as possible causes, including cytomegalovirus, Epstein-Barr virus, reovirus, rotavirus, and even SARS-CoV-2. Researchers believe that maternal rotavirus infection during pregnancy and transmission to the developing baby may be particularly important.^[5][7]

Problems with the immune system may contribute to the development of blocked bile ducts. In some cases, the body’s immune system may attack the bile ducts after birth for unknown reasons.^[6]

Genetic factors may be involved, especially in cases where babies have other birth defects along with the blocked bile ducts. About 3 to 20 percent of children with this condition have other abnormalities affecting organs such as the heart, spleen, kidneys, or intestines. This suggests that some genetic component may be present, although no single gene has been found to cause the condition.^[3][5]

Developmental problems during pregnancy may lead to the condition. The bile ducts develop in stages during pregnancy. Problems with how the bile ducts form or connect may result in blockages. The ducts outside the liver first become visible at about 20 days of pregnancy, while the ducts inside the liver appear at 45 days.^[3]

Exposure to toxic substances during pregnancy has also been suggested as a possible cause, though this has not been proven in humans.^[6]

Signs and symptoms

Babies with congenital absence of bile ducts typically appear healthy when they are born. In most cases, symptoms begin to appear a few weeks after birth, usually between 2 weeks and 2 months of age.^[1]

The first signs that usually appear include:^[1]

Jaundice is a yellowing of the skin and the white parts of the eyes. This occurs because bile contains a yellow substance called bilirubin that builds up in the blood when bile cannot drain properly. While jaundice is common in healthy newborns and usually goes away after a week or two, jaundice from blocked bile ducts lasts longer and gets worse over time.^[1]

Pale or light-colored stools are another early sign. Healthcare providers call these “acholic stools.” The baby’s poop may be light beige, pale, almost white, or clay-colored instead of the normal yellow, brown, or green color. This happens because bile gives stool its normal color, and without bile reaching the intestines, the stool becomes very light.^[1]

Dark or amber-colored urine develops because some of the bilirubin that builds up in the blood is filtered by the kidneys and comes out in the urine. Parents may notice yellow-stained diapers.^[5]

As the condition progresses, usually by the time the baby is 6 to 10 weeks old, additional symptoms may develop:^[1]

The baby may have itchy skin and become irritable. A swollen belly occurs due to fluid buildup and an enlarged liver. The baby may have trouble gaining weight, a problem doctors call “failure to thrive,” because nutrients are not being absorbed properly. The liver becomes firm and enlarged, and the baby may appear sick, too fussy, or too sleepy.^[6]

When to seek medical help

Parents should take their baby to see a healthcare provider right away if jaundice lasts beyond two weeks after birth. While jaundice is common in newborns and usually harmless, jaundice that persists could be a sign of congenital absence of bile ducts or another condition that needs treatment.^[1]

Any baby who is jaundiced after 1 month of age should be evaluated by testing the baby’s blood. The presence of yellowing of the skin at 2 weeks of age in an otherwise healthy infant requires investigation to determine the underlying cause.^[4][5]

Parents should also call their baby’s healthcare provider if they notice that their baby’s poop is not a normal color. Pale, white, or very light-colored stools need immediate medical attention.^[1]

Early diagnosis is crucial. The earlier the condition is found and treated, the better the chances that the baby will not need a liver transplant later in life. Surgery performed before the baby is 45 to 60 days old gives the infant the best chance of survival with their own liver.^[5][14]

How is it diagnosed?

Diagnosing congenital absence of bile ducts involves several steps. The healthcare provider will perform a physical exam of the baby and ask about symptoms and health history. The provider will look for signs such as jaundice, an enlarged liver, and pale stools.^[5]

Blood tests are usually the first step in diagnosis. These tests check levels of bilirubin and liver enzymes. When bile flow is blocked, both total and direct bilirubin levels are elevated. Liver enzyme levels also become high because the enzymes leak from the damaged liver into the bloodstream.^[5]

Other blood tests help rule out different conditions that can cause similar symptoms. These include tests for alpha-1 antitrypsin deficiency, which is another cause of liver problems in babies, and tests to check for viral infections that might affect the liver.^[5]

Imaging tests help doctors see the liver and bile ducts. An abdominal ultrasound uses sound waves to create pictures of the liver, gallbladder, and bile ducts. This test is not painful and does not use radiation.^[5]

A hepatobiliary scan, also called a HIDA scan, uses a small amount of radioactive material to track bile flow. The material is injected into the baby’s vein and a special camera takes pictures to see if bile is flowing from the liver into the intestine. If the radioactive material does not pass into the intestine, it suggests that the bile ducts are blocked.^[5]

A liver biopsy involves taking a small tissue sample from the liver with a needle or during surgery. The sample is examined under a microscope to check for damage and scarring. A biopsy can help confirm the diagnosis and rule out other liver problems.^[5]

Diagnostic surgery with an intraoperative cholangiogram is often the most definitive way to diagnose the condition. During this procedure, the surgeon can directly see the bile ducts and inject dye to determine if they are blocked or absent. This is often done at the same time as the surgery to treat the condition.^[2][14]

Treatment options

Congenital absence of bile ducts must be treated with surgery. Without surgical treatment, the condition is fatal, with reported survival of less than 10 percent at 3 years of age.^[3]

The standard surgical procedure is called the Kasai procedure, also known as hepatoportoenterostomy or porto-enterostomy. This surgery was first described by Dr. Morio Kasai in the 1950s and is now considered the standard treatment offered to all children with this condition.^[3]

During the Kasai procedure, the surgeon removes the blocked bile ducts outside the liver and creates a new pathway for bile to flow. The surgeon connects the liver directly to the small intestine using a loop of intestine. This allows bile to drain from the liver into the intestine, relieving symptoms and helping with digestion.^[1]

The earlier the Kasai procedure is performed, the better the results. Surgery before 45 to 60 days of life gives the baby the best chance of success. By this age, less liver damage has occurred, and there is a better chance that bile flow can be restored.^[5][14]

In very rare cases where the common bile duct is absent but other structures are present, surgeons may perform a different procedure called a Roux-en-Y hepaticojejunostomy. This creates a new connection between the liver and intestine to allow bile drainage.^[2]

Liver transplantation is another treatment option for babies with congenital absence of bile ducts. Some babies need a transplant if the Kasai procedure does not successfully restore bile flow or if advanced liver damage has already occurred. Many babies who have the Kasai procedure done successfully will still eventually need a liver transplant as they grow.^[1][3]

With advances in transplantation surgery, liver transplants are now an established option for children whose initial surgery failed or who developed severe liver disease despite treatment.^[3]

Possible complications

Without treatment, congenital absence of bile ducts leads to progressive liver damage. The trapped bile causes inflammation and scarring of the liver, a condition called cirrhosis. In babies, cirrhosis can develop very quickly, within weeks to months, compared to years in adults with other types of liver disease.^[14]

Cirrhosis can develop by 2 months of age if the condition is not treated. The scarring prevents the liver from working normally and blocks blood flow through the organ.^[5]

As cirrhosis worsens, it can cause portal hypertension, which means high blood pressure in the veins that carry blood to the liver. This can lead to serious complications including fluid buildup in the abdomen (called ascites), dilated veins in the abdomen, and bleeding from enlarged veins in the esophagus (called esophageal varices).^[5][14]

Babies with blocked bile ducts may have trouble absorbing fats and fat-soluble vitamins such as vitamin K. This can cause bleeding problems because vitamin K is needed for normal blood clotting.^[7]

Malnutrition can occur because the intestines cannot properly digest and absorb nutrients without bile. This leads to poor growth and failure to thrive.^[1]

Without treatment, the condition eventually leads to complete liver failure. Untreated babies typically do not survive beyond 2 years of age.^[14]

Outlook and survival

The outlook for babies with congenital absence of bile ducts has improved dramatically thanks to advances in surgery and liver transplantation. With specialized care, 80 to 90 percent of babies with this condition will now survive to adulthood.^[14]

The timing of treatment is crucial for the best outcome. Early diagnosis and surgery before 45 to 60 days of age gives babies the best chance of surviving with their own liver. The earlier the condition is diagnosed and treated, the better the chances that the baby will not need a transplant later in life.^[5][14]

Many babies who undergo the Kasai procedure successfully will still eventually need a liver transplant as they grow, due to progressive liver damage. However, the initial surgery can delay the need for transplantation and allow the baby to grow larger and stronger before transplant becomes necessary.^[1]

Thanks to medical advances, babies with congenital absence of bile ducts often go on to enjoy a long and healthy life with proper treatment and ongoing medical care.^[1]