Biliary Atresia

What happens in biliary atresia

Bile is made in the liver and drains through bile ducts into the intestine, where it helps digest fats and gives stool its yellow-green color. In biliary atresia, an inflammatory process destroys the bile ducts outside the liver, and often inside it as well. Bile is trapped, causing cholestasis (blocked bile flow). The trapped bile damages liver cells and causes scarring (fibrosis), which progresses to cirrhosis within months if not treated.

The cause is not fully understood. Theories include a viral infection around birth, an abnormal immune response, and a developmental problem in the formation of the ducts. It is not caused by anything the parents did, and it is not usually inherited. About 10 to 20% of babies have other birth differences, such as heart defects or abnormal positioning of organs (biliary atresia splenic malformation syndrome).

Symptoms

Babies usually look healthy at birth. Signs appear in the first 2 to 8 weeks:

• Jaundice (yellow skin and eyes) that persists or appears after 2 weeks of age. Ordinary newborn jaundice usually fades by 2 weeks
• Pale stools: pale yellow, gray, white or clay-colored, often the most important clue
• Dark urine that stains the diaper
• an enlarged, firm liver
• poor weight gain later
• swollen belly, a large spleen, easy bruising or bleeding as liver damage progresses

Many babies feed well and seem content, which can falsely reassure. Any baby with prolonged jaundice needs a blood test that measures conjugated (direct) bilirubin, which is high in biliary atresia. Our neonatal jaundice page explains how normal newborn jaundice differs.

Stool color matters

Several countries, including Taiwan and Japan and some US states and hospitals, give parents a stool color card to compare their baby's stools. Normal stools are yellow, mustard, green or brown. Pale stools should be reported to the baby's doctor the same day.

Diagnosis

1. Blood tests: conjugated bilirubin, liver enzymes (especially GGT), clotting tests.
2. Abdominal ultrasound: may show a small or absent gallbladder and the "triangular cord sign." It also excludes a choledochal cyst.
3. HIDA scan: shows whether bile reaches the intestine.
4. Liver biopsy: shows bile duct proliferation and blocked bile flow.
5. Intraoperative cholangiogram: dye injected during surgery confirms the diagnosis and, if positive, the surgeon proceeds directly to the Kasai operation.

Doctors also test for other causes of infant cholestasis, such as alpha-1 antitrypsin deficiency, Alagille syndrome, infections and metabolic disorders.

Treatment

Kasai portoenterostomy

The surgeon removes the scarred bile ducts and attaches a loop of small intestine directly to the liver where the ducts would emerge, so bile can drain. Results are best when surgery is done early, ideally before 30 to 45 days and certainly before 60 to 90 days of age.

• In about half to two-thirds of babies, bile drains well and jaundice clears.
• Even successful surgery is not a cure. The liver usually continues to be damaged slowly.

After surgery

• antibiotics to prevent cholangitis (infection of the bile ducts), the most common complication
• fat-soluble vitamin supplements (A, D, E, K) and special formulas rich in medium-chain fats to support growth
• ursodeoxycholic acid to promote bile flow
• steroids are sometimes used, though evidence of benefit is mixed
• regular monitoring of growth, liver function and complications

Liver transplant

If the Kasai procedure does not restore bile flow, or liver disease progresses, a liver transplant is needed. Biliary atresia is the leading reason for liver transplant in children. Many children need a transplant before age 2, and many more by adulthood. Living-donor transplants from a parent are common.

Complications

• cholangitis, causing fever and worsening jaundice
• portal hypertension, with varices that can bleed, an enlarged spleen and fluid in the belly
• poor growth and vitamin deficiencies
• liver failure

Outlook

Without treatment, most babies with biliary atresia develop liver failure and die within 2 years. With a timely Kasai procedure and access to transplantation, about 90% of children survive long-term, and many live into adulthood with their own liver. Long-term follow-up with a pediatric liver team is essential.

Frequently asked questions

What are the first signs of biliary atresia?

The first signs are jaundice that lasts beyond 2 weeks of age, pale or chalky white stools and dark urine. The baby often feeds and seems well otherwise. Any baby with these signs needs a blood test for conjugated bilirubin promptly.

What color is the stool in biliary atresia?

Stools are pale yellow, gray, white or clay-colored because bile, which normally gives stool its color, cannot reach the intestine. Healthy baby stools are yellow, mustard, green or brown. Report pale stools to your baby's doctor the same day.

Why is early surgery so important?

Liver damage progresses quickly. The Kasai procedure restores bile flow most often when done in the first 30 to 60 days of life. The later the surgery, the less likely it is to work and the sooner a liver transplant is needed.

Can biliary atresia be cured?

There is no complete cure. The Kasai procedure can restore bile drainage and let many children keep their own liver for years, but most eventually need a liver transplant. Transplantation offers excellent long-term survival.

What is the life expectancy with biliary atresia?

With timely surgery and transplant when needed, about 90% of children survive into adulthood. Some adults are living with their native liver decades after a successful Kasai procedure. Untreated, the condition is usually fatal in early childhood.