Biliary System and Biliary Atresia

Overview of Biliary System

• The biliary system consists of tubular structures and ducts.
• Functions to drain bile from the liver into the small intestine.
• Bile aids in digestion and consists of cholesterol, bile salts, and waste products like bilirubin.

Biliary Atresia

• Definition: Blockage in ducts carrying bile from the liver to the gallbladder.
• Consequences: Disruption leads to inflammation, fibrosis, cirrhosis, and potentially liver failure if untreated.
• Incidence: Affects 1 in 10,000 to 15,000 births, more common in girls (2:1 ratio).

Types of Biliary Atresia

1. Fetal Embryonic Form
   • Occurs in the first two weeks of life.
   • May be associated with other congenital defects (e.g., interrupted inferior vena cava, congenital heart abnormalities).
2. Postnatal Form
   • Appears in babies aged 2-8 weeks.
   • Not associated with other congenital defects.
   • Progressive inflammation and obliteration of extrahepatic bile ducts.

Causes

• Infectious agents: Reovirus, retrovirus, cytomegalovirus, human papillomavirus.
• Autoimmune mechanism: Body's cells destroy bile ducts.
• Congenital defects: Defective development in the biliary tree or ductal plate malformation.

Signs and Symptoms

• Jaundice: Yellowing of skin and eyes due to high bilirubin.
• Acolytic Stools: Clay-colored stools from lack of bile.
• Dark Urine: Bilirubin filtered by kidneys leading to dark urine.
• Enlarged Liver: Due to inflammation and cirrhosis.

Diagnosis Methods

1. Blood Tests: Assess liver function.
2. X-rays: Visualize enlarged liver or spleen.
3. Ultrasound: Detect gallbladder size and abnormalities.
4. Hepatobiliary Iminodiacetic Acid (HIDA) Scan: Uses radioactive dye to trace bile flow.
5. Cholangiography: Contrast material to check communication between biliary tree and GI tract.
6. Liver Biopsy: Exam of liver tissue.

Treatment Options

1. Kasai Procedure
   • Surgical operation to connect intestine to liver for bile drainage.
   • Not a cure but prolongs health and growth for several years.
2. Liver Transplant
   • Follows if Kasai procedure fails.
   • Damaged liver replaced by a donor liver.
   • Requires lifelong monitoring for transplant rejection.