BILIARY ATRESIA PROF. DR. SHAHENAZ M. HUSSIEN Definition Biliary atresia is a condition in which the normal extrahepatic biliary system is disrupted. Progressive damage of extrahepatic and intrahepatic bile ducts secondary to inflammation, leading to fibrosis, biliary cirrhosis, and eventual liver failure . Incidence Biliary atresia affects approximately 1 in 10,000-15,000 births and occurs in 2 distinct forms: fetal-embryonic and postnatal. Types • The fetal-embryonic form appears in the first 2 weeks of life and 10-20% of affected neonates have associated congenital defects. • The postnatal form of biliary atresia is typically found in neonates and infants aged 2-8 weeks. Progressive inflammation and obliteration of the extrahepatic bile ducts occur after birth. This form is not associated with congenital anomalies, and infants may have a short jaundice-free interval. Classification: Three main types of biliary atresia are surgicaly defined: 1 -In type I, the common bile duct is obliterated while the proximal bile ducts are patent. 2 -In type II, atresia of the hepatic duct is seen. In type IIa, the cystic and common bile ducts are patent, whereas in type IIb, the cystic, common bile duct and hepatic ducts are all obliterated. 3-Type III atresia refers to discontinuity of both right and left hepatic ducts to the level of the porta hepatis. Unfortunately, type III biliary atresia is common, accounting for >90% of cases. Pathophysiology • Infection with cytomegalovirus, group C rotavirus, and reovirus type 3 have been implicated in certain cases. Cholestasis almost certainly contributes to ongoing hepatocellular and biliary damage. • Histologic findings on liver biopsy typically include acute or chronic inflammatory change with obstruction, fibrosis, and the proliferation of ductal and glandular element. 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. Those symptoms include: -A baby with biliary atresia usually develops jaundice at two or three weeks after birth. -Dark urine - The bilirubin is filtered by the kidney and removed in the urine. -Acholic stools (clay-colored stools) -- because no bile or bilirubin coloring is being emptied into the intestine. -Also, the abdomen may become swollen from a firm, enlarged liver. -Weight loss and irritability -- develop when the level of jaundice increases. How is biliary atresia diagnosed? • Blood tests for liver function abnormalities. • 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. • A nuclear test, called an HIDA scan, determines the flow of bile. In this scan, a radioactive dye is injected into the infant's vein. The dye acts like bilirubin. If the baby has biliary atresia, the liver will take up the dye but it will not be able to flow through the damaged biliary system into the small intestine. • A liver biopsy tells if an infant is likely to have biliary atresia. If the biopsy shows that the infant probably has biliary atresia, further surgery will confirm the diagnosis. Investigations continue---- Cholangiography • Exploratory laparotomy with surgical cholangiography is recommended. This is done by injecting contrast material through the gallbladder. To fined the communication between the biliary tree and the gastrointestinal tract, • Sonography-guided percutaneous cholecystocholangiography; radiographic contrast material is injected into the gallbladder under sonographic guidance and the extrahepatic biliary system is viewed by using fluoroscopy. • Endoscopic retrograde cholangiopancreatography allows direct visualization of the extrahepatic biliary tree with the injection of radiologic contrast agent into the extrahepatic biliary system through the papilla of Vater. Duodenal intubation To perform this study, a nasogastric tube is placed in the distal duodenum. The absence of bilirubin in aspirated fluid suggests obstruction. Liver biopsy • Percutaneous liver biopsy is useful in evaluating neonatal cholestasis. • Histologic findings, including bile-duct proliferation and obstruction, may not be definitive in neonates younger than 2 weeks. • Results of repeat biopsy at 2-week intervals confirm the diagnosis in as many as 95% of patients. 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. • 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: • Heart defects. • Spleen (polysplenia). • Blood vessels (inferior vena caval anomalies, pre- duodenal portal vein). • Intestine (situs-inversus or malrotation). How is biliary atresia treated? -The Kasai procedure is an operation to create an open duct so bile can drain from the liver. It is named after the surgeon who developed it. -The surgeon removes the damaged ducts outside of the liver (extrahepatic ducts) and replaces them with a piece of the baby's own intestine. This new duct allows bile to pass from the liver into the intestine. -The Kasai procedure is not a cure for biliary atresia, but it does allow babies to grow and have fairly good health for several years. -When this procedure does not work, liver transplantation can correct this problem. Success with this procedure is related to: • Age. Surgery is most successful in infants younger than two to three months of age. • Extent of liver damage (cirrhosis) at the time of surgery. • The number and size of microscopic ducts in the scarred tissue that can drain bile. • The experience of the surgical and medical team. Guidelines from your doctor for your child's nutrition may include: • 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 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. • A well-balanced diet, consisting of three meals a day plus small snacks in between meals. • Vitamin supplements. • 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 naso- gastric tube. • 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? • After the Kasai procedure, it is common to get an infection in the bile ducts. This is usually treated using intravenous antibiotics. • Jaundice or itching may occur. These can often be treated successfully with phenobarbital (for jaundice), 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, nasal bleeding, retention of body fluid and varices in the stomach and esophagus. • If retention of body fluid occurs, it can be treated with diuretics and potassium replacement. Liver Transplant • If there is still not enough bile flow with the Kasai procedure, liver transplantation is a final option. A liver transplant operation removes the damaged liver and replaces it with a new liver from a donor. • After transplant surgery, the child's health may improve quite quickly. However, the child's body might reject the new organ. To prevent rejection, a strict schedule of anti-rejection medications must be taken. • After a transplant, ongoing lifelong care is required. Frequent contact with physicians and other members of the transplant team is also necessary.