What is Biliary Atresia?
Biliary Atresia is a rare gastrointestinal disorder in newborns that destroys the bile ducts that carry bile from the liver to the intestine. This disease is a progressive destruction of the bile ducts, which starts outside the liver (extrahepatic) and may progress to affect the bile ducts inside the liver (intrahepatic). Unable to drain, bile accumulates in the liver and causes liver damage (cirrhosis).
There is no racial predilection for this disorder. Biliary Atresia occurs in 1 out of every 15,000 live births and slightly more often in females than males (1.4:1). Researchers believe that there are two possible causes of biliary atresia: Embryonic (foetal) and perinatal. Unlike the embryonic form of this disease, perinatal type is characterised by a later onset of jaundice and may be caused by environmental factors.
Diagnosis of Biliary Atresia
The diagnosis of biliary atresia should be made as soon as symptoms appear. Early diagnosis (by 8 weeks of age) results in a better prognosis.
Blood Tests -- Should include CBC (complete blood count), LFTs (liver function tests) and PT/PTTs (blood clotting factors).
Liver Biopsy -- Removal and examination of a small sample of liver tissue.
Ultrasound -- Identifies any obvious abnormalities in the liver and other organs.
Nuclear Scan -- Determines how much, if any, bile is flowing from the liver.
Exploratory Surgery -- Performed to examine the liver and bile ducts.
Causes of Biliary Atresia
The cause of biliary atresia is uncertain, although several different theories are documented. Researchers are studying both Reovirus Type 3 and Cytomegalovirus as possible agents in the development of biliary atresia.
Symptoms of Biliary Atresia
There are many symptoms of Biliary Atresia, the first appearing between 2 and 6 weeks after birth.
Jaundice -- A yellow appearance of the skin and sclera (whites of the eyes) that does not improve within 1 to 2 weeks.
Urine -- Appears very dark yellow or brown (due to excessive bilirubin in the bloodstream which passes to the kidneys).
Stools -- Appear pale or clay-colored (acholic). This happens because there is little or no bile reaching the intestine to colour the bowel movements.
Enlarged Liver -- Feels larger and harder than normal.
Poor Weight Gain -- Infant is not gaining weight. This is due to the lack of bile which is needed to digest and absorb fat.
Enlarged Spleen -- due to the liver not functioning properly.
Treatment of Biliary Atresia
The Kasai Procedure, a surgical method, can be performed to help re-establish bile flow from the liver to the intestine. This surgery is done to bypass the bile ducts by joining using a section of the small intestine to attach the liver directly to the small intestine. Surgeons have found that they achieve better results if the Kasai is done during the infant's first 8 weeks of life. 25% of infants will have good bile flow after surgery while 50% will have some bile flow. The remaining 25% with little or no bile flow will require liver transplantation. Liver transplantation is the only cure for biliary atresia.
Complications of Biliary Atresia
Cholangitis -- An inflammation of the bile ducts caused by bacteria from the bowel. This is a common problem after a Kasai, because bacteria is present in the loop of the intestine used to correct the biliary system. Symptoms include irritability, fever, increased jaundice and poor appetite. Medical treatment should be sought immediately to prevent further liver damage. Infection is treated with IV antibiotics.
Portal Hypertension -- As the liver becomes scarred, it presses against the walls of the veins. This constricts the veins and blood cannot pass through them properly. High blood pressure in the portal vein results.
Varices -- A complication of portal hypertension, varices occur when veins encounter increased blood pressure which causes them to weaken and expand. There is no treatment for varices until they bleed. Stools will appear black and vomit will be blood-stained. Immediate medical attention is necessary to determine severity.
Ascites -- Another complication of portal hypertension, ascites occur when there is an abnormal build up of fluid in the space between the lining of the abdominal wall and the lining of the organs. Treatment is a low-sodium diet and medication.
Failure to Thrive -- Lack of bile salts in the intestine, needed for fat digestion, result in poor growth and fat-soluble vitamin deficiency in the infant. Vitamins A, D, E and K (water-soluble) can be given orally to aid in fat digestion.
Ammonia Intoxication -- An uncommon complication of biliary atresia. When the liver is severely compromised, it cannot convert ammonia (toxic) to urea (product of the liver's attempt to secrete nitrogen). Infants become weak, fatigued and lethargic. Treatment is medication and a low-protein diet.
Cirrhosis -- Occurs when there is severe damage to the liver. When cirrhosis develops, liver transplantation is considered.