Is Biliary Atresia Congenital?
Biliary atresia is a rare gastrointestinal condition in which there is complete or partial absence/destruction of the extrahepatic (outside the liver) bile duct. Bile duct is a tube that is responsible for carrying bile from liver to the gall bladder and eventually into the small intestine. Bile consists of waste products from the liver such as cholesterol and bilirubin along with bile acids that aids in the digestion and absorption of fat and fat-soluble vitamins. The absence or gradual destruction of bile duct can lead to abnormal accumulation of bile inside the liver, ultimately, leading to liver damage or cirrhosis.
Is Biliary Atresia Congenital?
Biliary atresia is a rare condition, which is seen in every 1:15000 live births. It is the most common cause of liver transplantation in US children. It is slightly more common in females than in males with a ratio of 1.4:1 and is also more common in Asian and African-American populations. Although, the cause of biliary atresia is yet unknown; however, it is hypothesized to be associated with a viral infection (usually cytomegalovirus, reovirus type 3 and rotavirus) during birth. Other causes that have been postulated include problems with the immune system, an abnormal bile component and an error in the development of bile ducts.
Biliary atresia is exclusively found in newborns and is classified into two types, known as, fetal (embryonic) form or perinatal form. Perinatal type of biliary atresia is usually evident after 2-4 weeks of a newborns life and is associated with symptoms of late onset jaundice. It is supposed to be acquired and caused due to environmental factors. Fetal type of biliary atresia is seen at the time of birth in the newborns and may or may not be associated with other congenital abnormalities. Extrahepatic biliary atresia that does not have any other congenital abnormality is known as classical biliary atresia and is the most common type, usually seen in 70-95% of all cases. Extrahepatic biliary atresia that is associated with one or more other congenital anomalies is seen in about 10-15% of all biliary atresia cases. The other congenital abnormalities that may be associated with biliary atresia are divided into four groups including hepatobiliary, gastrointestinal, cardiovascular and others. Hepatobiliary anomalies include hepatic vascular inflow anomalies, choledochal cyst, polysplenia or asplenia. Gastrointestinal abnormalities include intestinal malrotation, jejunoileal atresias, esophageal atresias, tracheoesophageal fistula and Meckel’s diverticulum. Cardiovascular defects include atrial septal defect or other congenital heart diseases and situs inversus. Other abnormalities include umbilical hernia and inguinal hernia.
Thus, fetal biliary atresia with or without other congenital diseases is congenital in nature. It is not hereditary or does not run in families. Perinatal is usually acquired, so biliary atresia can be both congenital or acquired in nature. The etiology of biliary atresia is largely idiopathic, but can be attributed to intrauterine or early neonatal malformations, disruptions or chromosomal abnormalities.
Symptoms and Treatment of Biliary Atresia
Biliary atresia presents with symptoms of persistent jaundice (yellowing of the whites of the eye and skin), dark yellow or brown urine, acholic stools (pale, clay or white colored bowels), enlarged liver and enlarged spleen along with abdominal distension, poor weight gain along with irritability, portal hypertension. If biliary atresia is not treated then it may result in liver cirrhosis and ultimately leading to hepatic failure.
Biliary atresia is a fatal condition, if left untreated. Treatment protocol is symptomatic and supportive care. In addition to that, surgical intervention is the only treatment to correct bile flow obstruction from liver via gall bladder to small intestine. Kasai procedure is used to establish bile flow from liver to small intestine by removing the anomalous extrahepatic bile ducts and attaching a segment of small intestine directly to the liver. This procedure helps regain bile flow in about 80% cases, but is unsuccessful in 20-25% of the corrected infants. In cases where Kasai procedure is unsuccessful, liver transplantation is the only option.