Biliary atresia is a rare condition that involves anomalous extrahepatic bile duct responsible for carrying bile from liver to small intestine. Biliary atresia includes partial or complete obstruction or destruction of bile duct outside the liver commonly and exclusively in infants. This serious condition proves to be fatal if left untreated.
Causes of Biliary Atresia
Biliary atresia can be either congenital or acquired depending on the type whether it is fetal type of prenatal type. It is found in one in every 15000 newborns all around the world. Although, it is spread equally in both males and females, it has slight female predilection with a female to male ratio of 1.4:1. Asians along with African-American babies are at a greater risk of developing biliary atresia. It is not considered an inherited disease; in fact, there have been cases where only one child has been born with biliary atresia and the other twin is normal. The etiology for biliary atresia still remains unclear; however, it has been postulated that it might develop due to malformations and disruptions in the formation of bile duct at the time of embryogenesis. It has also been linked with chromosomal abnormalities, but no specific genetic predisposition has been known. It has also been associated with problems with immune system and viral infections (especially cytomegalovirus, rotavirus and reovirus type 3, Epstein Barr virus, human papillomavirus) have also been accounted for its etiology.
What Are The Symptoms Of Biliary Atresia?
Generally, the babies appear healthy at birth with appropriate weight and no problem in thriving during the first few weeks of life. Symptoms start appearing within 2 to 6 weeks of life and are attributed to the obstruction in the flow of bile from liver through gall bladder to small intestine. This obstruction of bile duct leads to collection of bile and waste products in the liver itself, which presents with certain symptoms and gradually destroys liver cells.
Jaundice is the most common symptom that is present in all cases of biliary atresia. Jaundice is the yellowing of the whites of eyes and skin, technically known as icterus. It is caused by elevated levels of bilirubin in blood that cannot be removed by liver due to obstruction of bile duct. In general, most infants usually have symptoms of jaundice due to immature liver at the time of birth, but this usually resolves or decreases within 2 weeks after birth. However, the symptoms of jaundice start after 2 to 6 weeks of birth in cases of biliary atresia. The baby at the time of birth appears normal and might have jaundice due to immature liver, but if it continues to get worse with time, instead of resolving is a clear-cut indication of biliary atresia.
Dark colored urine is yet another sign of biliary atresia. This is also caused by increased levels of bilirubin in the bloodstream that is filtered by kidneys and excreted in urine that makes the color of urine darker and more yellow.
Acholic stools are another classical sign of biliary atresia along with jaundice and dark colored urine. Acholic stools are grey, clay or white colored stools excreted. Generally, feces is yellow tinged due to excretion of bilirubin through colon, but since bilirubin excretion is prevented by bile duct obstruction, there is no bilirubin to be excreted through small intestine, thus excreta is pale, grey or white in color.
The child also starts showing signs of weight loss and irritability with progression of jaundice. Weight loss results due to lack of proper functioning of liver and incomplete absorption of nutrients and vitamins.
Along with the above symptoms, other symptoms may also be present including distension of stomach due to hepatomegaly or splenomegaly due to portal hypertension. If the diseased process is not controlled or treated, then it may lead to liver fibrosis and scarring causing cirrhosis and ultimately liver failure ensues, which leads to death of the infant within 2 to 3 years of the onset of disease.
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