Biliary atresia: Description, Causes and Risk Factors:
Biliary atresia is a serious disease of the very young infant. It results in inflammation and obstruction of the ducts which carry bile from the liver into the intestine. When bile cannot flow normally, it backs up in the liver (a situation called biliary "stasis"). This causes "jaundice," or a yellowing of the skin, and cirrhosis
. Cirrhosis occurs when healthy liver cells are destroyed, in this case by disease, and replaced with scar tissue. This scarring interferes with blood flow through the liver, causing more cell damage and scarring.
There are two forms of biliary atresia. The more common “classical” form which accounts for 80-90% of cases presents in full term infants after about two weeks of age. Jaundice (yellow skin and eyes), dark tea colored urine, pale clay colored stool (non-pigmented stools), a large liver and spleen are the most common symptoms.
The less common “embryonic” form seen in up to 20% of cases usually appears soon after birth with jaundice, dark urine and pale stool in association with other abnormalities that include congenital heart disease, intestinal malrotation (abnormal position of the intestine), polysplenia (more that one spleen) or situs inversus (where the liver and spleen are in the wrong positions).
The cause of biliary atresia has not yet been discovered. Biliary atresia is not a hereditary condition (although in some very rare cases, more than one infant in a family may be affected). Many parents experience feelings of guilt, but they should be reassured that nothing they have done caused their child's illness.
The disease affects approximately one infant in every 20,000 live births. Girls are affected slightly more often than boys, but no racial or ethnic group appears to be more affected than any other.
The symptoms of biliary atresia are usually evident between two and six weeks after birth. The baby will appear jaundiced, and may develop a large, hardened liver and a swollen abdomen
. The stools are usually pale grey and the urine appears dark.
Some babies may develop intense itching, or "pruritus," which makes them extremely uncomfortable and irritable. The exact cause of this itching is not yet known, although researchers have found a connection between it and the backup of bile.
There are many liver diseases which cause symptoms similar to those of biliary atresia. Consequently, many tests may have to be performed before biliary atresia can be diagnosed conclusively.
It is important to make the diagnosis of biliary atresia early, preferably before twomonths of age because the long term outcome depends upon the ageof treatment. Therefore any newborn older than two weeks withjaundice should have a blood test to assess whether the jaundice is“obstructive”. If these tests demonstrate obstructive jaundice otherblood test will be done to see how well the liver is working. These testsmay include:Urine tests; liver function tests; blood counts and a test for clotting function. A painless examination using ultrasound (ECHO) is often done to study the liver and determine the size of the bile ducts and gallbladder.
Other tests which are often used are specialized X-ray techniques or radioactive scans of the liver which can be helpful in focusing on the true abnormality. A liver biopsy, in which a tiny sample of the liver is removed with a needle, allows the physician to examine the liver tissue microscopically.
The most successful treatment for biliary atresia to date is a type of surgery which creates drainage of bile from the liver when the ducts have become completely obstructed. The operation is called a portoenterostomy or Kasai procedure. In this operation the blocked bile duct is removed and a loop of small intestine is connected to the liver with the hope that the bile will flow again. When this operation is successful the jaundice disappears and the bilirubin levels (brownish yellow substance found in bile when the liver breaks down bilirubin) return to normal Bilirubin leaves the body as feces and gives stool its normal brown color. The operation has the best chance for success if done before 2 months of age, with up to an 80% chance of the jaundice clearing.
Even with early surgery, many infants with biliary atresia develop increasing scarring of the liver and eventual cirrhosis. These children will require liver transplants once the scarred liver's function fails. Recent evidence suggests that fewer than half of the children with biliary atresia after portoenterostomy survive into adulthood without requiring a liver transplant. In the remaining cases where the Kasai procedure does not work, the problem often lies in the fact that obstructed bile ducts are "intrahepatic" or inside the liver, as well as outside. No procedure has yet been developed to correct this problem except for transplantation.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.