Biliary atresia, a rare digestive disease in infants
At a Glance:
What is biliary atresia?
Atresia is a condition characterized by blockage or narrowing of an opening. Biliary atresia is a type of gastrointestinal disorder wherein the biliary duct, which carries bile from the liver, gets blocked. Biliary atresia is a rare condition and occurs most commonly in infants. It develops within 2-8 weeks after birth.
The biliary system comprises of the liver, gallbladder, and bile ducts. Cells of the liver, also known as hepatocytes, secrete a juice called bile. The bile gets collected within the liver by various small ducts or tubes and drains into the bigger right and left hepatic ducts. Bile from the right and left ducts drain into the common hepatic duct, which further unites with the cystic duct from the gallbladder to form the common bile duct. Almost half of the bile secreted by the liver gets stored in the gallbladder. Bile helps in digestion and also removes wastes from the body. When the bile ducts carrying the bile away from the liver gets blocked, as is the case in biliary atresia, bile gets accumulated in the liver and causes damage to the liver cells.
What are the symptoms of biliary atresia in babies?
As biliary atresia largely affects the liver, the symptoms in the initial stage are generally related to the liver. Some of the common symptoms of biliary atresia are:
Jaundice: It is one of the primary symptoms of biliary atresia. Jaundice in infants is of common occurrence. This causes difficulty in the diagnosis of biliary atresia in the first two weeks after birth.
Acholic stools: The normal color of the stool is because of bile. In the case of biliary atresia, bile does not flow into the intestine leading to clay-colored stools.
Enlarged liver and spleen: Because of building up of bile in the liver and resulting inflammation, the liver of the person gets enlarged, a condition known as hepatomegaly. Further, as the liver increases in size, it creates excess pressure on the spleen. This affects blood flow in the spleen and causes enlargement of the spleen.
Poor weight gain: Bile plays an important role in digestion. Since bile is not available to the digestive system, many nutrients are not properly absorbed, leading to poor development.
Irritability: An increased level of bilirubin in the blood and jaundice may cause irritability.
Dark urine: Because bile is not able to drain in the intestines, the level of bilirubin in the blood increases. This bilirubin is filtered by the kidneys and excreted out in urine making it appear dark.
Swollen abdomen: Biliary atresia results in hepatomegaly and splenomegaly because of which the person experiences an overall abdominal swelling.
What are the causes of biliary atresia?
The exact cause of biliary atresia is not known. It is believed that biliary atresia occurs in children due to anatomical abnormalities during fetal development. The bile ducts are not formed properly and the flow of bile gets blocked. Some also believe that in some children, although the bile ducts are properly formed, they get damaged because of the hyperactive immune system due to conditions such as viral infection soon after birth.
Biliary atresia is not contagious and genetic conditions have no role to play in its development. Other possible causes for biliary atresia are:
- A genetic mutation that involves changes in gene structure.
- Exposure to various toxins.
- Problem with the immune system.
What are the types of biliary atresia?
Based on the time of development of biliary atresia, the condition is of two types:
- Fetal biliary atresia: In this form of biliary atresia, the condition occurs in the baby while developing in the mother’s womb. Thus, biliary atresia in such babies is present from birth. This condition is not so common and occurs in almost 16% of the total cases of biliary atresia.
- Perinatal biliary atresia: This type of biliary atresia is not from birth, rather the baby acquires it within 2-4 weeks of birth. This is most common and occurs in the remaining 84% of cases of biliary atresia.
Another classification of biliary atresia is proposed by the Japanese Association of Paediatric Surgeons. It is based on the degree of biliary obstruction.
Types of biliary atresia according to this classification are:
- Type I or distal biliary atresia: In this condition, there is no obstruction in the cystic duct from the gallbladder and common hepatic duct from the liver. The problem occurs in the common bile duct that takes bile to the intestine.
- Type II or proximal biliary atresia: Type II biliary atresia is divided into type II a and type II b biliary atresia.
- In type II a biliary atresia, only the distal part of the hepatic duct is obstructed while the cystic duct and common bile ducts are open.
- In type IIb biliary atresia, distal hepatic duct, cystic duct, and common bile ducts are obstructed.
- Type III or complete biliary atresia: This type of biliary atresia is most common. This is characterized by the complete obstruction of the biliary system that includes intrahepatic biliary ducts as well as cystic and common bile duct.
What are the risk factors for biliary atresia?
The exact cause of biliary atresia remains unknown, however various factors increase the risk of this condition. Some factors that increase the risk of developing biliary atresia are:
- Preterm birth
- Poor maternal nutrition
- Maternal smoking
- Presence of congenital malformation
- Gender: females are more prone to biliary atresia as compared to males.
How is biliary atresia diagnosed by doctors?
Diagnosis of biliary atresia in infants is done following a complete medical and family history, physical evaluation, and investigations.
Physical evaluation: Physical examination of the infant is conducted to find out the signs of jaundice. During the physical evaluation, the liver and spleen are checked for any enlargement. The color of urine and stool are also assessed as it also helps in diagnosing biliary atresia.
Laboratory tests: Blood and urine tests are performed to determine the presence of bilirubin. High level of bilirubin in serum and urine indicate liver disease.
Hepatobiliary scan: Hepatobiliary scan is the process of visualizing the flow of bile through the bile ducts with the help of radioactive substance. Images of the flow are captured and studied to confirm blockage.
Liver biopsy: A small tissue from the liver is taken and examined under the microscope for liver problems. Liver biopsy not only helps in identifying biliary atresia but also gives information about other liver diseases.
Imaging techniques: Although ultrasound is not a confirmatory diagnosis for biliary atresia, it may help in excluding the presence of other congenital defects such as cardiac defects. This may give a preliminary idea about the presence of biliary atresia.
Surgical diagnosis: Exploratory surgery is done to evaluate the health of the liver and bile duct. Another option to surgical diagnosis is the laparoscopic diagnosis, in which a small incision is made and a tube is inserted to check for any dysfunction in liver and bile ducts.
What are the treatment options for biliary atresia?
There are two types of treatment options for biliary atresia.
Corrective surgery: that involves establishing the proper flow of bile from the liver to the intestine.
The surgery for facilitating the flow of bile from the liver to the intestine is termed as Kasai procedure or hepatoportoenterostomy. The procedure is named after the surgeon who was the first to perform it.
During this surgery, the part of the bile duct that is blocked is removed, and the intestine is attached directly to this duct. After the surgery, the bile is directly drained into the intestine.
The infant has to stay in the hospital for about a week after surgery during which medications like antibiotics, pain-relievers, steroids, etc are administered. Kasai procedure is successful in almost 60-85% of the infants.
Curative surgery: Individuals who are not benefited with corrective treatment or cases where Kasai procedure fails, are the candidates for liver transplantation.
What are the complications of biliary atresia?
Untreated biliary atresia may lead to life-threatening complications including severe liver complications. Some of the complications of untreated biliary atresia include:
- Severe itching: Increased level of bilirubin in the blood results in severe itching. This condition in the baby is significantly distressing. The condition can be managed with medicine.
- Cholangitis: Bacterial cholangitis is a complication of biliary atresia. Persons with cholangitis may experience fever and acholic stools.
- Portal hypertension: Due to damage in the liver, the patient may also experience portal hypertension.
- Stunted growth: Malabsorption of essential fats and vitamins may lead to poor growth.
Is biliary atresia preventable?
Prevention of biliary atresia is not possible because of the reason that either it occurs in the womb or within 2 to 4 weeks after birth.
However, the risk of developing biliary atresia can be reduced. Some of the measures to reduce the risk of biliary atresia include:
- Comprehensive maternal screening during pregnancy for any infection.
- Optimum nutrition during pregnancy.
- Lifestyle management like avoiding smoking to boost fetal growth and development.
Is treatment for biliary atresia done at all medical centers or is it only done at specialized centers?
The diagnosis and treatment of biliary atresia are recommended to be performed at specialized healthcare centers. Biliary atresia requires highly sophisticated diagnostic techniques for a conclusive diagnosis. Radioactive tracer techniques and surgical diagnosis require technologically advanced equipment along with experienced surgeons to perform these procedures. Treatment for biliary atresia involves complex procedures and comprehensive interdisciplinary care.
The experience of the surgeon and post-operative care are critical elements in success for Kasai procedure. Liver transplant, if required, cannot be done at all medical centers. For this, a team of experienced and highly specialized doctors is required.
Yashoda Hospitals’ Institute of Liver Transplant & Hepatobiliary Diseases is known for its highest quality liver transplantations and world-class Liver Intensive Care Units.
What is the outcome/prognosis of biliary atresia treatment?
With the advancement in surgical procedures and improved success rates of biliary atresia treatment, most persons with biliary atresia lead a normal life. Overall survival rate without liver transplant is about 40 percent at 10 years of age. Complications such as gastrointestinal bleeding and portal hypertension occur in some children. Approximately 85% of the children with biliary atresia require liver transplantation before they reach the age of 20 years.
Biliary atresia is a medical condition characterized by blockage in the bile ducts that prevents the bile to flow from liver to intestine. This results in the accumulation of bile in the liver, leading to the destruction of liver cells. Further, as the bile aids in digestion, biliary atresia results in poor digestion and malnutrition in children. Symptoms of the disease include jaundice, acholic stools, dark urine, irritability, and poor weight gain. Diagnosis is done through physical evaluation, laboratory tests, imaging techniques, and biopsy. Treatment options for biliary atresia are Kasai procedure and liver transplantation.
- Children’s Hospital, St. Louis, Biliary Atresia. Available at: https://www.stlouischildrens.org/conditions-treatments/biliary-atresia. Accessed on June 15, 2019
- Cincinnati Children’s, Biliary Atresia. Available at: https://www.cincinnatichildrens.org/health/b/biliary. Accessed on June 15, 2019
- Science Direct, Biliary Atresia. Available at: https://www.sciencedirect.com/topics/medicine-and-dentistry/biliary-atresia. Accessed on June 15, 2019
- National Institute of Diabetes and Digestive and Kidney Disease, Definitions and facts of biliary atresia. Available at: https://www.niddk.nih.gov/health-information/liver-disease/biliary-atresia/definition-facts. Accessed on June 15, 2019
- UPMC Children’s Hospital of Pittsburgh, Biliary Atresia Symptoms and Treatment. Available at: http://www.chp.edu/our-services/transplant/liver/education/liver-disease-states/biliary-atresia. Accessed on June 15, 2019