What Is Biliary Atresia? Know Its Causes, Symptoms, Signs, Risk Factors, Diagnosis, Treatment, Prognosis
Biliary atresia is a neonatal liver disease. The disease causes progressive fibro-inflammatory obstruction of extra-hepatic bile ducts. The obstruction is caused by stricture of hepatic or common bile duct. The stricture causes obstruction of bile flow known as cholestasis. The bile slowly accumulates in Liver and results in increased bilirubin level in blood. If not treated soon, the disease will advance to cause liver damage. In this article, we will read in detail various causes, symptoms, and treatments for Biliary Atresia.
How Is Biliary Atresia Defined?
- Hereditary- Infant is born with atrophy or stricture of hepatic duct or common bile duct.1
- Symptoms are observed during first 2 week.
- Viral Infection- In few cases viral infection triggers autoimmune response and results in autoimmune disease. White blood then causes injuries of epithelial cells of the bile duct and hepatic duct outside liver. The injuries results in inflammation, scarring and stricture of hepatic duct and/ or common bile duct.2
- Bile is secreted by liver
- Bile facilitates digestion of food.
- Blockage of bile flow into intestine causes lack of bile in intestine for digestion of food.
- Acquired Biliary Atresia-
- Bile duct outside liver following inflammation results in scarring. The scarred duct eventually atrophies and blocks the flow of bile.
- Liver is unable to discharge bile in to the intestine.
- Bile remains in liver and eventually spills over liver cells and causes cell damage resulting in liver failure and secondary cirrhosis.
- Such changes are often observed following liver and kidney transplant.
Extrahepatic Biliary Atresia- 3 types
- Type 1: Common Bile Duct Atresia
- Type 2: Common Hepatic Duct Atresia
- Type 3: Left and Right Hepatic Duct Atresia
Causes of Biliary Atresia
- Congenital Disease-
- Biliary atresia is a congenital disease found mostly in infants.1
- Symptoms are observed during first 2 weeks after birth.
- The rate of occurrence of biliary atresia in USA is 1:10,000 to 1:15,000.
- The congenital anomalies causes atrophy of common bile duct.
- Genetic Mutation- 3
- Genetic mutation causes increased sensitivity of extra-hepatic bile duct to autoimmune disease. The scientific literature do not yet suggests the specific gene variation.
- Autoimmune Disease-
- Acquired biliary atresia is caused by autoimmune disease.
- Seen in children and early adult hood. Symptoms are observed between age 2 and 8 years.
- Acquired biliary atresia follows inflammatory scarring of common bile duct or hepatic duct.
- Autoimmune response is also responsible for failure of liver transplant.
Risk Factors Of Biliary Atresia
- Maternal diabetes 3
- Viral infection during pregnancy
Symptoms and Signs Of Biliary Atresia
Initial Biliary Atresia Symptoms And Signs Are:-
- Symptoms appear during first 2 weeks after birth.
- Jaundice- Yellow skin and eyes
- Hepatomegaly- Enlarged liver, liver feels firm to hard when examined.
- Stool- clay and pale in color.
- Urine- yellow in color
Delayed Biliary Atresia Symptoms And Signs Are:-
- Growth retardation
- Fat soluble vitamin deficiency
How is Biliary Atresia Diagnosed?
- Color- Yellow.
- Bilirubin Level- Positive.
- Bilirubin Level- Direct/conjugated bilirubin levels are elevated. The positive results during first 2 week after birth suggest possible biliary atresia.4
- Liver Enzymes- Elevated if associated with liver failure.
- High frequency ultrasound image- Most effective diagnostic test to evaluate infant biliary atresia.5
- Findings of ultrasound examination of gall bladder-
- Abnormal lobulated contour of gall bladder surface
- Gall bladder small for the age
- Extra-hepatic duct atrophy observed.
- MRI images of gall bladder and bile duct are examined for abnormal findings.
- CT Scan
- CT Scan like MRI is used to examine gallbladder and bile duct.
- Surgical Cholangiography-
- Gall bladder is exposed following open surgery. Dye is injected into gall bladder. Dye passage through gall bladder into intestine is studied using X-Ray. Lack of evidence of communication between gallbladder and intestine confirms diagnosis of extra-hepatic atresia.
- Percutaneous Trans-hepatic Cholangiography-
- Dye is injected in liver under anesthesia
- Technically difficult procedure
- Cholangiography shows dye spread from liver to intestine if bile passage is normal.
- Useful to diagnose normal intrahepatic and extra-hepatic biliary system.
- Ultrasonography-guided Percutaneous Cholecysto-Cholangiography-
- Contrast material injected into gallbladder under the guidance of ultrasound.
- The passage of the dye is examined by MRI.
- Liver biopsy study is a diagnostic study to diagnose biliary atresia.
- Experimental investigation used in experimental lab to identify gene expression as biomarker of the biliary atresia disease.2
What Are The Treatments For Biliary Atresia?
- Unfortunately, till date there is no definitive nonsurgical treatment available to treat Biliary Atresia.
- Corticosteroids has been tried to treat autoimmune disease.
Surgical Treatment For Biliary Atresia:-
- Kasai Procedure-
- The blocked bile ducts is replaced with a length of the infant's own intestine thus acting as a new duct. This surgery is called Kasai Procedure.
- The main aim of this procedure is to allow passage of bile from liver to the intestine with the help of this new duct. If this procedure is performed early enough, then the success rate of this procedure is approximately 80%.
- Procedure has been modified to treat the specific area of atresia.6
- Liver Transplant
- There have been cases in which the Kasai procedure is not effective. In such cases liver transplant is indicated once liver function start deteriorating. The surgery is often urgent to prevent harm to infant.
What Is The Prognosis Of The Affected Child With Biliary Atresia?
- In the absence of a successful treatment, the infant rarely survives beyond two years of age.
- In cases where the Kasai procedure becomes successful then the infant is able to lead a normal healthy life.
- The children may undergo gradual liver damage during the growth.
- Infants, children and adults need specialized care for the entirety of their lives.
1. Recent progress in the etiopathogenesis of pediatric biliary disease, particularly Caroli's disease with congenital hepatic fibrosis and biliary atresia.
Nakanuma Y1, Harada K, Sato Y, Ikeda H.
Histol Histopathol. 2010 Feb;25(2):223-35.
2. Gene expression signature for biliary atresia and a role for interleukin-8 in pathogenesis of experimental disease.
Bessho K1, Mourya R, Shivakumar P, Walters S, Magee JC, Rao M, Jegga AG, Bezerra JA.
Hepatology. 2014 Feb 3. doi: 10.1002/hep.27045.
3. Aetiology of biliary atresia: what is actually known?
Petersen C1, Davenport M.
Orphanet J Rare Dis. 2013 Aug 29;8:128. doi: 10.1186/1750-1172-8-128.
4. Patients with biliary atresia have elevated direct/conjugated bilirubin levels shortly after birth.
Harpavat S1, Finegold MJ, Karpen SJ., Pediatrics. 2011 Dec;128(6):e1428-33.
5. The diagnostic value of high-frequency ultrasonography in biliary atresia.
Jiang LP1, Chen YC, Ding L, Liu XL, Li KY, Huang DZ, Zhou AY, Zhang QP.
Hepatobiliary Pancreat Dis Int. 2013 Aug;12(4):415-22.
6. Biliary atresia - a new derivative method?
Murar E, Barta A, Omanik P, Trnka J.
Bratisl Lek Listy. 2014;115(1):49-53.