Biliary atresia (BA) is a congenital biliary disorder, which is characterized by an absence or severe deficiency of the extrahepatic biliary tree. It is one of the most common causes of neonatal cholestasis, often causing cirrhosis immediately and leading to death and accounts for over half of children who undergo liver transplantation.
It is thought to affect 1 in 10,000-15,000 newborn infants. There is a recognized male predilection.
It precipitates within the first three months of life. Infants with biliary atresia may appear normal and healthy at birth. Most often, symptoms develop between two weeks to two months of life, and may include :
- jaundice (conjugated hyperbilirubinemia)
- dark yellow or brown urine
- pale or clay-colored (acholic) stools
It is thought to result from idiopathic destructive inflammatory process which leads to fibrotic remnants at porta hepatis.
Kasai classification is used to classify the three main anatomical types of biliary atresia.
Prompt diagnosis ensures early treatment and results in improved prognosis.
- echogenic fibrous tissue anterior to the portal vein: triangular cord sign 5
- larger hepatic arterial caliber 2
- gallbladder ghost triad 4
Nuclear medicine (hepatobiliary (HIDA) scan)
Tc-99m diosgenin (DISIDA) and mebrofenin (BRIDA) have highest hepatic extraction rate and shortest transit time of hepatobiliary radiotracers. Cases of biliary atresia typically demonstrate relatively good hepatic uptake with no evidence of excretion into the bowel at 24 hours. Pretreatment with phenobarbital (5 mg/kg/day for 5 days) to increase biliary secretion by stimulating hepatic enzymes is frequently helpful to minimize the possibility of a false-positive study in a patient with a patent biliary system but poor excretion.
Treatment and prognosis
Management options include
- Kasai portoenterostomy
- liver transplantation
General imaging differential considerations include
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