Most infants with biliary atresia are full term with a normal birth weight. Such infants present with persisting jaundice from the second day of life. Other features include pale stools, dark urine, failure to thrive and hepatomegaly. Splenomegaly may be found but is a late feature and implies significant hepatic fibrosis and early cirrhosis.8
Occasionally infants present with bleeding from vitamin K responsive coagulopathy which is more common in breastfed infants who did not receive vitamin K perinatally. About 5% of all infants will have had an abnormal antenatal maternal ultrasound. This is due to the presence of a cyst within the otherwise obliterated biliary tree and is detectable from around 22 weeks of gestation. Interestingly, these children usually do not have syndromic features such as polysplenia (see below).9
The diagnosis of biliary atresia may be difficult because of confusion with physiological jaundice (due to immaturity of the infant liver) and breast milk jaundice. Physiological jaundice normally lasts 2–3 days in normal term babies, while breast milk jaundice can last for up to 4 weeks. These physiological conditions can be differentiated from liver disease because in both physiological jaundice and breast milk jaundice, the bilirubin in the blood is mainly unconjugated (indirect), whereas in liver disease most of the bilirubin in time is conjugated (direct), typically>20 μmol/l or >20% of total.6
Confusion often arises in breastfed infants who may have a mixture of unconjugated (indirect) bilirubin and conjugated (direct) bilirubin. In time, the level of unconjugated bilirubin falls to normal, while the level of conjugated bilirubin rises. Professional teaching is based on the necessity to exclude liver disease if jaundice is prolonged beyond 14 days in a term infant or 3 weeks in a preterm infant.8,9,10
Diagnosis is based on the clinical presentation and the development of pale stools and dark urine, and is confirmed by abnormal liver function tests. These typically demonstrate a rise in conjugated (direct) bilirubin (>100 μmol/l; normal <20), alkaline phosphatase (>600 IU/l; normal <500 IU/l) and gamma glutamyl transferase (>100 IU/l; normal 20–40). Prothrombin time and albumin are usually normal in the early stages.
Key diagnostic investigations include abdominal ultrasound, which demonstrates an enlarged liver, and an absent or contracted gallbladder after a 4 h fast. Biliary dilatation is not seen. Hepatobiliary scanning using TEBIDA (N‐tert‐butyliminodiacetic acid) following phenobarbitone pre‐treatment (5 mg/kg/day for 3–5 days) usually demonstrates good hepatic uptake but absent or reduced excretion into the intestine within 24 h.
Liver histology, obtained by percutaneous biopsy, shows portal tract fibrosis, cholestasis and proliferation of biliary ductules.8
It is essential to exclude other neonatal liver diseases with similar clinical presentations such as alph‐1‐antitrypsin deficiency and other forms of neonatal hepatitis.8
The diagnosis is usually confirmed at laparotomy (with/without cholangiography) when the atretic biliary tree is evident. It is then usual to proceed to palliative surgery, the Kasai portoenterostomy. Some infants who present late (>100 days) and who have obvious established cirrhosis may alternatively be candidates for liver transplantation as a primary procedure. The natural history of this disease without medical or surgical management treatment is that most children die within 2 years of birth from end‐stage liver failure.