Predictive value of bile duct dimensions measured by ultrasound in neonates presenting with cholestasis.

OBJECTIVES

: The significance of extrahepatic bile duct dilatation on ultrasound examination in jaundiced infants is often uncertain. We wished to clarify the diagnostic and prognostic significance of the present finding in neonatal conjugated hyperbilirubinaemia.

PATIENTS AND METHODS

: We retrospectively enrolled all of the infants younger than 3 months with extrahepatic biliary dilatation > or =1.2 mm (nonfasting ultrasound) who presented during the study period. We reviewed clinical, radiological, and laboratory data to determine mode of presentation, diagnosis, interventions, and long-term outcome.

RESULTS

Seventy-six infants (41 male) were identified, all of whom were referred with conjugated hyperbilirubinaemia. Median gestational age was 39 weeks (range 24-42 weeks). Inspissated bile was the most common diagnostic category, whereas congenital choledochal malformation was the diagnosis made in 13% infants. Dilatation was an incidental finding in 9% of the infants. Seventeen percent of infants had required either surgical or radiological intervention by the time of follow-up. Overall, 41% infants had spontaneous resolution of bile duct dilatation, including 8% who had "grown into" an unchanged duct size rather than involution of dilatation. The median size of bile duct at presentation for those who required intervention was 4.7 versus 2 mm for the remainder (P < 0.001). Of those who resolved spontaneously, the median size of duct at presentation was 1.8 mm.

CONCLUSIONS

: Bile duct dilatation <3 mm (nonfasting ultrasound) with neonatal cholestasis is unlikely to be of significance whereas >4 mm is likely to be associated with choledochal malformation or need for intervention. The intermediate group is likely to be associated with inspissated bile syndrome following resolution of which innocent biliary dilatation may persist.