[The role of the abdominal ultrasonography and percutaneous liver biopsy in the differential diagnosis of neonatal cholestasis].

Neonatal cholestasis still presents a diagnostic challenge, both from the anatomic and etiologic point of view. Distinguishing intrahepatic from extrahepatic causes of cholestasis is of paramount importance since the latter may be treated by surgery but prognosis depends on the age at which operation is performed. Many tests have been proposed to help in differentiating these two entities, among which liver biopsy is the most frequently employed, and ultrasonography one of the most recently included. Our purpose is to present our experience with these two methods in the differential diagnosis of intra and extrahepatic causes of cholestasis. From January 1989 to July 1993, 35 patients with neonatal cholestasis were evaluated through a protocol which included liver biopsy and ultrasonography. The latter was performed after a 4 hour fast and was considered indicative of extrahepatic cholestasis when the gallbladder was not visualized, was hypoplastic or non-functioning, or if a cystic structure was seen at the extrahepatic biliary tree. Sensitivity, specificity, and accuracy were determined for these two tests. Seventeen patients were found to have extrahepatic cholestasis (all with biliary atresia) and 18 intrahepatic cholestasis, on the basis of clinical evolution or operative findings. Sensitivity was 100% for ultrasonography and 76% for liver biopsy in diagnosing extrahepatic cholestasis. Accuracy was 83% for ultrasonography and 86% for biopsy, rising to 96% when both tests were considered together. Based on these findings we strongly recommend ultrasonography with definite criteria as the initial investigation tool in the management of neonatal cholestasis, associated with liver biopsy.