Role of Hepatobiliary Scintigraphy and Preoperative Liver Biopsy for Exclusion of Biliary Atresia in Neonatal Cholestasis Syndrome.

Abstract

All diagnostic algorithms for Neonatal Cholestasis Syndrome (NCS) focus on differentiating numerous medical causes from Biliary Atresia (BA). No preoperative diagnostic algorithm has 100% diagnostic accuracy for BA and yet, timely diagnosis is crucial to optimize surgical outcome. Markers for high index of clinical suspicion for BA are: a "usually" well thriving infant with conjugated hyperbilirubinemia, raised gamma glutamyl transpeptidase, persistently "acholic" stools, firm hepatomegaly with dysmorphic, hypoplastic gall bladder. In the presence of above 'red flag' signs, there has been much debate on diagnostic accuracy of percutaneous liver biopsy (PLB) vs. hepatobiliary scintigraphy (HBS) to substantiate or exclude BA. Recent guidelines suggest a shift towards PLB (91.6% overall diagnostic accuracy) as the diagnostic cornerstone with key differentiating feature being 'bile ductular proliferation'. HBS has ahigh (98.7%) sensitivity but low specificity (37-74%) with an overall diagnostic accuracy of 67% for BA. Severe hepatocellular disease without anatomic obstruction would also have a non-excretory scan. Thus, while excretory HBS excludes BA, non-excretion does not confirm BA. Hence, diagnostic algorithms relying on non-excretory HBS as the primary standalone benchmark for surgical exploration would be mired by a high negative laparotomy rate revealing a normal peroperative cholangiogram (POC). However, an excretory HBS obviates need for laparotomy in case of equivocal stool color or PLB. A POC continues to be the ultimate gold standard. Hence, with high index of clinical suspicion but equivocal ultrasonography or PLB and a non-excretory HBS, the baby should not be denied a POC within time frame crucial for successful hepatoportoenterostomy.