BILIARY DUCTAL PLATE MALFORMATION WITH SECONDARY PORTAL HYPERTENSION AND MULTIPLE ACQUIRED SHUNTS IN A LITTER OF AMUR TIGERS (PANTHERA TIGRIS ALTAICA).

Abstract

Congenital abnormalities in tigers (Panthera tigris) are infrequently reported but have included ectrodactyly, cataracts, and vestibular disease. Primary hepatic disease has been documented in multiple nondomestic felid species but is considered uncommon in tigers. To the authors' knowledge, there are no previous reports of congenital abnormalities of the liver in tigers. In May 2022, two male Amur tiger cubs (Panthera tigris altaica) were born at a zoological institution via cesarean section to address dystocia, following the natural birth of a female cub. Between two and six months of age, all three cubs developed progressive lethargy, inappetence, and neurological signs consistent with hepatic encephalopathy, including obtundation and ataxia. In all three cases, serum biochemical values revealed progressive, marked elevations in hepatic enzyme levels with reduction in hepatic synthetic products (albumin, urea, cholesterol). Computed tomographic imaging showed a large cluster of aberrant tortuous vessels craniomedial to the left kidney in all three tigers, consistent with acquired extrahepatic portosystemic shunts. Histologic examination of the livers identified biliary ductal plate malformations. This report details the presentation, clinical findings, diagnoses, and therapeutic interventions attempted in three Amur tiger cubs with biliary ductal plate malformation and subsequent portal hypertension with multiple acquired portosystemic shunts, an unusual abnormality not previously reported in non-domestic felids.