Extrahepatic cholestasis in the dog and the differentiation of extrahepatic and intrahepatic cholestasis.

The clinical and pathological features of extrahepatic cholestasis in 19 dogs are presented. The condition was most often caused by partial or complete occlusion of the choledochal duct due to neoplastic diseases (12 cases), inflammatory processes (3 cases), or eventration and incarceration of the liver (1 case). In only three cases was the condition due to intraluminal obstruction of the choledochal duct. The anamnestic, laboratory and pathological parameters of these 19 dogs were compared with the findings in 21 dogs with intrahepatic cholestasis. Statistical analysis of these parameters indicated that the presence of acholic faeces, the degree of icterus and the level of plasma gamma GT where the only parameters of value in the clinical differentiation of extrahepatic from intrahepatic cholestasis. Histological examination of liver biopsies is a simple aid to a confident in vivo diagnosis of extrahepatic cholestasis.