HEPATOENCEPHALIC SYNDROME CAUSED BY A SHU NT OF THE PORTAL VENOUS SYSTEM WITH THE CAUDAL VENA-CAVA AND A LEFT AZYGOS VEIN IN A JACK-RUSSEL-TERRIER

A five months old Jack Russel Terrier was euthanized because of runtin g and progressive central nervous symptoms. A complex malformation of the venous system was found characterized by a porto-azygos (left)-shu nt. Lesions in the central nervous system consisted of spongiform dyst rophy, particularly in brain stem and spinal cord. The anatomy of the embryonic development of the venous system is described with regard to the presented case and major aspects concerning the pathogenesis of t he hepatoencephalic syndrome are pointed out.