Lesions of subclinical doberman hepatitis.

This investigation describes histologic lesions in the livers of 18 Doberman Pinschers suffering from subclinical doberman hepatitis (DH). The dogs' ages ranged from 2.5 to 7 years; 15 were females and 3 were males. At the time of liver biopsy, the dogs had no clinical signs of liver disease, although serum alanine aminotransferase (ALT) values had been elevated in two samples in successive months. In the histologic examination, all biopsies revealed parenchymal and portal mononuclear inflammation. In the parenchyma, the inflammation was diffuse, with multifocal clusters of inflammatory cells. The periportal reaction was usually mild to moderate. Bridging necrosis (3/18) and bile duct proliferation (2/18) were rare. Excessive copper was detected by rubeinic acid stain in every specimen. Postmortem liver samples were obtained from nine dogs 3.5-65 months after the initial biopsy specimen; five of these dogs had been euthanatized for reasons other than DH, and liver specimens revealed piecemeal necrosis (5/5), bridging necrosis (3/5), and bile duct proliferation (2/5). Four of them had been euthanatized because of DH. Liver lesions of these dogs were typical for chronic active hepatitis, with bridging and piecemeal necrosis (4/4), portal expansion (4/4), bile duct proliferation (4/4), and fibrosis (4/4). A scoring system was used to evaluate changes numerically from biopsy to postmortem samples. Lesions in all dogs had progressed. The most important histologic changes were expansion of portal areas (P = 0.008), increased periportal and bridging necrosis (P = 0.008), increased fibrosis (P = 0.016), and proliferation of the bile ducts (P = 0.063).