Lobular Dissecting Hepatitis in the Dog

Abstract

Abstract. Ascites and acquired portosystemic shunts were consistent findings in six dogs with a chronic hepatitis of unusual morphology and unknown etiology. The hepatitis was characterized by a mixed inflammatory infiltrate and dissection of the lobular parenchyma by reticulin and fine collagen fibers. While limiting plates were disrupted by this process, portal inflammation was inconstant and seldom marked. Biopsy samples generally had very small, sublobular regenerative nodules, but larger nodules sometimes were present postmortem. Dilated vascular channels, representing sinusoids and portal venous radicles were a prominent feature of most affected livers.The lesions differ from previously documented chronic hepatitis in the dog, and from the chronic hepatitides in man.Portosystemic shunts in the dog may be congenital [8] or acquired. Acquired shunts develop as the result of portal hypertension. They consist of multiple, frequently tortuous, anastomotic vessels which represent the opening up of preexistent portosystemic collaterals [23, 24]. The obstruction to blood flow responsible for the portal hypertension may be extrahepatic or intrahepatic. Acquired shunts resulting from intrahepatic portal hypertension have been described in dogs with chronic hepatitis/ hepatic fibrosis [5,6,10] and overt cirrhosis [5,10,21, 24]. Affected dogs ranged in age from nine months to 15 years.Chronic hepatitis is an etiologically diverse and morphologically variable condition which has been documented extensively in man. By contrast there are few descriptions of chronic hepatitis in the dog, and aggressive forms have been recognized only recently [3,6,13,17]. Portosystemic shunts have not been a common feature of the reports.Over the last five years we have recognized an unusual and histologically distinctive chronic hepatitis in six dogs with acquired portosystemic shunts. Case ReportsAs indicated in table I, three unrelated standard poodles were included. Males and females were represented in equal numbers, although all standard poodles were male. Ages at initial presentation ranged from seven months to five years. The common presenting sign was ascites of three to eight weeks duration. In addition, the dogs were inappetant (refusing, particularly, 179

Tenascin-C in Chronic Canine Hepatitis: Immunohistochemical Localization and Correlation with Necro-Inflammatory Activity, Fibrotic Stage, and Expression of Alpha-Smooth Muscle Actin, Cytokeratin 7, and CD3+ Cells

“…Severe inflammation has been described as a feature of NH/LDH. 3,50 In this study, the fibrosis in NH/LDH dogs was diffusely distributed throughout the parenchyma, surrounding individual cells, or groups of hepatocytes dissecting the lobular architecture. Conversely, in CH/CIRR, fibrotic septa radiated from the portal and/or central areas into the parenchyma.…”

“…These findings are in concordance with previous studies. 3,7,46,50 Most CH/CIRR dogs showed moderate-to-severe fibrosis, while those with NH/LDH showed only moderate fibrosis ( Table 2). The increase in the amount of fibrous tissue can be explained by the activation, migration, and accumulation of HSC in the parenchyma and myofibroblasts at the other locations.…”

Characterization of the Inflammatory Infiltrate in Canine Chronic Hepatitis

“…Over the years, CCH has been classified histomorphologically as chronic active hepatitis, chronic progressive hepatitis, and lobular dissecting hepatitis. 3,10,11,26 Four decades of histologic and immunopathologic investigations have led to remarkable progress in the understanding of chronic human liver diseases. An understanding of the composition of the inflammatory infiltrate and its relationship to the evolution of human hepatitis has been very helpful for determining the pathogenesis of liver disease.…”

Histological and Immunohistochemical Evaluations of Lobular Dissecting Hepatitis in American Cocker Spaniel Dogs

“…Lobular dissecting hepatitis (LDH) has been described in individuals and litters in young standard poodle, Rottweiler, German shepherd, golden retriever and American cocker spaniel dogs [2,13,20,23,32]. The disease usually occurs in an average of two years and has a poor prognosis and short survival time [23,32].…”

“…Mild infiltration of neutrophils, lymphocytes, plasma cells and macrophages and necrosis of individual hepatocytes, as well as cholestasis, are observed [2,13,20,23,32]. Immunohistochemical examination has not yet been conducted for the histogenesis of hepatic fibrosis of LDH.…”