Lobular Dissecting Hepatitis in Small Animals
Lobular dissecting hepatitis is a unique hepatic reaction pattern rather than a unique hepatic syndrome. The histologic features are typified by liver injury associated with intrasinusoidal nonsuppurative inflammatory infiltrates leading to panlobular sinusoidal fibrosis. Although more commonly described in juvenile to young adult dogs and in a small group of related Standard Poodles, this disorder seemingly has no breed, gender, or age predilection. Weight loss and ascites, with or without jaundice, are common clinical features. Laboratory abnormalities include hypoalbuminemia, hypocholesterolemia, low BUN, and increased TSBA concentrations in nonjaundiced dogs. Liver enzymes may be normal or mildly or markedly increased. APSSs develop due to acquired intrahepatic sinusoidal portal hypertension. Hepatic copper concentrations are not consistently increased. The syndrome commonly progresses to cirrhosis. Supportive treatment is recommended for HE, ascites, and control of fibroplasia and inflammation as described previously. Colchicine (0.03 mg/kg, PO, daily to every other day) has been used to control fibrosis and sinusoidal inflammation in some dogs. Other dogs have been managed with more conventional immunomodulatory protocols with PhosChol® (polyunsaturated phosphatidylcholine with 52% dilinoleoylphosphatidylcholine, 25–50 mg/kg/day), used as an antifibrotic with fewer adverse affects. This is a poorly understood and characterized syndrome and in some cases may reflect hepatotoxin exposure.