Breed Specific Hepatopathies: Scottish Terriers Maltese Dogs

摘要

In dogs, increased serum alkaline phosphatase (ALP) activity reflects necroinflammatory, neoplastic, or cholestatic disorders involving hepatic biliary or pancreatic ductal systems, canalicular cholestasis (i.e. altered organic anion pumps as in sepsis), or simply induction phenomena (endogenous or exogenous glucocorticoids, or acute phase response). Vacuolar hepatopathy (VH), a relatively common canine syndrome, accompanies many systemic illnesses (inflammatory, neoplastic, infectious, primary and secondary hepatic disorders). VH is linked with increased hepatic ALP gene transcription, enhanced production of the corticosteroid isoenzyme, and abnormally increased serum ALP activity (3-fold or much greater). Hepatocytes in VH accumulate excessive cytosolic glycogen leading to cell distention and increased fragility. While some clinicians consider this a "benign" syndrome, in some cases it unfortunately leads to diffuse hepatic remodeling (degenerative VH), a nodular cirrhotic appearing liver, and intrasinusoidal and splanchnic hypertension leading to acquired portosystemic shunts, ascites, and hepatic insufficiency. While any dog breed or mixed breed dog can be affected with degenerative VH, among most severely affected dogs are Scottish Terriers (ST). A pioneering study demonstrated the relationship between high serum ALP and excess serum adrenocortical steroid hormone concentrations in apparently healthy ST, and correlation between older age and androstenedione concentrations after ACTH stimulation. For clinicians that only occasionally examine Scottish Terriers, recognition of syndromic features usually leads to a presumptive diagnosis of either typical or atypical hypoadrenocorticism. Conventional adrenal-modulatory treatment with Lysodren has led to acute deaths or rapid onset of hypoadrenocorticism while use of Trilostane has made little difference in enzymology, hepatic features or clinical signs, and sometimes has ill effects.