CANINE MEDICINE
Vacuolar Hepatopathy in the Scottish Terrier
Remo Lobetti BVSc MMedVet ( Med ) PhD Dipl ECVIM ( Internal Medicine ) Bryanston Veterinary Hospital , PO Box 67092 , Bryanston , 2021 , South Africa , Email : rlobetti @ mweb . co . za , Reviewed by Dr Marlies Böhm
Vacuolar hepatopathy ( VH ) is a common and frustrating diagnosis often without a specific aetiology . When hepatocytes become injured , one response is for them to swell and become vacuolated . Hepatocellular vacuoles distending the cytosolic compartment may contain , fat , glycogen , intracellular water , metabolic waste products or metabolic intermediates .
Vacuolar hepatopathies may occur in conjunction with hydropic degeneration in which there is cytosolic swelling but devoid of distinct vacuoles . Vacuolar hepatopathies can be caused by a number of conditions - or lesions may develop because of secondary chronic stress ( presumed to be endogenous steroid induced ) resulting from concurrent disease .
In a retrospective study , it was shown that VH accompanied by a progressive increase in serum ALP activity was found in the Scottish terrier . These increases are marked - reaching the 2000-3000u / L range . Sequential monitoring over years in individual dogs has confirmed the progressive nature of this syndrome , with increases in serum ALP activity coinciding with development of diffuse increased hepatic parenchymal echogenicity and numerous small hypoechoic parenchymal nodules evident on ultrasonographic examination . Although ultrasonographic detection of features such as hyperechoic or coarse-appearing hepatic parenchyma , hypoechoic nodules contrasting against hyperechoic parenchyma , and discrete mass lesions is common , ultrasound cannot defini-
In dogs there are several ALP isoenzymes : bone , liver , and steroid induced , specific to dogs , being some . In dogs , elevated serum ALP activity may reflect inflammatory , neoplastic , or cholestatic disorders involving the liver , biliary tree , or pancreas . A common cause for VH in dogs is the endogenous overproduction of steroidogenic hormones or treatment with cortisone 2 . Increased hepatic production of ALP and its release into the systemic circulation accompanies VH , with the corticosteroid-induced ALP iso-enzyme predominating . Greater than a 3-fold elevation in serum ALP activity is common in dogs with VH .
Traditionally VH is considered a benign lesion , however , progressive VH can lead to diffuse hepatic remodelling resulting in the formation of parenchymal nodules and intra-sinusoidal hypertension secondary to hepatic remodelling . In its extreme manifestation , VH can result in splanchnic hypertension , acquired portosystemic shunts , ascites , and hepatic insufficiency .
Although degenerative VH can develop in any dog , it is recognized as a progressive VH in the Scottish terrier , a breed which also shows a high incidence of hepatic carcinoma . One study in healthy Scottish terriers showed a relationship between elevated serum ALP activity and increased adrenocorticosteroid hormone concentrations following ACTH stimulation as well as a correlative association between older age and concentration of androstenedione .
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Issue 03 | JUNE 2016 | 24