Vet360 Issue 2 Volume 3 | Page 10

INTERNAL MEDICINE Article reprinted with the permission of Clinician’s Brief. The article was originally printed in May 2013. CB is published by Brief Media. CB is the official publication of the NAVC. CB provides relevant diagnostic and treatment information for small animal practitioners. All rights reserved. The Top 5 Liver Diseases in Dogs Craig B Webb PhD, DVM, DACVIM (Small Animal) Colorado State University The liver can be exposed to ingested toxins, blood-borne pathogens, and drugs and their metabolites, providing numerous causes for acute insult. The liver serves as the control-and-command center for virtually all metabolic processes: production, packaging, and distribution of proteins, lipids, and carbohydrates; hormonal and enzymatic control of metabolic pathways; metabolism of biologics; transformation of xenobiotics; decontamination and removal of toxins; and recirculation, recycling, and refilling of gallbladder contents. When the liver does not function at full capacity, clinical manifestations are often ubiquitous and possibly devastating. 1 Hepatitis or hepatic insult Acute The liver can be exposed to ingested toxins, bloodborne pathogens, and drugs and their metabolites, providing numerous causes for acute insult. Signs can include anorexia, fever, vomiting, and abnormal mentation. Jaundice is the classic sign of hepatic failure, with RBC haemolysis as another important differential for hyperbilirubinaemia. Leptospirosis appears to be increasingly prevalent and usually involves both the liver and kidneys. Other possible infectious agents include infectious canine hepatitis (canine adenovirus-1), Clostridium piliformis, bacteria (especially Escherichia coli), and Toxoplasma gondii. Ingestion of Amanitum spp mushrooms, blue–green algae, and some drugs (eg, sulfonamides, carprofen, amiodarone) can result in acute and significant liver disease. Consequences of insult may be idiosyncratic and unpredictable, and signs may vary. ALT and bilirubin are the most pertinent biochemical indicators of hepatic insult, although low BUN, albu- min, cholesterol, and glucose levels along with prolonged clotting times are indicative of fulminant hepatic failure. Supportive care is essential. Glucocorticoids may be contraindicated (infection) or of minimal benefit in the acute setting. Acetylcysteine has been used in critical patients with a loading dose of 140 mg/kg IV, followed by additional treatments at 70 mg/kg. Chronic Signs of chronic canine hepatitis, often nonspecific and systemic, include vomiting, lethargy, decreased appetite, polyuria/polydipsia (PU/PD), and weight loss. Increased ALT enzyme activity, usually the most telling biochemical abnormality, is frequently monitored as a quantifiable indicator of treatment response. Although the primary disease cause may be undetermined, several treatable causes warrant diagnostic examination with histopathology, metal analysis, and bacterial culture. Chronic hepatitis may present as a slow progression of changes started by acute insult. Culturing bile, not liver tissue, may yield better growth.1 There is often an immune-mediated component to chronic hepatitis progression, warranting immunomodulatory therapy. Prednisone has been the preferred drug, but Colorado State University has recent- TOP 5 Liver Conditions in Dogs 1. 2. 3. 4. 5. Hepatitis or hepatic insult Hepatic fibrosis or cirrhosis Copper-associated hepatitis Congenital portosystemic vascular anomalies (PSVA) “Nonhepatic” hepatic disease vet360 Issue 02 | APRIL 2016 | 10 April 2016 Vet360 for Madaleen Review.indd 10 2016/03/24 2:24 PM