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
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