Many of the symptoms of liver failure including loss of appetite (inappetence), weight loss, and depression, are nonspecific for a particular disease. To further complicate the diagnosis of liver failure, you often find elevated liver enzymes in routine equine blood panels on apparently healthy horses. Relatively small insults to the liver, stress, and many drugs can result in increases in serum levels of liver enzymes, sometimes dramatic rises. The reason for the rarity of liver failure is because:

• The liver has a large reserve capacity and signs of liver failure does not occur until over 70% of the liver is dysfunctional.
• The liver has a large capacity for regeneration when it is damaged as long as anti-metabolite chemicals and/or scarring are not present.

It is important to remember elevated liver enzymes do not mean liver disease and liver disease does not always equal liver failure. In order to confirm liver failure frequently requires further laboratory work up looking for the toxic metabolites that accumulate with liver failure. Causes of liver failure include poisons, infection, immune disorders, intestinal disease, and cancer. Because many of the symptoms are the same regardless of cause diagnosis of the specific cause may require biopsy though not aways. This article deals with the symptoms, diagnosis, causes, treatment and prognosis of liver disease in general in horses. Links are provided to articles on specific liver diseases where present.

Summary The specific symptoms you will see with a particular disease causing liver failure will depend on the specific cause of the liver failure, whether there is acute or chronic disease of the liver leading to failure, and which functional part of the liver is mainly effected.

Few of the signs are specific for liver failure though jaundice is helpful in diagnosing liver failure when associated with the symptoms referable to the liver. The clinical signs of liver disease and failure can vary and depend mainly upon:

• How long the liver is affected: acute vs chronic damage
• How much of the liver is dysfunctioning. This is often related to whether the diseases is acute or chronic. Acute disease often effects the liver extensively while chronic disease often starts with effecting a smaller percentage of the liver and progressing to extensive damage
• Which areas of the liver are diseased: biliary system vs. the liver cells (hepatocellular injury)
• The specific cause of the liver disease

Acute vs Chronic

Biliary System vs. Hepatocytes (liver cells)

Specific Causes

To summarize the specific symptoms you will see with a particular disease causing liver failure will depend on the specific cause of the liver failure, whether there is acute or chronic disease of the liver leading to failure, and which functional part of the liver is mainly effected.