Liver Disease

Horses Common Treatments

Causes

The most common cause of liver disease in horses is ingestion of toxins most likely from feed, hay or grass consumption. These toxins could be mycotoxins, ragwort, drugs or chemicals. Liver disease can also be caused by infections (bacterial or viral), inflammatory diseases, bile duct stones, neoplasia, hyperlipaemia, parasites or be of unknown cause.

Symptoms

Due to the large functional reserve of the liver a lot of horses with mild liver disease will show no clinical signs at all and it will be picked up on routine blood tests. There can be a range of symptoms outlined below which often correlate with severity of disease. However, horses will often show no signs and then suddenly show the symptoms very quickly as the functional reserve of the liver is flooded and the liver can abruptly no longer cope with the challenge.

Signs of mild liver disease:

No clinical signs

Signs of moderate liver disease:

Not right
Appetite changes
Lethargy
Mild and possibly recurrent colic
Weight loss
Photosensitisation – dermatitis affecting just the white areas of the horse such as leg and face markings

Signs of severe liver disease and usually into liver failure:

Laryngeal paralysis – very loud breathing like a honking sound with the horse in respiratory distress
Hepatic encephalopathy – walking in circles, seem to be ‘not there’, pressing head against a wall, staring into space, wobbly on legs, may look ‘drunk’
Blindness
Fluid swelling under belly
Recumbency

Diagnosis

A blood test will identify liver disease and be able to provide some information regarding severity of damage and whether the liver is still functioning or is in failure. Blood tests are unlikely to identify a cause in most cases. For the most accurate information including type of disease, prognosis and possibly a cause then a liver biopsy is indicated. An ultrasound scan of the liver and the rest of the abdomen can also be helpful in assessing for a cause. Regarding identification of a potential toxin in foodstuff then samples of grass, soil, hay or hard feed can be sent for analysis.

Treatment

Treatment will vary depending on the cause if identifiable.

Remove any possible causes – If there is thought to be a toxin ingestion issue then altered forage should be provided as a trial, for example replacing the hay supply or moving paddocks.
Vitamin E – All horses with liver disease will be treated with supplementation with a high dose of vitamin E for its antioxidant properties supporting repair of the liver cells.
Steroids are often indicated for inflammation of the liver.
Antibiotics if there is bacterial infection.
Wormer – if parasites suspected
Lactulose – in cases of hepatic encephalopathy to remove excessive ammonia from the blood which is the mechanism of this manifestation of liver failure.
Fluid therapy in severely affected horses to maintain hydration and support all organs.
Euthanasia in severely affected horses in liver failure.

Prognosis

For liver damage where there is no loss of function the prognosis is largely good. In cases of liver failure especially if encephalopathy or laryngeal paralysis is present the prognosis is grave and euthanasia may be required.