Hepatitis is defined as inflammation of the liver. A vital organ that performs numerous metabolic functions that are necessary for life, much of the liver can shut down before the effects of the disease are apparent in horses.
Symptoms and Types
Hepatitis can occur acutely, as with ingestion of certain toxins, or can develop slowly, as with some underlying infections. However once the initial damage begins, any or all of following signs may appear:
- Depression
- Anorexia
- Colic (abdominal pain)
- Weight loss
- Yellowing of the mucous membranes (jaundice)
- Fluid accumulation (edema)
- Neurologic signs such as head pressing, incoordination, blindness, drowsiness, confusion
- Photosensitization
- Diarrhea
Causes
There are several causes of hepatitis in horses. Bacteria such as Clostridia can cause liver inflammation, and there are a few viruses that can cause it as well. There are also numerous toxins that can cause hepatitis, mostly found in certain plants such as ragwort, whitebush, and sometimes ryegrass. Another cause of hepatitis is called serum sickness. This occurs when a horse is exposed to a therapeutic agent that contains equine serum. Antibodies against the foreign horse proteins then destroy the horse’s own liver.
Diagnosis
A presumptive diagnosis of liver disease can be made by your veterinarian based on your horse’s clinical signs; however, additional laboratory tests will need to be done, such as blood work and perhaps even imaging such as abdominal ultrasound. Liver biopsies can also be performed to aid with the diagnosis.
Treatment
Treatment varies depending on the cause of the hepatitis. If it is bacterial in nature, prompt treatment with antibiotics is required. Other causes of hepatitis such as viral or toxin-induced usually rely on supportive care. Such care normally consists of IV fluid therapy, vitamin B, antioxidants, and medication to decrease the amount of ammonia in the blood.
Prevention
Fortunately, hepatitis is not very common in horses. To best help prevent against it, proper maintenance of your horse’s pasture is necessary to decrease exposure to toxic plants that can cause this condition. Bacterial and viral causes of this disease are harder to prevent, but ensuring your horse is up to date on vaccines may help.