What Causes Seizures?

Q. My eventer has recently been diagnosed with seizures. However, despite blood tests, we have no idea what causes them. The episodes last for approximately two minutes, and once they are over, he is completely normal again. He has never had them while being ridden, and they mostly occur in the paddock.

We've moved three times in the last few years, and his food has been altered, so those shouldn't be causes. He has never been injured or hurt before, and this illness has been a nasty shock. What causes this? Is there anything we can do?

Sarah, via e-mail

A. The problem with your horse fits the description of an adult animal with acquired epilepsy, or more specifically idiopathic epilepsy, assuming there has been no history of brain damage or current disease.

In general, if the seizures are predictable (typical signs appear ahead of the main event), and you feel comfortable about not riding when a seizure is coming on, I feel your horse's clinical signs are not severe enough to warrant treatment.

There are some drugs that will control these seizures, but they are not without risk. The drugs in question include detomidine, diazepam, pentobarbital, and other nervous system modulators. These are not appropriate medications for non-professionals, and they might actually cause more severe neurological signs. Should the horse deteriorate, it would be well to seek advice from a specialist in internal medicine. Your veterinarian should be able to help you locate someone with these skills.

Further, if the clinical signs become more severe and the horse becomes noticeably worse during episodes, it would be prudent to seek that consultation right away.

About the Author

A.C. Asbury, DVM

A. C. (Woody) Asbury received his DVM from Michigan State University in 1956, then spent 21 years in California in breeding farm practice and at UC Davis. He joined the faculty at the University of Florida in 1977 and was involved in teaching, research, and administration until 1996. An Emeritus Professor at Florida, he lives in Kentucky, where he and his wife are developing a small farm.

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