Brain matters

Sometimes chemical changes in various parts of the body can affect the brain; for example, liver failure can cause hepatic encephalopathy.

Liver failure

If the liver is damaged and unable to remove waste toxic substances such as ammonia from the body, the levels of toxic chemicals in the bloodstream may rise and mimic the effects of the brain’s usual chemical messengers (neurotransmitters). This can adversely affect brain function and lead to neurological signs such as depression, staggering, central blindness and weight loss. Around 50% of horses will recover from this stage of liver disease if the underlying cause is treatable.

Intestinal disease

Occasionally intestinal diseases, such as those causing some types of colic, can cause large quantities of undesirable chemicals to enter the bloodstream and ultimately affect the brain. Unlike many cases of hepatic encephalopathy, the prognosis for intestinal disease can often be good so it is essential to allow time for an accurate diagnosis to be made.

Epilepsy

Although epilepsy isn’t particularly common in horses it’s something to be aware of, not least because the seizures can take many different forms and in between the horse will appear to be perfectly healthy.

Signs of epilepsy may simply be an involuntary twitching and grimacing of the lips. In more extreme cases the ears may twitch, the neck may twist or move in circles, the body may spin and the horse may fall and its limbs can paddle violently. A seizure may last for a few seconds or may be almost continuous and can be highly dangerous for people around the horse as well as frightening to watch.

What will my vet do if brain trauma is suspected?

Unexplained injuries or damage to the stable may be the first clues that a horse has epilepsy or another brain disorder and it’s important for the horse to be checked by a vet as soon as possible.

The vet will:

Discuss your horse’s recent and long term history – noting any illnesses, medications, injuries, changes in management or uncharacteristic behaviour Observe your horse in the stable and when handledPerform a full physical examinationPerform a more specialised neurological examination to assess your horse’s responses to its environment and specific stimuliThey may want to take further tests such as bloods to look for underlying causes

If the horse is suspected of having seizures it is helpful if these can be videoed - easier said than done if you don’t know if or when your horse is having one but fitting a CCTV camera in the stable is a practical option.

Brain disorders may sound alarming but it’s not all gloom and doom. Thanks to diagnostic advances with CT and MRI many horses go on to make remarkable recoveries