Why might a horse fall to the floor without warning? Keith Chandler MRCVS discusses the difficulty in diagnosing the cause of faints, fits and seizures

TAGS:

One of the most frightening things that can happen to a rider is when a horse collapses. It doesn’t happen very often, fortunately. But when it does it can be dangerous for everyone around — as well as potentially fatal for the horse.

Horses don’t like to spend too long lying down. If a horse does collapse, he is often back on his feet by the time the vet arrives. Some horses only collapse once in a lifetime, while others suffer repeated episodes.

A key difference between the various causes of collapse is whether the horse loses consciousness or not. This can happen when the amount of blood reaching the brain is reduced, such as when the heart or circulation is not functioning normally. Horses that remain awake while recumbent may have collapsed because of a musculoskeletal injury or disease.

The automatic assumption made by many owners is that a collapsing horse has had some kind of “heart attack”. Horses can suffer devastating heart dysfunction, yet this is quite rare. It does not mirror the human heart attack, where the blood vessels in the heart become blocked and the heart muscle rapidly becomes diseased.

What causes collapse?

Unless death is immediate, most horses recover — albeit temporarily — from a collapse caused by heart disease. This allows the vet to make a complete assessment, before deciding on a course of action. Often, it is the small strands of tissue holding the heart valves in place that fail and this can result in heart failure.

Horses can suffer from epilepsy. This is distressing to witness, because there is little anyone can do to help a fitting horse. Recurrent seizures in mature horses are usually caused by an infection of some type and can, in some cases, be treated.

Narcolepsy is a common condition that causes horses to fall asleep on their feet. They collapse to the ground, but usually get straight back up again. It tends to affect mature or older horses and is not serious unless it recurs or causes repeated injury. A narcoleptic episode nearly always occurs when the horse is very relaxed — such as when he is being groomed or otherwise pampered — and can give everyone quite a fright. Once the vet has ruled out other more serious causes, these cases can often be managed by watching out for the signs of nodding off and waking the horse before he falls over.

Danger zone

Dealing with a collapsing horse or one struggling to rise is a veterinary emergency. Over the past few years, with the support of H&H, the British Horse Society and the British Equine Veterinary Association, many equine vets have undergone further training in safer horse rescues. Emergency services across the UK can access a directory of vets capable of dealing with such emergencies.

The first thing the vet will do is ensure the safety of those around the patient. A competent and confident handler should control the horse’s head with a long lead rope attached to the headcollar, and reassure the horse. It is worth waiting for a vet who is experienced with horses, as a small animal vet may not have the equipment or expertise needed.

Once the initial struggle has died down, most horses will lie or stand quietly unless they are in a great deal of pain. The vet can then make the first assessment. The vet needs to be clear that the horse is not suffering from another disease that may have caused the collapse, so examination may be very detailed. If the horse is still recumbent and unable to rise, the vet will need to roll him over gently to examine the limbs hidden from view. He may struggle and attempt to get back on his feet at this point, which is why an experienced person at the horse’s head is essential.

What to do for the fitting horse

Managing the fitting horse is much more difficult. If the seizure happens in a stable, turn all the lights off, close the top door and keep noise levels down. Most fits pass quickly, but keep everyone away and call for veterinary assistance as soon as possible. The vet will need to establish if the horse has collapsed before, which is not always obvious.

Unexplained wounds or injuries, nosebleeds or unusual disturbances in the bedding may signal that he has been collapsing without anyone realising. What exactly was the horse doing when he fell? Did he fall forwards or sideways, or did he lift his head and go over backwards? Was there any change in his behaviour just prior to falling over? Tell the vet about any recent changes in the horse’s management or medication, and whether he has been struggling to cope with his normal exercise routine or showing any signs of lameness or stiffness.

Veterinary care can be tricky if the horse stays down. Horses need to stand to pass urine and dung normally and their gut function is linked to being upright. Pressure sores develop quickly with recumbency, while both the respiratory system and oxygenation of the blood are badly affected. The horse’s eyes can easily be damaged when he is struggling and particular care needs to be taken of them, as well as keeping the surface of the eye moist with artificial tears.

Generally speaking, the longer a horse is down, the more damage caused to the muscles and other tissues. This combines to make it less likely that he will manage to get back up again, unassisted. The real diagnostic challenge lies with horses who have returned to normal after fainting, or appear normal between episodes. A complete examination, including blood tests, will help the veterinary team get to the bottom of the problem. If a heart problem is suspected, a heart scan and electrocardiogram (ECG) will be performed.

Because of the intermittent nature of equine heart problems, many vets now have access to remote recording of ECGs. The monitor is left on the horse for 24hr or longer — even during exercise — to monitor heart function throughout the day. The frequently collapsing horse can be tracked with video surveillance, either at home or at a clinic. This can help the vet understand the cause, so he can treat the horse or at least inform the owner more accurately of the chances of a full recovery.

Case study: ‘He was in a bad way’

When Diana Thompson found her children’s pony Gus collapsed and in distress, she feared the worst.

“He was upside down in his field, tangled in a bush and some fencing,” recalled Diana, who had noticed that the 12.2hh Welsh mountain pony had seemed a little shaky on his feet the evening before. “He could have been like that all night. His eyes were rolling back and he looked as though he was taking his last breath.”

With a lot of encouragement, Gus got back on his feet.

“He was quite weak and in a bad way,” recalls Diana. “Keith Chandler and his team were brilliant — they kept him at the clinic for some time, where he was diagnosed with hepatitis and treated.

“Gus is now back in action and looking healthier than I’ve seen him in a long time. Keep talking to a collapsed horse and don’t give up — Gus really seemed to respond to human contact.”

5 signs that a recumbent horse is unlikely to rise

  1. No attempt to rise after 1hr
  2. Partial paralysis for more than 4hr
  3. Coma or semi-coma for more than 48hr
  4. Persistently dilated pupils
  5. Uncontrollable struggling and/or pain

Collapse: possible causes

  • Limb or back fracture
  • Tetanus
  • Botulism
  • Syncope (true fainting)
  • Atypical myopathy
  • Heart disease
  • Electrical shock
  • Seizures
  • Narcolepsy
  • Head trauma
  • Winding
  • Exhaustion
  • Excessive bleeding
  • Hepatitis
  • Becoming cast or trapped

EMERGENCY!

Call your vet IMMEDIATELY in the case of a collapsed horse. If a horse is down and stuck in a more public place, ring the emergency services. Ask the operator for an equine vet from the directory of practices that provide safer horse rescues.