Jaw temporarily out of socket?

[baybrio]

A horse I’ve taken care of for many years is having very very strange episodes. I’ll explain in a minute but I want to let you know that we’ve had a really good vet do complete neuro exam and look in his mouth etc. She can find nothing wrong. Nothing. She really can’t figure it out. She told us the pitfalls of trying to x-ray his jaw socket, their bones are so dense in that area x-rays can be inconclusive.

Several months ago this sweet horse had an episode where he cantered around in a circle with his mouth open slightly to the side. He looked like someone was lunging him, practicing decreasing and increasing the circle size. He wasn’t panicking, he wasn’t slipping, he wasn’t racing, just cantering around with a confused look and his mouth slightly open. When he’d made the circle so small it looked like a pirouette (kind of) he slipped just a little and stopped. He shook his head and started walking around the hay feeder. His mouth was still to side a bit. In less than two minutes the whole thing was over. He stood for a minute then he started eating hay like nothing had happened.

I was literally standing with my mouth open watching this. I know he hadn’t fallen or gotten kicked before the episode because I was out in the paddock. He was normal, then he just started.

I immediately checked him over, mouth to tail and couldn’t find anything abnormal, sore, or even touchy. His owner and I watched him carefully for hours. Nothing out of the ordinary. We of course had the vet out immediately. Thoughts of poisoning, severe injury causing a neuro problem, EPM, something in his ear…
The vet couldn’t find anything. Which is good, but didn’t help to solve the puzzle.

The only thing I could think of is that he got his jaw caught in the hay feeder and somehow pulled it out of it’s socket. I have this horse specific hay feeder that accommodates small squares for 10 years, but we all know horses can get hurt on anything.

So fast forward several months. No sign of this happening again until last week. The person that helps me with the horses saw him make tiny circles and scramble. Then he just stopped, shook himself off, and went on like nothing happened. This time I know it wasn’t the hay feeder. He wasn’t anywhere near the hay feeder.

I’ve been a barn manager, then had my own horses at my place for 30 years and I’ve never seen anything even remotely like this.

Any ideas? The vet is coming out again later this week to try and x-ray his jaw, but I’d love to have some ideas to throw her way.

Thanks for reading this way too long post.

[joiedevie99]

Bone spur in the TMJ is also worth ruling out. I’d haul him in to the clinic for higher powered machinery if the vet is concerned about getting good enough quality images in the field, or talk to her about what they can see with other modalities like ultrasound, or CT scan.

I’d also want to scope his upper airway to make sure there isn’t some sort of mass making it hard to swallow properly, etc.

[baybrio]

joiedevie99,

Those are great suggestions. I’m going to send both possibilities to his owner and defiantly share them with the vet.

I never thought of something in his upper airway. A bone spur definitely makes sense.

I’m within an hour of the University of Madison. I believe they have all the diagnostic equipment you mentioned. Hmm, maybe the vet will suggest UW instead of trying the field equipment.

Thank you!!!

[Ghazzu]

Skull radiographs are certainly possible in the horse, though tricky in an ambulatory setting. A referral hospital ought to be able to get them, though.
A CT scan might be suggested, based on the findings w/radiographs.
Temporohyoid oseoarthropathy is certainly a possibility in this horse, from the signs described, if the vestibulocochlear nerve is being affected.

[RMJacobs]

Could it be a seizure? I’ve seen some odd behavior in a horse and a dog that were both prone to seizures.

Rebecca

[baybrio]

Ghazzu,
Thank you for clearing up the process of radiographs, and then moving on to CT scan. You sent me a new thought process by mentioning the vestibulocochlear nerve (I had to look that one up). I believe his behavior is consistent with that nerve being affected.

I’m beyond frustrated with the vet. I’m not questing her competence in anyway, just her conclusions in this case. My inquiry about the possibilities COTHer’s gave me were pretty much brushed aside without thought. Her new verdict - he’s a hyper sensitive horse and something we can’t hear set him off. This is just not consistent with his behavior.

The owner is going to have a very competent human/equine chiropractor come out and evaluate him. Perhaps we will gain some insight. If not, I believe we/she will go for the scans.

I’m very uncomfortable just letting it go. While he’s only done this while in turn out with plenty of room, I’m concerned he will begin one of these episodes when he’s being handled, in the run in or a stall. He’ll hurt himself, a human or another horse. Poor guy, he’s a very gentle horse.

[baybrio]

RMJacobs,

That was my initial thought. It’s still a possibility. Seizure doesn’t seem to fit, but as you said they can take on many forms.

I owned a mare who ultimately had to be put down due to seizures. It was horrible. She was my dressage partner for many many years. I still own her son.

[Simkie]

A friend’s horse did have a traumatic dislocation of the jaw, confirmed via radiographs at a referral hospital, and the options were to wire the jaw and hope it healed, or euthanize. The chance of success was pretty marginal with a difficult recovery, and the horse was put down.

Based on that, I just can’t imagine you’ve got something as traumatic as a dislocation and the horse has carried on. Definitely worth working up, but likely that it’s something more subtle?

[baybrio]

Simkie,
Thank you for that information. From your description of jaw dislocation, I agree dislocation does not sound accurate for this horse. It’s got to be something more subtle.

When I was grinding my teeth a lot I was diagnosed with TMJ (I believe that’s the acronym). Anyway, my jaw would kind of lock sideways. It wasn’t painful, but it wasn’t pleasant and kept me from trying to eat in public for a while. Perhaps it’s something like that. I’m pretty sure he’s not grinding his teeth. He just hangs out with the other horses and eats, he doesn’t currently have a job. I’m sure TMJ has many causes.

[joiedevie99]

TMJ is the name of the joint, the Temporomandicular Joint. Here’s a good picture of where it is on your horse: https://www.smartpakequine.com/content/tmj-in-horses

[hybriseris]

I’d just like to second @RMJacobs suggestion about possible seizures. The symptoms aren’t what you’d think of w/ seizures but a few years ago something similar happened with one of my dogs.

We were in the backyard when all the sudden he started running in circles and snapping at the air - it was really bizarre and frightening, but then it stopped and he went back to normal completely. Ate, drank, whole nine yards. Two weeks later same thing happened again and he was diagnosed with a specific form of epilepsy, can’t remember the exact name.

I’m not sure about prevalence or presentation in horses, but this sounds too similar not to mention it as a possibility!

[RMJacobs]

My epileptic Labrador would start a seizure by appearing to intently stare at something, then she would convulse. It was so hard to watch, but we found that if we got on the floor with her and held her, we could keep her from hurting herself, and she came out of the seizure much more calm with arms around her. Sometimes it was challenging holding onto 95 pounds of solid dog.

My Hackney pony had a couple of seizures in his senior years. I think he was about 27 the first time. He was throwing his head up and down, then started to shake and move consistently backwards. He never went down, but trying to get him to stop and not run into anything was difficult.

The first time happened when I had him on a lead rope in my saddling area. There were lots of hazards not too far away, so I tried to buffer him by getting in between him and a fence. The second time, he started the head behavior and I knew what was coming. So I moved him into a separate big pasture and got him out in the middle where he couldn’t hurt himself, and the other horses couldn’t bother him.

We never got a good explanation for the seizures, in spite of having the vet arrive within an hour of the first one. Later, he was diagnosed with a sinus tumor, and I wondered if that was somehow the cause. We couldn’t keep his nose clear, so I ended up putting him down.

I was glad that neither the dog nor the pony had frequent seizures, because I always ended up black and blue from trying to keep them from hurting themselves.

Rebecca

[baybrio]

Joiedevie99,
Thank you for that link. Sounds like a wide range of behaviors are possible. I think it’s still a possibility.

[baybrio]

hybriseris and RMJacobs, Thank you for your info on seizures. You both gave great examples of the variations in seizure behavior. This is so confusing.

[baybrio]

Ghazzu,
I hope I didn’t offend you in my previous reply. I did not know you were a vet! I hope I mentioned the vet in question is wonderful and very competent. I wouldn’t hesitate to use her in the future, nor would I ever use her name or the name of her clinic in any negative way. I’m just frustrated she didn’t seem to take your suggestions seriously. It’s very hard having my horses at my home, I’m often not take seriously. (And I always listen carefully) When I worked for a retired Olympic rider I never had this problem

[Ruth0552]

I think in this kind of situation it’s important to make it clear to your local/farm/gp vet that this is something that you are pursuing and willing to spend money on. I’d guess her thinking is that it happened twice and isn’t affecting the horse’s function so you’re going to spend a ton of money pursuing it and might still not know what the heck happened. So why bother? That’s not her call to make but I’ve seen it before.

You are already having a chiro out, which I was going to suggest. Honestly next thing is bring the horse to a reputable clinic for evaluation and hopefully get a referral to a specialist. I’d consider having a veterinary dental specialist check out his teeth and jaw just to rule things out.

Good luck.

[Ghazzu]

@baybrio

I hope I didn’t offend you in my previous reply. I did not know you were a vet! I

No offence taken.

[baybrio]

Ruth0552

You make a good point. The vet may not think it’s worth pursuing. The horse is not worth a lot in dollars. I’m concerned the vet doesn’t quite realize how dangerous this behavior is to the horse, and anyone around him when he starts. I’m just not sure how to communicate this. It’s so hard for the vet, she really doesn’t know me and may think I’m exaggerating.

Also, since I last wrote he had another episode. Again, one second standing, the next cantering in a slowly decreasing circle. Then a minute of confusion and back to himself.

After the chiro our next step is probably the University of WI large animal vet clinic, or a vet clinic toward Chicago. Whichever has more robust imaging equipment.

I like the idea of the veterinary dental specialist.

Thank you again for great advice.

[LCDR]

First, I am not a veterinarian. Before retiring, I was an oral and maxillofacial surgeon in an academic medical center, and have some experience with TMJ disorders, displacement, derangement, and have done both surgical and non-surgical management. And I taught this stuff for thirty years. Trying to compare equine and human disorders is problematic, but here goes.

TMJ is an acronym for an anatomical structure, the temporomandibular joint. As the name implies, the condyle of the mandible articulates with, or into, a “socket” in the temporal bone. The jaw articulation is unique, because the lower jaw can move from side to side, and can move forward as well. Put your index finger just in front of your own ear and move your jaw around. You will feel your mandibular condyle move forward, back, and in and out laterally.

Towards the front of the temporal bone part of the joint is an articular eminence; basically a ramp of bone that the lower jaw slides forward and down on when you open. Sometimes the eminence is big, sometimes it is almost flat. A horse has this eminence too.

If you open too far, as in yawning, or the muscles or ligaments supporting the joint are weak, or a muscle spasm yanks the lower jaw forward, the mandibular condyle can slide forward over the tip of the articular eminence, and this can lock the lower jaw in place so you can’t close. Usually it reduces spontaneously, if not it can be manipulated back into place, sometimes requiring an injection of local anesthetic to relax the muscle, or after an IV of a muscle relaxant like Valium.

There are a number of causes of this temporomandibular disarticulation in addition to yawning and ligament weakness. As mentioned in prior posts, there rarely may be systemic or central nervous system etiologies.

Remember that “TMJ” is an anatomic structure, not a specific disease or a disorder. You horse has TMJ disarticulation, or TMJ displacement. Determining the underlying cause is next.

Your vet may recommend consultation with a board certified equine dental specialist. There folks are veterinarians with advanced training. The one who practices near me is board certified in both equine surgery and in veterinary equine dentistry.

[Ruth0552]

If you happen to have your phone on you when he does it- whip that sucker out and video it. My blind cat was going in circles, and when the vet saw it he was convinced 100% it was neurological in origin.

It also might be worth keeping a journal of when he’s been witnessed doing this and what he was up to before it happened- was he grazing, standing around napping, eating hay, etc. I’m not a vet but if it always happened when he was eating hay, I’d guess more that it was a jaw/dental issue, or perhaps something going on in his neck, then in his brain. If it was in his brain it would be more likely to be happening randomly. Again though, not a vet.