Have you looked into MFM? https://www.ponyhorsetack.com/equine-myofibrillar-myopathy-the-mysterious-muscle-disorder/
OneTwoMany, is this what your horse was diagnosed with?? My former BO’s warmblood has it and it’s heartbreaking. She had all sorts of tests done until finally one vet did a biopsy. At the moment he’s just wasting away; he’s only 10 yrs. old.
I would call your vet out one more time to do a lameness with flexions and neuro exam. EPM is a tempting diagnosis to jump to when nothing else is working but often these type of horses actually have a subtle lameness that is preventing them from working correctly and results in loss of topline and decreased performance. Consider this next exam by your vet an investment - treating for EPM blindly is much more costly than a thorough workup.
I would also consider testing for Cushing’s. It can present with topline atrophy and lack of performance as well. This test also isn’t particularly cheap but luckily is fairly responsive to treatment. We are getting into the best season to test for Cushing’s!
I’m sorry you and your horse are going through this. I dealt with similar symptoms and lack of diagnosis for over 3 years with my horse. Learned that just as with humans, a negative reading on a Lyme test does not definitively mean they don’t have it, or some other tick-borne disease. We tried a round of Doxycycline in the springtime, and my horse showed dramatic improvement within one week. Two months later and she had improved so much that she doesn’t seem like the same horse. My humble advice is to ask your vet to prescribe Doxy for one week. If it helps continue, if not you haven’t spent much. Good luck and feel free to PM me.
I’m going to get a lot of hate for this, but if you are actively spending money on training and competitions, pay for testing and treatment.
I live in Maryland, and EPM and Lyme are very common. I hear everyone gripe about how most horses in the area have been exposed to those diseases, and are likely to have false positives- blah, blah, blah. spinal taps can fail, blah, blah, blah. The bottom line is, you have to figure it out. So pay for the spinal tap, or pay for a second opinion.
This may well be a compound issue that you are dealing with, so you need to make sure that you are treating everything. I’ve seen horses with crazy intestinal parasites go bald, I’ve seen horses with atypical symptoms of EPM or Lyme. So unfortunately deductive reasoning isn’t enough to diagnose whatever is happening with you mare.
The tests mentioned above don’t diagnose EPM per se. They will inform a vet regarding possible neurological abnormalities. Neuro abnormalities can be caused by many things. EPM might be one cause, but it isn’t the only possibility.
IME, most vets won’t “diagnose” EPM based on a positive neuro exam alone.
It would be worthwhile to test again. A Lyme test is not that expensive, and make sure that the vet does the Cornell test and not a snap test.
My previous horse had Lyme disease at least 3 separate times; my husband has had it at least twice. Horses (and people) often do not test positive for the disease when they are initially infected, because the body hasn’t had a chance to develop antibodies and that is what most tests are testing for. It can take a while for a test to come back positive even when the horse is well and truly infected.
There are also, of course, other tick-borne diseases that present a lot like Lyme but will not show up on a Lyme test.
So, I’d test again, and while the vet is there I’d have a long and involved discussion about what the various possibilities are. Do your homework before the vet visit so that you have a list of specific questions to ask.
In my region (western Mass), vets will often start a horse that is suspected of having Lyme on antibiotics while they wait for the results of the test. If the horse responds to the antibiotics that fact is considered along with test results.
Good luck.
These are not tests for EPM. They are tests for issues with the horse’s reactions to certain stimuli.
Other conditions can produce the same results, including Wobblers and sacroiliac problems, even some hip issues and muscle soreness, and others, some already mentioned in this thread.
Several years ago a vet diagnosed my horse with EPM based on the tail-pull and the other physical tests. Before we started treating I asked for a) a more definitive test (I believe it was a blood test, it was about $100) and b) a second opinion. Just to be sure where we were going and how best to treat.
Test results: Horse was negative for EPM. The revised diagnosis was sacroiliac. Very, very different treatment protocol.
The spinal shot and physical therapy over several months, with no riding, brought the horse right from the sacroiliac.
EPM meds would have done nothing. I do not have a lot to spend, and was very thankful that I chose to spend the money the way that I did for this horse.
We routinely run EPM and Lyme tests on the horses - at least once per year. The only definitive test for EPM is a spinal tap, but I don’t know any vets that still recommend one. The risk simply isn’t worth it. The blood test combined with manual testing is quite good, and Marquis is a very safe drug. The good blood test will give you a titer, and your vet can explain what the number means. There is a zero, which means no exposure. Then varying levels of low, medium, and high. Some vets don’t recommend treating a low result as that can simply mean past exposure - but my vet often does treat the low horses if they have any physical symptoms as well.
I’ve had horses that were actively competing test positive and horses that you would have sworn had EPM test negative. I’ve never treated a negative horse, but I have treated a low horse. That said, I do know of at least one vet who believes that Marquis treats some as-of-yet undiscovered illnesses that are like EPM, but not close enough to pop on the EPM test. If the horse tests negative, but has lots of neurologic signs, and they rule out other obvious answers like cervical arthritis, she will treat a negative horse for 2 weeks to see if she gets a response.
My late horse was treated for EPM before the test results came back. My vet had a few tubes left from another client so we started right away. Unfortunately by the third treatment things weren’t going well so I chose to euthanize. Eventually we got the results back and he had some of the highest levels for EPM she had seen. I still wonder if I continued treatment if he would have recovered but at age 34, with hock issues that prevented him from getting up after going down, I think I made the best decision as heartbreaking as it was to do.
This spring we struggled with her not being in front of the leg, lacking energy, etc.
Around May she started looking ROUGH, meaning balding patches of hair, shedding out unevenly, bleached out in spots, much slimmer, not really well muscled and lacking topline.
Things seemed to get better, but then the objecting to work started, back soreness, unwillingness to move back in a rein back, topline not developing.
Everything about this suggests Cushings. The only thing that is “off” is that she’s a 14 year old TB. Which doesn’t mean she can’t get Cushings but isn’t necessarily the first thing you might think. I’d test for that now; but I think I’d probably retest for Lyme and EPM as well.
I would agree that many vets will try to avoid spinal taps unless it is absolutely necessary. The test is not without risk. But when a horse is sick and the vet wants to chase down a diagnosis, sometimes a spinal tap is in order. Maybe GP’s don’t perform them often, but our internist certainly does them when warranted.
Toltrazuril works great and won’t hurt them. I have a giant growing wb who gets a little “trippy” and has trouble picking up hind feet at times and this eliminated it completely! Ask your vet for dosage, etc. And it is not expensive
The same thing can happen with Lyme vs. other tick-borne diseases. There are all kinds of other things besides Lyme that will respond well to doxy, oxytet, etc.
Not sure if this is what you are thinking of, but those early EPM tests only looked for antibodies to S Neurona, not N. Hughesi.
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