This is an archived Horseadvice.com Discussion. The parent article and menus are available on the navigation menu below:
HorseAdvice.com » Diseases of Horses » Nervous System » Incoordination, Weakness, Spasticity, Tremors » Equine Motor Neuron Disease (EMND) »
  Discussion on EMND, myositis, EPSM, at my wit's end
Author Message

Posted on Sunday, Apr 14, 2002 - 3:35 pm:

Okay, here is a puzzle for you.
My three yo warmblood had his spring shots in Feb. In less than a week he had an abcess in the injection site (yes, the vet put them all in the same place at once). The abcess was drained, the horse put on antibiotics and Tucoprin. Everything went away. There was a slight reoccurence of swelling about a week or two later, but another round of Tucoprin and everything was fine. Then on the 27th of March I noticed he walked a bit cautiously. On the 28th of March, I thought he had hyperextended a stifle as he was trotting sound but stumbled in the canter and when I got on him, he was distressed and didn't want to move. So his lesson that day was just 10 mins of standing under a rider. The next day I noticed a slight wobbling of his left front leg like a horse who is tied in will do. It progressed to a muscle flicking over the humerus as if he had a fly biting him and the wobbling front leg. I called the vet and over the phone he said it was grass founder and to give him bute and dry lot him. I did so for five days with the result that the horse began to get an upset stomach from the bute dosage and his trembling cautious gait continued, plus he was losing weight.
I called the vet again and could not get him out. So I called another vet two hours away. By the time she called back, the horse had fallen trying to canter up from the pasture (I had put him out and stopped the bute). He lay down for a few minutes then got up easily and walked cautiously up to the stable. I gave him a shot of banamine then because he was in obvious distress and pain. The vet arrived and arranged for me to transport the horse the next day up to a large vet med center.
They poked, prodded and tested him for five days. His blood work, xrays, spinal tap were all wnl. He has continued to lose weight and stands with his hind legs under (picture the horse in the sculpture, "End of the Trail")Prior to this, I have always had to watch his weight as he was an easy keeper. Four vets think it might be EMND, but not positively since the horse has always had green pasture, Vit E supplements, and is young. One vet just sent him home with the diagnosis of myositis and the prognosis open. He is on steroids now and banamine for pain. We plan on keeping him on 40ml of steroids for one week, then half the dose for two weeks, half again for two weeks and depending on how he is, wean him off. This is of course if he survives that long.
I read up on EPSM in the hope that it might be a solution, but he has always been on a high protein diet. I have been criticized by a lot of people for it in fact. Right now he gets 2# of Buckeye Grass Plus (16% protein) in the morning, 2# of crimped oats plus one cup Buckeye Ultimate Finish (high fat/high protein spplement) plus Vit e and selenium, biotin and L-methionine. High quality grass/alfalfa mix hay, plus green pasture.
The vets are perplexed, I am distressed and hoping that you can help! I don't want my horse to suffer, but I don't want to give up too soon either.

Posted on Monday, Apr 15, 2002 - 5:28 am:

Hello Christine,
With nothing more to go on than what sounds like some incoordination and, "He has continued to lose weight and stands with his hind legs under" I am afraid I cannot be much help.

The history suggests your abscess problem may not be resolved or cropped up elsewhere in his body. If the abscess were in the spinal cord in the neck region you might have clinical signs like you describe. The symptoms sound like a horse that is foundering but I presume there is no evidence of it since it is not mentioned as a possible diagnosis by the veterinarians? But then again how does the vet diagnose myositis if the labs reveal normal muscle enzymes?

If 4 vets think EMND they should test for this, see the article for more Equine Diseases: Nervous System: Equine Motor Neuron Disease (EMND). You will find also a list of rule outs in the article which all sound like possibilities though few of them have completely normal laboratory work ups like you state in your post. The one exception might be Grass Sickness which is not reported in NA but may be a form of botulism poisoning (Equine Diseases: Nervous System: Grass Sickness). There have been cases of botulism that entered through a wound. Lastly I would examine the article on Equine Diseases: Colic and GI Diseases: Weight Loss in Horses: Diagnosing Chronic Weight Loss.

You and your veterinarians are just going to have to plow through these lists and see what is and isn't likely and then devise a series of testing to rule them in or out. I am betting on either the botulism or spinal abscess based on the fact that what I presume are complete and double checked laboratory works keep coming up negative.
DrO
Home Page | Top of Page | Join Us!
Horseadvice.com is a BBB Accredited Business. Click for the BBB Business Review of this Horse Training in Stokesdale NC