re: 21 Y/o QH with front leg tremors

Question
Dear Bradford,
I have a 21 y/o QH that last year had a patella tendon tear in the RH. I rehab him for one year. He was doing well and then about 1 month ago, I was riding and he fell down on his knees. I contacted my Vet, we evaluated him, and not much came from that. He had epiphysitis I found out at a young age. He has started started tremoring in the front both legs, sometimes it is just when he is standing before you put his boots on and turned him out. Sometimes, I walk him for quite awhile and when I bring him back to the stall, he is trembling again. I have noticed he is cribbing again and I wonder if he is in discomfort. He has had tennis shoes on for several months and I am planning to take them off. I am so confused and lost he is in turnout everyday since he is arthritic and was on 1 gram a butte a day for some time. I recently stopped that and my Vet said we should try Equinox, which we did give for 10 days. She was going to prescribe prevacox it is cheaper and suppose to be better for his stomach than butte. I have retired him with great disappointment because I have had him since he was 9.I am going to put regular shoes on him he seems to grow long in the toe on one side and not on the other. My farrier trims him so he can have more rollover in the front. I love him dearly and want to know what to do. I am at a loss and very confused. He has been a wonderful horse and I want what is best for him.
Thank you so much for your reply.
Sincerely,
Bonnie  

Answer
I dont think it is pain causing this. Is the tremoring only in the front limbs?? This horse's age implies that he may have an acquired condition that is affecting his nervous system or his muscles. Pain can also cause trembling, but I would expect it to be more diffuse than just in the front legs. Quarter horses also get HYPP, a muscle disease that as a Quarter Horse owner Im sure you've heard about. I suggest starting with a good neurologic exam, and then a musciloskeletal exam to include a lameness evaluation. Somer horses with neck pain may exhibit signs like this only in the forelimb. This can be neck arthritis, or it can be impingement of a nerve coming from the spinal cord inthe neck to supply the foreleg(s). i dont think the prevacox has had any evaluation in the horse, so id be careful using it. Equiiox is a COX2 specific antiinflammatory drug and is licensed for use in horses. As a Cox2 drug, it provides the exact same benefits as the prevacox would, but will be safe.
In my hands, i dont think it is as effective as bute. Remember, it is not clear that this is due to pain. Steriods may be necessary if it is determined to be neurological in origin. Get this more fully evaluated before you assume anything. That should include bloodwork, Muscle evaluation with possible muscle biopsy if needed and a good neurological exam. These things would best be done by a specialist in internal medicine, as a specialist is the one who really needs to interpret the results of these tests and examinations. let me know if you have any more questions.