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  Discussion on EPM serum tests
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Member:
Mwebster

Posted on Wednesday, Dec 31, 2003 - 3:34 pm:

Dear DrO,

Do you ever see horses with classic EPM symptoms who have weak positives on the serum test and who turn out to in fact be EPM cases? From reading the site, I'm clear that positives on serum aren't diagnostic, but can you infer anything (rule in, rule out) from just how positive the result is?

Thanks,
Melissa
Member:
Mwebster

Posted on Wednesday, Dec 31, 2003 - 3:43 pm:

PS, just to clarify, the vet who did a CSF tap on my older gelding today mentioned he doesn't see positive CSFs in horses that don't show strong positives on serum tests. Of course, I'm hoping it's EPM, since none of the alternatives are treatable....
M
Member:
Mwebster

Posted on Thursday, Jan 1, 2004 - 11:33 pm:

Dear DrO,

While I'm asking questions, I may as well give you the rest of the picture. My older (arthritic) gelding (just turning 23) started to exhibit some very strange problem 2 weeks ago. Although he appears normal in most every way -- good appetite, no fever, cheerful, normal heart/resp rates, no apparent pain, normal blood tests -- he is centering his left hind leg under his back end when standing still (his right hind is resting out away from his body and pointed out a bit), and he travels sort of haunches-in to the left when walking (in a 3-track). It's easy to tail-pull him over to the left when walking (into a 4-track), but not to the right -- this seemed surprising as it's his left side that's supporting him, his right side shows muscle-wasting (the muscle-wasting happened very quickly, within a week of onset). His haunches-in is worse on hills (4-tracks).

He shows proprioceptive deficits when asked to turn in a tight circle (crosses legs and turns awkwardly), and turns much better clockwise than counter clockwise. The problem is much more apparent in the hind end, but blindfolding shows a mild deficit in the front end too, and he seems to be putting much less weight on his right front than the left front, you can see him buckle his pastern over a little and the knee move a little indicating he's not equally weighting that leg, so it seems like there's weakness on his entire right side.

He was nearly falling over on tranqs for the tap (.75 dermosodan, he's 16h3 and weighs about 1200 lbs, and has had at least this much before for the dentist). On tranqs he pretty much stumbled around in a tight circle, as his hind end would start to fall over to the left and he'd have to move a leg to catch himself -- kind of turns around the forehand with huge crossing staggering steps. The drugs challenged him pretty hard, he nearly went down a couple of times. I had noticed he seemed to react very strongly to the tranqs back in October when he had coffin joint injections, and seemed to go ataxic behind. I remember worrying he'd fall over.

If you watch him move from the side, you'd never know anything was amiss. He trots rythmically, no apparent incoordination is visible from the side, only from back/front where it's clear leg placement is very strange in the hind end laterally. He doesn't appear to be in any pain- he wants to move around, he tosses his head and trots and sometimes tries to canter and buck when he's feeling a little excited, but winds up cross-cantering and either doesn't know how to coordinate all his limbs or there's weakness and he reverts back to a trot. He's rolling in the pasture on both sides (he always gets up and down for each side, as he has big withers), so that seems a good sign. But he hasn't laid down at night in his stall since this started, and that's unusual for him.

He doesn't seem to be in danger of falling over, and he's pretty good about placing his feet safely -- he stepped neatly over a rubber feed bucket in the aisle when trying to avoid me (and my syringe), and he's avoiding rocks and uneven areas in the paddock quite ably. He can walk over ground poles without hitting them, but he'll knock them occasionally at trot. He backs up in an arc to his left. He seems a little stiffer than usual when asked to reach around for a treat, usually he can touch his nose to his ribs, but this may be hesitation given his deficit. He's limberer to his right. No head tilt, doesn't look dizzy. Seems more like a combination of weakness and lateral incoordination. Tail/anus are normal too. Sensitive everywhere to the little poke test (even a little hypersentive, but he just hates flies and has always had a strong skin flick response).

I'd been thinking there was something off in his hind end for several weeks and found myself doing tail pulls. A month ago I asked the vet who was over for blood work to watch him turn in circles and back up, but the vet thought he looked normal. So this is sudden in a way, but I think it's been brewing for a little bit longer. I thought maybe he was getting a little arthritis in his spine. But that may not be so likely: when this started to unfold, he got 2g Bute IV (no change!) and then 25mg Dex IV for 2 days (no change either!), so it doesn't seem to respond much to anti-inflammatories. Can't think of any trauma, except he bumped heads with our other gelding when playing faces from the adjacent stall, and he shook his head a couple times immediately after, but it seemed not to bother him at all after that.

The only management changes were taking him off his meclofenamate and putting him on doxy 3 weeks prior to onset of symptoms (thinking he might have Lyme), and worming him (ivermectin) just a day or two before symptoms started. He's current on worming (every 8 weeks, we've never had positive fecals here, closed herd). No changes in food. He's got hay free choice 7x24, so I don't think he's nibbled on anything strange, and anyhow there aren't any systemic issues.

We started him on SMZ/TMP and pyrimethamine, plus NSAIDs, a week ago since EPM is one of the obvious possibilities and probably the only thing we can treat. He looks just like the photo of the EPM horse at the UC Davis website in their "Puzzle" article, which comes up using the HorseAdvice search on "EPM": there's a horse standing on his left hind with that right parked out and slightly forward, pointing to 2 o'clock.

He's been on the meds now for a week, and he hasn't gotten any worse. Actually, he seems better -- he was leaning his left butt against the stall wall a lot until 2 days ago, he's doing it less. The past 2 mornings when I turned him out, I thought I saw a straighter horse as he trotted off to the pasture. He crabs more when he gets tired. I've noticed that if I walk at his left flank and give him a little poke on each step to ask him to position his hind end over to the right, he can track straighter/squarer. He's spending all day out. A few days ago, he'd be looking tired by 4pm, but today he was still looking strong at 7pm, and he'd done a lot of running around. Of course I'd love to believe he's responding to the meds, or getting better on his own, but maybe he's just learning to cope and the improvement is due to effort on his part. He focuses very well generally, and always tries hard.

I've read the great articles at HA on spinal cord and neuro problems, and tried to correlate his symptoms using the chart that maps specific symptoms to zones of the CNS, but I don't know whether I'm seeing pareis, ataxia, or both, in addition to postural issues, and I don't know what hypermetria and hypometria actually look like. He seems to have this extensor deficit on the left (doesn't push himself over to the right; easily pulled left by the tail when walking), yet the right is affected too - that's the side he's not standing as much on, and the muscle-wasting on the right is very apparent; also he knocks his left hind ankle with his right hind foot (he's in support bandages), so is that a paresis problem on the right, or a flexor problem? Since his trot looks so normal from the side (well, almost perfect, there's maybe a little shorter stride on the right hind), and since it's so rhythmic (it's crisp, the pairs of legs move in a well-synchronized way), does that tell us anything? Anything else we should test him for, short of xraying his entire spine? We're waiting for the results of the tap, but it was contaminated, unfortunately.

Since leaving the first post, I've discovered an article at thehorse.com that says the Ohio team that succeeded in experimentally inducing EPM back in May discovered that neuro signs occurred within 7-8 days, then a week or two later the blood serum titre went positive, and then another week or 2 after that the CNF went positive. So, maybe a 2nd serum titre will show a change and suggest that we caught it early.

I'd be grateful for any thoughts or suggestions.

Thank you!
Melissa
Moderator:
DrO

Posted on Friday, Jan 2, 2004 - 9:30 am:

To address your original question no, you cannot infer anything from how strong the positive test is. Unfortunately your description neither rules in or out EPM but is consistant with it. For a list of other rule outs Melissa the article on EPM contains a list.

If I strongly felt I had a EPM case I would be using the new therapy nitazoxanide (see the article). Though expensive it does appear to be a better treatment.
DrO
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 10:21 am:

Thank you DrO.

Agree, if we think it's EPM we will switch drugs. The vets haven't settled on a diagnosis yet. The referral vet is actually leaning more to something like lymphosarcoma of the spine, or a mass, as he said he's always seen a strong positive on the serum in cases that proved to be CNS EPM, thus my original question.

Unfortunately, our tap won't tell us if it is EPM, being contaminated, but they'll do a cytology to look for protein or any cancer, so normal cytology might change the referral vet's mind (although normal cytology still doesn't rule out cancer if there's a mass but it's not shedding yet). We're also repeating the serum test on Monday. So, we're in diagnostic limbo for a few more days.

Do you think it would be better to just go ahead and treat with the nitazoxanide at this point, regardless, as there's really no other possible therapy for him? (If it's EPM, would we at least see some dramatic improvement on it, i.e. would it be a diagnostic help? Diagnosis seems to be our problem right now.)

Best,
Melissa
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 12:45 pm:

One more (sorry!) question: as the symptoms started about 3 weeks from starting him on doxy for supposed Lyme, is there any chance doxy kills EPM protozoa and the onset of symptoms was due to a die-off that is well-documented with the other antibiotics/antimicrobials that are more targeted for EPM? I know doxy isn's prescribed for EPM, just wondered if it's purely coincidence that he comes down with this after starting doxy. He was galloping around his paddock, rearing and bucking just 4 weeks before this all started...

Thank you,
Melissa
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 2:07 pm:

PS - actually, having done more reading, I find doxy has in the past been prescribed for EPM, and is commonly used as a wide-spectrum against sarcocycstis in many species.... could the combination of taking him off his NSAIDs plus adding doxy (and starting to kill off the protozoa -- he was on 80 tabs a day) help explain the onset of obvious neuro symptoms, given my sense that he had something going on already?

Thank you so very much for any insights!
Melissa
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 3:11 pm:

PPS, he started the doxy on 12/8 PM. He could have started to have neuro symptoms as early as 12/15 (I was away), but definitely had them by 12/18. So wouldn't that be right in the window for a worsening due to "die-off"? Maybe this hasn't been observed with doxy in EPM cases before, but typical doxy doses used to be more like 50 x 100mg/day for a 1200 lb horse (the U. Fla. study that recommended 10mg/kg bwt came out in 2000, and we'd moved on to new drugs for EPM way before that). With nitazoxanide, you start with half a dose for the first 5 days specifically to avoid too much die-off burden on the animal.... I suppose this is all just conjecture, but I keep thinking the change in meds is more than just coincidence. Withdrawal of his NSAIDs doesn't explain it, but maybe together with a die-off reaction, it could. His symptoms are not any worse, in fact I think he's better.
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 3:21 pm:

Oops, I meant 10mg/kg bwt 2x/day, i.e. 110 110mg tabs/day. So double the historical dose....
Member:
Mwebster

Posted on Friday, Jan 2, 2004 - 5:08 pm:

One other thing: he has a pronounced heart murmur now. Last time vets listened to his heart was maybe 2 years ago, no murmur detected. This murmur is easy for me to hear, but I didn't hear it last time I listened to his heart, which would have been within the past 2 months. Does this point to anything?

Sorry about the length and number of my posts -- I'm worried about this very special horse...
M
Moderator:
DrO

Posted on Sunday, Jan 4, 2004 - 8:54 am:

The relation between your current symptoms and your drug changes are uncertain Melissa, you are treating your horse because he is positive for EPM and has symptoms that are consistant: everything else is just fluff. Whether you switch or not really depends on your goals and resources but if it is EPM this does seem a slightly better therapy than the other currently accepted treatments.
DrO
Member:
Mwebster

Posted on Wednesday, Jan 14, 2004 - 4:59 pm:

Dear DrO,

I'm back with an update. We continued the SMZ/pyrimethamine while working to firm up the diagnosis. At this point, the vets don't think it's EPM, partly because of the clinical signs, partly because of the weak positives on both serum tests, and partly because the spinal tap (significantly contaminated, high albumin) was also weak positive, i.e. not a stronger indicator than the serum test. Also, the neuro specialist at Cornell was kind enough to review a video, and he believes this is not a neuro horse, he thinks it's orthopedic pain. He has seen a number of cases that centered over one hind limb, that couldn't be confirmed as neuro even on autopsy. From his experience, this looks like a horse with lower back pain, L3-4-5, from a pinched nerve, which could be the result of DJD.

This leaves us with a new diagnosis to try to rule in/out, and the horse is too unstable to stand still for scintigraphy, tranq'd or not. My referral vet thinks perhaps he could do an epidural with high volume (lots of saline) to push analgesics far enough forward to let us see if it's pain, if it is we'll see a more normal horse right away, and could repeat the epidural prior to scintigraphy. But I understand that scintigraphy would be more an academic exercise than something that could translate into therapeutics for my horse: the scintigraphy will at best localize a 'hot spot', we'll still be left without any therapeutic options. Even if we knew just what nerve it was, we wouldn't be able to help him, would we?

I'm thinking perhaps the epidural would at least give me an idea as to whether my horse is in pain. If he is, that may influence my decisions on his behalf.

This is such a tough process.
Melissa
Member:
Jjet

Posted on Wednesday, Jan 14, 2004 - 10:15 pm:

Melissa: Boy, this really is tough! I've been following your posts and it's mystifying. One thing that seems incomprehensible to me is that his demeanor has been so upbeat. Like he's not really suffering...is it still like that? Is he still able to get up and down? I know your expenses are probably way up there but it seems like an epidural block would at least definitively rule out (or in) the back pain. I agree that that would be important to where you go from here.

Well Dr. O, what's the outlook if it is nerve damage?
Moderator:
DrO

Posted on Thursday, Jan 15, 2004 - 8:41 am:

Simpler for the diagnosis might be using a sling. I presume he is thinking about using methadone for the epidural which causes analgesia but not ataxia? While still I would also get a set of radiographs if the horses size does not prevent them from being taken. If vertebral instability of the lumbar vertebrae is proven the prognosis would be poor for a return to soundness.
DrO
Member:
Mwebster

Posted on Thursday, Jan 15, 2004 - 9:42 am:

Jan, thanks for writing. Yes, he continues to be upbeat, none of us see pain in his face, and he's pushy for treats. But he's looking a little tired, as though this is taking a toll. He's always been a horse that focuses incredibly well and gives his all, so my sense is that coping with this is taking all his energy. We upped the meclofenamate to 4g/day, will see if he feels a little better. He's still eating well. He hasn't gotten down to roll in a few days now, though he seemed to want to yesterday, but as he pawed the snow his hind end just pinwheeled around out of control, and he gave up. The best he can do as far as walking in a straight line is a half-pass. But maybe after a few days in his stall he'll be a little more rested and stronger. We give him a little time out every day, but he definitely wants a place to lean. So we've organized his hay and water so he can lean and much, and we've got his friends right on the other side of his door eating hay too, and it's a peaceful scene and he looks relaxed and content. He's definitely weaker than he was a week or 10 days ago, though, so this is progressing.

DrO, are you saying sling him to stabilize him for xrays or scintigraphy? My vet was thinking of using torubin (sp?) and xylazine for the epidural.

After sleeping on this, I'm not sure we'd get much value out of further diagnostics at this point: the scintigraphy only shows us where to do the xrays, and Tufts thinks it will be difficult to get xrays with enough detail to be useful in a horse this size, beyond the neck. And even if we do, and can localize the problem, then what? There is no therapy.

It would be stressful for him, to trailer him an hour each way for this, and scintigraphy would require an overnight, more stress. I'm not sure we can even say that this information would enable us to make a better decision as to timing for putting him down -- it would be difficult to trust "findings" over what I see when I look into his eyes. Looking at his face, and seeing how he interacts, and whether his eye is still bright feels like a better guide.

So I'm thinking my goal is to spend time with him, enjoying his company while I can, make him as comfortable as possible, make sure he doesn't suffer, and let him tell us when he's ready. And then, ease his passage so he's calm and comfortable and comforted. He's a wonderful horse, and I don't want to cause him stress or pain or worry, I want to let him keep his dignity, and I want him to feel loved to the end.

Could I be missing an opportunity to help him, maybe even safe his life, if I opt out of further diagnostics?

Melissa
Member:
Dres

Posted on Thursday, Jan 15, 2004 - 10:20 am:

Melissa, i have been reading your story... you know there is no crystal ball to predict what you might or might not find....

sounds to me that what you say above is a wise choice, follow your heart .. you WILL do best for you friend...

Ann
Member:
Jjet

Posted on Thursday, Jan 15, 2004 - 10:29 am:

Melissa, I didn't think about the discomfort of the trailer ride. Also I didn't understand about his prognosis if it is a spinal slip or whatever. (Is that more-or-less what it would be?) You are extremely thoughtful and considerate in your efforts to make him comfortable for as long as that is possible. If I were a horse, you would be my dream owner. The very best to you both.

Jan
Member:
Mwebster

Posted on Thursday, Jan 15, 2004 - 11:49 am:

Jan,

I think the suspicion is DJD of the spine, i.e. arthritis somewhere in the lumbar vertebrae that has starting to impinge on nerves. Not so much a slipped disc, but of course we don't really know exactly what it is. We don't think he had any trauma. I can remember a couple of months ago, as I brought him back into work at the walk after his right shoulder injury, things were going great and he was up to long walks over an hour and wanting to trot and canter, and then one day I realized he was traveling a little bit haunches left, subtle. And then he wasn't so keen to pick up the trot. So I stopped the work and figured that shoulder must not be healed yet. Now, I'm thinking that was the beginning of this lumber issue, or rather that was the early and clear manifestation of it. Looking back through HA posts, I even mentioned 2 years ago I thought there was something in his spine or lower back.

When his aggravated symtoms appeared just before Christmas, a Tufts professor consulted by phone by my vet put "old age" at the top of the rule-out list, followed by EPM, and then outliers like a mass or tumor. I think old age describes it best.

Thanks for the positive support. I have an incredibly strong bond with this horse, and losing him will leave a tremendous hole in my heart.

M
Member:
Mwebster

Posted on Thursday, Jan 15, 2004 - 11:40 pm:

DrO,
One symptom that no one has explained so far is my horse's hyperesthesia. He has always had a strong "skin flick" response to flies, but since this ataxia started it's become abnormally strong. Any ideas about what that might tell us?
Thank you,
Melissa
Moderator:
DrO

Posted on Friday, Jan 16, 2004 - 5:55 am:

I agree with your assessment Melissa. You are at the point that further diagnostic work will only "rule in" diseases that it do not have practical treatments other than what you can give now: rest and antiinflamatories. It is time to rest and enjoy the time you have left together.

Considering the whole case as you present here no I don't think the change in the skin reflex is significant.
DrO
Member:
Mwebster

Posted on Saturday, Jan 17, 2004 - 8:38 pm:

Thanks, DrO, for your reassurance.

Things are peaceful here, and I'm focusing on quality time with him while I still have him. He's still bright and alert, though there are times he looks very tired, or worried. I'm turning him out during the day, no point confining him to his stall, and he's still able to walk around, though he spins in circles frequently when he puts his head down to eat hay, and he travels on 4 tracks. He's trying hard to cope, and he seeks the comfort (and the 4 walls) of his stall during the day when he needs to rest. He's still eating well, still enjoying curries and rubs, still asking for treats.

So, my dilemma: since he's not systemically ill, or in apparent pain (at least his face doesn't tell me pain), I'm not so much confronted by the need to put him out of misery as I am by the need to avoid a really upsetting (for him) event. The most likely thing, as this progresses, is he'll fall and be unable to get up. He hasn't gotten down to roll in a week, and it's not because he doesn't want to -- he knows he can't control his hind end. So, my fear is he'll fall either outside or in his stall, and panic, or at least go through terrible distress unable to rise, and we'll have to put him down then, and what if it's in the middle of the night? I would feel awful if I were to allow that to happen to him.

So, I'm trying to get a perspective on the process, on how to make the decision. Is it worse to put him down "an hour too late" or "a day too early"? I think given his particular challenge, it would be easy to wind up "an hour too late", and find him cast in his stall, or floundering around outside, all upset. On the other hand, it seems hard to "pull the trigger" (that's a little how this would feel right now, like murder) given how normal he is personality-wise, and how healthy he seems otherwise.

Any guidance on how this particular disease (DJD spine we think) progresses, and how a responsible owner makes this awful decision?

And: do you think it would be kinder to the other 2 horses here at home if I took him to Tufts for this, or would they be ok with us digging a hole for him and burying him before their eyes?

Thank you,
Melissa
Moderator:
DrO

Posted on Sunday, Jan 18, 2004 - 11:03 am:

This is really a decision for you Melissa. If he does go down and can't rise he probably will not struggle much and you might find him calmly waiting for you. I have seen this many times. But no one can guarantee this.
DrO
Member:
Jerre

Posted on Sunday, Jan 18, 2004 - 11:55 am:

Melissa, I sympathize with the decisions you are making, and I want to offer some comfort about your other horses. I feel sure that they will feel your love and intentions, and your grief, and that will feel true to them. Horses have an amazing ability to honor our emotions when we are true to ourselves. The love, respect and responsibility you have for your horse at the end of his life will be more important to your other horses than the logistics of a burial.
With sympathy,
Jerre

Member:
Mwebster

Posted on Thursday, Jan 22, 2004 - 4:17 pm:

We put Sunny down yesterday afternoon, and buried him here at home, along the fenceline in the paddock with a wide open view out across the corn fields behind our place. It has been the hardest decision of my life, and intolerably painful. But I know it was the right thing to do, it was time. I could see the strain in his face. If there had been any hope for him, I know he'd have stayed brave and done his part to get well again, but all the vets agreed it wasn't anything treatable (like EPM), so asking for his continued bravery in the face of what must have been a struggle just wasn't fair. He went calmly, our primary vet and some close friends and my husband were all there to help, and I think we succeeded in making it merciful for him. I'm so lucky to have a wonderful vet, and wonderful friends.

I understand now what people mean when they say you just can't imagine the pain until you personally suffer the loss of an old, deeply loved, friend. The only thing worse would have been not to know him.

Melissa
Member:
Sunny66

Posted on Thursday, Jan 22, 2004 - 4:43 pm:

Your post brought tears to my eyes Melissa, my heart goes out to you.

Aileen
Member:
Hwood

Posted on Thursday, Jan 22, 2004 - 5:51 pm:

Ah, Melissa . . . how well do I know . . .
You are right . . . "the only thing worse would have been not to know him" . . .
Each time, it is hard, but the first was the hardest for me . . . There are many of us here who understand. A friend asked me to post about the passing of my 40 year old last night . . . since reading your post, I think I will do that in the inspiration section . . .
You are amongst friends who understand . . . and I believe, with all my heart, that our animal friends will greet us when we get to heaven . . .
Member:
Jjet

Posted on Thursday, Jan 22, 2004 - 10:26 pm:

Melissa, I empathize too well, it's too close to home for me, then again, I think it is for us all. Eventually time catches up... It is so painful to think about losing the oldest (or any) of my horses. You were very kind to your boy, I hope you can find solace in that you have helped him to find peace. Though you will miss him, you have the memories of his wonderful personality to warm your heart forever.
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