Polyarthritis Conditions in Dogs

Polymyositis and other Polyarthritis conditions

Question: Dear Dr Michael,

Thanks for your prompt reply.

She does go lame on more than one leg but it started with just one front leg.

She had many of the symptoms of polymyalgia in humans but my vet was not convinced because all the blood tests showed no abnormal enzyme activity in the muscle. He also felt that because only the white call count was raised and there were no other indicators for auto- immune that it could only be a bacterial infection.

Could this be otherwise? If so I would be willing for her to have more tests as I do not like giving pred unless I have to.

I find that if she stiffens up a lot I just keep her on liquids for 12 hours and she improves dramatically too but then tbis is often the case with humans having a flare of say RH so it would appear to be more auto -immune in it's reactions. But why the high white cell count ? Her joints are absolutely normal with no swelling and total mobility including her neck which is why I thought muscles originally until my vet put me off!! She can have muscle tremor fron time to time but this could be the pred I suppose.

Thr slight cough and husky throat has not re-appeared since May and came about with the disease onset.

Many Thanks, Joanne

Answer: Joanne-

Your vet is correct that elevated white blood cell counts are not typical of polymyositis cases, based on the clinical signs listed in the textbooks that I have. Despite this, with the other signs present, polymyositis would still be high on my list of differential diagnoses. Muscle enzyme levels are not consistently elevated when polymyositis is present, so the lack of a rise these levels is not a significant deterrent to this diagnosis.

Polyarthritis conditions, including systemic lupus erythematosus and Lyme disease, are also considerations and they would be more likely to elevate the white blood cell count. The clinical signs seem more in line with a myositis, to me, though.

The cough is a worrisome sign, since this is sometimes a sign of megaesophagus, which is a serious complication in myositis cases. So it is good that it has cleared up.

The best diagnostic test for polymyositis is an electromyelogram (EMG). Most veterinary neurologists do this testing so a referral to a veterinary neurologist should be a strong consideration. Muscle biopsy is another alternative but our experience has been that it can be pretty hard to figure out where to biopsy to get a definitive sample, since muscles are not all affected a the same time. X-rays to rule out megaesophagus would be a good idea, too. If lupus does seem like a major concern then doing an anti-nuclear antibody (ANA) test would be a good thing to consider.

It is always hard to figure out when to consider going to a specialist. Due to the potential for long term complications if myositis is present, both from the disease and from the necessary treatment, I think this is one situation in which it makes sense to do advanced testing, even if it all it does is rule out myositis as a consideration.

That would be my take on this situation. Your vet can see the overall picture better than I can, though. So do put more emphasis on his opinion than on mine.

Mike Richards, DVM 8/17/2000

Polyarthritis and other possibilities

Question: Dear Dr. Richards,

I'm writing to you again (see below) about my arthritic 11-year old lab. I took her to a specialist (internal medicine) nearly 2 months ago. The specialist X-rayed all her joints, did blood work and took a fluid sample from one of her joints. The X-rays showed that she does have some arthritis in all of her joints (the worst is in her front elbows) and that she has some displasia in the right hip. There is some degree of muscle wasting in both of her rear legs.

The specialist did not think that what the X-rays showed was sufficient to account for all of the pain the dog was suffering. Thus the other tests, which included testing for SLE, rheumatoid arthritis, Lyme disease, and hypothyroidism. All of the tests came back negative, but the specialist's tentative diagnosis was polyarthritis. I'm not sure I understand this, because the dog does not have a history of fever or anorexia -- the one constant with this dog is that she's ALWAYS had an appetite no matter what.

Anyway, we started treating the dog with prednisone, 20 mg. twice per day. It made her instantly incontinent, although she did show immediate improvement with regard to pain. Phenylpropanolamine was given for the incontinence, but it did not help. We cut back the dosage of the prednisone to 10 mg. twice a day, but the incontinence continued and the pain situation worsened. I put her back on Rimadyl, increasing the dosage to 400 mg./day -- I did this without my vet's approval (although I did tell him what I was doing), but after reading the package insert and deciding to have her blood tested monthly for any adverse effects on the liver and kidneys, I thought it was worth a shot. It worked for about a month. We then tried 50 mg. of Immuran twice a day with 200 mg. of Rimadyl a day for 5 days, but the pain situation got worse.

A few days ago, the dog was barely able to stand up and was putting no weight on her right rear leg. I went back to the vet, and now she is on dexamethasone (20 mg. twice a day for 5 days, with instructions to gradually decrease the dosage over the next 15 days) and DES (twice a day for 5 days, then twice a week). She's been on this therapy for 3 days now -- she is moving around better, is not incontinent (although she has had accidents on her way out the door), but cannot climb up and down stairs.

I've been told that surgery on the right hip is not an option for a number of reasons. I still think it's too soon for euthanasia, as the dog still has a GREAT appetite, she still follows me around as long as no stairs are involved, and seems happy and comfortable when she is sitting or lying down. I am working diligently on the weight -- she has lost 3 pounds (down to 77 lbs.)over the last 2 months, but it is tough because she is exercising so little.

Is there anything else you can think of that I should be doing? Any other testing that should be done? Just to remind you -- I've tried acupuncture, Adequan, glucosamine/chondroitin (she is still on this), vitamins (C with bioflavenoids, E and Lipiderm -- she is still on this), homemade diet (she is still on this). Should we be looking for cancer in this dog? I remember from some of your other writings that you often suspect cancer when the tests come back normal.

Also, if you can direct me to any information on polyarthritis (beyond the blurb in the Merck Veterinary Manual), it would be much appreciated.

As always, thanks for your time.

Carol

Answer: Carol-

There are a couple of things that I can think of that aren't discussed in your note, even though it contains a pretty thorough list of potential causes of arthritis in multiple joints.

One thing to think about in an older Labrador is lumbosacral instability, which is a degenerative condition affecting the spine at the junction of the lumbar and sacral vertebrae. This could lead to muscle wasting, pain and discomfort in the rear limbs. It would not explain front leg lameness but even a small amount of visible degeneration (on X-rays) in an elbow joint can be painful. If this were the situation, there would be two causes for the problems seen, rather than one, but that is a possibility.

Degenerative myelopathy has been reported mostly in German shepherds but is a slight possibility, as well.

The last thing that I can think of, as a rear leg problem, is degeneration of intervertebral discs in the lumbar spine. I do not know the incidence of this problem but in a recent seminar on the Veterinary Information Network, Dr. Lundgren, who is a veterinary neurologist, reported that this condition was much more common than previously suspected in older large breed dogs.

Pain alone is more likely to be associated with lumbosacral instability or degenerative disc disease. Neurologic signs, such as weakness, dragging toes when walking or improper placement of the feet are more likely with degenerative myelopathy and can occur with all three conditions.

I am pretty sure that your veterinarians considered these possibilities but it can be difficult to diagnose lumbosacral instability and the less obvious disc disease problems without magnetic resonance imaging (MRI) exams.

Degenerative myelopathy usually won't respond to administration of corticosteroids but arthritis in other joints would, making it hard to determine where the improvement is occurring, in some cases. The other disorders would respond to corticosteroids, at least to some degree.

I would be really reluctant to use Rimadyl in a Labrador retriever at the dosages you mentioned -- so please be careful with this medication. We use Rimadyl in combination with narcotics such as hydrocodone and this helps to provide additional pain relief for many of our patients.

I am not sure that there is a really good, in-depth discussion of polyarthritis in dogs that I can refer you to. I will check out the references I have at the clinic at see if there is one that is particularly good. My recollection is that most of the textbook descriptions of polyarthritis that is not due to systemic lupus erythematosus in dogs are pretty sketchy, though.

If there is someone in your area who has access to an MRI machine, this would be a diagnostic test to consider. If not, you might consider asking for a referral to a veterinary school or large referral center that does have this technology available.

Good luck with this.

Mike Richards, DVM 1/5/2000

Greyhound polyarthritis and other possibilites -

Question: Dr. Richards,

Thanks for taking the time to read and respond. As an update, the Rimadyl has allowed Brandy to stabilize (at least I'm assuming it's the Rimadyl). Also, removing her from the prednisone has begun to have an effect on reducing the abdominal bloating. Also, her weight loss has seemed to level off. That's the good news.

On the other hand, she remains nowhere near her normal self -- the right rear leg continues to be mostly non-functional. Again, the leg worsens the greater the duration from the dose of Rimadyl. And her energy level remains very low. She also seems more anxious/nervous than her normal demeanor, For instance, the testing left a small wound on her right front leg which she continuously licks raw. Even though, I continue to treat it with H2O2, and carefully wrap it , she manages to chew through the bandage and get to the wound. My other greyhounds tend to do the same thing when they get small cuts, so its not so unusual from that standpoint, yet it's almost as if this wound is driving her batty with irritation?

Since my message to you, the two vets did confer and our next steps are to redo the bile-acid test because two previous tests were muddied (I believe they're just trying to ensure that the liver problem was in fact caused by the pred, as opposed to something else). But more importantly, they now think it may be Cushing's disease, which they will test for on Oct. 23 (takes 3 weeks for pred to clear system?).

One other thought I had was some form of Lyme disease, just because we don't see that in Florida, but we did spend a week in No. Carolina a few years back where she conceivably could have been infected. Also, we do have a big tick problem here in South Fl. and we are constantly removing ticks from our dogs. Does that make any sense at all? It just occurred to me today, so I have yet to ask our vet.

Again, thanks for your concern. R.

Answer: R.-

I did find a reference to a condition referred to as "greyhound polyarthritis" since last writing to you. This is an erosive arthritis but I didn't find much in the way of treatment recommendations for it. I am assuming that prednisone or other corticosteroids are probably used as they are the most common agents used for these types of problems.

I also found an article on acetabular (socket of the hip joint) fractures in greyhounds. All the dogs in the study were young, and racing, but if this is a problem in the breed it is worth thinking about as these are painful injuries and the symptoms are the same as you describe, for the affected rear leg. Carefully reviewing X-rays for a fracture in this area might be worthwhile. I don't think I look carefully enough in this region routinely because it is not a common site for fractures. Other vets may have the same bad habit.

It also occurred to me that greyhounds are very prone to ehrlichiosis and babesiousis and that these conditions sometimes recur after infections at an earlier time in life. It might be worth looking for one of these. They are probably more likely than Lyme disease. I don't know the prevalence of Lyme disease in either NC or Florida but it is supposed to be less common South of the Mason-Dixon line, in general.

The sores on the legs are really tough. Antibiotic therapy helps some dogs, even when there is no obvious infection. I recently attended a continuing education seminar on dermatology and that was also the experience of the speaker. In addition, pain relievers can be useful. We sometimes apply a solution of flunixin (Banamine Rx) and Synotic (Rx), on otic preparation, to get a strong anti-inflammatory effect right at the site of the irritation. It only works some of the time but it is easy to use.

I hope that you do get some resolution of this problem, soon.