Dog with myopathy - Possible Cushing's?

[teritri]

My dog was recently tested for Cushings Myopathy, and although he has many of the symptoms, the test came back negative. The most pronounced symptoms are myopathy related: stiff legged, bunny hopping run, can't sit all the way down, stumbles on steps, can't jump up on furniture, etc. Is it possible for a cushings test to show a false negative? (He also has elevated liver enzymes, enlarged liver, and excessive panting. He used to have skin issues and hair loss but that has totally improved since we adopted him 3 years ago.)

I would appreciate any help or recommendations. Our vet has recommended a referral to the University of Missouri for testing, and I'm just trying to get as much info as I can so we're not just shooting in the dark while trying to diagnose my sweet doggie.

Thank you!

[labblab]

Hello and welcome to you and your sweet dog! I am so sorry about his problems, but very glad that you have found us. I noticed you had posted your reply on another member's thread, and I have taken the liberty of moving your reply and creating a new thread of your very own. This way, it will be easier for our members to reply to you directly. I made up a thread title, but I will be happy to change the title in any way that you may wish (members can't edit their thread titles themselves).

First off, it sounds as though the referral to the University of Missouri is probably an excellent suggestion. Anytime a member is confronted with complicated or confusing issues, we commonly suggest a referral to a specialist or a vet school. This does not mean that you will be losing your GP vet as a valued member of your treatment team -- just that you will be gaining the perspective of vets who have received specialized training in particular types of disorders.

However, can you tell us what testing was performed that turned out "negative" for Cushing's? There is no single perfect test, and both of the diagnostic blood tests (ACTH and LDDS) can return either false positives or negatives depending upon different factors. So if you can tell us the actual numerical results for any diagnostic testing that has been done, that will be a great start for us.

Thanks in advance, and once again, I'm so glad you've joined our family.
Marianne

[teritri]

Thanks for help with creating and posting my thread. I'll have to get his test results from the vet and post them. Hoping to get that posted later today, since I'm concerned about how far his symptoms have progressed.

BTW, my name is Teri, mother of 4 children and King is our first Canine family member. I grew up with cats, never cared for dogs (they were unfamiliar to me and I had a terrifying episode as a kid that sealed my preference for cats) We got King from a rescue for our kids (husbands family is allergic to cats) and I expected it to be all about them. Well, this sweet doggie has stolen my heart. My husband calls him my boyfriend because he follows me around. It hurts my heart because I realize now that some of the myopathy symptoms have been present since we got him 3 years ago, I just didn't recognize them at the time. Dogs and cats move so differently, that to my mind, I just thought that must be normal for a dog. Plus, I kinda counted on the vet to tell me if anything was wrong when we first got him. But as his symptoms became more pronounced, I realized something was up. I thought it must be arthritis, and they'd prescribe something and he'd be good. I was unprepared that it could be a difficult to diagnose, mysterious condition. So far he's seen our vet and a neurologist.

Anyways, that's my big, long intro. I'll get his test info posted later today. Thanks again!

[frijole]

HI from me as well. I would head to Univ of Missouri and let them do the testing. My dog had the exact same issues with falling down, tripping on steps etc. The way you described it sounded exactly like my Annie. AT times she could run around and seemed normal and then she'd stumble, do the bunny hop etc. She had some cushings symptoms also. She tested FALSE positive for cushings numerous times.... L O N G story short after going to Kansas State Vet School we found she had a very rare adrenal tumor called pheochromocytoma. It is so rare I wanted to share in case it helps you. If caught early enough surgery could be an option. It took us too long to figure it out.

Even if it is something else TRUST me you will save a ton of time, money and heartache by just going to the best possible place with the most up to date equipment to figure it all out.

Please keep us posted!!! Kim

[jmac]

Hi Teri,

I just wanted to welcome you as well. I agree that you should go to the specialist now and see if you can figure out what is going on. I am sorry your dog is not doing well, but I'm so glad you found us! You have found a wonderful group of caring, knowledgeable, helpful people and we will be here to support you with whatever you need. Please keep us updated on whatever you find out.

Julie & Hannah

[k9diabetes]

What was the neurologist's assessment?

Natalie

[teritri]

OK here's what's happened so far. My vet first feared his condition was some type of spinal issue and referred us to a neurologist. She also recommended about $500 in tests, none of which she believes now would have diagnosed him. The neurologist was sure it was Cushings Myopathy and recommended the cushings test. I was relieved to think it was something treatable and the neurologist sounded optimistic, but then the cushings test came back negative. Not having unlimited resources, I just want to be a little prepared when we go to the Univ of Missouri, so we're not just shooting in the dark with the testing. Here are his previous test results:

OK this is how it reads:
Time 1 845
Time 2 1250
Time 3 450
Corisol Sample 1 2.2 ug/dl (1.0-5.0)
Cortisol Sample 2 Dex 1.2 ug/dl (0.0-1.4)
Cortisol Sample 3 Dex 1.0 ug/dl (0.0-1.4)

A rather lengthy interpretation of the Dexamethasone Suppression Tests follows, and I can include that if necessary.

The vets conclusion, after consulting again w/the neurologist is that he go to MU for electrodiagnostics to determine which muscles are involved and obtain biopsies of those tissues for analysis (RO immunemediated vs paraneoplastic vs metabolic vs idiopathic) Muscle relaxant could be offered as treatment until further diagnostics is obtained.

Is that the kind of info you were looking for? This whole thing is new to me, so anything you guys can do to help me make sense of all this would be appreciated.

Thank you all for your comments and your time in considering King's situation. I really do appreciate it.
Teri

[frijole]

Teri, If a dog has issues (adrenal, neurological) that cause the body to fight pain then it natural creates excess cortisol as a defense mechanism. The result can be cushings like symptoms. That is what happened to me.

Since the liver enzymes are elevated and there is excess panting I would have an ultrasound done. I would do it at the university using their equipment which will be more sophisticated than most vet offices. That way they can look at the organs and see the adrenal glands as well as other organs.

They can also do a urine test called UC:CR that can rule out cushings. Its cheap and fast.

I would do both those things before going thru neurological tests.

Other simple ways to rule out cushings: 1. Does your dog concentrate urine (is it yellow still or is it clear)? 2. Does your dog have a pot belly? If your dog has yellow pee and no pot belly I would bet my house there is no cushings :)

Hope this helps. Kim

[k9diabetes]

Hi Teri,

I have a dog who is in a milder version of the same state. He has some kind of pain in his back or right back hip. We adopted him three years ago at 1-1.5 years of age and about two years ago after a long driving trip his back pain got much worse. With rest and Metacam, it improved but it did not go away entirely and he continues to take Metacam, an NSAID, every day, which generally allows him to get 25 minutes of moderate exercise a day without the pain flaring up.

We have had him fully worked up. Once past that acute episode after the road trip, his reflex responses have generally been normal. His x-rays showed the two bad disks right at the end of the rib cage that are theoretically the source of his pain. He has had them a long time - maybe hit by a car or some other kind of trauma in his first home (he's a rescue).

We went to a very good neurologist who I like a lot and have a lot of faith in and despite running the full gamut of neurological tests, he still is not certain exactly what causes Jack's pain. Which, per the neurologist, is unusual. He even had the surgeon do an orthopedic exam and she couldn't find anything else to cause him pain either.

We went all the way through the electro test and an MRI because he's a young dog with what we hope is many many years ahead of him and we didn't want to find out a decade later that surgery could have cured him when he was young. So we knew we probably wouldn't find anything - since the neurologist's tests showed no sign of a pinched nerve or spinal cord. We had the whole thing done at once so he only had to be put under anesthesia once.

I'm glad we went through the whole thing because it eliminated some concerns and some solutions - there's no surgery to fix it.

We still don't know exactly what all causes him pain - could be those disks or could be other issues.

But his pain is apparent. So even though we don't know what hurts exactly, we know that an NSAID makes it better so he gets that every day and we don't overwork him exercise-wise because we want to avoid him blowing a disc in the future.

The only way to know for sure if the spinal cord is pinched somehow is to do either the MRI or a myelogram.

Without signs of excess cortisol, it seems like there's not much point in pursuing any further Cushing's testing.

It might be worthwhile getting a copy of the neurologist's written report if you don't already have one - I'd be interested in seeing what the results of the tests were and that should be in the report.

The other thing we did upfront was to basically just try some medications and see if they helped. NSAID made our dog feel better, so we knew there was pain and probably some inflammation. He was briefly on prednisone and on gabapentin but neither one worked better than the NSAID and he didn't tolerate the prednisone at all.

You may wind up, as we did, going for the neurological tests just to rule those things out if you can find a way to pay for it. We had to save up for a while and we did have some help from pet insurance. If I had to do it over again, I would go through the tests again because not having any idea what might be going on with his spine was a constant worry since we knew he already had a couple of bad discs.

You could try anti-inflammatories and pain relief and see if they seem to help him. If they do, then you could probably focus more on joints / spinal issues.

And then the ultrasound could identify something rare like the pheochromocytoma Kim mentioned.

Natalei

[teritri]

The neurologist did not do any tests. He evaluated him and was sure it was Cushings Myopathy, so did not pursue any other diagnosis at that time. When I looked up pictures of dogs w/CM, I was convinced that's what it was as well. So we went straight to the cushings test.

King had x-rays when we first took him in, but the didn't reveal anything abnormal, other than the enlarged liver. No signs of arthritis, bone degeneration or spinal abnormalities, at least none that would show up on an x-ray

Is it possible to get a false negative for cushings? He actually had several symptoms of cushings when we first got him, like thin skin, excessive scratching, thin hair, etc. Now he's so much better, except for the myopathy symptoms. Poor thing has to stick his legs straight out to sit all the way down. His hind leg muscles are so tight he cant bend his knees very far.

I've lurked on this sight a little and have seen how knowledgeable you guys are and am trying to be better informed myself. Thank you all for any feedback or direction you can give me.

Teri

Teri

[Squirt's Mom]

Hi Teri,

Yes, it is possible to get false positives on Cushing's tests. Quite easily, in fact. Because cortisol is one of the bodies natural responses to stress of any kind, internal or external, it can be elevated for reasons unrelated to Cushing's yet cause the tests to be positive. My Squirt is a case in point. She had five tests, all positive for PDH but a tumor was found on her spleen and once it was removed, her cortisol returned to normal. Something as simple as a UTI can skew test results. This is one of the reasons we recommend more than one test to diagnose Cushing's. ;)

Hugs,
Leslie and the gang

[frijole]

:D Leslie, she wanted to know if there were false NEGATIVES on the test. I would say NO because the test measures cortisol so if it isn't there it isn't there.

Not sure if you saw my previous post but two easy way to rule out cushings are whether or not your dog has a rounded tummy (pooch) or normal colored urine (yellow).

I did a bit of research on myopathy and there are so many different causes that I would think the docs would want to investigate alternatives since the cortisol is not increased in your case. Here are some articles I thought might be helpful. Kim

http://vetneuro.com/Portals/124/Forms/Evans%20Myopthies.pdf
http://www.ivis.org/special_books/Braund/braund20a/ivis.pdf

[lulusmom]

Is it possible to get a false negative for cushings? He actually had several symptoms of cushings when we first got him, like thin skin, excessive scratching, thin hair, etc. Now he's so much better, except for the myopathy symptoms.

Now I'm going to totally confuse you and tell you that yes, you can get false NEGATIVE results on all of the diagnostic tests for cushing's. Those would be the UC:CR, LDDS and acth stimulation test. In order of likelihood, the acth stimulation test would be #1 as a good number of dogs with adrenal tumors will test negative. #2 is the LDDS with only a very small percentage of dogs with cushing's testing negative. #3, the UC:CR is highly unlikely to yield a false negative in a dog with cushing's, however, it happens. Here's a link to some good information on the various tests used to diagnose:

http://thehormonelab.com/handbook/adrenocortical-function/canine-hyperadrenocorticism-hac-cushings-disease

[Squirt's Mom]

:o:o duh :o:o Thanks for setting me straight, Kim! :D

[k9diabetes]

I'm assuming, perhaps incorrectly, that the neurologist went through the dozen or so hands-on non-invasive tests of a basic neurology exam. There is a lot of information that can be gained from those simple tests.

They usually check reflexes, whether they respond to a pin prick, whether they display signs of pain when various limbs and the back are manipulated. Check for balance, eye movements, etc.

One of the things they can sometimes determine is where the lack of nerve signals "starts" - whether in the neck, in the rib area, in the back, or at the base of the tail for example.

And there should be a report, if the neurologist did all of that, on what the findings were.

The attached article is somewhat technical but it gives you an idea of what can be learned from a basic neuro hands-on exam.

The problem with treating a dog who doesn't have Cushing's with Cushing's medication is that you can send them the opposite direction - too little cortisol, aka Addison's disease. And that is potentially quickly fatal if it gets bad enough. So you don't want to be giving meds to reduce cortisol levels unless you are awfully certain the cortisol levels are too high.

Natalie