Cushing with no typical clinical signs?

[Leon]

Hi, my name is Leon, I"m living in the Netherlands.

Our dog (cross chihuahua), has a mean uccr of 20.
She does not have the typical signs of Cushing.
She only has hair loss at the back of her hind legs, and an infection of the skin at that place. Furthermore, a few months ago, she had a big swelling (of a gland?) in her neck that went down on antibiotics.
Currently she is also being treated for an eye infection.
Apart from these infections, she shows no further clinical symptoms of Cushing, like the excessive drinking, or elevated liver enzymes. All these symptoms don't show up in her.

For tomorrow we have scheduled a ldds test.
Here in the Netherlands, usually the uccr is taken as "the golden standard", but we read about the ldds test and we decided we want to have that one done, too.

Our dog is very stressful, she comes from the asylum and we are the third owner. We have had her for 5 years by now and she will never leave us;-) But her behavior is almost impossible to change at 8.5 yrs old and when going for a walk, she barks at almost anyone/anything. And at home there are often quarrels with our other dog. So she is suffering a lot of stress and I am wondering whether her high cortisol levels could be due to stress.

Or maybe another ilness? The usual blood tests came back normal.

Any advice is welcome!

[AlisonandMia]

Hi and welcome,

I believe that the UCCR that is used in the Netherlands is usually actually a form of the LDDS test and this is one that is regarded as being the "gold standard". There are two types of UCCR - the simple one where a first-thing-in-the-morning sample of urine is taken (at home) and the cortisol level looked at. The other form of UCCR is the form of the LDDS test that is done in Europe where various urine samples are taken over time (usually two days or so, I believe) and dexamethasone tablets are given at certain times. That LDDS/UCCR is a very good test as stress is much less likely to affect the results because it is done at home.

If the UCCR you had done was of the first type (no dexamethasone involved) 20 is not that high a number - it doesn't rule out Cushing's (I believe 13 is the rule out number) but is by no means diagnostic. Many dogs with Cushing's will have much, much higher UCCR numbers. And yes, stress could well cause a UCCR number of 20.

In the US and in Australia (where I am) the LDDS test is usually done over 8 hours at the vets office and involves three blood samples being taken and IV dexamethasone being given. When the test is done that way stress is far more likely to affect the results.

Interestingly the LDDS/UCCR is the form of the test used in humans - I don't think the 8 hour test is ever used, presumably because it is more stressful especially with the typical human fear of needles!

The other test that can be done is the ACTH stim test and this test is much less likely to be affected by stress on the day the test is run although chronic stress can affect the results and cause a false positive.

Now a couple of questions: What color is your dog? Some colors in some breeds (chihuahuas are one such breed) can have coat and skin abnormalities. And has her thyroid function been checked? Thyroid problems can cause coat problems and result in irritability and aggression in some cases - and I think the immune system is affected too.

Alison

PS: It is most unusual for a dog with Cushing's to have normal liver enzymes. I don't know if normal liver enzymes absolutely rule out Cushing's but I'd think it would make it very unlikely.

[Leon]

Dear Alison,

Thank you very much for your quick and elaborate reply!
We did the LDDS/UCCR test.
The numbers are 23.2 , 16.0 and 3.0 (third day), indicating a pituary Cushing.
However, an earlier one-time measured urinary creatine/cortisol ratio was 87. So that's strange, isn't it?
Her blood creatinine is rather low, 45 umol/L and I wonder if this has negatively influenced also the UCCR test. If the creatinine in her urine would be higher , the ratio would be lower.
Here are all the numbers:

cortisol (1) 168 nmol/l (2) 150, (3) 17
creatinine 7244, 9371 and 5608

Her T4 is borderline low: 11.6 mmol/L

Maybe the blood test is more stressfull and could cause false positives because of that, but if I am not mistaken, the ldds test measures cortisol in the blood independent of creatinine, and is therefore maybe more reliable, or am I wrong?
Or should I opt for the ACTH test?

Her skin color is brown.

I really wonder if we are dealing with a very early detected stage of cushing or another disease. If it's early Cushing, it's bad enough, but if it's another disease, what could it be and what other tests could be done? She had an echo of her belly and everything was allright there.

[SasAndYunah]

Hi Leon,

welcome to this forum from a fellow Dutchie :) First of all, how was the UCCR test performed? Did you have to collect urine samples on day 1 and 2...and then did you have to give 3 tablets (dexamathasone) every 8 eight hours and collect another urine sample on day 3?

If thats the case, you really do not need a LDDS test done. Both tests are the same just performed in a different manner :)

I remember from my dog, that they gave me 3 results, one for each urine sample. Did you get 3 results? (in case you had the test done as I described?)

I kind of forgot the actual numbers and what they mean... It was something like "lower then ...?.. - no cushings", between ..?.. and ..?.. - possible Cushings" and finally "over ..?.. - definately Cushings" But again, I forgot what those numbers were, sorry :(

By the way, what's your dogs name? :) Was she seen by a general vet or a specialist? When did the skin/coat issues start? Did she already have them when you adopted her? Or are they more recent? Were there other tests performed? Like Alison mentioned, the thyroid test for example?

And indeed, chronic stress can cause permanent elevated cortisol levels. And eventhough it is not caused by actual Cushings disease, it still is important to try and get those elevated levels down because elevated cortisol levels (wether they are caused by Cushings or not) will do damage in the long run to the dogs system.

But lets go one step at the time and see if we can figure out what exactly is going on with your dog. And I agree with Alison, that normal liver enzymes would be very unusual in a dog suffering from Cushings. I am not sure where in The Netherlands you live but I could help you with the names of some specialists if you need it...

Best wishes,

Saskia en Yunah :)

[Leon]

Thanks Saskia, and to you, too, thanks for your elaborate reply!
You posted only minutes after me;-)

In my post above you will find the results of the test.
Are both tests really the same? Is creatinine also measured in the ldds test?

The numbers of the UCCR test should be lower than 10 (referentiewaarden/reference values).
Above these values, it is said that the dog has Cushing. However, a text from a laboratory I read on internet stated that dogs with Cushing have a cortisol/creatinine ratio higher than 30.
Well, I am just in-between 10 and 30....

My dog's name is Zusje and was seen by a general veterinarian with a special interest in internal medicine.
The skin problem started recently.
She was also checked for thyroid problems. T4 was borderline low, but that's not uncommon if other diseases (in casu Cushing) are present, according to our vet.

I live in the province of Limburg.

[SasAndYunah]

Leon, hi :)

Ah yes, I see you answered Alison before I replied, sorry :) I went to check my files to see if I could find some of the information about Cukie's Cushing's diagnosis (this was in 2006). I found that Cukie's urine tests were taken over a 5 day period, so 5 urine samples over 5 days. I also found the interpretation of the results...

If the cortisol is lower then 10, no Cushing's. Between 10 and 16, borderline. Anything over 16 means Cushing's. Cukie's results were all (5) in the borderline range, between 10 and 16. So the same test was repeated 3 months later. That time all 5 results were above 16.

As far as diagnosing (or excluding) Cushing's, the UCCR and the LDDS are the same. That is, if you get the 5 day urine sample test with the dexamethasone tablets on day 4...(after collecting that days urine sample) The creatine/cortisol ratio is not the number you look for when looking for Cushing's, just the plain cortisol levels in the urine.

I have to run now, but will be back later :-) By the way, I am in Gelderland, Doetinchem... And I love the name, Zusje :D Translated in English it means "Litle sister" ;)

Saskia en Yunah :)

[Leon]

I definitely don't trust a UCCR test anymore !

As said before, according to the results of the UCCR (urine cortisol/creatinine ration) -dexamethasone test, our little Zusje should be having Cushing.
But fortunately we were wise enough to do a ldds (blood) test, and these are the results!:

1) 2,20 μg/dl 61 nmol/L
2) 0,30 μg/dl 8 nmol/L
3) 0,50 μg/dl 14 nmol/L

Damn, you can't imagine how happy we are !

Excuse me for not posting earlier and a big thank you to all of you!
I want to say this again, never trust a UCCR-dexamethasone test only, but always do a ldds blood test, too.