Diagnosing Cushings/Addisons in my dog

[MK123]

Hi,
I have a 6 year old smooth fox terrier, about 4 months ago, she began to drink excessively and although she has always been food driven, the scrounging for food has began to take over. She has put on weight and constantly needs to go outside to pee, including overnight. I took her to our vets a couple of weeks ago and she underwent blood tests, which all looked clear. She had a urine test where the urine was very diluted. The vet then advised carrying out a stimulation test which should have diagnosed and confirmed whether she had cushings or not. Unfortunately after the test, the results came back with strange results, her level of cortisol was the same after she was injected with the hormone which was supposed to increase it. The vet chose to run the test again to be sure that it was not just an incorrect result and it came back again with the same results.
She is displaying symptoms of Cushings, but her test has come back signaling Addisons, which is apparently the opposite to Cushings. The only other thing which is abnormal in our dog is that she has not come into season for two and a half years. We feel that this may be affecting her and have asked the vet if we can get her spayed as soon as possible, however we have been advised that if she does have addisons disease they advise not to carry out any procedures as this affects their stress hormones and they can then become very poorly.

We have now been referred to a specialist, who wants to do a CT scan for £2,500 to £3,000. We feel that we are in a difficult position with not many options apart from having the CT scan, but I have concerns that the CT scan may not pick up any issues and then we will be out of insurance money and no further forward. What we are asking in this forum is whether anyone has had similar issues to us in the diagnosis of their dog with cushings please, we would be really grateful for any information

Many Thanks

[labblab]

Hello, and welcome to you and your girl — we’re so glad you’ve joined us! I am certainly sorry, though, about the confusing situation you’re in. It’s true that the ACTH stimulation test is the diagnostic “gold standard” for Addison’s, as well as being capable of diagnosing Cushing’s. But there are several questions about your dog’s presentation that are puzzling in terms of Addison’s. Can you possibly find out the actual numbers for the two ACTH tests? It’s true that a “flat” result is consistent with Addison’s as opposed to Cushing’s. But in my own mind, given your girl’s entire symptom profile, I’d be curious as to how high or low the numbers were. For instance, a result with both numbers being very low would definitely be consistent with Addison’s. If both numbers are higher, though (and the first perhaps even within “normal” range), I’d wonder whether perhaps the stimulating agent that your vet used for the tests was simply compromised. That can happen, and would account for the lack of change in the numbers even if a dog actually suffers from Cushing’s. Also, were any of her other lab values abnormal? With both Addison’s and Cushing’s, you’d expect to see some other abnormalities that are characteristic of the separate disorders.

Bear in mind that I’m not a vet, and if you’ve already seen a specialist who thinks the Addison’s diagnosis is valid, then I may be creating unnecessary uncertainty. But I’m also puzzled as to why the specialist would immediately leap to a very expensive CT scan when there may be other useful intermediate testing options to pursue. Here’s a quote from a related article:


Diagnosis is based on your pet's medical history, including any medications, clinical signs, and the results of common blood and urine tests, most notably electrolyte imbalances. The most definitive diagnostic test for Addison’s disease is the ACTH- stimulation test. In this test, cortisol levels are measured before and after injection of a synthetic form of ACTH (see handout “Testing and Monitoring in Addison’s Disease” for more information). Additional tests such as basal cortisol levels, natural plasma ACTH, electrocardiogram (ECG), radiographs (X-rays) or abdominal ultrasound may be performed to rule out another cause for your pet's clinical signs. In rare instances MRI or CT may be needed to diagnose a pituitary gland problem.

https://vcahospitals.com/know-your-pet/addisons-disease-in-dogs-overview

We can discuss all this in much more detail, but I’ll go ahead and close for now. Most importantly, I first wanted to welcome you! And again, if you could get the actual numbers for those ACTH tests as well as any other abnormalities, that would be a big help to us.

Marianne

[labblab]

One more quick question occurs to me, and that is to ask whether in recent months your girl may have been treated with any medication containing a steroid. If so, your vets undoubtedly would have been aware of this. But I go ahead and ask the question because the administration of supplemental steroids can cause the outward symptoms you’re describing, as well as a blunted response on the ACTH test. So I just didn’t want to leave that stone unturned.

Marianne

[MK123]

Hi Marianne,
Thank you for your response, it is lovely to have a friendly view on what is going on.
The stimulation test was carried out twice as the vet felt that the first test could have been compromised so wanted to run it a second time to be sure. The second set of results came in as the first reading 60 and the second as 74, he said that the second result should have been much higher.
We have not administered any steroids at all. All the bloods came back clear, if anything her liver enzymes came back low. The only thing they did mention was that her cholesterol was slightly high (however she has put quite a lot of weight on due to the excessive eating and not much wanting to walk). I have been feeding her smaller portions and trying to get out a bit more with her to keep the weight down a bit more.
She just is not displaying any symptoms of Addisons, her symptoms appear to be more Cushings, but we are at a loss. I did a trawl around lots of forums last night just attempting a bit of research and I did find something about a dogs bark changing too and that being something else. Occasionally Elbie’s bark goes a little weird, like she has a sore throat! Up until now she has been a really healthy bouncy normal terrier.
I must admit, the vet mentioned originally that they will refer her for an ultrasound, but it has jumped from that to a CT scan, I am just hoping that it will actually show something that provides an answer as to what is going on with our little girl!