Cushings and false positive?!

spotty_pony2

spotty_pony2

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I have emailed my vets about this but was wondering if anybody could shed any light on this for me please.

So our Friesian has skin issues on his legs and is currently under a specialist. He’s currently on steroids which haven’t made any difference. We want to run some bloods to check for anything internally and I am keen to test for cushings as I know it can present as skin issues. Specialist is really against me wanting to test for cushings and says it will be a false positive due to his condition..! The cynical side of me can’t help but think they want to drag it out and do other things first and cost us more money. I don’t really understand how it could be a false positive. Maybe because of the steroids? In which case we will stop them and test once they are out of his system… can anybody shed any light?
 
Zoeypxo said:
Don’t quote me on it but i think inflammatory conditions or illness/pain can cause a temporary rise in ACTH
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Interesting but I don’t understand how we would know if this was a positive or a false positive. 🤔 also surely then every horse that has Laminitis would test positive for it? he did have a bacterial infection but we have got this under control with antibiotics. He is moulting but very slowly and I don’t think his coat looks as good as it usually does at this time of year. All for have been slow to moult but the other two have a good summer coat coming through. He seems to be keeping hair on his belly etc. He is only 12 and it may not be cushings but would be worth ruling out.
 
They are absolutely correct. Anything that causes a raise in cortisol will also cause the hormone ACTH to rise. ACTH is the hormone that is tested for in the Cushings test. Inflammation, steroid administration, stress, concurrent illness, some sedatives and yes, laminitis. That is why we try not to test in the acute phase of laminitis. Th TRH test is better in this respect as it eliminates these causes (but not necessarily all causes) of false positives, but we can't currently obtain the drug required to conduct a TRH test, so it's measure ACTH at the moment or nothing. Your vet is trying to save you money by not carrying out a test that will be inconclusive, not spin things out.

Additionally although we do see PPID in 12yos (I have diagnosed it once in a 6yo), it is uncommon at that age so whilst you could never assume your horse is too young, PPID would be a lot lower on the list than it would be for a 20yo.
 
spotty_pony2 said:
Interesting but I don’t understand how we would know if this was a positive or a false positive. 🤔 also surely then every horse that has Laminitis would test positive for it? he did have a bacterial infection but we have got this under control with antibiotics. He is moulting but very slowly and I don’t think his coat looks as good as it usually does at this time of year. All for have been slow to moult but the other two have a good summer coat coming through. He seems to be keeping hair on his belly etc. He is only 12 and it may not be cushings but would be worth ruling out.
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When a pony on my yard came down with suspected laminitis they were told to box rested and soak weighed out hay etc.
The vet said they will come back in 10-14 days to take bloods so that the acute pain levels didnt create a false positive. Pony came back negative
 
Gamebird said:
They are absolutely correct. Anything that causes a raise in cortisol will also cause the hormone ACTH to rise. ACTH is the hormone that is tested for in the Cushings test. Inflammation, steroid administration, stress, concurrent illness, some sedatives and yes, laminitis. That is why we try not to test in the acute phase of laminitis. Th TRH test is better in this respect as it eliminates these causes (but not necessarily all causes) of false positives, but we can't currently obtain the drug required to conduct a TRH test, so it's measure ACTH at the moment or nothing. Your vet is trying to save you money by not carrying out a test that will be inconclusive, not spin things out.

Additionally although we do see PPID in 12yos (I have diagnosed it once in a 6yo), it is uncommon at that age so whilst you could never assume your horse is too young, PPID would be a lot lower on the list than it would be for a 20yo.
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The TRH is available again as one of the other liverys gad the TRH Stim test carried out on Tuesday.
 
As above, pain and stress will elevate cortisol levels, so your vets are correct. It’s another reason why the blood is best pulled at home when the horse is calm, and not at horsepital undergoing multiple investigations.

My own IDx tested as a true positive for Cushing’s on a screening test as an 11yo. She’s now 19yo and it has always been well controlled on Prascend, but don’t rule Cushing's out on age alone.

Too many owners (and come to that, some vets) won’t test for Cushing’s as they don’t think that the horse looks Cushings-ey enough or is old enough. Then they get proved wrong.
 
I lost a 6 yr old Shire to what I now believe was Cushings, it started with skin issues, then a hoof abscess and eventually she foundered. Farrier has always said that the vet was responsible for the outcome and I've never used that practice again BUT I had never heard of Cushings at the time and I have no idea if there was a test then.

OP, I would have the TRH-Stim test done, if it's available, we have had false negatives on ACTH tests.
 
Friesians are prone to skin conditions anyway, so cushings wouldn't be the first thing I'd jump to either. Mine tested borderline when she had an abscess that wouldn't clear up, but the vet said they wouldn't treat on those levels. I wish I'd have got another opinion now as she also foundered and was pts :(. I'll never know if it was cushings related, but it seems likely.
 
mine had a terrible skin problem at 11. It was seriously becoming a welfare problem. He had many cushings symptoms, tested 18, didn't believe it so tested a week later 11.
Trialled prascend. Skin condition completely went and never came back, neither did the abscesses and other cushings symptoms. Vet told me not cushings based on the test results but as they couldn't find any other reason for the cushings symptoms no choice but to trial.
 
meleeka said:
Friesians are prone to skin conditions anyway, so cushings wouldn't be the first thing I'd jump to either. Mine tested borderline when she had an abscess that wouldn't clear up, but the vet said they wouldn't treat on those levels. I wish I'd have got another opinion now as she also foundered and was pts :(. I'll never know if it was cushings related, but it seems likely.
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was yours a friesian too? vets were adamant it was mites but he’s been treated for mites and stable disinfected etc and it made no difference which is why we went to a professional. I’m thinking possible liver issues due to the circular lesions that keep multiplying. 🤔
 
spotty_pony2 said:
was yours a friesian too? vets were adamant it was mites but he’s been treated for mites and stable disinfected etc and it made no difference which is why we went to a professional. I’m thinking possible liver issues due to the circular lesions that keep multiplying. 🤔
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Yes mine was a Friesian. She also had skin issues and the best thing I did was to clip her feather and wash and scrub with Coatex dog shampoo daily when she had scabs. Typically her legs were wonderful when she developed the abscess that eventually finished her off. In hindsight I should have pushed for the TRH test.
 
One of mine was 12 when he was diagnosed for Cushings, so it can happen. He’s always been on the lower end and I often wonder if he was originally a false positive. He’s 23 now and I have stopped the meds, or rather he has as I’ve run out of ingenious ways to get him to take the tablet!
 
meleeka said:
Yes mine was a Friesian. She also had skin issues and the best thing I did was to clip her feather and wash and scrub with Coatex dog shampoo daily when she had scabs. Typically her legs were wonderful when she developed the abscess that eventually finished her off. In hindsight I should have pushed for the TRH test.
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Unfortunately I can’t clip his legs without veterinary sedation so not possible for us. i did trim them off with scissors but tbh it didn’t make much difference. Currently been told not to wah him in any shampoos and only use water as he reacts to some products.
 
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