Testing for Cushing's (PPID)

[stimpy]

Has anyone got a horse who tested negative for the standard ACTH test and then went on to have the TRH stimulation test and tested positive? I have a horse who is showing many of the clinical signs of Cushing's but her results for resting ACTH were normal. My vet, after consultation with Liphook, is suggesting that we do the TRH stimulation test as well and I am trying to decide what to do.

 

[JillA]

Would he not agree to a Prascend trial to see if it got rid of the symptoms. I always think that is more reliable, given that generally for an average sized horse 1mg/day is the normal dose

 

[stimpy]

Would he not agree to a Prascend trial to see if it got rid of the symptoms. I always think that is more reliable, given that generally for an average sized horse 1mg/day is the normal dose

It's a good suggestion and I discussed this at the time but the vet feels that you should only give Prascend if it is needed, and for a horse that doesn't have elevated ACTH it would be difficult to monitor. She was also worried about inflicting the possible side effects of loss of appetite and general miserableness if it wasn't warranted. Having a friend with a mini-shetland who is terribly miserable on a tiny dose of Pracsend I have to say that I would hate for my horse to feel like that unnecessarily

 

[Pearlsasinger]

Has anyone got a horse who tested negative for the standard ACTH test and then went on to have the TRH stimulation test and tested positive? I have a horse who is showing many of the clinical signs of Cushing's but her results for resting ACTH were normal. My vet, after consultation with Liphook, is suggesting that we do the TRH stimulation test as well and I am trying to decide what to do.

Yes. Our 22 yr old had been tested last summer, with a ACTH reading of 27, then again this summer, reading up but still within normal range. We and the vet felt that she had enough symptoms to warrant a TRH test, which came back at 823 (normal limit is 110), ACTH done at the same time was still only just over limit at 50. She has responded well to Prascend and is due for retest shortly.

 

[stimpy]

Yes. Our 22 yr old had been tested last summer, with a ACTH reading of 27, then again this summer, reading up but still within normal range. We and the vet felt that she had enough symptoms to warrant a TRH test, which came back at 823 (normal limit is 110), ACTH done at the same time was still only just over limit at 50. She has responded well to Prascend and is due for retest shortly.

Wow, that is really interesting, thank you Pearlsasinger. Did you have any worries about doing the stimulation test? I'm still reading up about it but as my horse has a history of laminitis I am ultra-cautious.

Out of interest what were your horse's symptoms? My mare's topline has just vanished, she has developed a pot belly (as a former laminitic I keep her very slim), her resting respiration rate is high even though her lungs are clear, and she sweats just standing in the field. She is normally extremely forward going and although she still has the will to go, she tires incredibly easily.

 

[Pearlsasinger]

TBH, the vet, who knows her quite well, advised the RH test and we went with it, as we were pretty convinced that she did have Cushings.
Her symptoms were: general anxiety, particularly separation anxiety, which is very unusual for her. She has never been keen on being left behind but has always gone out happily on her own. Hanging onto her coat well into summer, pot belly along with ribbiness, which had happened over the last 18 months or so. She had also developed breathing problems, although vet originally couldn't hear anything in the lungs. We had to get vet in an emergency in early summer, she was given steroids, we thought it was an allergic reaction but she has had to have steroids a few times over the last few months. Her breathing has been much better since starting the Prascend. Fortunately no laminitis symptoms but we did question the vet closely before agreeing to steroids not that there was much choice really. She has had steroid powders, which I think are less of a risk that injections.

 

[stimpy]

Her symptoms were: general anxiety, particularly separation anxiety, which is very unusual for her. She has never been keen on being left behind but has always gone out happily on her own.

Crumbs, his has happened to my girl. I've had her almost ten years and she has always hacked on her own fine, but now we do loads and loads of fairly hysterical shouting and she is always tense.

 

[Pearlsasinger]

I am not sure what the laminitis risk is with the TRH is but in your position, I would discuss it fully with your vet. If she feels that the risk is too great, I would discuss the pros and cons of a Prascend trial. I certainly wouldn't want to leave the horse until next year's test.

 

[paddy555]

Crumbs, his has happened to my girl. I've had her almost ten years and she has always hacked on her own fine, but now we do loads and loads of fairly hysterical shouting and she is always tense.

that is one of the symptoms my cushings horse has when the dose needs increasing. He is very nervous to ride, spooks at everything. Increase the dose and he is perfect again.
Mine tested negative but had all the symptoms. I did a prascend trial and never looked back. I haven't tested since he went on prasced 5 years ago and work purely on symptoms. For example if a horse is lethargic does it improve after a reasonable time on prascend. If it has a skin condition does this improve. If it always gets infections, hoof abscesses do they become less common/non existent. Does the top line improve after prascend. (you can also help the top line improve with high dose natural vit e oil) Dr Kellon I think recommends 5000iu per day for PPID horses. I probably used a higher dose and got all my top line back.

Whilst some horses don't do well on prascend many of the side effects can be avoided by introducing it very slowly, say quarter tablet building up to one over a month. I did this and had no side effects on my three.

 

[stimpy]

that is one of the symptoms my cushings horse has when the dose needs increasing. He is very nervous to ride, spooks at everything. Increase the dose and he is perfect again.
Mine tested negative but had all the symptoms. I did a prascend trial and never looked back. I haven't tested since he went on prasced 5 years ago and work purely on symptoms. For example if a horse is lethargic does it improve after a reasonable time on prascend. If it has a skin condition does this improve. If it always gets infections, hoof abscesses do they become less common/non existent. Does the top line improve after prascend. (you can also help the top line improve with high dose natural vit e oil) Dr Kellon I think recommends 5000iu per day for PPID horses. I probably used a higher dose and got all my top line back.

Whilst some horses don't do well on prascend many of the side effects can be avoided by introducing it very slowly, say quarter tablet building up to one over a month. I did this and had no side effects on my three.

Thanks so much paddy555. In parallel with the "has she or hasn't she got Cushing's" thought process I had been wondering if she was also suffering from a vit E deficiency, it's really interesting that you are dealing with those two things together.

When you are watching/evaluating symptoms what is a 'reasonable time' to see a difference for your horse? And thanks for the tip about a really gradual introduction, I'll bear that in mind if we get that far.

 

[paddy555]

Thanks so much paddy555. In parallel with the "has she or hasn't she got Cushing's" thought process I had been wondering if she was also suffering from a vit E deficiency, it's really interesting that you are dealing with those two things together.

When you are watching/evaluating symptoms what is a 'reasonable time' to see a difference for your horse? And thanks for the tip about a really gradual introduction, I'll bear that in mind if we get that far.

re your final para I would think 3 months on a full dose. One of mine built up over a month, went onto a full dose and after a week or so went crazy. Trashed the yard and the field. Wouldn't have dared to get on him. Suddenly he was his old naughty self. After 3 weeks or so he settled down. His horrible skin problem probably took 3 months or so to go completely but it started to reduce fairly soon, he was a horse who lived for infections and antibiotics but never had anything since the day he started. (I may regret saying that!!)
When he needed the dose increasing as he got very spooky the effect was within a couple of days. Within less than a week he went from nightmare who took ages to get anywhere with his spooking and stopping to just wandering along normally with not a single spook.

Until this happened I didn't really relate spooking on a previously calm horse as being a symptom. Mine tested very negative twice yet he had very bad cushings so I don't have that much confidence in the ACTH test.

On the vit E side some of these cushings horses, especially the lami risk ones, live on restricted grass or a track so even in summer low vit e may be a problem.

 

[OldNag]

Has anyone got a horse who tested negative for the standard ACTH test and then went on to have the TRH stimulation test and tested positive? I have a horse who is showing many of the clinical signs of Cushing's but her results for resting ACTH were normal. My vet, after consultation with Liphook, is suggesting that we do the TRH stimulation test as well and I am trying to decide what to do.

Yes, borderline ACTH but high reading for TRH. Pony had definite symptoms hence re-testing. Definitely worth the extra cost.

 

[southerncomfort]

Has anyone got a horse who tested negative for the standard ACTH test and then went on to have the TRH stimulation test and tested positive? I have a horse who is showing many of the clinical signs of Cushing's but her results for resting ACTH were normal. My vet, after consultation with Liphook, is suggesting that we do the TRH stimulation test as well and I am trying to decide what to do.

I have a similar situation. I'm not a fan of the TRH test so my vet and I have agreed that as my girl is currently happy & healthy we'll retest in the Spring when the ACTH levels begin to rise again.

 

[Micky]

Mine was borderline (29) but because he had low grade laminitis and a pot belly, incredibly lethargic, we decided to trial him on prascend..and I’ve never looked back and very glad I gave him the magic pills! Gradually I built it up and he’s now 20 and on 2 and half tablets a day (eek) but he’s still jumping hacking and generally a plonker on pleasure rides...he lost a lot of muscle in the first 6 months but once I sorted his feed and regime he built it all back again...I’m not keen on trh test from reading others experiences but you must do what you thinks best..as paddy555 said, start off very low dose and build it up slowly if you decide to go down the magic pill route..good luck and have a look at thelaminitissite..it ha great info on there..

 

[stimpy]

Thanks OldNag, Micky and southerncomfort

 

[claracanter]

This thread is really interesting. My Cushing's horse doesn't have many of the conventional symptoms. He's just quite hairy at the moment and recently been drinking a lot so we have had his bloods redone and are increasing his prascend as a result. Incidentally, he hates it when my other horse comes in to be ridden despite there being other horses around him. We have always just thought it was him being him as I had only had him a year before he was diagnosed. He is also very spooky. I'm now thinking this could all be related to the Cushings and maybe these things will improve with the increased Prascend.

 

[Micky]

Claracanter yes they are all related to Cushings, quite common symptoms...you can increase the dosage by a quarter tablet (easy when you find the best tablet splitter!)..and it makes a difference! My horse still gets grumpy with other horses who hassle him in the field, fine with others that leave him alone! Spooky, he was but chilled out again now...please have all look at the site I mentioned, seasonal rise occurs from autumn onwards and some owners find it better to increase the dosage for this period..anyway, it’s all about management and being watchful over our beloved nags!

 

[claracanter]

Thanks Micky. I shall be watching him very carefully as we increase his meds to see if he is less spooky and less worried when his friend isn't in the field next to him.