Lethargic since July


I am looking for feedback and suggestions to further resolve symptoms of lethargy in my Dorado.

Since July 2021 he has become more laid back and easy.  Not to complain and to some degree its because I handle or ride him every day and include practices to desensitize him and show him everything I can, but its just not him and I think it coincides with the fall rise.  During the summer he was lethargic while still in shoes.  We had planned to get him to barefoot and riding in boots which occurred in August and he made that transition well.

Originally Dorado started Prascend 1/2 mg in Sept 2020 and never had any veil or lethargic symptoms in the beginning.

Beginning of the fall rise on August 3rd 2021 we tested ACTH and found he was not controlled and raised his dose from only 1/2 mg of Prascend to 1 1/2 mg during August/Sept.  There were no sore foot symptoms until Sept 23.  I was able to get it resolved in a week.  We X-rayed 2 weeks later and he had no rotation. Dorado rested 30 days and hand walked easy lines another until recently.   On November 12th we tested ACTH again at that time ACTH was controlled at 27 but the TRH test went to 809.  Since then he is on 2 mg of Prascend per my vet and partially because of my comments about the way he goes.

He does seem to be starting to be more energetic. Typically he wants to trot off and you have to insist on walking to keep it.  During the period of time July forward he was happy walking and you had to ask for a trot 2 or 3 times.   Keeping in mind not all is equal living in Michigan July was hot and November is cool with wind and things blowing everywhere.  We are just starting to W/T/C again and had one recent wild episode on the lunge which is the normal response from him, not the laid back horse from this summer & fall.

I appreciate your support and comments to better his health and avoid mistakes.  You're a great resource I treasure.
Cathie Y in MI 2020


Hi, Cathie.
You describe lethargy really well. I step up to say I appreciate the behavior changes in a horse that's a firebrand. But lethargy is a symptom of uncontrolled PPID or of hoof pain from uncontrolled insulin. It's not good, no matter how tractable it makes our horses.

Two good reads about the seasonal rise are in Files here:  https://ecir.groups.io/g/main/files/3%20Cushings%20Disease%20-%20PPID/Cushings%20Disease%20Treatments/Pergolide/2.%20Pergolide%20Dosage/Seasonal%20Influences%20on%20ACTH.pdf 
at the ECIRhorse.org website. https://www.ecirhorse.org/seasonal-rise.php  
This chart is a visual of the build-up of ACTH during the seasonal rise. https://www.thelaminitissite.org/ppid-faq/acth-interpretation It makes sense that he's feeling better now that the seasonal rise is on the decline. I've seen the same in my own PPID horses, who are now frisking, bucking and galloping around normally. The absence of that behavior is part of lethargy.

Keep in mind that PPID is a progressive neurodegenerative disorder. Pergolide dosage that worked a year ago may not be effective now. Control is a moving target for most of us.

A final factor is that increasing pergolide dose during the period the seasonal rise is rapidly advancing in August and September seems to be almost ineffective in controlling ACTH. That's the observation here made by Dr Kellon. It's my own experience also, shown by lab results.

Based on my personal experience with 3 PPID equines, my approach is: 
1. Make sure ACTH is well-controlled by the first week in July. That means ACTH in the high teens to low 20's gauged by pg/ml. If it isn't, begin to adjust dose immediately. Aim for normal ACTH outside the seasonal rise. 
2. Even with well-controlled ACTH, be prepared to increase pergolide dose by the second or third week in July in anticipation of the big peak in August, September and October. There's lag time in pergolide effectiveness, maybe around 3 weeks. Everyone's experience is different, but increases of 2 - 2 ½ mg help my horses IF I start early enough. I don't mean increasing to 2 mg. I mean adding an additional 2-2 ½ mg pergolide. Adding "too much" pergolide does no harm. Not increasing pergolide makes ACTH almost impossible to control during the rise, leading to lethargy, possible laminitis, weight loss and other symptom of uncontrolled PPID.
Cass, Sonoma Co., CA 2012
ECIR Group Moderator
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Kandace Krause

This is very informative Cass, I have not read this but find more in what I missed every time I read through the files.
Kandace K
Rocky Mountains, Alberta, Oct 2020