Jack update - positive for PPID and starting Prascend


Hilary McGregor
 

Jack recovered for a short time from his July foot soreness. Off Prevequine mid-August to mid-September. Unfortunately, he got foot sore again near the start of September, markedly in his right. Unable to weight his right hoof. No sign of abscess. He got more comfortable by Sept 22 onward. Blood test on September 20 indicates he has PPID (despite normal resting ACTH in February). Alternate PPID testing is not available here.

I'm still waiting for full test result, but numbers are as follows:
insulin 92.3 ulU/ml
ACTH 145 pg/ml

Jack started ½ tab (0.5 mg) Prascend last night with vet recommendation to give every second day for 1 week, then every day after that.
Also recommended to take him off Metformin in 3 weeks.

Questions:
  • Is Prascend given once per day?
  • Should we be starting it slower? Is it okay to cut a tab into quarters?
  • What is recommended and available in Canada to support veil symptoms?
  • Since Jack's insulin went from 170 to 25 on Metformin alone earlier this year, what is the likelihood that his issues are PPID only? Or is that suggestive that he has IR + PPID? How can we know?
  • Should we be stopping Metformin or keeping him on it? What would the rationale be to take him off? Are we in a try and see situation?
  • When should we recheck ACTH and insulin? How often should we recheck? I understand that since we are chasing the seasonal rise, we may not be able to get his ACTH in normal range until we are out of the rise? 
  • Is it possible Jack will only need pergolide during the seasonal rise and if so, how would we know?
Thank you for the support!
Jack's case history is up-to-date.

--
Hilary and Amika
Prince George, BC, Canada
Joined July 2019
NRC+ proficient grad January 2022

Amika's Case History Folder
Amika's Photos Folder

Jack's Case History
Jack's Photos Folder


Eleanor Kellon, VMD
 

Do you know how old Jack was when he had his first episode of laminitis? It seems like your vet is thinking his laminitis/insulin is PPID related rather than EMS.
--
Eleanor in PA

www.drkellon.com 
EC Owner 2001
The first step to wisdom is "I don't know."


Hilary McGregor
 

We don't now his age of first laminitis episode. He was bought in 2016 with evidence of coffin bone remodelling (x-rays in photos folder).

He has been managed as IR/EMS since - not super strictly, but enough to keep him from acute laminitis except for an episode in 2018 when he got into winter grass and recovered when access was removed (x-rays in photos folder).

This most recent episode began in January 2022 and has been an ongoing challenge to stabilize. Something has changed for Jack and diet management is no longer sufficient. To our knowledge, he has not had laminitis in the fall before.

--
Hilary and Amika
Prince George, BC, Canada
Joined July 2019
NRC+ proficient grad January 2022

Amika's Case History Folder
Amika's Photos Folder

Jack's Case History
Jack's Photos Folder


Sherry Morse
 

Hi Hilary,

Prascend (Pergolide) is given once a day and must be given DAILY to be effective.  Giving it every other day is quite pointless.  If you want to titrate up you start at a smaller dose daily for 4 - 5 days and then increase for 4 - 5 days and increase again.  Given his test results I would start on the .5 tab daily for about the 4 - 5 days and then do a full tab.  If you want to go slower you could try 1/4 tab for 4 days, then a half, then 3/4 and then the full tab. 

I would not take him off Metformin unless you retest him and see that his insulin is still increasing in spite of the addition of Prascend.  At this point you have every indication he is PPID as well as being IR and the elevated ACTH could be driving up the insulin.  You're already in the danger zone for laminitis so unless you see it's truly no longer working you don't want to stop it and see how high it will go.

You can recheck levels 3 weeks after reaching the target dose of Prascend.

With a level of 145 now I would be surprised if Jack only needed Prascend during the rise but the only way you would know for sure would be to stop giving him the medication and retesting after 3 weeks to see what his ACTH level is at that point.





Eleanor Kellon, VMD
 

  I think there's a good chance Jack is both EMS and PPID.  The unexplained fall laminitis points to PPID but his breed and prior history also say EMS. The alternate day pergolide is your vet's version of a taper. Your vet is also probably thinking this is all PPID but that's debatable and personally I wouldn't stop metformin as long as it's working.

I would be taking him off pergolide in December and looking into domperidone testing. The alternative is to leave him on pergolide.
--
Eleanor in PA

www.drkellon.com 
EC Owner 2001
The first step to wisdom is "I don't know."


Eleanor Kellon, VMD
 

I should add that Jack's trim is way worse than the condition of the coffin bone. You should get a trim consultation.
--
Eleanor in PA

www.drkellon.com 
EC Owner 2001
The first step to wisdom is "I don't know."


Hilary McGregor
 

Sherry, Jack is a pony approx 540 lbs. Are suggesting his starting target dose should be 1 mg? Can you please clarify what you mean by "I would not take him off Metformin unless you retest him and see that his insulin is still increasing in spite of the addition of Prascend." 
Do you mean you would only take him off Metformin if it doesn't seem to be working to manage his insulin anymore?

Dr. Kellon, unfortunately, domperidone testing is not available here. Tough because we don't want him on medication he doesn't need, but he's suffered a lot this year and it would sure be amazing to have him stabilize for a while! Is it the case that even if his resting ACTH levels are in the normal range outside the seasonal rise that his PPID may not actually be adequately managed?

I appreciate that his trim is not optimal. I'll look into requesting another consult.

--
Hilary and Amika
Prince George, BC, Canada
Joined July 2019
NRC+ proficient grad January 2022

Amika's Case History Folder
Amika's Photos Folder

Jack's Case History
Jack's Photos Folder


Sherry Morse
 

Prascend is dosed based on effectiveness, not on the weight of the horse.  If you put him on .5mg for 3 weeks and retest and that's brought his ACTH down to the lower 20s upper teens that's all the dose you need.  However, given his current level is so high, I would be surprised if that was enough.  The only way to determine which dose is correct is to test once you get to what you think your target dose is. 

As far as Metformin - that's correct, there's no reason to stop it unless it is no longer working.  As of right now you don't have enough information to determine that.






Kirsten Rasmussen
 

This most recent episode began in January 2022
This suggests to me that he should stay on pergolide year-round, although there are other factors (mainly cold).  I would do at least 1 mg through the rise, then if you want to experiment you can drop to 0.5 outside the rise for now.  In Shaku's case we had steadily worsening EMS starting in 2017 (age 20) despite tighter and tighter diet.  ACTH was normal on spring bloodwork in 2018, 2019, and 2020.  The first fall laminitis was in 2020 and we finally got a fall ACTH that was barely a positive (102 pg/ml) but we didn't start pergolide until the following March.  Keeping him on pergolide has allowed me to not be so strict about diet (ie, carefully weeding the paddock and having to soak his 7% s+s hay to reduce ESC even further).  I am very aggressive about keeping his pergolide dose high enough to minimize ACTH in the fall, and I do not reduce it after the rise is over.  But it has paid off.  This spring, Shaku was eating unsoaked hay that tested at about 8.5% s+s, which prior to pergolide would have caused laminitis, and his insulin came back at 25 uIU/ml (a bit high but not worrying).  I attribute this success to finally treating his PPID, even though he had normal ACTH outside the rise until finally spring 2022, 5 years after we began this journey.

With Jack, I would check ACTH in early July to see if you need to increase his dose, and again at peak rise to see how well managed his ACTH is.  I'm not sure that testing him again this fall would be helpful since you're starting medication late and his baseline ACTH outside the rise is normal, so that's not going to tell you anything.

In Canada, you can give jiaogulan to help with the veil, although we don't recommend jiaogulan if the trim isn't in order as it increases hoof growth noticeably.  You can also titrate in 1/4 mg doses by either cutting the pill into quarters (not very accurate but that's what I did) OR dissolving half a pill in 4 ml of water and giving a 2 ml dose (store the other 2ml in the fridge for the next day).

--
Kirsten and Shaku (IR + PPID) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
 
Shaku's Case History
Shaku's Photo Album


Eleanor Kellon, VMD
 

ACTH is only one of the hormones produced by the middle lobe of the pituitary. It starts with a precursor called POMC https://neurosciencefacts.files.wordpress.com/2010/12/screen-shot-2010-12-01-at-12-07-40-am.png . Of all those hormone products, ACTH is produced in the lowest amount. However, because the signs of PPID made early researchers think of ACTH excess, that is what they started testing and still do. In advanced cases, ACTH is just as accurate as MSH but that may not be the case in early disease and it's also possible that not all horses produce identical levels of all the hormones. This makes it difficult to accurately diagnose all cases. It's important to realize that ACTH is not the only hormone with effects. For example, all of the hormones produced can reduce insulin sensitivity.

Domperidone is legal in Canada. You might want to consult a compounding pharmacy like Island. Otherwise, you could just leave him on pergolide and plan to check ACTH at the peak of the seasonal rise each year. Sooner or later his ACTH levels will also rise above normal and you are most likely to catch that in late September.
--
Eleanor in PA

www.drkellon.com 
EC Owner 2001
The first step to wisdom is "I don't know."


Kirsten Rasmussen
 

Hilary, once you settle on the dose you'll use this year for Jack, ask your vet to write a prescription to Island Pharmacy on Vancouver Island for compounded pergolide at an equivalent dose (1 Prascend = 1.3 mg compounded).  They are the main supplier in Canada and they perform regular 3rd party stability testing.  We have also tested the stability of their pergolide in the past and found it to be well within FDA requirements.  It will be much more affordable for you to keep him medicated year-round.

--
Kirsten and Shaku (IR + PPID) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
 
Shaku's Case History
Shaku's Photo Album