High blood glucose question


Maxine McArthur
 

I'm so sorry to keep asking questions. I do search the message archives and the files fairly obsessively, and I'm doing the CIR course, but I really couldn't find the answers to this. 

The issue: I'm worried that Indy's blood glucose has come back at 6.2mmol/L (111mg/dl) twice now, in two blood tests taken 3 weeks apart. Case history is updated and uploaded, but summary of results is:

2014/06  glucose 4.4mmol/L insulin 3.4mU/L. In yard with dry untested hay.

2016/03/30 glucose 4.68mmol/l  insulin 2mU/L ACTH  33.9pg/ml . [Yarded all night and some possibility they didn't get enough soaked hay before this test and that the I/G was artificially low. Started Prascend, titrated up to 0.75mg over 10 days. Improvement in attitude, energy.]

2016/07/08 glucose 6.23mmol/L  insulin 12mU/L ACTH  117pg/ml . [Increased Prascend over a week to 1.5mg. Test time:11.30am air temp around 12deg C. Tested after soaked hay and small bp feed around 9.30am, winter pasture all night.]

2016/07/29 glucose 6.2mmol/L insulin [still waiting for result]. Also ran a PCV as in the past it had been under 30, result was 33. {Test time: 8.30am, air temp a bit cold, about 1 degree C. Tested after winter pasture all night.]

Obviously I need to really tighten the DIET. She will go in the muddy yard with soaked hay and I'll rotate her companions. I am looking for new agistment but it is not easy to find. Ditto low s/s hay, but I'm working on it.

My (admittedly limited) understanding is that on forage the blood glucose should be under 100mg/dL or 5.6mmol/L. And that uncontrolled PPID can cause high blood glucose. 

Indy's ACTH on 8 July (when I finally got the results, as the clinic hadn't sent the blood when they should have) was 117pg/ml. The clinic said the blood was chilled, spun within 2 hours of the draw, then frozen. The blood was only in transit overnight and the lab did the test on the day the blood arrived. 

She was on 0.75mg of Prascend. She is now on Day 5 of 1.5mg Prascend, and I am planning to retest when it is 3 weeks on that dose.

So my questions are: 1. Could the uncontrolled PPID be the cause of the high BG? The insulin last time wasn't through the roof, although I am still waiting for the results for the blood taken yesterday.  

2. If so, when the ACTH comes down, is it likely we will see an improvement in the BG levels? 

3. If the PPID is causing the high BG, will we likely see any improvement in the BG levels until the ACTH drops, even with strict diet control? Dr Kellon wrote a post where she said in reference to an IR horse (this post was a huge lightbulb moment for: me)  **the magnitude of the insulin rise will be

directly proportional to how high her glucose goes** and that is

determined by diet. 

Does this still apply if PPID is causing the BG to stay high? (sorry for the large font, I can't get rid of it)

4. Is it worthwhile monitoring the BG with a glucometer until the vet comes in 2 and a bit weeks to test again? If nothing more than for my peace of mind...

5. What are the health and management implications of diabetes type 2 in horses? There seem to be some members whose horses' BG is never in normal range--what does this mean on the ground?

She is not noticeably footsore, or stranger than usual. Hollows over her eyes not puffy. She seems to be handling the 1.5mg of Prascend okay now. She is very hungry, but so are the other horses as we don't have much grass at the moment. She has just come into season. She is not starting to shed even though most of the other horses are losing the top wispy hairs on their coats. She is getting ridden or hand walked most days, from 30min to 1 hour, mostly walk, some trot/canter. I would have said in fact she has slightly more energy than a few weeks ago, so I was hoping this was a good sign that the increased Prascend was working, but if her BG is still high, perhaps it is not?

Thank you all so much again for 'being there'. I'm feeling very overwhelmed at the moment and this group is the only place I have to turn to for truly informed advice. 


--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Lavinia Fiscaletti
 

Hi Maxine,

It's OK to ask questions - that's what we're here for.

Diet affects glucose, with or without the additional push from uncontrolled PPID, so getting the diet optimized is important.

Getting the PPID well controlled should help in getting the IR further controlled.

High glucose doesn't affect horses the way elevated insulin does, so although it isn't a good thing, it's preferable (sort of) to having sky-high insulin as it normally doesn't trigger laminitis. If it helps - one of mine has glucose over 200mg/dL at the moment with PPID well controlled, tight diet so I know that panicked feeling all too well.

That Indy has just started coming into season may also be a factor in the insulin/glucose levels being elevated as you are heading into your spring time now (correct?) and when mares first begin cycling again it can wreak some havoc on the hormonal systems.

That she seems bright, more energetic and sound are all good signs. Not shedding isn't a reliable indicator of PPID status once a horse is already confirmed PPID as the coat may never respond "normally" again.
--

Lavinia, Dante, George Too and Peanut

Jan 05, RI

EC Support Team


Eleanor Kellon, VMD
 

Rise in blood glucose with PPID is secondary to the insulin resistance that it causes.  If the insulin resistance is not completely compensated for by increased insulin levels, glucose will be elevated.

Although I agree this level is higher than it should be, it's not high enough to cause any panic.  In fact, the only consequence of elevated BG I've consistently noted in horses is weight loss.  If there are other hyperglycemic consequences occurring they are not being noticed but it's also worth pointing out that human diabetics can run BG considerably higher than what the horses do.  I don't recall any horses being 200 or higher.

Back in the 1980s there were a report of pergolide suppressing insulin release and elevating glucose in rats:

http://www.ncbi.nlm.nih.gov/pubmed/6147289

and another showing no effect of pergolide:

http://www.ncbi.nlm.nih.gov/pubmed/6135620

Durham et al in Equine Veterinary Journal (2009) 41 (9) 924 - 929 reported on 3 horses with type 2 DM and pancreatic beta cell dysfunction (low insulin with hyperglycemia). One horse was diagnosed with PPID and started on pergolide.  After the first dose of pergolide there was a spike in insulin to 35 uIU/L and a drop in glucose from 14.1 mmol/L to 7.5 mmol/L.  Thereafter, glucose remained around 5 and insulin progressively dropped to a high of 5 after feeding.

An abstract in  2013 JEVS found that injection of 5 mg cabergoline in a slow release vehicle in nonPPID mare did not have any effect on IR or insulin response to glucose:

http://www.j-evs.com/article/S0737-0806(13)00198-6/fulltext?mobileUi=0

These two studies suggest that low dose pergolide is not likely to reduce insulin in horses but there is still a possibility that high doses may do so, especially since this study found low dose pergolide to stimulate insulin in rat pancreas (as Durham saw) while high dose suppresses the insulin response to glucose:

http://onlinelibrary.wiley.com/doi/10.1080/15216540600687993/full


--

Eleanor in PA

www.drkellon.com

EC Owner 2001


Maxine McArthur
 

Oh thank you, Lavinia! I feel a little less panicked now. First order of the day--get diet tightened. Good to know the non-shedding coat is not necessarily an indication of a problem.

Yes, you are right that we are coming into our spring now. Everyone around me is delighted at the new green grass, while I'm secretly plotting ways to kill it all. The mares are being very tarty. 

--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Maxine McArthur
 

I just got the insulin result--it's only 3mU/L. Does this mean she's diabetic? She probably didn't have much in her tummy at the time and she was standing around in the sun, but it's very low. 


--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Maxine McArthur
 

On Fri, Jul 29, 2016 at 02:38 pm, Eleanor Kellon, VMD wrote:

Rise in blood glucose with PPID is secondary to the insulin resistance that it causes.  If the insulin resistance is not completely compensated for by increased insulin levels, glucose will be elevated.

Although I agree this level is higher than it should be, it's not high enough to cause any panic.  In fact, the only consequence of elevated BG I've consistently noted in horses is weight loss.  If there are other hyperglycemic consequences occurring they are not being noticed but it's also worth pointing out that human diabetics can run BG considerably higher than what the horses do.  I don't recall any horses being 200 or higher.

 Thank you, Dr Kellon. I think I'm getting a glimmering of understanding about this. I very much appreciate your advice.
--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Eleanor Kellon, VMD
 

Yes, she's diabetic.
--

Eleanor in PA

www.drkellon.com

EC Owner 2001


Maxine McArthur
 

So -- her insulin production is not keeping up with the glucose production. This is new, as in March her BG was normal. What could be suppressing her insulin? It's not the increased pergolide, because she was high before we upped the dose from 0.75mg to 1.5mg. But on that test she had had a feed of bp and soaked hay, and her insulin was 12mmol/L. She is definitely a CUshings horse with an ACTH of 117 in mid-winter, so it's not like I'm giving pergolide to a non-PPID horse.

I'm feeding Alcar for muscle tightness and insulin sensitivity--should I stop this? 

Is there anything I should be particularly concerned about with management? e.g. keeping food in front of her constantly? This is going to be really hard at our current agistment unless she's on grass, which we want to avoid because of the unknown sugar/starch content--yes? The correct amount of soaked hay and beet pulp is what we want to feed--am I right? She is not losing weight at present. She was lacking energy but seems to have improved a little, possibly because of the increased pergolide and because I am feeding her a bit more.

Is there anything I should look out for in case the condition worsens--weight loss? Lack of energy? Should I check for liver function next time the vet draws blood? (in around 2 weeks)

Just when I think I've got it all in place, something changes. 

Off to do another archives search... 





--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Maxine McArthur
 

I think I understand now. Could one of the mods please correct me if I've got it wrong?

For whatever reason, Indy's BG is high. For whatever reason, her insulin production is not coping.

This means that the glucose is not reaching into her cells because the there aren't enough workers to move the boxes into the rooms from the halls (thank you Robin). If she keeps eating high-sugar/starch feed, all I am doing is increasing the number of boxes. She can't access the energy and will be lethargic and lose weight. If this continues, the body will start to try to use fat for energy (not quite clear on this process), leading to hyperlipidemia. 

However, horses have alternate pathways for energy to enter the cells, such as acetate from fermentation. So if we feed them a diet high in low-sugar fermentable fibre, they don't need to stress the insulin pathway. Could we say that another group of workers is moving the boxes into the rooms from a back door? 

I'm still not sure what happens to all the boxes stacked in the hall--I guess the insulin workers can take their time putting them into the rooms because more boxes aren't stacking up all the time? 

I think I'm clear now on the rationale for the low s/s high fermentable fibre regime in the case of high BG--it's to make sure the cells can get enough energy without relying on the insufficient insulin production. 

Please tell me I'm on the right track!


--

Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933



Eleanor Kellon, VMD
 

You're definitely on the right track!  Some of that glucose is getting in, just not as much as normally (workers aren't moving as much as they should).  The excess glucose goes into cells that do not require insulin to take up glucose (only muscle and fat do), and excess also goes out in the urine.
--

Eleanor in PA

www.drkellon.com

EC Owner 2001