Actual vets: hyperkalemia in horse with HYPP

Having an interesting discussion on FB about a person whose horse went down at an event with an acute episode of hyperkalemia. A vet came into the discussion and said that’s why you should always carry Karo for this in case and I’m like, whhhhaaaa??? They are missing a key component: insulin. It is insulin that drives the potassium back into the cell and lowers serum potassium levels and if the patient has normal glucose levels, glucose is given so they don’t drop their glucose when given insulin. Glucose is not the treatment. Glucose alone in a hyperkalemic patient will cause their potassium to go higher. Or is there something in horses that this is not true.

Feeding glucose increases insulin secretion which helps drive potassium across cell membranes.
On a more practical note–do you propose an owner keep insulin around in case of an emergency? And how would they calculate an appropriate dose? And administer it ?


My thought is the owner should not give Karo syrup. I’m still scratching my head. It’s not how we deal with it in people. Insulin is given with glucose but never straight glucose to move potassium back into the cell.

whether r not you think owners should, the fact remains that it is an effective treatment for severe attacks in a situation other than on the premises of a veterinary facility.

horses are not large hairy people.


The entirety of the AAEP recommends Karo syrup as one mechanism to help an attack

What?s The Hype Over HYPP? | AAEP

Feed dry grain (oats, or corn-oats-barley, or you may use light Karo syrup for a glucose supplement). Feeding carbohydrates supplies glucose, which stimulates the release of insulin, which promotes potassium uptake in cells.

In a severe case, a vet may:

To reduce the serum potassium, intravenous dextrose (6 ml/kg of a 5 percent solution) alone or combined with sodium bicarbonate (1 to 2 mEq/kg) can be used to enhance intracellular movement of potassium.


Nice one. I think I will steal it for future use!


I used to ride with a trainer whose personal mare had HYPP and there was always a jar of Karo in the barn fridge for her. The mare could be on the ground in an attack and you could just pour it into her mouth and it would stop the attack surprisingly quickly. The mare even “self-regulated” and wouldn’t take any more once it started working.


I’ve been around numerous halter horse people and have never heard of them keeping insulin on hand for a HYPP attack. Kayo - always.


No I wasn’t suggesting g the average owner keep insulin around. I was mistakenly trying to apply people ,medicine to horses. Straight syrup did not make sense.

In humans, we shift high potassium with 10u of regular insulin IV followed by 50 ml of 50% dextrose IV. We monitor the glucose and potassium levels as we shift, and repeat the D50 and insulin as needed until the potassium levels normalize.

If someone’s background is human medicine in an acute setting, I can understand why it might seem odd to use only the sugar to shift the potassium. I would echo though, that without access to quickly returned labs at an equine clinic or hospital, I would really be hesitant to suggest anything IV to shift a potassium. You can get into a lot of trouble if you swing a potassium too far the other way, and that is a much higher risk if you’re shifting with IV meds than oral. Not to mention the whole differences between species too :wink:


Thank you! You can see why I was confused at the use of glucose only!

No, really, I can’t, because it just sounds bizarre to think that in the average stable setting, one could safely administer insulin to a horse having an HYPP episode.


You are missing the point. I never said the average owner should be using insulin. I said it is insulin that drives the potassium back into the cell not the glucose.

You’re being disingenuous.
You questioned the judgement of a veterinarian in advocating for the use of oral sugar solution (Karo is a mixture of several), and implied that “they are missing a key component: insulin”.

You even stated that use of oral sugar solution would increase the potassium level.

The clear implication is that insulin, instead of Karo syrup, ought to be used.


Ok, I have not had enough coffee for arguing. Have a good day.

Excessive caffeine can induce hypokalemia.


Yeah but wheres the insulin???

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I’d like to know the OP’s caffeine and potassium levels during the first post and the “I haven’t had enough caffeine post.” This could be a very interesting study!

The thing is, OP, that in an emergency situation, SOMETHING has to be done for these horses. They can’t necessarily wait for a field vet, let alone be shipped to a hospital. The something that is best over years of people doing it is oral karo. Is it gold standard for a hospital situation? Nope. Is it a great patch in the moment of need? Yup.


Another important aspect the OP seems to be missing is the logistics of treating these horses in ANY kind of setting. An HYPP attack can be as mild as light muscle twitching or as severe as sudden cardiac arrest. Many of these horses experience seizures. Try to picture the average horse owner attempting to administer IV insulin to a seizing 1,200+ pound animal…


what bothered me most about that FB post is that I got the feeling the owner did not know the horse was HYPP+