Joint Injections in a Cushings Horse

As readers will know, since I mention it more or less incessantly, Tristan has Cushings. He is also 26 years old and still in moderate work, which means that his body needed a little bit of extra help.

I’ve thought about joint injections many times in his past, and this summer was when all the stars finally aligned for them: I had the extra funds, he was struggling a little bit to truly sit in his hind end, and we have a team of vets who are very familiar with him and his way of going.

I want to be clear that he wasn’t obviously “off” or anything that I was dragging my feet on supporting him through. It was more like we wondered if his disinterest in really flexing deep through his hind end was some stiffness or discomfort, or a training issue.

Injecting steroids into a horse with Cushings is always a dicey thing. Cushings is a disease that greatly impacts the metabolism and many horses with Cushing’s are also exquisitely sensitive to steroids. Many are insulin resistant and prone to laminitis as well, and have to be carefully managed. Some people choose different joint therapies for their Cushings horses for that reason – whether non-steroidal injections or different treatments entirely. That’s totally a fine and smart choice for some situations! But as I’ll describe below, we felt comfortable going with traditional steroid joint injections.

There were a couple of factors working in my favor.

• Tristan is not insulin resistant. Though it’s extremely common for Cushing’s horses to have IR as a comorbidity, Tristan does not – something we have verified through testing as well as observation. He is an air fern, but he does not pack on fat in the way that horses who struggle with their metabolism often do.
• Tristan is not prone to laminitis or foot-soreness. Though we take great care to adjust him to grass, he has never shown even a tiny bit of heat in his hooves, indications of pain, or anything of that kind. In the past, when he has run high fevers, he has not shown any heat in his hooves (though we packed in ice just to be careful).
• Tristan has been able to receive small doses of steroids in the past with no incident. Once or twice each summer we’ve had to resort to dexamethasone to control his hives, 10mg at a time, and he has shown no signs of intolerance to that.
• Tristan is overall in very good health right now; he has no other stresses on his immune system except for some summer allergies. That is not always the case for him! But it is for this moment in time.
• Finally, Tristan’s Cushings is well-controlled. He does not change presentation with seasons, he does not show any of the outward typical symptoms like hairiness, and his levels are consistently good. He tolerates Prascend, and is on the lowest possible dose of one pill a day.

With all of those background factors in mind, we also did a couple of extra things to be very sure it was okay.

• We pulled blood for an ACTH test to make sure his levels were acceptable at the time we were injecting him. We did not want to depend on the test we’d done a little less than a year previously.
• Each time he got injections, it was first thing in the morning and barn staff kept a very close eye on him through the day.
• We worked closely with both of his vets – his regular vet and the lameness vet – leading up to the injection. Both of his vets know him very well at this point. His regular vet did his last round of shots a few weeks before the planned hock injections and gave him an overall clean bill of health, and his lameness vet watched him trot out, did a chiropractic adjustment, and was in the loop with our regular vet on everything leading up to the injections, including his near-perfect ACTH test.

On June 1, he had both hocks injected, and on September 7 he had both stifles injected. Both injections were without incident! In between them, he also had to get another dose of dexamethasone for his allergies, and he tolerated that extremely well too.

It was a lot of work and a lot of preparation, much more so than the average joint injection for a sport horse, but it was absolutely worth the time and planning to be sure. Part of the deal with managing a senior horse is the extra planning involved for just about everything – and honestly, it’s a privilege to be able to still do this for him, so I have no complaints.