Take home message: If your arthritic horse is insulin resistant, ask your veterinarian about the risk and possible alternatives prior to agreeing to corticosteroids injections, particularly triamcinolone.
Background on joint injections and laminitis
For the last 20 years on the ECIR list, there has been anecdotal evidence that corticosteroid injections might be a tipping point into laminitis. But back in those days, we weren’t even sure exactly what caused laminitis.
In 2001, a French national dressage horse was given corticosteroid injections before a large competition. Several joints were injected. Days later, this horse developed laminitis and was subsequently euthanized. The owners sued the veterinarians because they were not informed of the potential side effect. A judge ruled in favor of the owners. This caused an outcry within the scientific community. Numerous papers and commentaries pointed out that there was no scientific evidence that corticosteroids caused laminitis.
Over the next 10 to 15 years, studies emerged indicating that the risk of laminitis was low when corticosteroids were given. These studies did not establish that there was a significant link between corticosteroids and laminitis. Those were the days before we fully understood that laminitis was most frequently caused by hyperinsulinemia.
One particular study reviewed the historical records of horses that received corticosteroid injections at one of the large clinics in the UK. This practice was primarily focused on racehorses, age 2-5. It showed that out of thousands of corticosteroid injections given, only 1 or 2 elderly horses possibly developed laminitis related to the injections. Thus, the consensus was that the risk was very low, almost nonexistent.
The horse populations in these studies leaned towards younger, fit horses. This is in contrast to a population of the older horses, which many of us have. As horses age, they often develop issues, such as PPID. Also, horses that have arthritis and are insulin resistant, may be moving less due to stiffness. This lack of exercise may contribute to elevated baseline insulin levels. Therefore, the studies conducted on younger, exercising horses do not necessarily apply to the types of horses that we have with significant arthritis.
Intra-articular injections:
As horse owners, we strive to do the best for our horses. The internet abounds with anecdotal evidence that a horse was injected with triamcinolone for arthritis and subsequently developed laminitis. But where’s the proof?
Fast forward to 2024, there has been a surge of published papers that show an increase in insulin levels after triamcinolone administration, when given topically or by intra-articular injections. Further, it’s been shown that insulin levels rise higher in horses that already have elevated insulin numbers.
The data from Hollowell, et al (2024), is telling for several reasons. From the figure above, you can see that horses with an elevated baseline insulin had a greater increase than horses with a normal baseline insulin. From the figure below, you see that there was a wide variability in responses from a modest increase to a large increase. This large increase is important because it was demonstrated that horses with an insulin above 200 uU/ml frequently experienced laminitis (De Laat, et al, 2012).
Often, if the horse copes well with the corticosteroid insult, the insulin level may return to normal after a week. However, if the horse had an exaggerated response, the damage to the hooves may already be done. Once a horse experiences a full-blown laminitis case, where it is reluctant to walk, reversing the situation is not possible because the lamina have already stretched. It can take months for the horse to regain a normal gait and cadence, making it difficult to return to exercising.
As a horse owner, it is crucial to understand that while triamcinolone injections may provide comfort and reduce inflammation in the joint, they carry risks, especially for older horses, or those with elevated insulin levels. Certain breeds, such as Arabians, Morgans, and ponies, are genetically predisposed to insulin resistance.
Alternatives
What can you do to help your horse? You want to care for your horse effectively.
➡ Non-drug strategies to cope with arthritis
» Proper hoof alignment and trim
» Consider supplements to nutritionally support the horse
➡ Drug alternatives:
Consult with your veterinarian regarding the use of prescription drugs.
» Phenylbutazone
» Equioxx
» Injectables, such as hyaluronic acid, polysulfated glycosaminoglycans, or pentosan.
Ultimately, the goal is to keep your horse as healthy as possible.
Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay 2024