At the 2020 Northeast American Association Equine Practitioners (NEAEP) Symposium, Tom Divers, DVM, ACVIM, ACVECC, of Cornell University, discussed some relevant and new discoveries in equine care. One topic he addressed is not a new finding, but it does stress the importance of appropriate lab measurements that might help identify a horse’s risk of developing laminitis when afflicted with pituitary pars intermedia dysfunction (PPID) and/or equine metabolic syndrome and insulin dysfunction [Karikoski, N.P.; Pattrson-Kane, J.C.; et al. Lamellar pathology in horses with pituitary pars intermedia dysfunction. Equine Veterinary Journal July 2016, 48 (4); 47208; doi: 10.1111/evj.12450].
Divers urged that fasting insulin be measured in addition to ACTH levels in identifying potential laminitis risk in horses with PPID. He described the following example on how the combination of insulin and ACTH can help an evaluation:
- PPID without laminitis: Insulin <20.0; ACTH 106.1
- PPID with laminitis: Insulin 74.1; ACTH 70.5
Just having a high ACTH level does not mean a horse will develop lamellar morphological pathology, which might, in fact, be more associated with increased circulating insulin.