Equine Metabolic Syndrome and Laminitis

"Equine Metabolic Syndrome" (EMS) is the latest addition to the horse health lexicon. Speaking at the University of Wisconsin's School of Veterinary Medicine's 2003 Equine Symposium on Laminitis on Jan. 31, Philip J. Johnson BVSc (Hons), MS, MRCVS, Dipl. ACVIM, of the University of Missouri's School of Veterinary Medicine, used updated terminology to describe his recent endocrinology research.

In the 1990s, Johnson's study of "easy keeper" laminitis cases helped coin the descriptive term "peripheral Cushing's syndrome" for chronic laminitis sufferers which did not test positive for Cushing's syndrome, yet showed some similarities in clinical signs.

"We used that term a few years ago based on similarities with the human condition," Johnson remarked. "Yet that same human condition actually had 10 different names. Recently, the World Health Organization decided to refer to it simply as 'metabolic syndrome' (in humans)," he explained. "Therefore, we elected to do the same with the equine corollary."

Johnson shared the podium with Robert J. Hunt, DVM, Dipl. ACVS, of Hagyard-Davidson-McGee Associates in Lexington, Ky. Together, the two presented a blitz of research and clinical papers on the causes and treatment of the many forms of laminitis seen in horses.

Johnson's research focuses on endocrine system function and dysfunction, especially related to the horse's production of cortisol by the adrenal glands. He presented an interesting model for the links between laminitis and cortisol's potential action as an inflammation suppressant.

Of particular interest to horse owners was Johnson's black-and-white linkage of the newly termed EMS condition with laminitis and obesity. "Obesity-associated insulin refractory state" was Johnson's precise description of EMS in these non-Cushing's horses, many of which also suffer from recurrent laminitis.

Johnson's research on insulin insensitivity in obese horses explained how that condition can lead to glucose intolerance, or more explicitly, a delay in the horse's ability to remove excess glucose from the circulatory system, tipping the odds for an insufficient metabolic response to inflammation. He carefully outlined marked differences between insulin insensitivity in horses, cats, and humans.

Hunt is active in the clinical and surgical management of acute and chronic laminitis cases in Kentucky. He stressed how the many variations of laminitis--such as infinite combinations of clinical signs and radiographic findings--increase the difficulty of prognosis. The numerous mechanical and surgical options he presented were evidence of the enormous effort and experimentation that many practitioners are undertaking in an attempt to increase the odds of successful treatment of laminitis in the horse.

About the Author

Fran Jurga

Fran Jurga is the publisher of Hoofcare & Lameness, The Journal of Equine Foot Science, based in Gloucester, Mass., and Hoofcare Online, an electronic newsletter accessible at www.hoofcare.com. Her work also includes promoting lameness-related research and information for practical use by farriers, veterinarians, and horse owners. Jurga authored Understanding The Equine Foot, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.

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