Pathology of Metabolic-Related Conditions

Abstract

SUMMARY Older horses are at risk for developing ECD and pergolide is an effective treatment for the condition. Clinical signs and available diagnostic tests will confirm the presence of advanced disease, but may not be sensitive enough to detect early ECD. Horses with EMS present a diagnostic challenge because they may develop ECD at an earlier age. The owner or veterinarian must recognize the transition from EMS to ECD and initiate pergolide therapy when it occurs. Equine Metabolic Syndrome INTRODUCTION Equine metabolic syndrome (EMS) is an endocrine and metabolic disorder, where insulin resistance (IR) is the primary problem encountered and this condition increases the risk of pasture-associated laminitis.Equine metabolic syndrome is defined by the detection of chronic IR in a horse or pony. Other potential causes of IR include pituitary pars intermedia dysfunction (ECD, also called equine Cushing’s disease), stress, and pregnancy, and these conditions must therefore be ruled out before the diagnosis of EMS is made. Genetic differences in energy metabolism are likely to play an important role in this disease because clients consistently report that horses are “easy keepers”with respect to their caloric needs. This syndrome is currently defined by (1) insulin resistance, (2) the presence of obesity and/or regional adiposity, and (3) prior or current laminitis. Evidence of prior laminitis comes from the history provided by the client or detection of obvious growth rings on the hooves (founder lines), which are assumed to result from previous subclinical laminitis episodes.“Metabolic syndrome”has been used to describe this syndrome in the past, but it is preferable to use the descriptor “equine” when referring to horses and ponies (Johnson, 2002). Metabolic syndrome is a term used in human medicine to describe a set of factors that identify people who are at risk for developing coronary heart disease, stroke, or diabetes. In contrast, EMS describes a clinical syndrome that is