Browsing by Author "Horn, Isabella"

Laminitis is a common painful condition in horses that often has a poor outcome. The aetiology of laminitis has been widely studied, but still not completely understood. There is some evidence that pasture associated laminitis is one of the most common forms of laminitis , and this is most likely associated with underlying endocrine dysfunction i.e. insulin resistance. However, what the prevalence of insulin resistance in horses presented with laminitis is, that is currently unknown and it has not been studied previously. Endocrinopathic laminitis is a term including laminitis developing subsequently to Equine Cushing's Disease, equine metabolic syndrome and iatrogenic corticosteroid-induced laminitis. The term equine metabolic syndrome includes a history of laminitis, insulin resistance and a characteristic phenotype of a cresty neck, bulging supraorbital fat and increased fat deposits. Horses suffering from laminitis and insulin resistance seem to have a slow recovery process, but recovery is more likely if insulin sensitivity is improved. Increased exercise, maintaining optimal body condition, avoidance of high-glycaemic meals and molasses should be incorporated in the treatment of laminitis. Horses with insulin resistance have a higher risk of developing laminitis and to find and treat horses with insulin resistance would be a means of preventing laminitis. The purpose of the study was to determine the prevalence of insulin resistance in laminitic horses and ponies in Helsinki University Equine Clinic between April 2007 and October 2008. Associations between endocrinopathic laminitis and sex, age, body condition score, breed, season, Obel grade, the presence of laminitic rings, cresty neck, and bulging supraorbital fat were studied in 50 horses. The associations of the same variables with insulin resistance were similarly studied in the 37 laminitic horses. The hypothesis was that a high degree of laminitic horses would be insulin resistant and that age, body condition score, breed, season, Obel grade, the presence of laminitic rings, cresty neck, and bulging supraorbital fat would be associated with endocrinopathic laminitis. The body condition of the horses was scored using the 0-5 graded Carroll & Huntington body condition scoring. Insulin resistance was defined as a basal insulin level of over 30 µIU/ml. The prevalence of insulin resistance in these 37 laminitic horses/ponies was 84% (95% CI 69-92%). Bulging supraorbital fat, laminitic rings and severe lameness was significantly correlated with endocrinopathic laminitis. The mean age of horses with endocrinopathic laminitis was significantly higher than the mean age of horses without endocrinopathic laminitis. Laminitic rings were statistically more frequent in horses with insulin resistance and laminitis than horses with laminitis and normal insulin level. The result implies that a high proportion of the horses admitted to the clinic because of laminitis also have insulin resistance. The study results justifies including the presence of laminitic rings and bulging supraorbital fat as a phenotypic indicators of endocrinopathic laminitis and the equine metabolic syndrome. In this study only basal insulin was measured of the horses and it is not the most accurate method of diagnosing insulin resistance. This means that some cases of insulin resistance could have been missed. The lack of controls has probably also affected the results.