Resumen de Short communication: Prevalence and clinical features of exertional rhabdomyolysis in Andalusian horses

Verónica Chamizo Blanco, Carlos Mauricio Acevedo Naranjo, J. L. L. Rivero

• SPECIFIC forms of exertional rhabdomyolysis (ER) are common within specific breeds. Polysaccharide storage myopathy (PSSM), a disorder of muscle glycogen metabolism (Valberg and others 1992), is common in Quarter Horses but not Thoroughbreds (McCue and others 2006) or Standardbreds (Isgren and others 2010), whereas recurrent ER, an inherited defect in sarcoplasmic calcium regulation (Lentz and others 1999), is reported to occur in Thoroughbreds but not Quarter Horses (Valberg and others 1999). As recurrent ER is managed in practice without a definitive diagnosis, it seems more appropriate to assign it to an idiopathic category of ER (Stanley and others 2009). Few reports of exertional myopathies have been conducted in Andalusian horses (Quiroz-Rothe and others 2002). The objective of this study was to compare the within-breed prevalence, age and sex distributions, clinical signs and serum muscle enzyme profiles at the time of presentation of PSSM and Idiopathic-ER among Andalusian horses and a variety of horse breeds within a population of muscle samples submitted to a diagnostic laboratory in Spain over a 15-year period.

  A cross-sectional design by using retrospectively a database of horse muscle biopsies submitted to one diagnostic laboratory in Spain over a 15-year period was used (n=486 biopsies). Data included breed, age, sex, clinical history, presenting clinical signs, and (in some cases) serum creatine kinase (CK) and (or) aspartate transaminase (AST) activities at the time of presentation. This information was provided by the referring veterinarians on the submission form. Horses were grouped into four breed categories: Andalusian and crosses, warmblood breeds and crosses, Arab and Anglo-Arab, and light breeds (Thoroughbred, Standardbred and …