Novel Insights Into the Management of Atypical Myopathy in Grazing Horses Based on Recent Series of European Outbreaks and Advances in Etiological Investigations

Atypical myopathy is a pasture-associated syndrome characterised by the sudden onset of acute rhabdomyolysis not associated with exercise. This frequently fatal acquired condition is intimately linked with the environment. In Europe, large clinical series occur primarily in autumn (van Galen et al. 2010). About one thousand cases of this emergent condition have been reported since the new millennium by the “Atypical Myopathy Alert Group” (AMAG; http://www.myopathieatypique.be).

Lately, major advances have been made in the understanding of the pathophysiology of the condition and causative hypothesis. The metabolic defect occurring in atypical myopathy affects mitochondrial fatty acid energy metabolism but not the use of carbohydrates for energy supply (Westermann et al. 2008). The development of atypical myopathy is probably multifactorial but the condition has been associated with Clostridium sordellii lethal toxin (Unger-Torroledo et al. 2010). However, no specific treatment of the condition exists and the most effective way of controlling the disease is prevention including specific management practices at the horse and pasture levels (Votion et al. 2009). The information given in this review is based on findings from recent series of European outbreaks. This review aims at helping equine practitioners in the recognition and handling of suspected cases in the event of atypical myopathy outbreaks. […]