Exertional myopathy results from overly strenuous muscular exercise and can be precipitated by pre-existing conditions such as selenium deficiency. Inadequate energy metabolism, and/or mechanical stresses occurring during contraction are thought to be the cause of myofiber degeneration.

The lesions can be monophasic (resulting from a single event, eg, transport, capture, or restraint myopathy as with turkey leg edema syndrome) or polyphasic (with repeated or ongoing events).

Early gross lesions include pallor with edema or bloodstained transudate. There is swelling, degeneration, necrosis, and mineralization of muscle fibers, with edema, hemorrhage, and infiltration of heterophils and macrophages.

Among zoo and wild birds, long-legged wading birds are particularly susceptible to capture myopathy. Treatment of single valuable birds can be attempted and may be successful. Such treatment may consist of a combination of corticosteroids, vitamin E, selenium, parental fluids, and forced feeding in conjunction with physiotherapy.

Last full review/revision March 2012 by Arnaud J. Van Wettere, DVM, MS, DACVP