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exertional myopathySports medicine A condition that may affect any individual who exercises beyond his/her normal capacity Etiology Dehydration, HIV, alcohol and illicit drug use, prescription drugs Management Short-term, nada; long-term, regular exercise ↑ mitochondria in slow-twitch muscles, allowing them to process O2 more efficiently for longer periods without damaging muscle cells
strictly speaking, any disease of a muscle. Common usage is to restrict its use to describe the noninflammatory degenerations of skeletal muscle characterized by hyaline degeneration of muscle fibers, muscle weakness, myoglobinuria and a high serum level of muscle enzymes. This includes post-exertional rhabdomyolysis, enzootic nutritional muscular dystrophy, congenital myopathies, neurogenic atrophy and pale, soft, exudative pork. See also muscular.
an acute myopathy occurring most frequently in wild animals after a long chase or with a lot of struggling. The course is short and the death rate high. Affected animals are recumbent, dyspneic, hyperthermic and show muscle tremor. It is basically an exertional myopathy.
congenital myotonic myopathy
see myotonia congenita.
equine polysaccharide storage myopathy
(EPSM) a form of exertional rhabdomyolysis that occurs in several breeds but particularly the Quarter horse and draft horse breeds, resulting in muscle tremor and weakness. Affected horses have enhanced glucose storage and glycogen synthesis, elevated muscle glycogen and polysaccharide storage inclusions in type II muscle fibers, but a specific enzyme defect has not been identified.
fibrous adhesions between the muscle masses in the posterior thigh muscles in horses. A sequel to traumatic mysositis. See also ossifying myopathy (below).
Golden retriever myopathy
a congenital disorder of muscles seen from a very young age in male Golden retrievers that show a stiff gait, abduction of thoracic limbs, bunny-hopping in the pelvic limbs, and enlargement of the tongue. The clinical signs worsen with exercise and as the dog matures. Now recognized as an X-linked inherited deficiency of dystrophin, analogous to the human disorder, Duchenne muscular dystrophy.
see feline hypokalemic polymyopathy.
lipid storage myopathy
increased amounts of lipid accumulate in myofibers causing weakness, muscle pain and atrophy and rarely cardiomyopathy. Reported in dogs; the cause is unknown but abnormalities in levels of lactate, pyruvate and carnitine have been found.
caused by a deficiency of pyruvate dehydrogenase; reported in Clumber spaniels, Sussex spaniels and Old English sheepdogs.
a form marked by myofibers resembling those of early fetal muscle, i.e. myotubules.
a rare inherited neuromuscular disease of humans characterized by myotonia and the presence of fine fibrous threads called nemaline rods. Reported in cats.
calcification of the adhesions of fibrotic myopathy. A special occurrence is in the semimembranosus, semitendinosus and biceps femoris muscles of Western performance horses. See ossifying fibrotic myopathy.
see exertion myopathy (above).
after a period of recumbency with general anesthesia, affected horses are usually unable to rise. If they do rise, they show severe tremor, weakness and easy falling. Serum muscle enzyme levels indicate gross muscle damage and both fore- and hindlimbs are affected.