Muscle Lesions Dynamic and Severity in Acute Rhabdomyolysis in Horses

Abstract

There were examined two mixed breed mares that had acute rhabdomyolysis. Necropsy revealed spread areas of acute muscular dystrophy, hypostatic lungs congestion and hyperemia, and myoglobinuria due to nephrosis. In h istological samples muscle fibers were hypertrophied and showed sarcoplasm homogenization. Hypertrophied myofibers were necrotized and hyalinized. The majority of myofibers that have deg enerative and necrotic lesions with hyaline deposits inside (Zenker hyaline necrosis) were frag mented. Despite of the presence of necrotic lesions local cell reaction degree is quite discreet indica ting a fast evolution. Rhabdomyolysis affected only some myofibers not all muscle, which is in conformi ty with bibliographic dates. In areas with extended myofibers necrosis circulatory disturbance s are intense, being accompanied by pronounced interstitial edema. Despite of that the capillaries maintained their structural integrity.