A condition in which skeletal muscle is broken down, releasing muscle enzymes and electrolytes from inside the muscle cells. Risks of rhabdomyolysis include muscle breakdown and kidney failure because the cellular component myo- globin is toxic to the kidneys. Rhabdomyolysis is relatively uncommon, but it most often occurs as the result of extensive muscle damage as, for example, in crush injury or electrical shock. Drugs or toxins may also cause this disorder. Underlying diseases that can also lead to rhabdomyolysis include collagen vascular diseases, such as systemic lupus erythematosus.