Rhabdomyolysis.
Rhabdomyolysis is a potentially life-threatening syndrome resulting from the breakdown of skeletal muscle fibers with leakage of muscle contents into the circulation. The most common causes are crush injury, overexertion, alcohol abuse and certain medicines and toxic substances. Several inherited genetic disorders, such as McArdle's disease and Duchenne's muscular dystrophy, are predisposing factors for the syndrome. Clinical features are often nonspecific, and tea-colored urine is usually the first clue to the presence of rhabdomyolysis. Screening may be performed with a urine dipstick in combination with urine microscopy. A positive urine myoglobin test provides supportive evidence. Multiple complications can occur and are classified as early or late. Early complications include severe hyperkalemia that causes cardiac arrhythmia and arrest. The most serious late complication is acute renal failure, which occurs in approximately 15 percent of patients with the syndrome. Early recognition of rhabdomyolysis and prompt management of complications are crucial to a successful outcome.