ABSTRACT
You're working in the ED when a 68-year-old woman comes in with her family complaining of general weakness, muscle aches, and dark-colored urine. You obtain a medical history from her that reveals an extensive cardiac history. She's on several medications for her heart, along with simvastatin (an HMG-CoA reductase inhibitor) to control her cholesterol. Her simvastatin dosage was recently increased to 80 mg daily, and she's scheduled to follow up with her primary care provider in 2 weeks. However, because she has been feeling so badly for some time, her family encouraged her to be seen in the ED.You reflect on a journal article that you recently read about the adverse reactions of statin drugs, including rhabdomyolysis. You consider whether your patient may be experiencing this condition.According to the National Institutes of Health, rhabdomyolysis is defined as "the breakdown of muscle fibers that leads to the release of muscle fiber contents (myoglobin) into the bloodstream." Breaking down the word, rhabdo is translated as striated, myo as muscle, and lysis as breakdown.There are many causes of rhabdomyolysis, but one of the main causes is related to certain medications (lipid-lowering drugs, corticosteroids, and erythromycin just to name a few), alcohol abuse, illicit drug use (heroin, cocaine), muscle overexertion (marathon running), and muscle compression (compartment syndrome, prolonged immobilization). Other causes may be trauma related, such as a crush injury, lightning strike, and third-degree burns; heat related, such as malignant hyperthermia and neuroleptic malignant syndrome; or related to infections and/or inflammatory conditions, such as Epstein-Barr virus and polymyositis.Whatever the cause, the end result is damage to the myocyte (muscle cell) and/or depletion of adenosine triphosphate (ATP) within the myocyte. With direct trauma to the muscle, such as with a crush injury, the cell membrane is damaged and contents spill out and are released into circulation.
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