Rhabdomyolysis is an uncommon peril of extreme workouts
DEAR DR. ROACH: Last night, I was watching a reality show on TV. A 20-something woman was at the hospital complaining of sore muscles and an inability to lift her arms. She reported that she had previously worked out two days in a row at a gym. It was her first time at a gym. The ER doc ran some blood tests and told her that, on a particular test, her number should have been between 0 and 135, but that her actual number was 24,000. The doctor praised her for coming to the ER and thus preventing total kidney failure. I’ve NEVER heard that working out two consecutive days, when you’re out of shape, can lead to kidney failure. Is this for real, or did I misunderstand? — S.N.
ANSWER: This is for real, but fortunately not common. The blood test is called a creatine phosphokinase, CK or CPK for short, and it measures a breakdown product of muscle. People who overexert their muscles can develop a condition called rhabdomyolysis. (“Rhabdo” is Greek for “rod”; “myo” is Greek for “muscle.” The type of muscle in your arms and legs appears to have a rod in it under the microscope. “Lysis” is also Greek, for “dissolving.”)
Rhabdomyolysis is increasingly getting exposure because some people are doing extreme exercise when they aren’t used to it. The muscles break down, and the muscle protein (myoglobin) is released into the blood. The kidneys try to keep protein out of the urine, but with so much protein in the blood, the kidney can become damaged. Muscle cells also contain large amounts of potassium, and the elevated potassium in someone with severe rhabdomyolysis can be life-threatening.
The muscles should be somewhat sore after an intense workout. However, in people with rhabdomyolysis, the muscles are extremely sore and tender to the touch. People also may complain of dark urine, muscle weakness and fatigue. That combination of symptoms certainly should prompt a visit to the ER: Excessive pain and tenderness themselves deserve medical attention.