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Your Good Health: Overexertion can lead to kidney failure

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.

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.

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.

There are many medical conditions that predispose a person to rhabdomyolysis; many of them are disorders of the mitochondria. Some of these are severe and are diagnosed in childhood, but others are subtle and will not show up until adulthood, in times of extreme stress. Any adult with rhabdomyolysis should at least be considered for evaluation for muscle diseases that predispose a person to breakdown (a muscle biopsy is the usual test if the expert evaluating the case, such as a neurologist, deems it necessary).

However, more severe overuse when not accustomed to it can cause rhabdomyolysis. That’s why it’s important to build up strength gradually and not overdo it.

Dear Dr. Roach: I have a spot on my upper right cheek. It doesn’'t bleed, but never heals over with good skin. This has been going on for over a year. I saw a dermatologist last year and got some precancer treatment, but the spot continues to scab slightly, and never completely heals. I do keep lotion (Aveeno) on it constantly, at the pharmacist’s suggestion.

M.K.

Any nonhealing skin lesion definitely needs to be checked out, and a year is too long to go without checking back in with the dermatologist. Both basal cell cancers and squamous cell cancers can look very much like normal skin with a small area of bleeding. The dermatologist may be able to tell by a careful exam, but I suspect that it is time for a skin biopsy, which is a minor office procedure.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.