Dear Dr. Roach: Since 2013, my CPK has been elevated. It was 488 in September 2013, and I was told to stay on atorvastatin for high cholesterol. In December 2013, the CPK was 533 and I stopped the atorvastatin. I was retested six weeks later and it went up to 562. In February 2014, it came in at 574. At my last physical, in March 2015, it was 417. There was no baseline from the past to refer to, so my physician says my CPK may just run high.
My heart health is good, with coronary calcium score of zero and good results from thorough screenings. I am 59, with a good BMI. My diet is great and I work out and walk a couple of kilometres daily, but nothing too strenuous. My cholesterol is elevated at 233 total, but down from 273 through diet and exercise.
My gynecologist mentioned that one of her patients had a high CPK and a muscle biopsy was performed and revealed an issue. A friend said I should have the doctor do further testing to determine the type of muscle damage. I mentioned this to my doctor. He said he didn’t know of any testing that could show this, but he would look into it.
Is the high CPK of any concern? Should I push for additional testing?
M.B.
Asymptomatic elevations of CPK (creatine phosphokinase, also called creatine kinase or CK, a muscle enzyme) are common. We worry about elevated CK levels because they often mean that muscles are breaking down. All muscles release CK to some extent, and this tends to increase with heavy exercise, so the first step when seeing an asymptomatic elevation is to recheck after refraining from exercise for a few days.
The degree of elevation is also an important issue. Extremely high levels — in the thousands — are indicative of severe muscle breakdown, after a crush injury or rhabdomyolysis (“rhabdo” and “myo” for “rod-shaped muscle;” “lysis” for “breakdown”), which is a very dangerous situation, partly because of the severe damage to the muscles and partly because the muscle proteins can damage the kidney.
A 2007 study in the Netherlands suggested that the blood levels for CK need to be evaluated by sex and ethnicity. CK levels should be considered abnormal in men of European descent if over 500; for men of African descent, over 1,200. For women of European descent, the abnormal level is over 325, while for women of African descent it’s 650. Levels tend to decrease as we get older, but this largely depends on muscle mass, so those who stay active might not have lower values.
Your friend is right that a muscle biopsy can reveal the reason for high CK. However, most often the condition found does not need to be treated. Since the prognosis of unexplained high CK is excellent, I would not push for additional testing.
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 [email protected]
