Elevated creatine kinase refers to the rising level of the enzyme creatine kinase, or creatine phosphokinase, after damage to the heart, skeletal muscles or brain, says Healthgrades. Several kinds of creatine kinase are measurable: CK-MB, which is mostly in the heart; CK-MM in the skeletal muscles and heart; and CK-BB in the brain. A blood test measures elevated levels of creatine kinase and is an indication of a heart attack, skeletal muscle trauma, a stroke and other brain injuries.
In a heart attack, elevated CK-MB occurs as the enzyme level rises in conjunction with dying heart muscle cells. This can last for 18 to 24 hours, after which the creatine kinase level goes back to normal within days. In addition to elevated creatine kinase, a troponin test can help to verify a heart attack, notes Healthgrades.
Damaged skeletal muscle because of trauma also raises the level of creatine kinase. The blood test that detects elevated CK-MM levels can also detect an inflamed muscle condition, called polymyositis, and the test can roughly measure the amount of muscle damage.
Besides occurring in strokes and brain injuries, creatine kinase levels also increase in the following conditions: severe alcohol withdrawal, muscular dystrophy, myocarditis and muscle destruction called rhabdomyolysis.