Creatine phosphokinase, or CPK, is an enzyme that is found in your heart, brain and skeletal muscles. When these organs break down, it can cause the total amount of CPK in your blood to rise. CPK actually comes in three different types, or isoenzymes, that can allow your doctor to pinpoint the damaged organ. If your total serum creatine phosphokinase is elevated, your doctor will need to perform additional blood tests to determine exactly what is causing it to elevate. This further testing measures the isoenzymes; they are much more accurate in pinpointing the cause of elevated creatine phosphokinase.
Total Creatine Phosphokinase
Your total serum creatine phosphokinase, or CPK, can elevate for a number of reasons. Some of these reasons include heart attack, stroke, convulsions, alcohol withdrawal, death of lung tissue and rhabdomyolysis, or death of muscle tissue, according to the University of Maryland Medical Center. Some medications such as ampicillin, blood thinners, aspirin, morphine, furosemide, alcohol and cocaine can also cause a high total CPK. However, simple, innocuous items such as strenuous exercise or the inflammation from lupus can also elevate this blood test, according to John Hopkins Lupus Center.
Isoenzyme CPK-1, also called CPK-BB, is found in the brain and lungs. If this isoenzyme is elevated, you can expect to see damage to these areas of your body. Brain cancer, stroke, electroconvulsive therapy and seizure are some of the reasons that this enzyme will show higher than normal results in a blood test. Death of lung tissue through a pulmonary infarction is another common cause of elevated CPK-1 readings.
Isoenzyme CPK-2, or CPK-MB, is the isoenzyme most commonly referenced because it determines whether you have had a heart attack. These levels will rise 2 to 3 hours after a heart attack, peak at 12 to 24 hours if there is no further insult to heart muscle tissue and return to normal 12 to 48 hours after the cardiac incident. Other causes of elevated CPK-MB involve injury to the heart such as open heart surgery, myocarditis or inflammation of the heart, heart trauma, heart defibrillation and electrical injury.
Isoenzyme CPK-3, or CPK-MM, is found in the skeletal muscles. This is the isoenzyme that elevates from strenuous exercise. Other causes of elevated CPK-3 are crush trauma, rhabdomyolysis, myositis, or muscle inflammation, many intramuscular injections, muscular dystrophy, recent surgery and recent seizures.