Creatine kinase, or creatine phosphokinase, is a type of specialized protein, called an "enzyme," found in your skeletal or voluntary muscles, as well as in your heart and brain. It plays a vital role in helping your body use an internal fuel source called "creatine." You can develop abnormal increases in your blood levels of creatine kinase if you damage your muscle tissue in any one of several ways.
Creatine Kinase Basics
Enzymes support your health by triggering, or catalyzing, a wide assortment of chemical reactions throughout your body. Creatine kinase, in particular, triggers the chemical reaction that allows your body to combine a breakdown product of creatine, called "creatine phosphate," with a substance called "adenosine diphospate" or ADP and creates an essential source of energy called "ATP," or adenosine triphosphate. This conversion process takes place whenever you need energy for short-term, high-energy physical activities, such as sprinting, high jumping or weightlifting.
Statin Myopathy and Rhabdomyolysis
The use of statins, which are certain cholesterol medications, can potentially lead to the onset of statin myopathy, a condition marked by tenderness and pain in your muscle tissue. In turn, statin myopathy can trigger an increase in your normal blood levels of creatine kinase. In extreme circumstances, use of statins can also lead to rhabdomyolysis, a serious condition that occurs when your muscle tissue breaks down and leaks myoglobin, a kidney-damaging protein, into your bloodstream. Rhabdomyolysis is also characterized by elevated creatine kinase levels. The higher your statin dose, the greater your likelihood of developing muscle problems, MayoClinic.com reports.
Heart Attacks
Your heart is made from cardiac tissue, which is muscle tissue. If you have a heart attack, damage in your heart cells will lead to blood elevations of creatine kinase. Typically, creatine kinase elevations start to manifest within four to six hours following a heart attack, then reach a peak within 18 to 24 hours before dropping back to normal after a period of roughly 48 to 72 hours. If you exhibit heart attack signs or symptoms, your doctor may diagnose your condition with the help of a blood test that measures your levels of the enzyme.
Additional Causes and Considerations
Additional potential sources of muscle damage and elevated creatine kinase levels include surgery, car accidents, accidental falls, extremely heavy exercise and muscle injections, as well as rhabdomyolysis triggered by alcoholism, heat stroke, oxygen deprivation in muscle tissue, seizures, low levels of phosphorus or phosphate, or an overdose of drugs, such as PCP, heroin, cocaine or amphetamines. People with lots of muscle mass typically have a higher everyday creatine kinase level than people with average muscle mass. In addition, people with African-American heritage appear to have naturally higher creatine kinase levels than people of other ethnic backgrounds. Consult your doctor for more information on the relationship between creatine kinase and muscle damage.
References
- Medline Plus: Creatine Phosphokinase Test
- University of Maryland Medical Center: Creatine
- Biology Online: Creatine Kinase
- American Association for Clinical Chemistry - Lab Tests Online: CK; The Test
- MayoClinic.com: Statins; Are These Cholesterol-Lowering Drugs Right for You? (Page 1); February 11, 2010
- PubMed Health: Rhabdomyolysis
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