Serum creatine kinase measurement is used to diagnose and monitor myocardial infarction and various myopathies such as progressive Duchenne muscular dystrophy.
Creatine kinase (or phosphocreatine kinase, CK or CPK) is an enzyme found in the striated and in cardiac muscle tissue and in smaller amounts in the brain and reflects tissue catabolism as a result of cellular injury. Creatine kinase catalyzes the metabolism of creatine into creatinine.
The test is performed to detect myocardial or skeletal muscle or central nervous system (CNS) damage, which results in increased tissue catabolism in these areas. It is possible to determine the type of tissue that has been damaged (which is the tissue that is subjected to increased catabolism) by performing a screening test for creatine kinase isozymes.
CK levels should be monitored at the start of statin therapy, as asymptomatic elevation of CK is relatively common. Determination of creatine kinase levels prior to patient initiation of treatment will prevent incorrect accountability of statins in case of increased CK later (probability of rhabdomyolysis).
In patients suspected of having an acute myocardial infarction, the CK-MB test alone may reveal more information than determining the total creatine kinase concentration, which may initially not be elevated. Measurement of CK-MB at 9 hours after onset of symptoms provides an accurate clinical evaluation in 99% of myocardial infarction cases.
Possible Interpretations of Pathological Values
- Increase in Total Creatine Kinase: Amyotrophic lateral sclerosis, anoxia, biliary atresia, intestinal damage, brain tumor, burns (thermal, electrical), cancers (breast, lung, gastrointestinal, prostatic), carbon monoxide poisoning, cardiomyopathy, Duchenne muscular dystrophy, cerebrovascular accident, CNS injury, hepatic coma, convulsions, severe cough, crushing syndrome, tremor delirium, dermatomyositis, ectopic pregnancy, eosinophilia-myalgia syndrome, exercise, head injury, dialysis, severe hypokalaemia, hypothermia, hypothyroidism, hypothyroid myopathy, infarction (intestine, stroke, myocardial) intoxication (alcohol, salicylates), recent intramuscular injection, leptospirosis, malignant hyperthermia, meningoencephalitis, muscle spasm, muscular dystrophy, myocarditis, myoglobinuria, myopathy (from alcoholism), myotonic dystrophy, myxedema, striated muscle necrosis, malignant neuroleptic syndrome, transplant rejection (heart transplant), childbirth, polymyositis, pregnancy, prostate injury, psychosis, pulmonary edema, pulmonary embolism, renal failure, Reye's syndrome, rhabdomyolysis, Rocky Mountain spotted fever, shock, skeletal muscle disorders, seizures, acute skeletal muscle atrophy, subarachnoid hemorrhage, surgeries (intestine, heart, CNS, prostate), tachycardia, thyrotoxicosis, toxic shock syndrome, muscle trauma, typhoid fever and in very muscular people. Medications: Anabolic steroids, fluvastatin, isotretinoin, amphotericin B, ampicillin, anticoagulants, aspirin, clofibrate, cocaine, dexamethasone, ethanol, furosemide, lithium, morphine, some anesthetics.
- Decrease in Total Creatine Kinase: Addison's disease, anterior pituitary sub-secretion, connective tissue diseases, alcoholic liver disease, people with low muscle mass, metastatic neoplasia, pregnancy (first half). Medications: Steroids
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.