Creatine kinase (CK)

Clinical significance

Elevated levels of CK are associated with myocardial infarction and various muscle disorders.
In myocardial infarction, peak CK levels occur 24 to 36 hours after onset of chest pain and depending on the extent of damage can reach more than 10 times normal levels.

There are several causes of increased serum CK levels:
• after exercise (CK tends to peak 16 to 24 hours after exercise and remains elevated for approximately 72 hours.)(142),
• after injections,
• after therapeutic electric countershock,
• cardiac catheterization,
• cardioversion, surgery,
• coronary arteriography,
• in pregnancy (increase in late pregnancy),
• inflammation of skeletal or heart muscle,
• injury of skeletal or heart muscle,
• Intramuscular injections of various drugs,
• necrosis of skeletal or heart muscle.

Decreased CK serum values have been observed:
• in patients with cancer cachexia,
• In pregnancy (second trimester),
• in small, sedentary persons,
• neurogenic muscular atrophy usually have very low serum CK activities.

1) Physiologic changes in the catalytic concentration of CK in serum
CK are increased in normal newborns. The adults level reached after the first months.
Serum levels CK are increased at 8 – 16 h after exercise, in the absence of training. After proper training CK is little or no increase. After near-maximum exercise serum CK levels reach peak values by 24 h, and consist of predominantly the MM isoenzymes.

2) Pathologic changes in the catalytic concentration of CK in serum
Increased values of the catalytic concentration of CK in serum are found in:Decreased values of the catalytic concentration of CK in serum are found in:
• acute manic depressive illness
• acute poliomyelitis
• carbenoxolone therapy
• carbon monoxide poisoning
• cardiomyopathy
• cerebral ishemia
• cerebral vascular accident
• chronic alcoholism
• clofibrate therapy (early stages)
• diabetic acidosis
• following hornet stings
• following intramuscular injection, due to skeletal muscle damage
• gas embolism
• hypokalemia
• hypothermia
• hypothyroidism
• infections
• ischemic heart disease
• leptospirosis
• malignant hyperpyrexia following anaesthesia
• McArdle’s disease
• Muscle crush injuri
• Myocardial infarction
The serum level increase by 3 h reaching peak values by 36 h (10 – 25 times upper limit of normal), returning to normal values by 4 days.
• necrotic glioma
• Progressive muscular dystrophy,
Range of values up to 50 times normal upper limit with higher results in the younger patients.
• prolonged coma due to hypnotic drugs
• Reye’s syndrome
• rhabdomyolysis
• severe hemophilia
• tetanus
• trauma
• trichinosis
• typhoid fever
• hereditary spherocytosis (143)
• hyperthyroidism (144)
• rheumatoid arthritis (145)