Creatine Kinase (creatine phosphokinase)

The role of creatine kinase (CK) in the body

Creatine kinase is a key enzymeEnzymes are proteins that accelerate chemical reactions in the body. They ensure the occurrence of metabolic processes such as food digestion, energy release, cell formation, and many others. of energy metabolism, especially important for muscles and the brain. It catalyzes the conversion of creatine to creatine phosphate – the’ energy currency ‘ of cells.

Main functions:

1. Energy supply to muscles (skeletal, cardiac)
2. Maintaining the nervous system
3. Regulation of cellular metabolism
4. Marker of cell damage (in case of heart attack, injuries)

There are 3 isoforms:

• CK-MM (muscle) – 95% of the total level
• CK-MB (cardiac) – 5%, increases in case of heart attack
• CK-BB (brain) – almost undetectable in normal conditions

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The norm of CPK in the blood test

Group	Reference range (U/L)
Men	38–174
Women	26–140
Children	Up to 2 years: 50–400 2–17 years: 30–200

Note: References depend on the analysis method. After physical activity, an increase of 2-3 times is possible.

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Reduced CPK (Hypocreatine Kinasemia)

Reasons:

• Physical inactivity
• Taking statins
• Pregnancy (physiological decline)
• Rare genetic diseases

Symptoms:
Usually absent, but in hereditary forms there may be:

• Muscle weakness
• Rapid fatigue
• Convulsions

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Increased CPK (Hypercreatine Kinasemia)

Critical levels:

• > 500 U / L – significant muscle damage
• > 5000 U / L – rhabdomyolysis (risk of kidney failure)

Main reasons:

1. Myocardial infarction (CK-MB >6% of total CPK)
2. Injuries/Surgeries
3. Myositis (muscle inflammation)
4. Taking statins
5. Convulsive seizures

Symptoms:

• Muscle weakness
• Muscle pain
• Dark urine (with rhabdomyolysis)
• Shortness of breath (in case of a heart attack)

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What should I do if there are deviations?

• When the CPK increases:

1. Exclude infarction (ECG, troponin)
2. Urinalysis for myoglobin
3. Discontinue statins (if taken)
4. With CPK > 1000 U/L -urgent hospitalization!

• If the CPK is lowered:
  Usually does not require treatment, but for muscle weakness – consult a neurologist.

Important: After an intense workout, you need to wait 48 hours before taking the test!