Creatine Kinase (CK)

Authors
Affiliations

Doctor of Physical Therapy

B.S. in Kinesiology

Doctor of Physical Therapy

B.A. in Neuroscience

AKA

Overview

Creatine Kinase (CK) is an enzyme

CK functions to catalyze the reaction of creatine and adenosine triphosphate (ATP) to phosphocreatine (PCr) and adenosine diphosphate (ADP)1

Chemical Reaction

CK is used to catalyze the following reversible reaction:

\[ ADP + PCr ⇌ ATP + Cr ΔG′° = −12.5 kJ/mol \]

ATP can be generated from PCr and ADP.

The phosphocreatine (PCr) created from this reaction is used to supply tissues and cells that require substantial amounts of ATP, like the brain, skeletal muscles, and the heart, with their required ATP

Chemical structures

See McLeish (2005) Relating structure to mechanism in creatine kinase2

Elevated CK Blood levels

Physical activity

  • CK levels transiently rise after exercise or heavy manual labor
  • Post-exercise (strenuous physical activity) Serum CK levels increase (up to 30x) within 24 hours and then declines over 7 days3
  • Amount of CK increase is dependent upon the type and duration of exercise3
    • Untrained individuals experience greater elevation3

Nonneuromuscular causes

  • Endocrine disorders3
    • Hyperthyroidism (rare)3
    • Hypothyroidism3
    • Hyperparathyroidism3
    • Acromegaly3
    • Cushing syndrome3
  • Metabolic disturbances3
    • Hyponatremia3
    • Hypokalemia3
    • Hypophosphatemia3
  • Muscle trauma3
    • Strenuous exercise3
    • Intramuscular injections3
    • Needle electromyography3
    • Seizures3
  • Medications3
    • Statins3
    • Fibrates3
    • Antiretrovirals3
    • Beta-blockers3
    • Clozapine3
    • Angiotensin II receptor blockers3
    • Hydroxychloroquine3
    • Isotretinoin3
    • Colchicine3
  • Others3
    • Celiac disease3
    • Malignancy3
    • Macro CK3
    • Surgery3
    • Pregnancy3
    • Cardiac disease3
    • Acute kidney disease3
    • Viral illness3
    • Predisposition to malignant hyperthermia3

Further reading

Journal club

Creatine Kinase-Myocardial Band (#creatine-kinase-mb)

Discussed in the cardiac evaluation

References

1.
Aujla RS, Patel R. Creatine Phosphokinase. In: StatPearls. StatPearls Publishing; 2023. Accessed January 22, 2024. http://www.ncbi.nlm.nih.gov/books/NBK546624/
2.
McLeish MJ, Kenyon GL. Relating structure to mechanism in creatine kinase. Critical Reviews in Biochemistry and Molecular Biology. 2005;40(1):1-20. doi:10.1080/10409230590918577
3.
Moghadam-Kia S, Oddis CV, Aggarwal R. Approach to asymptomatic creatine kinase elevation. Cleveland Clinic Journal of Medicine. 2016;83(1):37-42. doi:10.3949/ccjm.83a.14120

Citation

For attribution, please cite this work as: