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Causes of elevated MB fraction of creatine kinase
Last reviewed: 06.07.2025
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The presence of the BB fraction in the blood can simulate an increase in the MB fraction, up to an excess of the MB fraction activity over the total creatine kinase. CK-BB appears when the blood-brain barrier is damaged (after brain surgery or trauma). The BB fraction also appears when there is serious damage to the intestine and after childbirth (especially with cesarean section).
Increased activity of total creatine kinase and MB-fraction is detected after operations or diagnostic manipulations on the heart. Radiation therapy of the chest area can also cause a slight hyperenzymemia. Tachyarrhythmia or heart failure rarely cause an increase in the activity of creatine kinase and CK-MB.
An increase in the CK-MB fraction is possible in some cases with myocarditis and myocardial dystrophy, but it usually accounts for less than 3% of total creatine kinase.
Damage to skeletal muscles is accompanied by a significant increase in the activity of the MM fraction, which can "simulate" the MB fraction. In rhabdomyolysis, the diagnostic sensitivity of the creatine kinase activity test (increases 5 times or more) is higher than that of aldolase, AST and LDH.
Diseases and conditions associated with increased activity of creatine kinase and CK-MB in blood serum
- Physical stress and muscle injuries.
- Increased muscle mass as a result of exercise.
- Physical stress (overload).
- Surgical interventions, direct trauma, intramuscular injections.
- Acute psychosis, acute brain injury, coma (muscle necrosis in bedsores).
- Spasms (epilepsy, tetanus), childbirth.
- Severe burns; electric shock.
- Degenerative and inflammatory lesions.
- Muscular dystrophy.
- Myositis (collagenosis, viral infections, trichinosis).
- Myocarditis.
- Toxic muscle damage.
- Acute alcohol poisoning, delirium tremens.
- Exogenous intoxication (bromides, barbiturates, carbon monoxide).
- Tetany.
- Medicines (clofibrate, bronchodilators).
- Toxic rhabdomyolysis (heroin, amphetamines).
- Malignant hyperthermia.
- Metabolic muscle damage.
- Hypothyroidism.
- Metabolic rhabdomyolysis (hypokalemia, hypophosphatemia, hyperosmolar states).
- Glycogenosis (type V).
- Hypoxic muscle damage: shock, peripheral embolism, hypothermia.