Which myopathies are associated with elevated serum CK levels?
CK catalyzes the reversible reaction of adenosine triphosphate (ATP) and creatine to form adenosine diphosphate and phosphocreatine. It is elevated in many myopathies due to myofiber disruption or degeneration.
Serum CK is especially high in limb-girdle muscular dystrophies (dysferlinopathies and sarcoglycanopathies), Duchenne and Becker muscular dystrophies, inflammatory myopathies, and rhabdomyolysis.
However, CK levels may be normal in some patients with an ongoing myopathy. Examples include profound muscle wasting and selected conditions such as hyperthyroidism.
