Statin induced myopathy classification

Statin induced myopathy is a spectrum of muscular problems caused by the intake of statins. Myopathy is, by definition, any pathology of the muscle. The spectrum of statin induced myopathy can be classified into: myalgia, asymptomatic increase in creatine kinase, myositis and rhabdomyolysis.^[1][2]

• Myalgia is defined as one or combination of symptoms of muscle weakness, tenderness or pain in the context of a normal or minimally elevated creatinine kinase level.
• Patients usually complain of cramping feeling in the muscles.

• Myositis is the inflammation of the muscle.
• Myositis is defined as the presence of symptoms of muscle weakness, tenderness or pain in the setting of an elevated creatine kinase up to ten folds the upper limits of normal.

• Rhabdomyolysis is the acute degeneration of the skeletal muscle.
• It is a potentially lethal condition due to its associated nephrotoxicity caused by myoglobinuria and myoglobinemia.
• Creatine kinase is elevated in rhabdomyolysis more than ten folds the upper limits of normal.
• The complications of rhabdomyolysis are acute tubular necrosis, hypocalcemia, hyperkalemia, metabolic acidosis, hyperuricemia, DIC and cardiomyopathy.^[3]

• Elevated creatine kinase after statin withdrawal.^[1]
• Autoimmune myopathy requiring immunosuppressive therapy.^[2]