Toxic Myopathies

For many drugs myopathy can occur as sideaffect, with statins being the most frequent cause. However, other substances, e. g. amiodarone, chloriquin, antiretrovirals, corticosteroids, and checkpoint-inhibitors are also potentially myotoxic. Alcoholism is the most common trigger in toxic myopathy of other origin. Pathogenetic mechanisms are diverse and often poorly understood. Symptoms vary from mild myalgia and cramps to severe muscular weakness, myoglobinuria and life threatening rhabdomyolysis. Diagnosis is based on the exposure to noxious agents and individual risk factors, clinical examination, determination of CK value and eletromyography. A muscle biopsy is often required to confirm the diagnosis. Early detection of toxic myopathies ist relevant, since termination of the trigger leads to prompt improvement of symptoms in most cases. Immune-mediated muscle damage is a rare complication that requires a specific immunotherapy.