[Steroid-induced myopathy].

Steroid muscle-related involvement is a frequent but often underestimated adverse effect of steroid treatment. Clinical presentation may differentiate two features: the less frequent, represented by acute myopathy, essentially observed in resuscitation, in patients treated with high dosages, and the more frequent feature, insidious, painless, chronic myopathy, characterized by a progressive proximal deficit. Diagnosis is mostly based on the clinic, muscle biopsy should remain exceptional, performed to detect other myopathies, since there are no specific anatomopathological findings. Muscle enzymes are rarely increased, electrophysiological analyses demonstrate unspecific and variable abnormalities. Pathophysiology of steroid-induced myopathy is multifactorial, related to protein metabolism modifications (change of both metabolism and catabolism), cellular transcription, growth factors (IGF-1, myostatine). Treatment is unspecific, mostly based on the prevention that should firstly consider steroid dosage reduction.