[Acute myopathy and hyperthyroidism].

A 40 year-old woman with a rapidly progressive proximal muscle deficit of all four limbs had an acute myopathy secondary to hyperthyroidism. Biopsy of the quadriceps femoris revealed signs of non specific muscle impairment with type II fiber atrophy. Treatment with methimazole and correction of the thyroid condition led to rapid disappearance of the disorders. Eighteen months later the clinical status was normal and a second quadriceps femoris biopsy showed that the muscle had normalized.