[Subacute myopathy revealing hyperthyroidism]

Progressively increasing muscle weakness of the proximal regions of the lower limbs over a period of two months in a 57-year-old woman was found to be due to an undiagnosed hyperthyroidism. Total relief from muscle weakness was obtained when euthyroidism was restored. In spite of its rarity, hyperthyroidal myopathy should be suspected in all cases of acquired myopathic disorders in adults inasmuch treatment of the hyperthyroidism leads to recovery.