[Various problems of the pathogenesis of myopathy in patients with thyrotoxicosis].

In patients with thyrotoxic myopathy, histological investigation showed the decrease in mean diameter of skeletal muscles, and increased collateral branching of distal axons. The percentage of afflicted fibers was not high with focal pathology. The signs of true reinnervation were absent. Electroneuromyographic investigation confirmed mild myopathy. The authors discuss the possible participation of cyclic nucleotide system disorders in muscular weakness in these patients.