Endoneural vessel involvement in hypothyroidism.

Light-microscope findings and pathological ultrastructural changes in sural nerve biopsies from two patients affected by hypothyroidism, one with overt signs of peripheral neuropathy, the other asymptomatic, were studied. In both patients the endoneural vessels showed clear pathological changes similar to those of other metabolic neuropathies, but more marked in the symptomatic patient. It is proposed that the changes observed in the nerve fibers in hypothyroid neuropathy are secondary to changes in the endothelial cells and in the vessel wall.