The relationship of hyperthyroidism and Parkinsonism.

The simultaneous occurrence of Parkinsonism and hyperthyroidism in the same patient is an interesting relationship and one that presents problems of diagnostic and therapeutic importance. Several such cases have been cited in European literature and were offered as proof of the diencephalopituitary origin of primary hyperthyroidism. 6,9 The essential pathology in Parkinsonism is a degeneration of the projection fiber system of the globus pallidus, with some changes of a milder degree in the substantia nigra. 8 These areas, located deep in the cerebral hemispheres, are immediately adjacent to the diencephalic areas of the brain. The diencephalon includes the thalamus, subthalamus, epithalamus, and hypothalamus, which, in turn, includes the neurohypophysis. The neurohypophysis, in combination with the adenohypophysis, forms the pituitary gland. It seems apparent, then, that a disease process in either one of these areas might well affect both, owing to the proximity of their boundaries. Since most endocrinologists agree as