Idiopathic orthostatic hypotension and the Shy and Drager syndrome; Physiological studies in four cases; pathological report of one case.

Five cases of idiopathic orthostatic hypotension are presented. Physiological tests were performed in four cases which demonstrated that the lesion in the sympathetic system was most probably situated in the intermediolateral columns in three cases. In one case the lesion was localized on the efferent pathway either at the preganglionic or the postganglionic level. These four patients had also evidence of parasympathetic dysfunction. In the fifth case the clinical diagnosis of Shy and Drager syndrome was confirmed by pathological examination of the nervous system which revealed intermediolateral cell loss and the pathological findings commonly observed in the striato-nigral and olivo-ponto-cerebellar degenerations.