Normal Pressure Hydrocephalus and Hypertensive Cerebrovascular Disease

Neither the diagnostic criteria nor the pathogenesis of the normal pressure hydrocephalus (NPH) syndrome has been fully clarified. In two cases fulfilling currently accepted clinical and radiologic criteria, autopsy showed extensive hypertensive cerebrovascular disease with multiple small infarcts of the deep cerebral and cerebellar gray and white matter but normal leptomeninges and arachnoid villi. Therefore, hypertensive vascular disease with multiple deep cerebral infarctions may be the initial pathologic process in some cases of NPH. Such infarctions could reduce periventricular tissue tensile strength and elastic properties permitting the ventricles to enlarge under the stress of the intraventricular pulse pressure. Some patients with so-called arteriosclerotic parkinsonism and arteriosclerotic dementia clinically resemble patients with NPH. Some of these cases could represent NPH due to multiple small infarctions and, as in one of the cases reported here, might improve following ventricular shunting.