VII. A study of etiologic mechanisms

Abstract

This study is a review of the present status of the significance of exogenous and endogenous factors in cerebral atherosclerosis, based on a study of 1175 autopsy cases. In all these cases, a uniform, fairly simple coding system was used for the atherosclerotic changes so that these studies can easily be extended or compared by other investigators. Cerebral atherosclerosis is primarily an intimal change involving the connective tissue elements. Fatty deposits appear to be a secondary process rather than a primary event and may be entirely absent, particularly in the smaller vessels. Of all the factors studied, only 2 seem to play a role in this cerebrovascular degenerative process[long dash]hypertension and malignant disease. Patients with hypertension, as indicated by heart weights of more than 450 g, show a considerable increase in the frequency and severity of this degenerative process, while those with malignant disease showed considerably less. There is a suggestion that diabetes may also hasten the cerebral atherosclerotic process, but our cases were too few to offer any definite conclusions. The frequency and severity of the atherosclerotic process definitely increases with age. However, since this process does occur in many young individuals and is absent in many older subjects, it would appear that it is not due to the aging process itself but is probably the result of some intrinsic changes which act in a chronic fashion and hence would be more prominent in the older age group. Such factors as mechanical stress at points of vessel bifurcation, endocrine disturbances, obesity or malnutrition, chronic infections, and other somatic disease appear to play very little role in cerebral atherosclerosis. Race as a factor in cerebral atherosclerosis is still a moot question. No difference in the frequency and intensity of this process exists between the American and Norwegian population. However, other racial groups will have to be studied with similar technics so that the results can be compared.