DEGENERATION OF WHITE MATTER IN HYPOXIA, ACIDOSIS AND EDEMA

Abstract

In contrast to its usual effect, hypoxia appears at times to induce selective injury of the white matter with sparing of the gray. The factors involved were studied in the human brain at autopsy, with seven cases serving to illustrate the mechanisms though to be operative in this and related phenomena. It is suggested that such white matter injury results from the simultaneous effect of hypoxia and edema. The edema may be due to unrelated cause, such as trauma or hypertensive disease, but it may also be due to acidosis or other consequence of hypoxia, particularly generalized hypoxia which affects the body as a whole including the circulating blood. The uniformly diffuse, generalized cerebral edema that may result in such circumstances cannot be locally severe, even when producing severe swelling of the brain as a whole, and this results in difficulties in recognition and interpretation. With gold sublimate stains, the changes in astrocytes characteristic of edema are evident in generalized hypoxic states, and at times these may be the only recognizable histologic change. The pattern of change is like that in other cases of edema, and is thought to indicate that here too, the edema is essentially extracellular.