破裂脳動脈瘤極急性期における脳腫脹の検討

Abstract

The severity of ruptured intracranial aneurysms may be determined by the volume of subarachnoid hemorrhage, the volume of intracerebral hematoma, the presence of intraventricular hemorrhage, or an acute hydrocephalus on the CT scan. But in some cases, brain swelling seemed to be the only determinant factor of severity.We have experienced 32 such cases among 515 patients with ruptured intracranial aneurysm who were admitted within 72 hours of attack (6.0%). Five cases had previous convulsions (group 1), and 15 cases had preceding hypoxia and/or hypotension episodes (group 2). But in the remaining 13 cases, we could not find such a preceding episode (group 3).In group 1, clinical grade on admission varied from 3b to 5, and blood pressure varied from 118/80mmHg to 190/100 mmHg. Outcomes of this group were one GR, two SD and three death.Because brain swelling in this group may be a reversible brain edema caused by a convulsion, a delayed operation must be employed.In group 2, the clinical grade on admission of all patients was five, and blood pressure varied from zero to 210/110 mmHg. The outcomes of this group were miserable (death: 13, PVS: 1).Since brain swelling in this group is a manifestation of hypoxic brain damage, there is no indication for an operation.In group 3, 12 of 13 cases had marked hypertension and the average MABP was 130mmHg. Regional cerebral blood flow measurement by means of Xe inhalation was performed in two cases whose CT scan showed hemispheric swelling, and hyperperfusions of the swelling side were noted. In three cases autopsies were performed, and marked brain swelling, dilated small vessels and diapedesis of erythrocytes were found.We speculate that acute brain swelling of unknown etiology may be brought about by disautoregulation caused by SAH concomitant with persistent hypertension.It must be stressed that lowering of blood pressure in the acute phase of a ruptured intracranial aneurysm is very important not only for preventing rebleeding but also for impeding the development of brain swelling.