Orthostatic Transient Cerebral Ischemia: Two Case Reports

直立性一過性腦缺血－兩病例報告

10.6200/TCMJ.2014.11.2.08

詹金烈(Jin-Lieh Chan)；林志遠(Chih-Yuan Lin)；李黔芳(Chyan-Fang Lee)；詹麗琴(Li-Chen Chan)

無低血壓的直立性腦缺血 ； 顱內大血管嚴重狹窄或阻塞 ； orthostatic cerebral ischemia without hypotension ； intracranial large vessel severe stenosis or occlusion

北市醫學雜誌

11卷2期（2014 / 06 / 01）

200 - 205

英文

直立性、短暫性腦缺血是指因站立引起暫時性、全面性（致暈厥）或局部性（致頭暈、無法站立、單側症狀）腦缺血。直立性暈厥常因站立而誘發血壓下降所導致。但在沒有血壓降低的情況下，直立性短暫性腦缺血，全面性或局部性，顯然與顱內大血管嚴重狹窄或阻塞有關。這些病人的顱內側枝循環原只勉強夠用，無法支應正常的姿勢性腦血流自我調控。當排除可能的誘發因素（如不當的降壓劑使用、脫水、腹壓憋氣相關之血管迷走神經反射、等）或靜脈內／口服液體補充以增援腦部灌流，待姿勢性腦血流自我調控機轉恢復，完全康復是可預期的。如若不然，缺血性腦梗塞後遺神經缺陷將不可避免。

Orthostatic transient cerebral ischemia refers to transient generalized (causing syncope) or focal (causing dizziness, unsteadiness, lateralizing signs) cerebral ischemia. Orthostatic syncope is usually caused by a fall in systemic blood pressure, precipitated by standing. Without a fall in systemic blood pressure, however, orthostatic transient cerebral ischemia either generalized or focal, is related to intracranial large vessel severe stenosis or occlusion, apparently. In these patients, the collateral blood supply is marginal and unable to support autoregulation of cerebral blood flow in normal posture. A complete recovery is expected on removal of possible precipitating factors (e.g., inappropriate antihypertensive use, dehydration, Valsalva maneuver-related vasovagal reflex, etc.) or on supporting cerebral perfusion by intravenous/oral fluid supply, in which postural autoregulation of cerebral blood flow is reestablished. If not, neurologic sequelae caused by cerebral infarction will be inevitable.