一病例報告單側顱內椎動脈狹窄所致之換氣過度眩暈症

A Case Report of Unilateral Intracranial Vertebral Artery Stenosis Relating Hyperventilation Vertigo

椎動脈狹窄須與椎動脈發育不全鑑別診斷，動脈粥狀硬化是造成椎動脈狹窄的主因。一55歲男性，在最近兩年內發生換氣過度眩暈症共計兩次而求診。理學檢查時，換氣過度測試引發了劇烈的眩暈，遂收治住院接受一系列的檢查。向左溫差眼振比向右溫差眼振明顯，兩者均無法為開眼所抑制。彩色動脈超音波顯示換氣過度會使腦血流減少，3D飛行時間效應血管磁振造影顯示右側椎動脈發育不全及左側顱內椎動脈狹窄，擴散加權顯影顯示換氣過度會使兩側小腦小葉顯影增強。出院後，建議每日服用阿斯匹靈，並調整生活習慣。爾後半年，情況依然穩定。椎動脈狹窄通常見於缺血性中風患者，在僅僅合併換氣過度眩暈症之正常活動者身上，其實是相當地少見。

Vertebral artery (VA) stenosis should be differentiated from VA hypoplasia. Atherosclerosis is the dominant pathology for VA stenosis. A 55-year-old man presented with hyperventilation vertigo twice in recent two years. When he visited our clinic, a hyperventilation test provoked severe vertigo. He was admitted for a series of study. The leftward caloric nystagmus was more prominent than the rightward one, and neither was suppressed by eye opening. A color-coded duplex sonogram showed that hyperventilation could reduce the cerebral blood flow. 3D time-of-flight magnetic resonance angiogram showed that the right VA was hypoplastic and the left intracranial VA was stenotic. The diffusion weighted image showed the bilateral flocculus became more intense by hyperventilation. After he was discharged, daily oral aspirin and life-style change were recommended. Over the following half year, it was uneventful. VA stenosis is usually noted in a victim of ischemic stroke, and is rarely noted in an ambulatory patient with simply hyperventilation vertigo.