Unilateral Sudden Deafness with Vertebrobasilar Arterial Hypoplasia: A Case Report

一病例報告單側突發性耳聾合併椎基底動脈發育不全

Unilateral sudden deafness (SD) is often accompanied by vertigo and attributable to ipsilateral vestibular labyrinthintis or neuritis. Remission is often accompanied by episodic dizziness caused by residual problems with ipsilateral vestibular function. A 56-year-old woman visited our otorhinolaryngologic clinic complaining of episodic dizziness when she walked fast or when she stood up abruptly. She reported that she had been undergoing treatment for it from the time she experienced and was treated for SD six months earlier. Applied during purposely induced episodic dizziness, a caloric test found no abnormalities, though an optokinetic electronystagmogram and air conductive vibration-cervical vestibular evoked myogenic potential, indicating impairments of the bilateral upper and lower brainstem. Three-dimensional time-of-flight magnetic resonance angiography showed vertebrobasilar arterial hypoplasia. She received conservative medical treatment and was recommended a change in life-style. Over the following week, there were few recurrences of dizziness, and the following six months were uneventful. Although our patient's right SD could not be attributed to vertebrobasilar arterial hypoplasia, her subsequent episodic dizziness was caused by both SD-related mild residual right peripheral vestibular dysfunction and vertebrobasilar arterial hypoplasia-related bilateral central vestibular dysfunction. Therefore, episodic dizziness should not be routinely and completely attributed to peripheral vestibular dysfunction in a person who experiences SD, as it could also be caused by a central vascular anomaly related to central vestibular dysfunction.

突發性耳聾發作時常常會伴隨著眩暈，可歸咎於同側前庭迷路炎或前庭神經炎；突發性耳聾發作後常常會出現陣發性的頭暈，可歸咎於同側前庭功能尚未完全恢復。一56歲女性，自從罹患右側突發性耳聾後，屢屢因快速走路或突然站起就會陣發頭暈，病程已經6個月。當她有症狀時，兩耳溫差測試無異常發現，但視運動性眼振和頸部前庭誘發肌性電位檢查顯示有腦幹的障礙，三維飛行時間效應血管磁振造影顯示椎基底動脈發育不全。建議藥物保守治療和生活習慣調整。往後1週，頭暈就很少發作了。往後6個月，情況依然穩定。本個案之右側突發性耳聾很難歸咎於椎基底動脈發育不全，但是，爾後的陣發性頭暈不僅可歸咎於部分的右側週邊前庭功能未恢復，亦可歸咎於椎基底動脈發育不全所致之中樞性前庭功能失調。因此，當遇到突發性耳聾患者合併陣發性頭暈時，我們不能常規將之全然視為週邊性前庭功能失調，也要考慮是否有中樞神經血管變異所致之中樞性前庭功能失調。