Wernicke脳症でみられた異常眼球運動の1例

Abnormal ocular motility in a case of Wernicke encephalopathy

（B6-2-22）　慢性アルコール中毒に伴う低栄養状態が原因となり，意識障害で発症したWernicke脳症の患者に特異な眼球運動障害を経験し，電気眼球運動図を含む検討を行ったので報告する。症例は，両側外転神経麻痺，水平と垂直の衝動性眼球運動のdysmetria，水平と上方への滑動性追従運動障害，下向きの衝動性眼球障害，および第一眼位にて大振幅，上転で増強，下転で減弱する上眼瞼向き眼振を認めた。Wernicke脳症の早期診断には，眼球運動障害の検出が有用である。上眼瞼向き眼振は稀であるが，本眼振の出現したときにはWernicke脳症も考慮に入れる必要がある。

A 44-year-old male developed acute coma secondary to malnutrition and chronic alcoholism. He was diagnosed as Wernicke encephalopathy. Electro- oculography was performed on day 40 of the episode after recovery of systemic symptoms. It showed : bilateral abducens palsy, horizontal and vertical saccadic dysmetria, impairment of horizontal and upward smooth pursuit movements, horizontal and downward saccadic movements, and large-amplitude upbeat nystagmus in the primary position which increased on upward gaze and decreased on downward gaze. This case illustrates the usefulness of abnormal ocular motility in the early diagnosis of Wernicke encephalopathy. Upbeat nystagmus in the primary position, which is an unusual occurrence in general, can be suggestive of Wernicke encephalopathy.