エアバッグ展開による片側外傷性内側縦束症候群の1例

A case of unilateral medial longitudinal fasciculus syndrome following activation of safety air bag

要約　目的：交通事故で展開したエアバッグにより内側縦束症候群（MLF症候群）が片側性に生じた症例の報告。症例：63歳男性が乗用車を運転中に電柱に衝突し，展開したエアバッグで眼鏡の上から打撲された。意識障害はなかった。受傷直後から複視があり，受傷の5日後に受診した。所見：矯正視力は左右とも1.0で，対光反射は正常であった。全方向に複視があり，右眼の上斜視と，左方視で増大する外斜視があった。右眼の内転制限があった。左眼に水平眼振があり，右側MLF症候群と診断した。右眼の上斜視，両眼の右方視と右下方視での時計回りの回旋眼振は，受傷から6週後にほぼ消失した。結論：この症例でのMLF障害は，事故の衝撃による頸部伸展で起こった可能性が高い。

Abstract.　Purpose：To report a case of medial longitudinal fasciculus（MLF）syndrome following activation of safety air bag during traffic accident. Case：A 63-year-old male collided with a telegraph pole while driving a car. He was wearing eyeglasses and was hit by a billowed air bag. There was no loss of consciousness. He noted diplopia soon after the accident. Findings：When seen 5 days later, his corrected visual acuity was 1.0 in either eye. He noted diplopia in all directions. The right eye showed limited adduction and exotropia which aggravated in left-side gaze. The left eye showed horizontal nystagmus. These findings led to the diagnosis of right-side MLF syndrome. Hypertropia of right eye and torsional nystagmus in both eyes spontaneously disappeared 6 weeks later. Conclusion：The observed MLF syndrome may have been caused by extension of the neck during the accident.