非典型的な臨床経過を示した重症筋無力症の1例

Atypical clinical course in a case of myasthenia gravis

要約　目的：眼球運動障害のみで初発した重症筋無力症の症例の報告。症例：23歳男性が5日前からの複視で受診した。裸眼視力は左右とも1.5で，左眼の上転障害と軽度の外転障害のみがあった。血液検査と画像検査所見には異常がなかった。5週後に右眼に眼瞼下垂が生じ，アイステストが陽性であり，抗アセチルコリン受容体抗体が陽転し，重症筋無力症と診断された。結論：重症筋無力症は眼球運動障害で初発することがある。原因不明の眼球運動障害では，重症筋無力症を鑑別する必要がある。

Abstract.　Purpose：To report a case of myasthenia gravis with impaired ocular motility as the sole initial manifestation. Case：A 23-year-old male presented with diplopia since 5 days before. Findings：Visual acuity was 1.5 in either eye. The left eye showed impaired superior gaze and abduction. Other ophthalmological findings were within normal limits. Hematological and other diagnostic imaging gave normal findings. The patient developed blepharoptosis in the right eye 5 weeks later. He showed positive ice test and antibody to anti-acetylcholine receptor,leading to the diagnosis of myasthenia gravis. Conclusion：The present case illustrates that impaired ocular motility may be the initial manifestation of myasthenia gravis. This possibility has to be kept in mind in the differential diagnosis of oculomotor disturbance.