両眼の急激な視力低下をきたし，ステロイド治療により改善をみた視交叉炎の1例

Systemic corticosteroid was effective in a case of chiasmal optic neuritis with abrupt visual loss in both eyes

要約　目的：両眼に急激な視力低下があり，副腎皮質ステロイドで寛解した視交叉炎の若年例の報告。症例：11歳男児が10日前からの視力低下で受診した。所見：視力は右指数弁，左光覚弁で，両眼に耳側半盲があった。MRIで視交叉の高信号と腫脹があり，視交叉炎と診断した。抗アクアポリン4抗体は陰性であった。メチルプレドニゾロンによるパルス療法を3クール行い，1か月後に視力は右1.2，左0.9になり，視野も改善した。MRIでの異常信号域は減弱した。以後14か月後の現在まで再発はない。結論：副腎皮質ステロイドのパルス療法で視神経炎が寛解した。本症例はわが国での報告例では最年少である。

Abstract.　Purpose：To report a case of acute chiasmal optic neuritis that responded to pulsed corticosteroid therapy. Case：An 11-year-old boy presented with impaired vision since 10 days before. Findings：Visual acuity was counting fingers right and light perception left. Bitemporal hemianopia with central scotoma was present. Anti-aquaporin 4 antibody was negative. Magnetic resonance imaging（MRI）showed swelling and high intensity in the chiasmal area, leading to the diagnosis of chiasmal optic neuritis. One month after 3 courses of pulsed methylprednisolone therapy, visual acuity increased to 1.2 right and 0.9 left with improved visual field. MRI showed attenuation in abnormal signal area. There has been no recurrence for 14 months until present. Conclusion：Pulsed corticosteroid therapy was followed by improvement of chiasmal optic neuritis. To our best knowledge, the present patient is the youngest reported case in Japan.