治療方針の決定に磁気共鳴画像検査が有用であった小児の特発性視神経炎の1例

Magnetic resonance imaging（MRI）as a therapeutic guide for idiopathic optic neuritis in a child

要約　目的：磁気共鳴画像検査（MRI）が治療方針の決定に有用であった特発性視神経炎の小児例の報告。症例：9歳女児が6日前からの左眼視力低下，1日前からの右眼視力低下で受診した。矯正視力は右0.05，左0.04で，両眼に視神経乳頭の腫脹と視野狭窄があった。MRIで両側の視神経が視交叉直前までびまん性に腫大していた。第6病日からメチルプレドニゾロンのパルス療法を3クール行い，視野とMRI所見が改善した。視力は第34病日で右0.3，左0.4になり，2か月後に両眼とも1.0に改善した。結論：本症例の特発性視神経炎では，ステロイドのパルス治療により，視野とMRI所見がまず改善し，これに遅れて視力の回復が得られた。治療方針の決定にMRIが有力な指針になった。

Abstract.　Purpose：To report a child in whom magnetic resonance imaging（MRI）served as a useful guide in treatment for idiopathic optic neuritis. Case：A 9-year-old girl presented with impaired vision in both eyes. The left eye had been affected since 6 days and the right since one day before. Findings：Corrected visual acuity was 0.05 right and 0.04 left. Both eyes showed swelling of optic disc with constricted visual field. MRI showed diffuse swelling of bilateral optic nerve up to the chiasma. She was treated by three courses of pulsed corticosteroid therapy followed by improvement of visual field and MRI findings. Visual acuity improved to 0.3 right and 0.4 left on day 34 of the disease. It improved to 1.0 in either eye 2 months later. Conclusion：Idiopathic optic neuritis in the present case responded to pulsed corticosteroid therapy by improved visual field and MRI findings followed by improved visual acuity later. MRI was useful as a therapeutic guideline.