エタネルセプト治療中に球後視神経炎を発症した関節リウマチの1例

Retrobulbar optic neuritis in a case of rheumatoid arthritis under etanercept therapy

要約　目的：関節リウマチに対し，腫瘍壊死因子α阻害薬であるエタネルセプトで治療中に球後視神経炎が発症した症例の報告。症例：39歳女性が3週前からの左眼運動痛と2週前からの左眼霧視で受診した。9年前に関節リウマチが発症し，5か月前からエタネルセプト治療を開始し，リウマチ症状は寛解していた。所見：矯正視力は右1.2，左0.2で，眼底に異常はなかった。左眼に中心暗点があった。磁気共鳴画像（MRI）で左視神経に腫大と高信号があり，左球後視神経炎と診断した。エタネルセプトを中止し，ステロイドパルスを行い，19日後に視力は1.0に回復した。歩行障害などのリウマチ症状が再燃し，トシリズマブ投与で改善した。以後8か月間，経過は良好である。結論：エタネルセプト投与で視神経炎が発症し，投与中止で寛解することがある。

Abstract.　Purpose：To report a case of rheumatoid arthritis who developed retrobulbar optic neuritis while under etanercept therapy. Case：A 39-year-old woman presented with pain during eye movement followed by blurring of vision in the left eye since 2 weeks before. She had been diagnosed with rheumatoid arthritis 9 years before and been receiving etanercept since 5 months before. Findings：Corrected visual acuity was 1.2 right and 0.2 left. Fundus findings were normal. Central scotoma was present in the left eye. Magnetic resonance imaging（MRI）showed swelling and high intensity in the left optic nerve. These findings led to the diagnosis of retrobulbar optic neuritis. After discontinuation of etanercept,she was treated by pulsed corticosteroid therapy. Visual acuity in the left eye improved to 1.0 19 days later. Recurrence of difficulty in walking was controlled by tocilizumab. She has been doing well for 8 months until present. Conclusion：This case illustrates that retrobulbar optic neuritis may develop during etanercept therapy and may improve after withdrawal.