重度の視神経炎のみを呈した視神経脊髄炎spectrum disorderの1例

A case of neuromyelitis optica spectrum disorder with severe optic neuritis as the sole manifestation

要約　目的：重篤な視神経炎のみを呈し，抗アポクリン4抗体が陽性で，neuromyelitis optica spectrum disorderが疑われた症例の報告。症例：抗アポクリン4抗体が陽性である43歳女性が精査のため受診した。16か月前に頭部の打撲後に左眼視力が低下し，左視神経炎と診断された。プレドニゾロン全身投与で4か月後に視力は0.01から1.0に回復した。3か月前に右眼が見えにくくなり，右視神経炎と診断された。右眼に乳頭浮腫と外下方1/4盲があった。所見：右眼に光覚がなく，乳頭が蒼白であった。左眼の眼底と視野に異常はなかった。MRIで右視神経に軽度の腫脹があった。単純血漿交換と二重膜濾過血漿交換を行ったが視力は回復しなかった。結論：視神経のみがあっても，抗アポクリン抗体が陽性のときにはneuromyelitis optica spectrum disorderの可能性を考えて対処すべきである。

Abstract.　Purpose：To report a case of optic neuritis suspected of neuromyelitis optica spectrum disorder. Case：A 43-year-old female was referred to us for optic neuropathy with positive anti-aquaporin-4 antibody. She had impaired left visual acuity following head trauma 16 months before. She was diagnosed with left optic neuritis. Systemic prednisolone was followed by improved visual acuity from 0.01 to 1.0 4 months later. She noticed blurring of right vision 3 months before and was diagnosed with right optic neuritis. The right eye showed reportedly papilledema and quadrantanopia in the lower temporal sector. She was positive for anti-aquaporin-4 antibody. Findings：The right eye showed no light perception with pale optic disc. The left eye showed normal fundus and visual field. Magnetic resonance imaging（MRI）showed slightly swollen right optic nerve. Two sessions each of plasma exchange and double-infiltration plasma exchange failed to improve vision in the right eye. Conclusion：Optic neuritis may be manifestation of neuromyelitis optica spectrum disorder when anti-aquaporin-4 antibody is positive.