悪性貧血と亜急性連合性脊髄変性症に合併した栄養欠乏性視神経症の1例

Nutritional optic neuropathy in a case of pernicious anemia and subacute combined degeneration of the spinal cord

要約　目的：悪性貧血と亜急性連合性脊髄変性症に続発した栄養欠乏性視神経症の症例の報告。症例：51歳男性が2週間前からの右眼視力障害で受診した。その2日前から右上肢と下肢の脱力感としびれがあった。所見：矯正視力は右0.3，左0.5で，右眼に相対的瞳孔求心路障害があった。眼底と視野に異常はなかった。脳の画像検査では異常がなく，全身検査で悪性貧血，ビタミンB₁₂欠乏，亜急性連合性脊髄変性症があった。ビタミン複合剤と副腎皮質ステロイドの投与で，2か月後に左右眼とも視力が0.8に回復した。結論：本症例での視力障害は悪性貧血による栄養欠乏性視神経症と診断される。原因不明の視神経炎には，ビタミンB₁₂欠乏が関与する可能性がある。

Abstract.　Purpose：To report a case of nutritional optic neuropathy secondary to pernicious anemia and subacute combined degeneration of the spinal cord. Case：A 51-year-old male presented with impaired vision in his right eye since 2 weeks before. He had noticed weakness and numbness in the right upper and lower extremity 2 days before onset of visual disturbance. Findings：Corrected visual acuity was 0.3 right and 0.5 left. The right eye showed relative afferent pupillary defect. Diagnostic imaging of the brain was inconclusive. Systemic studies showed pernicious anemia,vitamin B₁₂ deficiency,and subacute combined degeneration of the spinal cord. Systemic treatment with vitamin B complex and corticosteroid was followed by improved visual acuity of 0.8 in either eye 2 months later. Conclusion：This case was diagnosed with nutritional optic neuropathy secondary to pernicious anemia. There is a possibility that idiopathic optic neuritis may be secondary to vitamin B₁₂ deficiency.