外転神経麻痺を呈した特発性低髄液圧症候群の1例

Abducens palsy in a case of spontaneous intracranial hypotension

要約　目的：外転神経麻痺が生じた特発性低髄液圧症候群の症例の報告。症例と経過：43歳男性が2週前からの頭痛と複視で受診した。矯正視力は左右とも1.5であり，眼位は近見，遠見とも8⊿内斜位で，左眼にわずかな外転制限があった。2週間後に内斜位はやや悪化した。磁気共鳴画像検査（MRI）で硬膜にびまん性で均一な肥厚があり，造影効果の増強があった。特発性低髄液圧症候群と考えたが，神経内科では外転神経麻痺以外に病変はなかった。2か月後に複視は消失し，頸部痛が出現した。MRIで両側大脳半球に硬膜下血腫があった。結論：特発性低髄液圧症候群では硬膜下血腫が併発することがあり，MRIやMRミオグラフィなどで画像診断を繰り返すことが望ましい。

Abstract.　Purpose：To report a case of spontaneous intracranial hypotension with abducens palsy as the initial clinical manifestation. Case and Findings：A 43-year-old male had diplopia and headache since 2 weeks before. His corrected visual acuity was 1.5 in either eye. Esophoria was present both for near and far by 8⊿. The left eye showed slightly limited abduction. Esophoria became more manifest 2 weeks later. Magnetic resonance imaging（MRI）showed diffuse and uniform thickening of dura mater with enhancement. The findings were suggestive of spontaneous intracranial hypotension. Neurological examinations showed no pathological findings except abducens palsy. Diplopia disappeared 2 months later followed by neck pain. MRI showed subdural hematoma in both cerebral hemispheres. Conclusion：Subdural hematoma may develop in spontaneous intracranial hypotension. Repeated diagnostic imaging by MRI and MR myography is advocated.