経時的に突発性難聴および硬膜下血腫を併発した特発性頭蓋内圧低下症の1例

Spontaneous Intracranial Hypotension Manifesting as Sudden Deafness Followed by Chronic Subdural Hematoma

要旨　経過中に突発性難聴と硬膜下血腫を併発した特発性頭蓋内圧低下症の1例を報告した。症例は31歳女性で，坐位・立位にて増強する頭痛を主訴に当科を受診した。臨床的に特発性頭蓋内圧低下症が強く示唆され，頭部MRIにて硬膜のびまん性増強病変が確認された。安静臥床およびステロイド内服にて症状は軽減したが，発症3週間目に急激な左聴力低下をきたし突発性難聴と診断された。ステロイド静注に切り換え，難聴は速やかに回復し頭痛も消失した。しかし，発症4カ月目に臥位にて増強する頭痛をきたし，当科を再診した。Mass effectを伴う右硬膜下血腫を認め，穿頭ドレナージ術を施行した。本症例では，脊髄レベルでの髄液瘻や硬膜外腔への髄液貯留は確認されなかったが，経時的に突発性難聴および硬膜下血腫を併発した稀なケースであり，文献的考察を加えて報告した。

Abstract

We report a case of spontaneous intracranial hypotension （SIH） manifesting as sudden deafness followed by chronic subdural hematoma in the course of the disease. The patient was a 31-year-old female presenting with an orthostatic headache. Judging from her characteristic symptoms, SIH was strongly suggested. MR images with gadolinium were consistent with the diagnosis of SIH with a diffuse dural enhancement. Her symptoms improved gradually by conservative therapies with bed rest and oral steroid, but she developed poor hearing at 3 weeks after the onset of the symptoms. She was diagnosed as having sudden deafness. After altering the therapeutic modality to intravenous steroid administration, her perceptive deafness resolved earlier, and her symptoms of headache disappeared. However, she was readmitted to our hospital at 4 months after the onset, complaining of the aggravation of headache with a different type, which was worse in the recumbent posture. Follow-up MR images revealed a development of subdural hematoma with mass effect, and the hematoma had to be treated by burr hole drainage. In this case, the site of CSF leakage along the spinal axis was not identified by spinal MR images. This case is considered to be a rare one, complicating sudden deafness followed by chronic subdural hematoma during the clinical course of the SIH.