両側に急激に難聴のおきた2症例の側頭骨

HISTOPATHOLOGICAL FINDINGS IN CASES OF SUDDEN DEAFNESS

　比較的急激におきて来る原因不明の感音性難聴については，古くから知られていたが，Hallberg^1）らによりこれを突発性難聴とはじめて提唱された。以来突発性難聴は一つの症候群として多くの報告がなされてきた。しかし突発とはどの位の期間か，高度とはどの程度か，原因不明とは，他の種々の検査を行なわないためで，もつと詳しい検査をすれば原因がわかつたのではないか，など定義についても異なつたまま報告^2）3）4）されてきた。またこの症候群の患者が，他の疾患で死亡した時の内耳所見の報告も比較的少なく，その中には内耳の病態がウイルス感染によりおきた難聴の所見と類似することより，ウイルス感染説^5）6）をとる者もあり，また血管炎，白血病の出血などを伴つた所見より出血，血管閉鎖による栄養障害説^7），やアレルギー反応説^{10）10′）}を唱えるものもあつた。

　著者らは左側の耳がおよそ1カ月の経過で急激に，右側は発熱後突発性にメマイの症状を伴つて高度の感音性難聴になつて14年後に死亡した1例と，両側同時に，メマイなどのはつきりした前庭症状を現わさずに突発性に高度の感音性難聴を起こして5カ月後に死亡した1例の側頭骨の病理所見を調べることができたので，その結果を報告し，突発性難聴に対する考案を加えたので諸家のご批判を仰ぎたい。

The inner ear pathology of two cases with sud-den onset of deafness is presented with detailed report of the examination of the four temporal bones.

Case Ⅰ. The patient noted a gradual loss of hear-ing in the right ear which diminished to a com-plete loss within the period of one month wi-thout any apparent cause. The left ear was like-wise affected with added symptoms of tinnitus, vertigo and nausea. The patient died 15 years later.

The histopathological findings of both inner ears were nearly similar in appearance. The perilymphatic space of the semicircular cannals appeared to be partially fibrotic and becoming ossified. The sacculus showed its walls to be col-lapsed and adherent to its neural elements and hair cells ; the supporting cells were completely degenerated. However, the utriculus was well preserved with its neuroepithelium in a healthy state. The cochlea showed a collapsed Reisner's membrane and degenerated hair cells;the supporting cells were degenerated;the striae vascularis and the spiral ligaments were becoming atrophic, but there was no pathological findingsin the perilymphatic space. The spiral gangliong cells were found to be atrophied and degene-rated, and, so also, the Scarpa's ganglion cells, partially atrophied and degenerated.

From these pathological findings involving the cochleo-sacular degeneration, the authors believe, the causative factor of this disease might have been a viral infection.

Case Ⅱ. The patient was affected with a sud-den onset of hearing in both ears soon after the lumbar puncture pumping which was perform-ed for the treatment of lumbago. The patient died 6 months later. The histopathological findingsof both ears were similar to each other.The metastatic growth of the adenocarcinoma which originated in the lungs was found to be invading the brain stem and the inner ear.The internal auditory meatus was filled with tumor cells rea-ching the cribrosal area. Fibrotic changes and invasion with capillary growths and tumor cells were observed in the scala tympani and Rosen-thal canals.No hair cells, nor supporting cells were found in the scala media. The tumor cells were,also, observed in the saculus among its neuro-epithelium.