アブミ骨奇形が感染ルートとなった反復性髄膜炎症例

Recurrent Meningitis due to Infection through the Congenitally Deformed Stapes Footplate: Report of a Case

I．緒言

　われわれは，感染ルート不明の髄膜炎を繰り返していた9歳女子で，内耳奇形による髄液耳漏を確認し，これを手術により治癒せしめることができた。髄液耳漏の原因には頭部外傷，骨破壊を伴う炎症，頭蓋内腫瘍，中耳手術後後遺症などが知られているが，内耳奇形による特発性髄液耳漏はきわめて稀であり，その診断も困難である。しかし近年，X線ならびに造影技術の向上，CT scanの開発などによって，前庭，半規管，蝸牛および内耳道のより詳細な形態観察が可能となり，報告数も増加しつつある。そこで本症例の概要を報告するとともに若干の文献的考察を加えた。

　A 9-year-old girl with bilateral congenital sensorineural deafness developed recurrent meningitis. Careful examinations including polytomograph, CT scanning and RI-cisternography revealed an inner ear dysplasia of Mondini type, namely, dilation of the lateral semicircular canal and vestibule, and cystic degeneration of the cochlea on both ears. Particularly, RI-cisternography demonstrated abnormal accumulation of radioisotope in the left mastoid region, suggesting of congenital cerebrospinal fluid (CSF) otorrhea. During exploratory tympanotomy of the left ear, the CSF leak was found from a round defect in the middle portion of stapedial foot plate. The CSF leak was controlled successfully by packing the vestibule with temporal fascia. Congenital CSF otorrhea is a seldom cause of meningitis but has to be taken into account especially if it was associated with a dead ear and with recurrent meningitis. The authors discussed the diagnosis and management, and reviewed the literature.