単純型頭部外傷の10時間後に突発した一側聾

Unilateral Deafness after 10 Hours following Minor Head Injury: Report of a Case

I．はじめに

　頭部外傷，音響外傷，気圧変化などのエピソードが突発性高度感音難聴の発症に先行している場合には，たとえ両者の因果関係が明らかでない場合でも突発性難聴と診断しないのが普通である。この度われわれは突発性難聴の疑診で入院後，詳細な問診によってこの突発難聴発生の10時間前に軽度の頭部外傷のあったことが判明した1例を経験した。本症例における"頭部外傷後無症状に経過した10時間（以下silent 10 hoursという）"がその診断上いかなる意味をもつかという点を中心に考察を加え報告する。

　A 31-year-old man developed severe deafness and tinnitus in his right ear and vertigo after 10 hours following minor head injury without loss of consciousness.

　When he stood straight from bending posture, he struck the right occipital region of his head to the crossbeam behind him.

　After that accident he had no complaint but local headache for 10 hours. The findings at the first visit were as follows.

　1. Normal ear drum. 2. Spontaneous horizontal nystagmus toward the left side. 3. No fracture line on ear x-ray film. 4. Total hearing loss.

　The possible causes of his severe deafness were discussed from the following 4 points. 1. Transverse fracture of the temporal bone. 2. Disturb-ance of the inner ear circulation. 3. Perilymphatic fistula. 4. Sudden deafness.