造影剤ショック後の耳鳴で初発した聴神経腫瘍の1例

A Case of Acoustic Tumor presented Tinnitus as Early Symptom after Contrast Medium Shock

　はじめに

　内耳道内に限局したり，後頭蓋窩にわずかに突出するような早期の聴神経腫瘍（AT）では典型的な症状が認められないことが多く^1〜3）診断は必ずしも容易ではない。今回造影剤ショック後より一側耳鳴を自覚し，当初感音難聴は認められたが内耳道拡大や内耳温度刺激反応低下（CP）は認められず，経過を追っていくうちに内耳道内に限局したAT （ear tumor）の診断が確定された症例を経験した。診断確定後に症状や検査所見を見直し，発症早期の段階でATを疑えなかったのか検討を行った。

In a 46-year-old man, tinnitus appeared after shock due to contrast medium. A slight sensor-ineural deafness on the affected side was found, but no enlargement of the internal auditory canal and canal paresis were found. After observation of clinical course, a small acoustic tumor in the internal auditory canal was detected.

The observation of clinical course is important to make a diagnosis of early stage of acoustic tumor.

It is recommended that air CT should be the final examination after investigation of the right-left difference of auditory brain stem response and galvanic body sway test.