トロンボーン奏者にみられた特発性縦隔気腫の1例

A case of spontaneous pneumomediastinum in a trombonist

　縦隔気腫は胸部X線写真で診断が可能な疾患であり，古くから多くの報告がなされてきた。しかし，外傷，外科的処置等によらない，いわゆる特発性縦隔気腫の中で基礎疾患，発症誘因が明らかでない例は稀でありその発症要因が注目されている。今回，著者らはトロンボーン演奏による頻回の急速な肺の過膨張，肺胞内圧上昇が発症に関与したと思われる若年女性の1例を経験したので若干の文献的考察を加えて報告する。

A case of spontaneous mediastinal emphysema in a 21-year-old female trombonist was reported. Dur-ing light work, she experienced pain in her neck which later radiated into her chest. She had neither causal disease nor episode of straining at the onset of her work.

On admission, physical examination revealed sub-cutaneous emphysema over the upper part of the chest and neck, and mediastinal crunch on ausculta-tion (Hamman's sign). Roentgenograms revealed the presense of a considerable amount of air in the me-diastinum and this extended upward through the me-diastinum into the soft tissue of the neck bilateral_ ly. The chest and neck CT yielded clearer infor-mation concerning the location and degree of media-stinal emphysema. She was treated with bed rest and recovered completely within five days.

Spontaneous mediastinal emphysema without cau-sal disease or apparent precipitating episode is infre-quently recognized. In our case, though the trombo-nist had no apparent straining episode, the causative factor can be assumed to be the tenderness of the alveoli originating from frequent overinflations of the lungs and high intra-alveolar pressures of about 150 cmH₂O during trombone performance, which may result in alveolar rupture under normal intra-alveolar pressures.