Nocardia asteroidesによる角膜炎の1例

A case of Nocardia asteroides keratitis

82歳女性が農作業中に木の枝で左眼に受傷した。その2か月後に疼痛と視力低下が生じ，近医で細菌性角膜炎と診断されたが悪化し，ヘルペス性角膜炎が疑われたが前房蓄膿が生じ，受傷から7か月後に当科を受診した。矯正視力は右0.7，左光覚弁であり，角膜全面に上皮欠損を伴う境界不鮮明な斑状の浸潤巣が多発し，前房蓄膿があった。角膜擦過物に糸状菌様の所見があり，角膜真菌症として抗真菌薬で治療したが改善しなかった。その後すぐにNocardia asteroidesが培養で同定され，ミノサイクリンの局所投与を主体とする治療に切り換え約1か月で軽快した。Nocardia角膜炎の診断では，糸状菌による角膜真菌症との鑑別が重要であることを本例は示している。

An 82-year-old woman was injured in her left eye by a branch of a tree. She developed pain and impaired vision in the affected eye 2 months later. No improvement set in after initial treatment as bacterial keratitis and later as herpetic keratitis. She was then referred to us 7 months after initial injury. Her corrected visual acuity was 0.7 right and light perception left. Her left cornea showed numerous ill-defined infiltrates and epithelial defects. Hypopyon was also present. Corneal scraping showed filamentous fungi suggestive of keratomycosis. After antifungal agents proved futile,Nocardia asteroides was isolated from cultured corneal scrapings. Topical minocycline induced clinical cure one month later. This case illustrates the importance of differentiation from keratomycosis in the diagnosis of Nocardia keratitis.