不明熱と硝子体混濁を契機に確定診断に至った感染性心内膜炎の1例

A case of infective endocarditis with fever of unknown origin and vitreous opacity

要約　目的：問診と眼底所見より初診時に感染性心内膜炎を疑い，確定診断および治療によって良好な経過を得た1例を経験したため報告する。

症例：66歳，男性。2020年12月より38℃台の発熱が持続し，2021年6月X日に近医内科にてリウマチ性多発筋痛症と診断され，ステロイド治療を開始したが改善しなかった。6月X＋1日から両視力低下を自覚し，6月X＋12日に近医眼科より精査加療目的で和歌山県立医科大学附属病院を紹介されて受診となった。初診時の視力は右0.06（矯正不能），左0.1（矯正不能）。両眼の前房内炎症細胞は認めなかったが，両眼の硝子体混濁とRoth斑を認めたため，同日精査加療目的で入院となった。造影CTにて脾梗塞，右下腿の脂肪織濃度上昇，直腸炎の所見を認め，血液培養検査からStaphylococcus hominisが検出された。入院3日後に当院循環器内科での経食道心エコー検査にて大動脈弁に疣贅の付着と大動脈弁閉鎖不全を認め，感染性心内膜炎と診断された。抗菌薬治療および大動脈弁置換術にて解熱，硝子体混濁の軽減，Roth斑の消失を認めた。入院71日後の矯正視力は右0.5，左0.8と改善し，9月X日退院となった。

結論：初診時に内因性眼内炎の可能性を強く疑い，全身精査を行うことで感染性心内膜炎の確定診断に至った。眼科初診時に不明熱，硝子体混濁，Roth斑を認める際には，他科と連携し，原因検索を行う必要がある。

Abstract　Purpose：We report a case of infective endocarditis that was definitively diagnosed based on the interview and fundus findings at the first visit and was treated.

Case：The patient was a 66-year-old man. From December 2020, the patient had a persistent fever of 38 degrees on June X, 2021, he was diagnosed with polymyalgia rheumatoid arthritis at a local internal medicine clinic, and steroid treatment was started. However, this treatment did not help his symptoms. On June X＋1 day, he noticed decreased vision in both eyes, and on June X＋12 days, he was referred to Wakayama Medical University by a local ophthalmologist for a detailed examination and treatment. The corrected visual acuity at the first visit was 0.06 in the right eye and 0.1 in the left eye. Although no anterior chamber inflammatory cells were observed in both eyes, vitreous opacities and Roth's spots were observed in both eyes. Contrast-enhanced computed tomography revealed splenic infarction, increased fat tissue concentration in the right lower leg, and proctitis, and a blood culture test revealed Staphylococcus hominis. On July X, transesophageal echocardiography revealed aortic wart attachment and aortic regurgitation, and a diagnosis of infective endocarditis was made. The fever resolved with antibiotic treatment and aortic valve replacement. His vitreous opacity was reduced and the Roth's spots disappeared. On September X, his vision with correction improved to 0.5 in the right eye and 0.8 in the left eye. He was discharged on September X＋6 days.

Conclusions：Because of the suspicion of endogenous endophthalmitis, a general examination was performed, leading to a definitive diagnosis of infective endocarditis. When fever of unknown origin, vitreous opacity, and Roth's spots are observed at the first ophthalmologic examination, it is necessary to search for the cause in collaboration with other departments.