大腸憩室出血に対する抗血小板薬休薬後に非動脈炎性前部虚血性視神経症と急性冠症候群を発症した1例

A case with nonarteritic anterior ischemic optic neuropathy after cessation of anti-platelet medications due to massive hemorrhage from a colonal diverticulum

要約　目的：消化管出血に対し，抗血栓薬の中止後に左非動脈炎性前部虚血性視神経症（NAION）を発症した1例を経験したので報告する。

症例：60歳台，男性。2009年，心筋梗塞発症後よりクロピドグレル硫酸塩とバイアスピリンを内服していた。2019年1月，下血にて当院救急外来を受診，多量の大腸憩室出血による出血性ショック状態のため緊急入院，抗血栓薬を中止し輸血が開始された。入院3日目の午後より左眼全視野での霧視が出現し，さらに4日目の未明に左眼の著明な視力低下を自覚し当科紹介となった。視力は右0.6，左光覚なし。視神経乳頭は左眼のみ蒼白浮腫状で，蛍光眼底造影検査では左眼視神経乳頭の充盈が不良のため，NAIONと診断した。同日よりステロイドパルス療法を開始するも，翌日には急性冠症候群からの心室頻拍を発症し，緊急治療を要した。全身状態を考慮し，ステロイドパルス療法は中止した。その後は視力の改善はみられなかった。

考按：アスピリンの中止により心血管イベント，脳梗塞が約3倍に増加するとされ，脳梗塞の発症はアスピリンの休薬後10日以内が70％を占めるといわれている。本症例は透析中，小乳頭，低血圧，冠動脈疾患既往などNAION発症のリスクを有しているが，発症の翌日に急性冠症候群を発症していることなどを考慮すると，抗血小板薬の休薬がNAION発症の要因の1つであった可能性も考えられた。

Abstract　Purpose：To report a case in unilateral nonarteritic ischemic optic neuropathy（NAION）that occurred after cessation of anti-platelet medications due to massive hemorrhage from a colonal diverticulum.

Case：A male patient in his 60s was referred to our clinic because of a sudden visual loss in his left eye. Although he had been prescribed aspirin and clopidogrel sulfate for 10 years, these anti-platelet medications were temporarily suspended as he had massive hemorrhage from a colonal diverticulum. His noncorrected visual acuity was 0.6 OD and no light perception OS. A fundus examination revealed a pale-colored optic disc edema in his left eye. Fluorescein angiography showed decreased perfusion in the left optic disc area. We diagnosed him as having NAION in his left eye. Although we started corticosteroid pulse therapy, he developed acute coronary failure the day after NAION diagnosis and we stopped the pulse therapy.

Discussion：Cessation of aspirin reportedly increases the incidence of cardiovascular events and/or cerebral infarction by three-fold. In addition, 70％ of cerebral infarction cases occur within 10 days after the cessation of aspirin. Although our patient had many risk factors for NAION, including hemodialysis, chronic renal failure, a small optic disc, hypotension, and coronary heart disease, the cessation of anti-platelet medications may have been another causal factor in this particular patient. We need to pay attention to the cessation of anti-platelet agents as a risk factor for the development of ocular ischemic diseases, including NAION.