投薬量減量で改善し治療が継続可能となった重篤なインターフェロン網膜症の1例

Reduced dosage of interferon induced improvement of severe retinopathy in a case of hepatitis C

　32歳男性の慢性C型肝炎患者に対し，インターフェロンβを600万単位（6MU）連日投与したところ，両眼眼底後極に多数の軟性白斑と網膜出血，左眼眼底に嚢胞様黄斑浮腫が出現し，矯正視力右眼0.7，左眼0.15に低下した。フルオレセイン蛍光眼底造影にて，軟性白斑に一致した低蛍光と網膜静脈からの著明な蛍光漏出がみられた。患者の強い希望のため投与を中止せず，投与量を3MU週2回投与に減量したところ，網膜症が改善し視力も両眼矯正視力1.0に回復した。減量後も約2か月間，C型肝炎ウイルス陰性が維持された。インターフェロン投与により重篤な視力障害をきたした場合でも，一律に投与を中止するのみでなく慎重な経過観察を行いながら，減量して投与を継続することも選択肢として考慮されるべきである。

A 32 year-old man with chronic hepatitis C was treated with interferon β 6×10⁶ unit (6 MU) every day. He complained of visual loss and his corrected visual acuities decreased 0.7 in the right eye, 0.15 in the left eye. His fundi, including macula, had numerous cotton woolspots and retinal hemorrhages, and cystoid macular edema was seen in the fundus of the left eye. Fluorescein angiography revealed marked leakage from the retinal veins and nonperfusion areas. Because of his request, administration of the drug was reduced to 3 MU twice a week, instead of the cessation of the treatment. His visual acuities gradually improved 1.0 in both eyes. The treatment was continued for 6 month and he kept HCV- RNA (-) for 2 months after the reduction. Dose reduction of the interferon should also be considered other than discontinuance for a patient with severe visual loss due to interferon retinopathy.