ネコひっかき病に高血圧性視神経網膜症を併発した1例

A case of cat scratch disease complicated by hypertensive optic neuroretinopathy

要約　目的：ネコひっかき病に高血圧性視神経網膜症を併発した小児例を経験したので報告する。

症例：3歳，女児。健診を契機に前医を受診し，眼底病変の精査加療目的に当科を紹介され受診となった。初診時の視力は右0.01，左0.15で，両眼に視神経乳頭発赤と腫脹，黄斑部の星芒状白斑を認めた。光干渉断層計で両眼に漿液性網膜剝離，網膜浮腫，蛍光眼底造影検査で両眼の視神経乳頭から色素漏出を認めた。1週間前に発熱の既往，ネコとの接触歴があるためネコひっかき病を疑った。右前房水のBartonella henselae PCR検査は陰性，B. henselae IgM抗体は陰性，B. henselae IgG抗体は基準値以下だが高値であった。視神経網膜炎に対しステロイドパルス療法，アジスロマイシン水和物・リファンピシンの内服を開始し，漿液性網膜剝離が改善した。しかしパルス療法2クール目の開始直前に収縮期血圧が203mmHgに上昇し，投与を中止した。精査した結果，右腎低形成・右腎動脈狭窄による腎血管性高血圧症と診断され，漿液性網膜剝離と網膜浮腫は拡大した。右腎摘出術により血圧が安定し退院となった。以降，漿液性網膜剝離と網膜浮腫は消退し，治療後6か月の視力は右0.1，左1.0である。

結論：本症例ではネコひっかき病を疑い治療を開始したが，ステロイド投与を契機に高血圧性視神経網膜症を併発したと考える。小児でも稀に高血圧性視神経網膜症を発症することがあるため，高度の視神経乳頭腫脹と星芒状白斑が遷延する場合には，全身の検索を含め小児科と連携して慎重に治療するべきである。

Abstract　Purpose：To report a pediatric case of cat-scratch disease complicated with hypertensive optic neuroretinopathy.

Case：A 3-year-old girl was referred to our department by her previous ophthalmologist for a complete ocular examination and treatment of fundus lesions. The visual acuities（VAs）of the right and left eyes, respectively, were 0.01 and 0.15. The bilateral fundus examination showed redness and edema of the optic disc and a macular star. Optical coherence tomography showed serous retinal detachments（SRDs）and retinal edema in the fundus of both eyes；fluorescein angiography showed leakage from optic discs in both eyes. We suspected cat-scratch disease because of a history of both fever 1 week earlier and contact with cats. Polymerase chain reaction tests for Bartonella henselae in the aqueous of the right anterior chamber and for IgM antibodies to B. henselae were negative；IgG antibodies against B. henselae was within normal range but slightly high.

　The SRDs improved after steroid pulse therapy and azithromycin hydrate and rifampicin for optic neuroretinitis. However, just before the start of the second course of pulse therapy, the systolic blood pressure rose to 203 mmHg, which necessitated discontinuation of the pulse therapy. Renal vascular hypertension might be caused by stenosis of the right renal artery and hypoplasia of the right kidney, and the SRDs and the areas of retinal edema increased in size. After a right nephrectomy was performed, the blood pressure stabilized, and the patient was discharged. Since then, the SRDs and retinal edema resolved, the VAs in the right and left eyes 6 months after treatment were, respectively, 0.1 and 1.0.

Conclusion：Treatment was initiated in this suspected case of cat-scratch disease, but it was thought to have been triggered by steroid administration and complicated with hypertensive optic neuroretinopathy. Because hypertensive optic neuroretinopathy rarely develops in children, when the findings include severe swelling of the optic nerve papillary and a macular star, treatment requires careful, thorough systemic examination with the cooperation of a pediatrician.