眼科受診から診断に至った若年女性の間質性腎炎ぶどう膜炎症候群の1例

A case of TINU syndrome in a young woman diagnosed by ophthalmology consultation

要約　目的：間質性腎炎ぶどう膜炎症候群（TINU症候群）は急性間質性腎炎にぶどう膜炎を合併する症候群である。今回，眼科受診を契機にTINU症候群と診断した若年女性の1例を経験したので報告する。

症例：患者は16歳，女性。右眼の結膜充血，羞明，眼痛を認め近医内科および眼科を受診した。内科では頭部MRIを施行するも異常なく，眼科では右眼結膜炎の診断で点眼加療行うも改善なく市立東大阪医療センター（当院）眼科へ紹介となった。

所見と経過：初診時視力は両眼とも（1.5），眼圧は両眼とも12mmHgであった。右眼に結膜充血，両眼に角膜後面沈着物，前房内炎症細胞を認めた。眼底は特記所見を認めなかった。心電図と胸部X線撮影に異常はなかった。血液検査では血清クレアチニン1.89mg/dl，CRP 2.04mg/dlと高値を認めた。尿検査で尿蛋白と尿糖が陽性で，尿中β2-MG 49,600μg/lと著明な高値を認めたためTINU症候群を疑い，当院腎臓内科を紹介した。腎生検で尿細管間質へのリンパ球などの炎症細胞の密な浸潤を認め急性間質性腎炎と診断され，眼所見と併せてTINU症候群と診断した。眼科ではステロイド点眼の強化，腎臓内科ではステロイド内服を開始したところ，前眼部炎症や結膜充血は消退し，腎機能も改善を認めた。

結論：TINU症候群は本症例のように若年者に多いとされている。若年者の前眼部ぶどう膜炎ではTINU症候群を鑑別に入れ，血液検査および尿検査での腎機能の確認と他科との連携が有用である可能性がある。

Abstract　Purpose：Tubulointerstitial nephritis and uveitis（TINU）syndrome is diagnosed in patients who develop both acute interstitial nephritis and uveitis. We herein report the case of a young woman with TINU syndrome.

Case：A 16-year-old female patient experienced conjunctival hyperemia, photophobia, and ophthalmalgia in her right eye, for which she consulted a local physician and ophthalmologist. Head magnetic resonance imaging revealed no obvious findings, and the ophthalmologist diagnosed a case of right eye conjunctivitis. She instilled eye drops to her right eye, but her symptoms did not improve.

Findings and clinical course：On her first visit to our department, her corrected visual acuity and intraocular pressure were 1.5 and 12 mmHg, respectively, in both eyes. Right eye conjunctivitis was noted, and both eyes had keratic precipitates and cells in the anterior chamber. Fundoscopy of both eyes showed no abnormal signs, and an electrocardiogram and pulmonary X-ray were normal. Serum creatinine and C-reactive protein levels were 1.89 mg/dl and 2.04 mg/dl, respectively；urine was positive for sugar and protein, and urinary β2-microglobulin（β2-MG）levels were 49,600 μg/l. Because urinary β2-MG was extremely high, we suspected TINU syndrome so consulted a nephrologist. Renal biopsy revealed that lymphocytes had infiltrated the renal tubule interstitium, and other differential diagnoses, such as sarcoidosis, were ruled out. Therefore, we diagnosed TINU syndrome. The application of more effective corticosteroid eye drops and the administration of systemic corticosteroid by a nephrologist led to improvements in her anterior uveitis and renal dysfunction.

Conclusions：It is reported that TINU syndrome is more common in young people like her case. Therefore, we consider that TINU syndrome can be cited as a differential diagnosis and a renal function of a young patient with anterior uveitis should be examined by serologic test and urine test, and team medicine would be useful.