尿細管間質性腎炎ぶどう膜炎症候群4症例の経験

Four cases of tubulointerstitial nephritis and uveitis syndrome

要約　緒言：眼科で診ることは稀な尿細管間質性腎炎ぶどう膜炎（TINU）症候群を4症例経験し，尿細管間質性腎炎の診断につながった検査項目を検討した。

症例1：14歳，女児。前眼部は両眼に肉芽腫性虹彩毛様体炎，隅角結節があった。シスタチンC（CysC），クレアチニン，尿Nアセチルグルコサミニダーゼ（NAG），尿β2-マイクログロブリン（β2-m）が高値のため，総合病院小児科へ紹介した。臨床所見よりTINU症候群と診断された。

症例2：10歳，男児。前眼部は右眼に肉芽腫性虹彩毛様体炎，隅角結節があった。左眼に炎症所見はなかった。1か月後に左眼の虹彩毛様体炎を発症した。CRP，CysC，尿NAG，尿β2-mが高値のため，静岡県立こども病院（以下，こども病院）腎臓内科へ紹介した。腎生検にてTINU症候群が確定した。

症例3：15歳，男児。前眼部は両眼に肉芽腫性虹彩毛様体炎，隅角結節と視神経乳頭腫脹があった。CRP，CysC，尿β2-mが高値のため，こども病院腎臓内科へ紹介した。腎生検にてTINU症候群が確定した。

症例4：8歳，女児。前眼部は右眼に肉芽腫性虹彩毛様体炎，虹彩結節があった。硝子体前部に炎症細胞があった。左眼に炎症所見はなかった。2か月後に左眼の虹彩毛様体炎を発症した。CRP，CysC，尿β2-mが高値のため，こども病院腎臓内科へ紹介した。腎生検にてTINU症候群が確定した。

結果：血液検査では1症例でクレアチニン，4症例でCysC，尿検査では2症例でNAG，4症例でβ2-mが異常値を示し，尿細管間質性腎炎の診断に寄与した。

結論：小児の虹彩毛様体炎では片眼，両眼にかかわらずTINU症候群を疑い，通常の腎機能検査だけでなく，CysCを含む血液検査に加え，β2-mとNAGを含む尿検査が必要である。

Abstract　Introduction：In this case series we outlined four cases of tubulointerstitial nephritis and uveitis（TINU）treated in our ophthalmology department and discussed the steps that led to the diagnosis.

Case 1：A 14-year-old girl with bilateral granulomatous iridocyclitis and goniotic nodules in the anterior segment was referred to the pediatric department of a general hospital due to high levels of cystatin C（CysC）, creatinine, urinary N-acetylglucosaminidase（NAG）, and urinary β2-microglobulin（β2-m）. This patient was diagnosed with TINU based on clinical findings.

Case 2：A 10-year-old boy had right granulomatous iridocyclitis in the anterior segment of the eye and a goniotic nodule. There was no evidence of inflammation in the left eye. One month later, iridocyclitis developed in the left eye. Due to high levels of CRP, CysC, urinary NAG, and urinary β2-m, he was referred to the Department of Nephrology at Children's Hospital. TINU was confirmed by renal biopsy.

Case 3：A 15-year-old boy with bilateral granulomatous iridocyclitis in the anterior segment, angular nodules, optic disc swelling（＋）, high levels of CRP, CysC, and urine β2-m was referred to the nephrology department of Children's Hospital. TINU was confirmed by renal biopsy.

Case 4：An 8-year-old girl with right anterior segment granulomatous iridocyclitis and iris nodules was evaluated in our clinic. There were inflammatory cells in the anterior part of the vitreous and no evidence of inflammation in the left eye. Two months later, iridocyclitis developed in the left eye. Due to high levels of CRP, CysC, and urine β2-m, she was referred to the Department of Nephrology at Children's Hospital. TINU was confirmed by renal biopsy.

Results：Blood tests showed abnormal values for creatinine in one case and CysC in four cases, and urine tests showed abnormal values for NAG in two cases and β2-m in four cases, contributing to the diagnosis of tubulointerstitial nephritis.

Conclusion：In pediatric iridocyclitis, TINU is suspected regardless of whether it is in one or both eyes. In addition to regular kidney function tests, blood tests including CysC and urine tests including β2-m and NAG are required.