酸性尿酸アンモニウム結石の1例

Abstract

32歳女。2006年10月, 突然の右腰部痛を主訴に受診した。CTで右尿管結石, 両側腎結石を認め, 前者は1ヵ月後に自然排石を得た。左腎結石には体外衝撃波腎結石破砕術(ESWL)を施行し, 徐々に排石を認めた。結石分析で98%以上の酸性尿酸アンモニウムと診断した。2007年4月, 右腰痛, 発熱を認め, CTで両側腎結石の急激な増大を認めた。左右尿管には長径5mm大の破砕片がstone streetを形成し, 両側とも水腎症を呈していた。血液検査で急性腎後性腎不全と診断し, 緊急に両側に尿管ステントを留置した。飲水と食事制限にて上昇していた尿酸値をコントロールし, 腎不全の改善を待って経尿道的尿管破石術, ESWL, 経皮的腎破石術を施行した。食事指導の徹底により高尿酸血症のコントロールも良く, 治療効果は良好であった。同年12月のCTでは両側腎に極少量の残石を認めるのみで, 残石の増大や再発は認めなかった。

We report a case of ammonium acid urate urinary stone. A 32-year-old woman with no past medical history presented with right back pain. The kidney-ureter-bladder X-ray and computed tomography revealed right ureteral and bilateral renal stones. The right ureteral stone was excreted spontaneously without treatment. The left renal stone was too large to be excreted and required extracorporeal shock-wave lithotripsy (ESWL). The analysis of the excreted stone revealed that it consisted of pure ammonium acid urate. Flakes of the left renal stone by ESWL were impacted in the left lower ureter and also rapidly grew in the left kidney. The right renal stone grew rapidly and right hydronephrosis developed due to the newly-formed right ureteral stone. As post-renal acute renal failure developed subsequently, ureteral stents were placed bilaterally. We finally treated the bilateral ureteral stone with transurethral ureterolithotripsy, the right renal stone with ESWL and the left renal stone with percutaneous nephrolithotripsy. During the course, dietary instruction was intervened for hyperuricemia. Although there were a few stones left after ESWL, they were halfway excreted without rapid growth of stones.