緩下剤の長期内服により生じた酸性尿酸アンモニウム結石

Ammonium acid urate urinary stone associated with chronic abuse of laxatives：A case report

　症例は22歳の女性。右腰背部痛および悪寒，悪心を主訴に近医を受診した。以前より便秘のため下剤を常用していた。KUB上，両側尿管結石を認め当院を受診した。受診時の血液生化学検査においてBUN 28.6mg/dl，Cr 4.8mg/dlと腎不全の状態であった。このため緊急に両側尿管ステントを挿入した。腎不全の改善を待ち，体外衝撃波結石破砕術（ESWL）および経尿道的尿管砕石術（TUL）を行った。結石分析の結果では，酸性尿酸アンモニウム結石であった。現在，下剤内服の中止と高尿酸血症薬内服を行い，経過観察中であるが，再発の所見は認められない。

A-22-year old female was referred to our hospital complaining of right lumber and back pain,nausea and vomiting. She had a long history of laxative abuse for constipation. KUB demonstrated bilateral ureter stones and blood examinations showed renal failure（BUN 28.6mg/dl,Cr 4.8mg/dl）. She was immediately hospitalized and bilateral ureteral stents were inserted. After improvement of renal failure right ureter stone was treated by extracorporeal shock wave lithotripsy and left ureter stone was treated by transurethral lithotripsy. Calculographic analysis revealed that both stones were composed of ammonium acid urate. At present the patient is taking antihyperuricaemia medicine with discontinuation of laxatives and free of stone.