Lande Marc B, Varade William, Erkan Elif, Niederbracht Yvonne, Schwartz George J
Division of Pediatric Nephrology, Department of Pediatrics, University of Rochester Medical Center, Rochester, NY 14642, USA.
Pediatr Nephrol. 2005 Apr;20(4):491-4. doi: 10.1007/s00467-004-1779-3. Epub 2005 Feb 17.
Timed urine collections are a standard part of the evaluation for predisposition to stone formation in children with urolithiasis. Supersaturation is defined as the ratio of the concentration of dissolved salt to its solubility in urine. The purpose of the present study was to determine if adding supersaturation to the standard timed urine collection increased the ability to detect a metabolic predisposition to stone formation. Thirty-two children with urolithiasis had 24-hour urine measurements of calcium, oxalate, citrate, uric acid, and cystine (the "traditional" evaluation), as well as supersaturation for calcium oxalate, calcium phosphate, and uric acid, on the same urine sample. Nine (28%) of the 32 were hypercalciuric, 2 (6%) hyperoxaluric, and 4 (12%) hypocitraturic. In total, 14 (44%) had a metabolic predisposition that was detected by the traditional evaluation. Supersaturation was elevated in 18 (56%), including nine who did not have metabolic predisposition detected by traditional evaluation. Urine volume was low in 17 (53%) of 32 children, including eight of nine children with abnormal supersaturation but normal traditional evaluation. Only one child with normal traditional evaluation and normal urine volume had elevated supersaturation. These results show that the benefit of adding supersaturation to the traditional evaluation was largely negated by consideration of urine volume.
定时尿液收集是评估小儿尿石症结石形成易感性的标准组成部分。过饱和度定义为溶解盐浓度与其在尿液中溶解度的比值。本研究的目的是确定在标准定时尿液收集中加入过饱和度是否能提高检测结石形成代谢易感性的能力。32例尿石症患儿对同一尿液样本进行了24小时尿钙、草酸、枸橼酸盐、尿酸和胱氨酸的测定（“传统”评估），以及草酸钙、磷酸钙和尿酸的过饱和度测定。32例中有9例（28%）高钙尿，2例（6%）高草酸尿，4例（12%）低枸橼酸尿。总体而言，14例（44%）有代谢易感性，通过传统评估检测到。18例（56%）过饱和度升高，其中9例传统评估未检测到代谢易感性。32例患儿中有17例（53%）尿量低，其中9例过饱和度异常但传统评估正常的患儿中有8例。只有1例传统评估正常且尿量正常的患儿过饱和度升高。这些结果表明，考虑尿量在很大程度上抵消了在传统评估中加入过饱和度的益处。
