Parks Joan H, Coe Fredric L, Evan Andrew P, Worcester Elaine M
Department of Medicine, Nephrology Section, University of Chicago, Chicago, IL 60637, USA.
Nephrol Dial Transplant. 2009 Jan;24(1):130-6. doi: 10.1093/ndt/gfn420. Epub 2008 Jul 28.
Calcium phosphate (CaP) renal stones appear to be increasing in prevalence, and are caused by high urine CaP supersaturation, which arises from genetic hypercalciuria and high urine pH. Renal damage from stones or procedures, or treatments for stone could raise urine pH; alternatively pH may be intrinsically high in some people who are thereby predisposed to CaP stones.
To distinguish these alternatives we sequenced changes in urine pH and stone CaP content asking which occurs first in patients whose stones showed progressive increase in CaP over time. From 4767 patients we found 62 in whom we could document transformation from calcium oxalate (CaOx) to CaP stones, and 134 CaOx controls who did not transform. Laboratory and clinical finding were contrasted between these groups.
Even when patients were forming relatively pure CaOx stones, those destined to increase stone CaP had higher urine pH than controls who never did so. Their higher pH was present before and during treatments to prevent new stone formation. Shock wave lithotripsy was strongly associated with increasing stone CaP but urine pH bore no relationship to number of procedures.
We conclude that high pH may not be acquired as a result of stones or their treatments but may precede transformation from CaOx to CaP stones and arise from diet or possibly heredity.
磷酸钙（CaP）肾结石的患病率似乎在上升，其由高尿CaP过饱和度引起，而高尿CaP过饱和度源于遗传性高钙尿症和高尿液pH值。结石或手术造成的肾损伤，或结石治疗都可能使尿液pH值升高；另外，在一些易患CaP结石的人群中，尿液pH值可能本身就较高。
为区分这些情况，我们对尿液pH值和结石CaP含量的变化进行了测序，以确定在结石CaP含量随时间逐渐增加的患者中，哪种情况先出现。在4767名患者中，我们发现62名患者的结石从草酸钙（CaOx）转变为CaP结石，还有134名未发生转变的CaOx结石对照患者。对比了两组患者的实验室检查结果和临床发现。
即使患者形成的是相对纯的CaOx结石，那些结石CaP含量会增加的患者的尿液pH值也高于从未出现这种情况的对照患者。在预防新结石形成的治疗前及治疗期间，他们的尿液pH值就较高。冲击波碎石术与结石CaP含量增加密切相关，但尿液pH值与手术次数无关。
我们得出结论，高pH值可能不是由结石或其治疗导致的，而是可能在从CaOx结石转变为CaP结石之前就已出现，且源于饮食或可能的遗传因素。
