Heilberg I P, Martini L A, Draibe S A, Ajzen H, Ramos O L, Schor N
Nephrology Division, Escola Paulista de Medicina, Säo Paulo, Brasil.
Nephron. 1996;73(2):145-53. doi: 10.1159/000189031.
The absorptive or renal origin of hypercalciuria can be discriminated using an acute oral calcium load test (ACLT). Of 86 patients with calcium oxalate kidney stones, 28 (23%) were found to be hypercalciuric (HCa) and 58 (67%) normocalciuric (NCa) on their customary free diet, containing 542 +/- 29 mg/day (mean +/- SE) of calcium. Since the apparently normal 24-hour calcium excretion of many calcium stone formers (CSF) may be due to a combination of high calcium absorption with moderately low calcium intake, all patients were investigated by ACLT. Of 28 HCa patients, 13 (46%) were classified as absorptive (AH) and 15 (54%) as renal hypercalciuria (RH). Of the 58 NCa patients, 38 (65%) presented features of intestinal hyperabsorption and were therefore designated as AH-like, and 20 (35%) as RH-like. To further elucidate the role of dietary calcium in these CSF, a chronic calcium load test (CCLT), consisting of 1 g/day of oral Ca for 7 days, was designed. A positive response to the CCLT was considered to occur when urinary calcium (uCa) was > or = 4 mg/ kg/24 h on the 7th day. Among NCa patients, 29% of AH-like subjects responded to the CCLT and 71% did not; 50% of RH-like subjects also responded and 50% did not. In HCa patients, 85% of AH and 67% of RH subjects maintained uCa > or = 4 mg/kg/24 h after the CCLT and 15% of AH and 23% of RH subjects did not. However, a significant additional increase in mean uCa was not observed among HCa patients. All patients were submitted to a second evaluation of fasting calciuria (Ca/Cr). A modification of this parameter was noticed in 89% of RH-like and 78% of RH patients. In conclusion, these data suggest the presence of subpopulations of patients sensitive or not to calcium intake, regardless of whether the acute response to a calcium overload test suggested AH or RH. The CCLT disclosed dietary hypercalciuria in 21/58 (36%) of previously NCa patients. In these NCa patients, the ACLT may be replaced by the CCLT. The distinction between AH and RH initially evidenced by the ACLT was not further confirmed. These data suggest that either fasting Ca/Cr is not adequate for subclassification of HCa or that AH and RH represent a different spectrum of the same disease, and that a primary resorptive component should also be considered.
可通过急性口服钙负荷试验（ACLT）来区分高钙尿症的吸收性或肾性起源。在86例草酸钙肾结石患者中，按照其日常自由饮食（钙含量为542±29毫克/天，均值±标准误），发现28例（23%）为高钙尿症（HCa）患者，58例（67%）为正常钙尿症（NCa）患者。由于许多含钙结石形成者（CSF）看似正常的24小时钙排泄可能是高钙吸收与适度低钙摄入共同作用的结果，因此所有患者均接受了ACLT检查。在28例HCa患者中，13例（46%）被归类为吸收性（AH），15例（54%）为肾性高钙尿症（RH）。在58例NCa患者中，38例（65%）表现出肠道吸收亢进的特征，因此被指定为类AH，20例（35%）为类RH。为进一步阐明饮食钙在这些CSF中的作用，设计了一项慢性钙负荷试验（CCLT），即连续7天每天口服1克钙。当第7天尿钙（uCa）≥4毫克/千克/24小时时，认为对CCLT有阳性反应。在NCa患者中，29%的类AH受试者对CCLT有反应，71%无反应；50%的类RH受试者也有反应，50%无反应。在HCa患者中，85%的AH和67%的RH受试者在CCLT后uCa维持在≥4毫克/千克/24小时，15%的AH和23%的RH受试者未维持。然而，HCa患者中未观察到平均uCa有显著额外增加。所有患者均接受了空腹尿钙（Ca/Cr）的二次评估。在89%的类RH和78%的RH患者中发现了该参数的变化。总之，这些数据表明，无论钙负荷试验的急性反应提示为AH还是RH，都存在对钙摄入敏感或不敏感的患者亚群。CCLT在21/58（36%）之前的NCa患者中发现了饮食性高钙尿症。在这些NCa患者中，ACLT可被CCLT替代。ACLT最初证明的AH和RH之间的区别未得到进一步证实。这些数据表明，要么空腹Ca/Cr不足以对HCa进行亚分类，要么AH和RH代表同一疾病的不同谱系，并且还应考虑主要的吸收成分。
