Division of Endocrinology, Diabetes and Metabolic Bone Diseases, Hospital Agamenon Magalhães, University of Pernambuco Medical School, Recife, Brazil.
Division of Radiology, Hospital Agamenon Magalhães, University of Pernambuco Medical School, Recife, Brazil.
Kidney Blood Press Res. 2019;44(5):1189-1195. doi: 10.1159/000502578. Epub 2019 Sep 20.
Normocalcemic primary hyperparathyroidism (NPHPT) is characterized by elevations in serum parathyroid hormone levels in the presence of normal serum calcium concentrations after exclusion of secondary hyperparathyroidism. We have previously demonstrated no differences in the prevalence of clinically active urolithiasis between NPHPT and hypercalcemic asymptomatic PHPT, and that it is significantly higher in postmenopausal osteoporotic women with NPHPT in comparison to women with normal serum PTH and calcium concentrations. Few studies have addressed the occurrence of silent or occult kidney stones in asymptomatic hypercalcemic PHPT, but no data are available for NPHPT.
To determine the presence of occult urolithiasis in NPHPT patients using routine abdominal ultrasonography.
We studied 35 patients with NPHPT (mean age 63.2 ± 10.7 years, 96% women; serum PTH 116.5 ± 39.2 pg/mL, 25OHD 38.5 ± 6.82 ng/mL, total calcium 9.1 ± 0.56 mg/dL; albumin 4.02 ± 0.37 g/dL; BUN 34.35 ±10.23 mg/dL; p = 3.51 ± 0.60 mg/dL; estimated glomerular filtration rate 88.44 ± 32.45 mL/min/1.73 m2, and 24-h urinary calcium excretion 140.6 ± 94.3 mg/24 h). The criteria for the diagnosis of NPHPT were as follows: serum PTH above the reference range (11-65 pg/mL), normal albumin-corrected serum calcium concentrations, normal 24-h urinary calcium excretion, serum 25OHD above 30 ng/mL, estimated GFR (MDRD) above 60 mL/min/1.73 m2 (with the exclusion of medications such as thiazide diuretics, lithium, bisphosphonates, and denosumab), a history of clinical symptoms of urolithiasis, and a family history of kidney stones. Thirty-five patients were evaluated and 25 of them met the inclusion criteria. Five patients presented nephrolithiasis corresponding to 20% of the study population. There were no statistically significant differences in any of the clinical or laboratory variables studied between patients with or without urolithiasis, although mean serum PTH levels were higher in patients with stones (180.06 ± 126.48 vs. 100.72 ± 25.28 pg/mL, p = 0.1). The size of the stones ranged from 0.6 to 0.9 cm and all of the stones were located in the renal pelvis.
We found a high prevalence of occult kidney stones in NPHPT patients, similar to what is observed in clinically manifested urolithiasis, in hypercalcemic PHPT.
正常血钙性原发性甲状旁腺功能亢进症（NPHPT）的特征是在排除继发性甲状旁腺功能亢进症后，血清甲状旁腺激素水平升高，而血清钙浓度正常。我们之前的研究表明，NPHPT 和高钙无症状 PHPT 之间的临床活动性尿路结石患病率没有差异，而且在伴有 NPHPT 的绝经后骨质疏松症女性中，其患病率明显高于血清 PTH 和钙浓度正常的女性。很少有研究探讨无症状高钙性 PHPT 中隐匿性肾结石的发生情况，但 NPHPT 尚无相关数据。
通过常规腹部超声检查确定 NPHPT 患者是否存在隐匿性尿路结石。
我们研究了 35 例 NPHPT 患者（平均年龄 63.2 ± 10.7 岁，96%为女性；血清 PTH 116.5 ± 39.2 pg/mL，25OHD 38.5 ± 6.82 ng/mL，总钙 9.1 ± 0.56 mg/dL；白蛋白 4.02 ± 0.37 g/dL；BUN 34.35 ±10.23 mg/dL；p = 3.51 ± 0.60 mg/dL；估计肾小球滤过率 88.44 ± 32.45 mL/min/1.73 m2，24 小时尿钙排泄量 140.6 ± 94.3 mg/24 h）。NPHPT 的诊断标准如下：血清 PTH 高于参考范围（11-65 pg/mL），白蛋白校正后的血清钙浓度正常，24 小时尿钙排泄正常，血清 25OHD 大于 30 ng/mL，估计肾小球滤过率（MDRD）大于 60 mL/min/1.73 m2（排除噻嗪类利尿剂、锂、双膦酸盐和地舒单抗等药物），有尿路结石的临床症状史，有肾结石家族史。对 35 例患者进行了评估，其中 25 例符合纳入标准。5 例患者出现肾结石，占研究人群的 20%。有结石和无结石患者的任何临床或实验室变量均无统计学差异，尽管结石患者的平均血清 PTH 水平较高（180.06 ± 126.48 vs. 100.72 ± 25.28 pg/mL，p = 0.1）。结石大小为 0.6-0.9 cm，均位于肾盂。
我们发现 NPHPT 患者隐匿性肾结石的患病率较高，与临床上表现为尿路结石的高钙 PHPT 相似。
