Normocalcemic versus Hypercalcemic Primary Hyperparathyroidism: More Stone than Bone?

Abstract

Introduction. Normocalcemic primary hyperparathyroidism (NPHPT) is considered a variant of the more frequent form of the disease characterized by normal serum calcium levels with high PTH. The higher prevalence of renal stones in patients with HPTP and the well established association with bone disorders show the importance of studies on how to manage asymptomatic patients. Objective. To compare the clinical and laboratory data between the normocalcemic and mild hypercalcemic forms of PHPT. Methods. We retrospectively evaluated 70 patients with PHPT, 33 normocalcemic and 37 mild hypercalcemic. Results. The frequency of nephrolithiasis was 18.2% in normocalcemic patients and 18.9% in the hypercalcemic ones (P = 0.937). Fifteen percent of normocalcemic patients had a previous history of fractures compared to 10.8% of hypercalcemic patients, although there was no statistically significant difference (P = 0.726). Conclusion. Our data confirms a high prevalence of urolithiasis in normocalcemic primary hyperparathyroidism, but with the preservation of cortical bone. This finding supports the hypothesis that this disease is not an idle condition and needs treatment.

Diagnosis and management of primary hyperparathyroidism: a scientific statement from the Department of Bone Metabolism, the Brazilian Society for Endocrinology and Metabolism

“…A retrospective case series study compared the clinical and laboratory data of patients with mild hypercalcemic PHPT (n = 37) with patients with NPHPT (n = 33). The frequency of nephrolithiasis was similar between the two groups (18.9% vs. 18.2%, p = 0.937) (46). This was also observed when NPHPT patients were compared with non-PHPT controls (47) (C-4).…”

Interdisciplinary Aspects of Primary Hyperparathyroidism: Symptomatology in a Series of 100 Cases

“…This difference may be partly related to the special features of the current study group, which was a small population dominated by postmenopausal women with a risk of osteoporosis due to estrogen deficiency, so the low BMD level may be a result of both PHPT and additional factors other than PHPT. This also concerns some other available studies [16,19,20]. In the present study 16 bone symptomatic patients (23.8%) had a previous history of fragility fractures, 1/3 of them with multiple fracture localizations, mainly the spine and wrist, and less frequently the femoral neck.…”

“…The reason for this may be the low prevalence of PHPT (3%) reported among urolithiasis patients [12]. Recent retrospective studies have presented a lower incidence of nephrolithiasis in PHPT patients (18.2% to 28.6%) than observed in the current study [16,13]. Due to the small size of the study groups, the incidence may be hard to compare [13].…”

“…In large retrospective studies conducted in Scotland on 904 PHPT patients, the mean s-Ca concentrations in hypercalcemic patients fluctuated mildly, reaching 2.62 mmol/L and 2.67 mmol/l, respectively, at 12 and 15 year intervals [14,15]. Meanwhile, a study of Brazilian PHPT patients reported a mean s-Ca level of 2.83 mmol/L [16]. In the current study, hypercalcemia dominated significantly, affecting over 3/4 of the patients, while hypercalcemia, hypercaliciuria and hypophosphatemia coincided in 1/4 of the cases.…”

Normocalcemic primary hyperparathyroidism: long-term follow-up associated with multiple adenomas

“…In MrOS (The Osteoporotic Fractures in Men Study), the prevalence of normocalcemic hyperparathyroidism was 0.4% in a population of 2,364 males, while in the DHS (Dallas Heart Study), in a population of 3,450 individuals of males and females, it was 3.1% (4). As in most cases of primary hyperparathyroidism, the elevation of PTH is the result of a single parathyroid adenoma, which is removed by surgery, leading to clinical and laboratory resolution (3,5). The case described below illustrates the long-term follow-up of a postmenopausal woman with NPHPT patient who progressed with multiple adenomas.…”