Clinical, Biochemical, and Radiological Profile of Normocalcemic Primary Hyperparathyroidism

Abstract

Context The clinical and radiological aspects of normocalcemic hyperparathyroidism (NHPT) are confounded by the differing methods used to rule out secondary hyperparathyroidism and by the small sample size. Objective To assess the clinical, biochemical, and radiological profile of NHPT compared with primary hyperparathyroidism (PHPT) and control subjects Design Multicentric cross-sectional study Setting Outpatient clinic Patients 47 NHPT, 41 PHPT, and 39 age- and sex-matched control subjects. Main Outcome Measures Calcium metabolism and bone turnover markers (BTMs). Lumbar spine, total hip, femoral neck, one-third distal radius bone mineral density (BMD). Morphometric vertebral fracture (VF) assessed by dual-energy X-ray absorptiometry. Results NHPT patients had significantly higher parathyroid hormone, 25(OH)-vitamin D levels and lower calcium × phosphorus product than controls (P < .001). Compared with PHPT, the NHPT group had significantly higher 25(OH) vitamin D levels (P = .016). NHPT had BTM levels similar to controls and PHPT. NHPT, PHPT, and controls have similar lumbar spine and femoral neck BMD. NHPT and controls had a similar radial BMD, while patients with PHPT had a lower radial BMD than both patients with NHPT (P = .031) and controls (P < .05). Using the control group as the reference, after adjustment for interacting factors, there was no increase in risk of moderate–severe VF in NHPT (odds ratio [OR] 1.04, 95% confidence interval [CI] 0.25-4.55), while PHPT had an increased risk (OR 3.81,95% CI 1.15-15.12). Seventy-nine percent of NHPT and 59% of PHPT patients fulfilled the criteria for asymptomatic hyperparathyroidism. Conclusions The biochemical phenotype of NHPT is intermediate between PHPT and controls. In contrast, the bone phenotype resembles controls with normal bone turnover, no significant BMD impairment, and no increased risk of VF.

Echocardiographic Findings in Patients With Normocalcemic Primary Hyperparathyroidism Compared With Findings in Hypercalcemic Primary Hyperparathyroid Patients and Control Subjects

“…For example, in the latest study, serum calcium levels were higher in PHPT patients compared to the serum levels found in our PHPT sample. However, the serum calcium levels in our PHPT population are in line with the current presentation of the disease in western countries, especially in Italy (29)(30)(31)(32).…”

Normocalcemic Hyperparathyroidism: A Heterogeneous Disorder Often Misdiagnosed?

“…Palermo and colleagues performed a cross‐sectional study to characterize the clinical, biochemical, and radiological profile of NHPT. ( 47 ) They recruited and analyzed three consecutive groups: 41 patients with PHPT, 47 patients with NHPT, and 39 age‐ and sex‐matched controls. The NHPT cohort was precisely defined compared with other studies, meeting the criteria of the Fourth International Workshop.…”

Normocalcaemic primary hyperparathyroidism: what is the role of parathyroid surgery?

“… 13 Compared with hPHPT patients, studies have shown no significant difference in the incidence of both osteoporosis and fractures between nPHPT and hPHPT patients. 14 – 17 However, a recent comparative prospective study by Gómez-Ramírez et al found certain bone resorption markers (osteocalcin, P1NP and B-CTX) to be significantly lower in nPHPT patients compared with those with hPHPT, 18 which may be suggestive of reduced skeletal impact in this patient group (see Table 1 ).…”

“…18 Other studies have reinforced these findings, with no significant differences reported in the incidence of hypertension or nephrolithiasis between the nPHPT and hPHPT patient groups. 14,15,17,21 However, a study by Beysel et al revealed that whilst the incidence of all other associated co-morbidities was comparable between nPHPT and hPHPT patients, 16 the incidence of nephrolithiasis was significantly lower in those with nPHPT.…”