Impact of vitamin D deficiency on the clinical and biochemical phenotype in women with sporadic primary hyperparathyroidism

Calcium/phosphate ratio: an additional tool for the clinical management of asymptomatic primary hyperparathyroidism?

PURPOSE

Serum calcium/phosphate ratio (Ca/P) has been recently proposed as an additional tool to identify primary hyperparathyroidism (PHPT), especially in patients with subclinical presentation, with a proposed cut-off of 3.3 when both values are expressed in mg/dL. No data are available on the relationship between Ca/P and the clinical presentation of PHPT. We thus evaluated this relationship in a large, single-center, unselected series.

METHODS

515 consecutive PHPT patients (mean age 65 ± 13.15 years, 77.1% females) were retrospectively evaluated at diagnosis.

RESULTS

Mean Ca/P was 4.54 ± 1.5 (range 2.36-13.9), being higher than 3.3 in 88.5% of patients. Ca/P was significantly higher in (1) males, (2) symptomatic PHPT, (3) patients with 25-hydroxy vitamin D levels lower than 20 μg/L, (4) patients with osteitis fibrosa cystica, (5) patients with T score < - 2.5 at the radial site. In a multivariate regression analysis, Ca/P resulted significantly associated with PTH levels. After the exclusion of 57 patients with asymptomatic PHPT (aPHPT) patients and serum Ca higher than 1 mg/dL above the upper limit of normal range, no differences were found in Ca/P between aPHPT meeting or not surgical criteria.

CONCLUSIONS

In PHPT Ca/P ratio is associated with increased biochemical and clinical severity of disease and represents a direct indicator of clinical bone damage. However, it does not seem an additional tool to identify aPHPT patients reaching surgical indication.

Vitamin D Deficiency and the Presentation of Primary Hyperparathyroidism: A Mini Review

The clinical presentation of primary hyperparathyroidism (PHPT) has evolved over the years from a symptomatic disorder to a predominantly asymptomatic condition. Altered vitamin D metabolism seems to play a role in the presentation of PHPT and may exacerbate the severity of disease. The epidemiology of PHPT differs in the developing versus the developed world, where more severe phenotypes occur in regions where vitamin D deficiency is common. Although it has been validated that patients with PHPT should be vitamin D sufficient, the threshold to supplement in relation to the severity of PHPT and the degree of vitamin D deficiency remains controversial. This review will highlight some of the controversy regarding vitamin D deficiency and the different phenotypes of PHPT.

The Impact of Moderate Hypophosphatemia on the Clinical Management of Primary Hyperparathyroidism

Background and objective The impact of moderate hypophosphatemia (hypoP) on primary hyperparathyroidism (PHPT) and its use as an independent surgical criterion has not been adequately evaluated in the literature. In light of this, we conducted this study to address the scarcity of data on this topic. Methods We conducted a retrospective evaluation of data related to 164 (133 females and 31 males) patients with PHPT who met the criteria for inclusion in the study. HypoP, which is indicated by phosphorus (P) levels lower than 2.5 mg/dL, was found in 78 (47.5%) patients, and moderate hypoP (1-1.99 mg/dL) was found in 25 patients (15.2%). Results PHPT severity was worse in hypoP patients than non-hypoP patients, as evidenced by higher levels of mean serum calcium (12.9 ±1.0 mg/dL vs. 11.1 ±0.3 mg/dL respectively, p<0.001), parathormone (PTH) [median (interquartile range, IQR): 455.3 (455.3) ng/L vs. 124.0 (84.0) ng/L respectively, p<0.001] and mean 24-hour urinary calcium (414.6 ±168.5 mg/day vs. 291.5 ±161.4 mg/day respectively, p=0.026) as well as lower levels of mean BMI (25.6 ±3.9 kg/m2 vs. 29.0 ±4.0 kg/m2 respectively, p=0.18) and mean 25-hydroxy vitamin D3 (13.8 ±7.3 µg/L vs. 18.2 ±7.8 µg/L respectively, p=0.001). Among the whole study population as well as among patients with Ca levels <1.0 mg/dL according to the upper limit of normal, P level was determined to be an independent factor affecting the indication for surgical treatment [β: -1.96,p=0.038, odds ratio (OR): 0.14, 95% confidence interval (CI): 0.02-0.89 and β: -2.3, p=0.034, OR: 0.10, 95% CI: 0.12-0.84 respectively]. Conclusion We found a strong correlation between moderate hypoP and the severity of the biochemical manifestations of PHPT. In asymptomatic PHPT patients, moderate hypoP was predictive of surgical indication, independent of age and level of hypercalcemia.

Surgery for primary hyperparathyroidism in Germany, Switzerland, and Austria: an analysis of data from the EUROCRINE registry

PURPOSE

EUROCRINE is an endocrine surgical register documenting diagnostic processes, indication for surgical treatment, surgical procedures, and outcomes. The purpose was to analyse data for PHPT in German speaking countries regarding differences in clinical presentation, diagnostic workup, and treatment.

METHODS

All operations for PHPT performed from 07/2015 to 12/2019 were analysed.

RESULTS

Three thousand two hundred ninety-one patients in Germany (9 centres; 1762 patients), Switzerland (16 centres; 971 patients) and Austria (5 centres; 558 patients) were analysed. Hereditary disease was seen in 36 patients in Germany, 16 patients in Switzerland and 8 patients in Austria. In sporadic disease before primary operation, PET-CT showed the highest sensitivity in all countries. In re-operations, CT and PET-CT achieved the highest sensitivities. The highest sensitivity of IOPTH was seen in Austria (98.1%), followed by Germany (96.4%) and Switzerland (91.3%). Operation methods and mean operative time reached statistical significance (p<0.05). Complication rates are low. Overall, 656 (19.9%) patients were asymptomatic; the remainder showed bone manifestations, kidney stones, fatigue and/or neuropsychiatric symptoms.

CONCLUSION

Early postoperative normocalcaemia ranged between 96.8 and 97.1%. Complication rates are low. PET-CT had the highest sensitivity in all three countries in patients undergoing primary operation as well as in Switzerland and Austria in patients undergoing re-operation. PET-CT could be considered a first-line preoperative imaging modality in patients with inconclusive ultrasound examination. The EUROCRINE registry is a beneficial and comprehensive data source for outcome analysis of endocrine procedures on a supranational level.

Levels of bioavailable, and free forms of 25(OH)D after supplementation with vitamin D3 in primary hyperparathyroidism

The 25 hydroxyvitamin D [25(OH)D] is the major metabolite for ascertaining vitamin D status, which circulates bound to a specific carrier (vitamin D-binding protein - VDBP). A portion that circulates unbound vary according to the VDBP genotype. This study evaluates the behavior of different forms of 25(OH)D, before and after supplementation with 14,000 IU of vitamin D3, weekly for 12 weeks, in individuals with primary hyperparathyroidism and controls. Fifty-six patients with active primary hyperparathyroidism (PHPT) and 64 paired controls (CTRL), not taking vitamin D3 for the last three months, were enrolled. The genetic isotypes of VDBP were determined to calculate bioavailable and free 25(OH)D. A p < 0.05 was considered significant. There were no statistical differences in free, bioavailable, and total 25(OH)D levels between PHPT and CTRL groups at baseline. The distribution of VDBP haplotypes 1s/1s, 1f/1f, 1s/1f, 2/2, 1s/2, and 1f/2 was similar between groups. After supplementation, all three forms of 25(OH)D proportionally increased within each group, although the percentage increment was lower in the PHPT group (p < 0.05). Total 25(OH)D is better correlated with PTH in the PHPT group than bioavailable and free 25(OH)D (r = -0.41; p < 0.05). The concentrations of total, free, and bioavailable 25(OH)D were similar in both PHPT and CTRL groups, and all forms increased proportionally after supplementation, although this increment percentage was higher in the CTRL group, with a subsequent reduction of PTH and AP. Total 25(OH)D correlated better with PTH than other forms, suggesting no advantages in measuring free or bioavailable 25(OH)D in these situations.

Concentrations of total, bioavailable, and free 25OHD in individuals with and without primary hyperparathyroidism and their correlations to DXA and trabecular bone score

Objective

This study aimed to investigate the association between 25OHD (total, bioavailable and free) with bone mass and microarchitecture among primary hyperparathyroidism (PHPT) patients and controls.

Subjects and methods

Sixty-four patients in the preoperative period of PHPT and 63 matched controls, who had not taken vitamin D in the last three months. To calculate the bioavailable and free 25OHD, the genetic variants of the vitamin D-binding protein (DBP) were determined. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry (DXA). The distributions of total, bioavailable and free 25OHD and their correlation with TBS and DXA were evaluated.

Results

PHPT showed BMD and TBS values lower than CTRL in all locations (p < 0.05). There were no statistical differences in the levels of free, bioavailable and total 25OHD between the PHPT and CTRL groups [mean, min-max: 3.4 (1.4-8.6) vs. 3.1 (1.0- 9.8) pg/mL, 1.51 (0.43-3.58) vs. 1.41 (0.38-3.48) ng/mL, 22.6 (11.0-39.9) vs. 20.6 (8.9-35.3) ng/dL, respectively; (p > 0.05). The distribution of DBP haplotypes was similar between groups. DXA showed no correlation with any form of 25OHD in both groups. TBS presented a weak correlation with the total 25OHD in PHPT (r = 0.28; p = 0.02) and a moderate correlation with the total, free and bioavailable 25OHD in CTRL (r = 0.42; r = 0.42; r = 0.43; respectively, p < 0.01).

Conclusion

The concentrations of total, free and bioavailable 25OHD were similar in both the PHPT and control groups. 25OHD concentrations correlated positively with TBS and not with DXA, especially in controls, suggesting that this method may be more sensitive to assessing the consequences of vitamin D deficiency on bone quality in individuals without PHPT.

Digital spatial profiling of human parathyroid tumors reveals cellular and molecular alterations linked to vitamin D deficiency

Primary hyperparathyroidism (PHPT) is a common endocrine neoplastic disorder characterized by disrupted calcium homeostasis secondary to inappropriately elevated parathyroid hormone (PTH) secretion. Low levels of serum 25-hydroxyvitamin D (25OHD) are significantly more prevalent in PHPT patients than in the general population (1-3), but the basis for this association remains unclear. We employed a spatially defined in situ whole-transcriptomics and selective proteomics profiling approach to compare gene expression patterns and cellular composition in parathyroid adenomas from vitamin D-deficient or vitamin D-replete PHPT patients. A cross-sectional panel of eucalcemic cadaveric donor parathyroid glands was examined in parallel as normal tissue controls. Here, we report that parathyroid tumors from vitamin D-deficient PHPT patients (Def-Ts) are intrinsically different from those of vitamin D-replete patients (Rep-Ts) of similar age and preoperative clinical presentation. The parathyroid oxyphil cell content is markedly higher in Def-Ts (47.8%) relative to Rep-Ts (17.8%) and normal donor glands (7.7%). Vitamin D deficiency is associated with increased expression of electron transport chain and oxidative phosphorylation pathway components. Parathyroid oxyphil cells, while morphologically distinct, are comparable to chief cells at the transcriptional level, and vitamin D deficiency affects the transcriptional profiles of both cell types in a similar manner. These data suggest that oxyphil cells are derived from chief cells and imply that their increased abundance may be induced by low vitamin D status. Gene set enrichment analysis reveals that pathways altered in Def-Ts are distinct from Rep-Ts, suggesting alternative tumor etiologies in these groups. Increased oxyphil content may thus be a morphological indicator of tumor-predisposing cellular stress.

The impact of vitamin D deficiency on clinical, biochemical and metabolic parameters in primary hyperparathyroidism

BACKGROUND

It has been suggested that vitamin D deficiency is associated with worse clinical outcomes in primary hyperparathyroidism (PHPT). We aimed to evaluate the relationship between vitamin D deficiency and clinical, biochemical and metabolic parameters in PHPT patients.

METHODS

A total of 128 patients with biochemically confirmed PHPT were included. Patients were categorized as vitamin D deficient if 25-OH vitamin D was <50nmol/L, or normal if vitamin D was ≥50nmol/L. Biochemical parameters, bone mineral densitometry (BMD), and urinary tract and neck ultrasonography were assessed.

RESULTS

In the study group, 66 (51.6%) patients had vitamin D deficiency and 60 (48.4%) had normal vitamin D levels. Nephrolithiasis and osteoporosis were found in 26.6% and 30.5% of subjects, respectively. The prevalence of metabolic syndrome (MetS), obesity (BMI≥30kg/m²) and hypertension (HTN) were higher in the vitamin D deficient group when compared to the normal group (p=0.04, p=0.01 and p=0.03, respectively). There was no difference regarding the presence of nephrolithiasis and osteoporosis between the groups. The mean adenoma size was similar in both groups.

CONCLUSIONS

Vitamin D deficiency was not associated with osteoporosis, nephrolithiasis, adenoma size or biochemical parameters in PHPT. However, vitamin D deficiency may be a risk factor for developing HTN and MetS in PHPT.

Serum calcium levels are associated with cognitive function in hypoparathyroidism: a neuropsychological and biochemical study in an Italian cohort of patients with chronic post-surgical hypoparathyroidism

PURPOSE

Hypoparathyroidism (HypoPT) is a rare endocrine disease and conventional therapy is based on calcium and vitamin D analogues. Conventional therapy does not restore calcium homeostasis and patients complain with neuropsychological symptoms, which have been evaluated with nonspecific self-administered questionnaires. This study aims to evaluate cognitive functions of patients with chronic post-surgical (PS)-HypoPT compared to a control population, using a standardized neuropsychological approach and evaluating the relationship with serum calcium (Alb-Ca).

METHODS

Observational, monocentric study on 33 patients with PS-HypoPT and 24 controls, in whom biochemical testing and a standardized neuropsychological assessment by a trained psychologist were performed.

RESULTS

In patients with PS-HypoPT, low Alb-Ca correlated with a worse performance on semantic memory abilities and executive function, as suggested by a significant inverse correlation between Alb-Ca and Trail Making Test A (TMT-A) scores (r = - 0.423; p = 0.014) and by a positive correlation with Semantic Fluency Test scores (SF)(r = 0.510; p = 0.002). PS-HypoPT patients with Alb-Ca ≤ 8.9 mg/dl had a significantly lower test performance compared with PS-HypoPT patients with Alb-Ca > 8.9 mg/dl, both at the TMT-A test (mean score: 34.53-18.55; p < 0.0001) and at SF test (mean score: 41.94-48.68; p = 0.01) and also a significantly lower test performance compared with control patients' group at TMT-A (mean score: 34.53-25.5; p = 0.0057).

CONCLUSIONS

Patients with chronic PS-HypoPT in conventional therapy do not show a severe cognitive impairment; however, cognitive functions namely visuo-spatial attention, executive function and semantic memory appear to be modulated by Alb-Ca and impaired by its low levels.

Vitamin D deficiency is associated with single gland parathyroid disease

BACKGROUND

Primary hyperparathyroidism (PHPT) with low preoperative vitamin D levels is thought to be related to 4-gland hyperplasia. We reviewed final parathyroid pathology in relationship to preoperative vitamin D levels.

METHODS

A retrospective review was performed for all PHPT patients undergoing parathyroidectomy from 2001 to 2019. Patient demographics, laboratory studies, and final pathology were reviewed.

RESULTS

2230 patients were included in the analysis, 78.1% were female with a mean age of 59 years. Patients were stratified into 3 groups based on their preoperative 25-hydroxy vitamin D levels; "deficient" (<20 ng/mL) (n = 319), "insufficient" (20-30 ng/mL) (n = 1108), or "sufficient" (>30 ng/mL) (n = 803). Patients with deficient vitamin D had a higher frequency of single adenoma (71%) compared to sufficient vitamin D patients (62%) (p < 0.001) and fewer hyperplastic glands (19%) compared to sufficient vitamin D level patients (25%) (p < 0.001).

CONCLUSIONS

Vitamin D deficiency is more strongly associated with single-gland parathyroid disease than 4-gland hyperplasia. Further investigation into the complex interplay between vitamin D levels and autonomous parathyroid function is warranted.

Accessing the influence of 99mTc-Sesta-MIBI-positive thyroid nodules on preoperative localisation studies in patients with primary hyperparathyroidism

Purpose

Curative treatment for primary hyperparathyroidism (PHPT) is parathyroidectomy (PTX) with removal of the hyperfunctioning gland(s). In an endemic goitre region, 35–78% of PHPT patients show concomitant thyroid disease. This study aimed to evaluate if ^99mTc-sestamibi (MIBI)-positive thyroid nodules decrease sensitivity in regard to localising the hyperfunctioning parathyroid gland(s) in PHPT patients.

Methods

Within 5 years, 497 consecutive patients with biochemically proven PHPT were included in this study. The data was analysed retrospectively.

Results

In total, 198 patients underwent PTX with thyroid surgery and 299 patients underwent sole PTX. Sensitivity of MIBI scan for PTX with and without thyroid surgery was 72.1% and 73.6%, respectively. A statistically significant difference in sensitivity of ultrasound for PTX with and without thyroid surgery (57.0% and 70.9%, respectively) was observed (p = 0.029). Thyroid nodule histology did not have a significant effect on the MIBI scan. Unilateral neck exploration (UNE) was performed in 110 patients and bilateral neck exploration (BNE) in 177 patients. The probability of surgical conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Conclusions

Concomitant benign thyroid nodules did not influence MIBI sensitivity. No correlation between thyroid carcinoma and MIBI uptake was determined. However, MIBI detection of thyroid malignancy is important in patients initially being considered for minimal invasive parathyroidectomy. Sensitivity and positive predictive value of ultrasound were significantly lower in patients with thyroid nodules. The probability of conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Serum Phosphate: A Neglected Test in the Clinical Management of Primary Hyperparathyroidism

BACKGROUND

Although the inverse correlation between serum PTH and phosphate (P) levels in patients with primary hyperparathyroidism (PHPT) is well known, the relationship between P levels and the clinical picture of the disease has not been well investigated. This was thus the aim of this paper.

PATIENTS

A total of 472 consecutive patients with PHPT attending our center were retrospectively evaluated at diagnosis.

RESULTS

P levels lower than 2.5 mg/dL (HypoP) were found in 198/472 patients (41.9%). HypoP was mild (2-2.5 mg/dL), moderate (1-1.9 mg/dL), and severe (<1 mg/dL) in 168 (84.9%), 30 (15.1%), and 0 cases, respectively. P levels were lower in males than females. Patients with more severe bone density impairment at the radial (but not the vertebral or femoral) site had P levels significantly lower than other patients. PHPT severity was worse in HypoP patients, both clinically (higher prevalence of renal stones, but not of osteoporosis) and biochemically (higher serum calcium and PTH levels). All patients in the moderate HypoP group were either symptomatic or asymptomatic reaching surgical indication according to the latest guidelines.

CONCLUSIONS

We observed a relationship between P levels and biochemical and clinical features of PHPT severity. In asymptomatic PHPT patients, even moderate HypoP is predictive of surgical indication, regardless of age and hypercalcemia severity.

Skeletal abnormalities in Hypoparathyroidism and in Primary Hyperparathyroidism

Both hypoparathyroidism (HypoPT), as well as its pathological counterpart, primary hyperparathyroidism (PHPT), can lead to skeletal abnormalities. Chronic deficiency of PTH in patients with HypoPT is associated with a profound reduction in bone remodeling, with consequent increases in bone density, and abnormalities in microarchitecture and bone strength. It is still not clear whether there is an increase in fracture risk in HypoPT. While standard therapy with calcium supplements and active vitamin D does not restore bone homeostasis, treatment of HypoPT with PTH appears to correct some of those abnormalities. In PHPT, the continuous exposure to high levels of PTH causes an increase in bone remodeling, in which bone resorption prevails. In the symptomatic form of PHPT, patients can present with fragility fractures, and/or the classical radiological features of osteitis fibrosa cystica. However, even in mild PHPT, catabolic skeletal actions of PTH are evident through reduced BMD, deterioration of bone microarchitecture and increased risk of fragility fractures. Successful parathyroidectomy improves skeletal abnormalities. Medical treatment, such as bisphosphonates and denosumab, can also increase bone density in patients with PHPT who do not undergo surgery. This article reviews skeletal involvement in HypoPT and in PHPT, as assessed by bone remodeling, DXA, trabecular bone score, and quantitative computed tomography, as well as data on bone strength and fracture risk. The effects of PTH replacement on the skeleton in subjects with HypoPT, and the outcome of parathyroidectomy in patients with PHPT, are also reviewed here.

Primary hyperparathyroidism and vitamin D deficiency

Primary hyperparathyroidism (PHPT) is the third most common endocrine disease after diabetes mellitus and thyroid pathology. Recent epidemiological and experimental data have shown that long-term maintenance of low vitamin D levels in the blood can lead to the development of hyperplastic processes in the cells of the parathyroid glands, followed by autonomous production of parathyroid hormone. In PHPT vitamin D insufficiency or deficiency according to various sources occurs with a frequency of 5377% of cases. The literature review indicates more severe disease in patients with concomitant vitamin D deficiency. The expediency of preoperative assessment of vitamin D levels in all patients with PHPT in order to minimize the risk of hypocalcemia after parathyroidectomy is discussed. This article presents the relationship between vitamin D deficiency and PHPT, as well as possible methods for correcting vitamin D deficiency in PHPT. Molecular and cellular mechanisms of the occurrence of pathological processes in the parathyroid glands under conditions of low vitamin D levels are presented.

The Impact of Observation Versus Parathyroidectomy on Bone Mineral Density and Fracture Risk Determined by FRAX Tool in Patients With Primary Hyperparathyroidism

To study impact of observation (OBV) vs parathyroidectomy (PTX) on biochemistry, bone mineral density (BMD) and fracture risk calculated by Fracture Risk Assessment (FRAX) tool in primary hyperparathyroidism (PHPT). Retrospective study of 60 patients (OBV - 26; PTX - 34 patients). Mean adjusted calcium improved in both groups [OBV - 2.76 ± 0.07 vs 2.51 ± 0.20 mmol/L; p < 0.00001, PTX - 2.87 ± 0.21 vs 2.36 ± 0.12 mmol/L; p < 0.00001]. Mean parathyroid hormone level declined in both but more in PTX group [OBV - 11.4 ± 5.2 vs. 9.7 ± 5.6 pmol/L; p = 0.04, PTX - 14.3 ± 8.2 vs 4.6 ± 2.2 pmol/L; p < 0.00001]. In OBV group, BMD and T scores declined at all sites. Mean percentage change of BMD was -5.8 % at femoral neck (FN), -4.9 % at total hip (TH), -6.2 % at lumbar spine (LS) and -10.0 % at lower 1/3^rd radius (LR). PTX led to stabilization of BMD at FN (3.0 %), TH (-0.6 %) and LS (2.2 %) but significant improvement at LR (13.9 %; p = 0.0005). In OBV group, 10 year risk of hip fracture (HF) (7.5 ± 9.0 % vs. 8.6 ± 9.0; p = 0.01) and major osteoporotic fracture (OF) (16.6 ± 10.9 % vs 18.3 ± 10.8 %; p = 0.002) worsened with time whereas in PTX group, risk of both type of fractures remained stable (HF; p = 0.48 and OF; p = 0.43). Comparison between groups showed greater improvement in median % change of fracture risk for both HF and OF in PTX group. OBV in PHPT lead to greater decline in BMD at all skeletal sites and imparted significant risk of HF and major OF. PTX offered stabilization of BMD at most sites but improvement at LR with unchanged fracture risk. FRAX tool should be used more frequently and universally.

Trabecular Bone Score (TBS) in Primary Hyperparathyroidism (PHPT): A Useful Tool?

Primary Hyperparathyroidism (PHPT) often leads to bone loss, even in its asymptomatic presentations. Trabecular Bone Score (TBS) is a method to assess the trabecular bone structure of the spine. This study aimed to evaluate TBS measurements combined with Dual X-ray Absorptiometry (DXA) values in the search for more accurate bone fragility risk assessment among PHPT patients. From 2017 to 2019, patients diagnosed with PHPT (n = 64), before surgery, were invited to participate in this study. Bone mineral density (BMD) by DXA at the lumbar spine, total hip, femoral neck, distal third radius, and TBS were determined in patients and controls (n = 63). The vertebral fracture was defined using the Genant method in vertebral images by DXA and vertebral fracture assessment (VFA). Patients and controls did not differ in age, sex, menopausal status, or body mass index (BMI). The PHPT patients presented significantly lower BMD values than the controls in all sites evaluated. The TBS measurements were also statistically lower in PHPT patients than controls (mean TBS PHPT = 1.233 vs TBS controls = 1.280, p = 0.044). Osteoporosis was observed in 50% of PHPT patients and 26.6% of controls (p = 0.02). However, lumbar spine T-Score < -2.5 was observed only in 21.8% of PHPT patients. Vertebral fractures were detected in nine individuals (14%) from the PHPT group and four (6.3%) in the controls (p = 0.24). The TBS area under the curve (AUC) was higher than DXA AUC in all sites, for vertebral fracture assessment. The TBS AUC was significant in the PHPT group (0.75, 95% CI 0.62 - 0.88, p = 0.02) and not significant in the DXA analysis. The ROC curve showed that TBS values < 1.187 are associated with a significantly higher risk of vertebral fracture among PHPT patients (p = 0.02). The TBS used as a complement to DXA measurements is a useful tool which may better assess fragility risk among PHPT patients.

Primary Hyperparathyroidism: A Narrative Review of Diagnosis and Medical Management

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the outpatient setting. Symptomatic presentation includes non-specific signs and symptoms of hypercalcemia, skeletal fragility, nephrolithiasis and nephrocalcinosis. The majority of individuals present at an asymptomatic stage following routine biochemical screening, without any signs or symptoms of calcium or parathyroid hormone (PTH) excess or target organ damage. Indications for surgery have recently been revised as published in recent guidelines and consensus statements. Parathyroidectomy is advised in patients younger than 50 years old and in the presence of either significant hypercalcemia, impaired renal function, renal stones or osteoporosis. Surgery is always appropriate in suitable surgical candidates, however, medical management may be considered in those with mild asymptomatic disease, contraindications to surgery or failed previous surgical intervention. We summarized the optimal medical interventions available in the care of PHPT patients not undergoing parathyroidectomy. Calcium and vitamin D intake should be optimized. Antiresorptive therapy may be used for skeletal protection in patients with an increased fracture risk. Cinacalcet, a calcimimetic agent, has been shown to effectively lower serum calcium and PTH levels. The effect of medical treatment on the reduction in fracture risk is unknown and should be the focus of future research.

Low 25-Hydroxyvitamin D in Primary Hyperparathyroidism: Enhanced Conversion Into 1,25-Hydroxyvitamin D May Not Be "True" Deficiency

Vitamin D deficiency is reported in individuals with primary hyperparathyroidism (PHP). However, decreased 25OHD may be attributed to enhanced conversion into 1,25‐hydroxyvitamin D [1,25(OH)D]. To examine vitamin D metabolism in individuals with PHP, serum calcium, PTH, 25OHD, and 1,25(OH)D levels were determined in 210 adults: 102 with PHP, 40 with normal 25OHD, and 68 with vitamin D deficiency. Concentrations were redetermined in 37 individuals with PHP following vitamin D supplementation and 43 patients postsurgery. Comparisons were conducted by Student's t test and ANOVA. Correlations were assessed between PTH and 25OHD, 1,25(OH)D, and 1,25(OH)D/25OHD in individuals with PHP. Calcium, PTH, and 1,25(OH)D were higher (p < 0.001) in individuals with PHP (11.4 ± 0.4, 116 ± 21, 79 ± 6) than in individuals with normal 25OHD (9.6 ± 0.2, 49 ± 5, 57 ± 6) and vitamin D deficiency (9.3 ± 0.2, 62 ± 6, 32 ± 4). Compared with individuals with normal 25OHD (47 ± 5), 25OHD was lower (18 ± 3), but not different from subjects with vitamin D deficiency (15 ± 2). In individuals with PHP, vitamin D2 supplementation induced rises in 1,25(OH)D and calcium without lowering PTH, whereas postsurgery, calcium, PTH, 25OHD, and 1,25(OH)D normalized. Finally, in individuals with PHP, significant correlations (p < 0.01) were documented between PTH and calcium (r = 0.74), 25OHD (r = −0.43), 1,25(OH)D (r = 0.52), and 1,25(OH)D/25OHD (r = 0.46); and between 1,25(OH)D/25OHD and calcium (r = 0.47). Subnormal 25OHD in most individuals with PHP may be attributed to enhanced conversion to 1,25(OH)D—not “true” vitamin D deficiency—although in some patients, both PHP and vitamin D deficiency coexisted. Moreover, vitamin D supplementation exaggerated hypercalcemia in individuals with PHP. © 2020 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Hypomagnesuria is Associated With Nephrolithiasis in Patients With Asymptomatic Primary Hyperparathyroidism

CONTEXT

The pathogenesis of nephrolithiasis in primary hyperparathyroidism (PHPT) remains to be elucidated. The latest guidelines suggest parathyroidectomy in patients with asymptomatic PHPT with hypercalciuria (> 400 mg/d) and increased stone risk profile.

OBJECTIVE

The objective of this work is to evaluate the association of urinary stone risk factors and nephrolithiasis in patients with asymptomatic sporadic PHPT and its clinical relevance.

DESIGN

A total of 157 consecutive patients with sporadic asymptomatic PHPT were evaluated by measurement of serum and 24-hour urinary parameters and kidney ultrasound.

RESULTS

Urinary parameters were tested in the univariate analysis as continuous and categorical variables. Only hypercalciuria and hypomagnesuria were significantly associated with nephrolithiasis in the univariate and multivariate analysis adjusted for age, sex, body mass index, estimated glomerular filtration rate, parathyroid hormone, 25-hydroxyvitamin D, serum calcium, and urine volume (odds ratio, OR 2.14 [1.10-4.56]; P = .04; OR 3.06 [1.26-7.43]; P = .013, respectively). Hypomagnesuria remained associated with nephrolithiasis in the multivariate analysis (OR 6.09 [1.57-23.5], P = .009) even when the analysis was limited to patients without concomitant hypercalciuria. The urinary calcium/magnesium (Ca/Mg) ratio was also associated with nephrolithiasis (univariate OR 1.62 [1.27-2.08]; P = .001 and multivariate analysis OR 1.74 [1.25-2.42], P = .001). Hypomagnesuria and urinary Ca/Mg ratio had a better, but rather low, positive predictive value compared with hypercalciuria.

CONCLUSIONS

Hypomagnesuria and urinary Ca/Mg ratio are each associated with silent nephrolithiasis and have potential clinical utility as risk factors, besides hypercalciuria, for kidney stones in asymptomatic PHPT patients. The other urinary indices that have been commonly thought to be associated with kidney stones in PHPT are not supported by our results.

Hypercalciuria: its value as a predictive risk factor for nephrolithiasis in asymptomatic primary hyperparathyroidism?

CONTEXT

The latest guidelines of the 4th International Workshop on Asymptomatic Primary Hyperparathyroidism (aPHPT) reintroduced hypercalciuria (i.e. urinary calcium > 400 mg/day) as criterion for surgery. However, the value of hypercalciuria as a predictor of nephrolithiasis and the correct cut-off values still need to be confirmed.

OBJECTIVE

To evaluate the prevalence of silent kidney stones in a large series of patients with aPHPT and the sensibility, specificity and predictive value of different cut-off values of hypercalciuria in identifying patients with nephrolithiasis.

DESIGN

One hundred seventy-six consecutive patients with aPHPT were evaluated at our Institution by serum and urinary parameters and kidney ultrasound.

RESULTS

Silent nephrolithiasis was found in 38 (21.6%) patients. In the univariate and multivariate model, hypercalciuria was a predictor of nephrolithiasis using the criterion of 400 mg/24 h [(OR 2.30, (1.11-4.82) P = 0.025], 4 mg/kg/bw [OR 2.65, (1.14-6.25) P = 0.023], gender criterion [OR 2.79, (1.15-6.79) P = 0.023] and the cut-off value derived from the ROC analysis [(> 231 mg/24 h) OR 5.02 (1.68-14.97) P = 0.004]. Despite these several predictive criteria, however, hypercalciuria had a low positive predictive value (PPV), ranging from 27.4 to 32.7%.

CONCLUSIONS

Hypercalciuria is a predictor of nephrolithiasis, but its PPV is low.

Risk factors for vertebral fracture in primary hyperparathyroidism

PURPOSE

Screening for vertebral fractures (VF) in primary hyperparathyroidism (PHPT) is recommended, but there are limited data regarding which patients are at greatest risk for VF. We evaluated risk factors for VF in PHPT.

METHODS

This is a retrospective cross-sectional analysis of 117 participants with PHPT. We assessed Grades 2 and 3 VF by vertebral fracture assessment (VFA) and the association of VF with the trabecular bone score (TBS), other skeletal parameters and clinical risk factors. VFA was performed only in those who met National Osteoporosis Foundation criteria for VFA screening.

RESULTS

T-scores were in the osteopenic range and TBS was degraded. Overall VF rate based on VFA or other imaging was 12.8%. Serum PTH, calcium and TBS were not associated with VF. Those with VF were older (p = 0.04), had worse renal function (p = 0.04), were more likely to have received osteoporosis treatment (p = 0.03), and tended to have had a prior fracture (p = 0.06). T-scores did not differ by fracture status at any skeletal site. Those with VF had nine times the odds of osteoporosis at the hip (95% CI 2.4-34.5), but this risk factor had low sensitivity (46.7%) for VF. Hip T-score < -2.6, Age > 78.6 years, and GFR < 58.8 ml/min/1.73 m² (thresholds maximizing sensitivity and specificity) had areas under the curve of 0.60-0.67 for VF (all p < 0.05) and low sensitivity. Findings were similar when analyses were limited to women.

CONCLUSIONS

In PHPT, VF risk factors included older age, prior fracture, worse renal function and osteoporosis at the hip, but not osteoporosis at other sites, TBS or biochemical indices of PHPT. Since identified risk factors had low sensitivity and were generally inaccurate for categorizing those with VF, the data do not support limiting screening to PHPT patients with these specific VF risk factors.

Effectiveness of anti-osteoporotic treatment after successful parathyroidectomy for primary hyperparathyroidism: a randomized, double-blind, placebo-controlled trial

PURPOSE

After successful surgery for primary hyperparathyroidism, bone mineral density (BMD) does not improve equally in all patients. As no trial has so far aimed to influence normalization of BMD, it was the goal of this investigation to determine whether pharmacological treatment is effective in improving regain of BMD after successful parathyroidectomy in patients with preoperatively diagnosed osteoporosis or osteopenia and to evaluate when treatment may be indicated.

METHODS

In this randomized, placebo-controlled, double-blind trial, 52 patients were treated with strontium ranelate 2 g daily + 1000 mg calcium + 800 IU vitamin D (strontium group; SG) or with 1000 mg calcium + 800 IU vitamin D alone (placebo group; PG) for 1 year. The main outcome measures were BMD (lumbar spine, femoral neck, radius) and bone turnover markers.

RESULTS

The baseline characteristics were similar in both groups. Absolute BMD (1.007 ± 0.197 vs. 0.897 ± 0.137 g/cm2; p = 0.024) and both relative (9.94 vs. 3.94%; p < 0.001) and absolute (0.09 ± 0.06 vs. 0.03 ± 0.04 g/cm2; p < 0.001) changes in lumbar-spine BMD were significantly higher in the SG than in the PG. Compared to baseline, BMD significantly increased in both groups at the lumbar spine (p < 0.001 and p = 0.001, respectively) and femoral neck (both p < 0.001), whereas radius BMD only changed significantly in the SG. However, the proportion of patients with osteoporosis/osteopenia significantly declined only at the lumbar spine in the SG (from 69.0 to 37.9%; p = 0.034), whereas no decrease was found in the PG. No severe adverse events occurred.

CONCLUSIONS

Postoperative anti-osteoporotic treatment can positively influence regain of BMD mainly in the lumbar spine and should be considered. Without treatment, most patients and especially those with low preoperative markers of bone turnover remained osteoporotic/osteopenic 1 year after surgery.

Who Benefits from Treatment of Primary Hyperparathyroidism?

Parathyroidectomy (PTx) is the only definitive treatment for primary hyperparathyroidism (PHPT), but is commonly underutilized. Most patients are medically observed, whereas approximately 30% of patients are treated operatively. PTx is a low-risk surgical procedure and the most cost-effective treatment option. An international consensus statement was published in 1990 to guide clinicians in the management of patients with PHPT, particularly those with asymptomatic disease. Most patients with PHPT and low perioperative risk benefit from surgical treatment, regardless of whether they meet consensus criteria, due to fracture risk reduction, health-related quality-of-life improvements, and prevention or mitigation of disease progression.

A Comparison between Silent and Symptomatic Renal Stones in Primary Hyperparathyroidism

BACKGROUND

Nephrolithiasis is a common complication of primary hyperparathyroidism (PHPT), and in a subgroup of patients stones are clinically silent. Patients with silent and symptomatic stones may differ biochemically. There is a scarcity of data available comparing patients with silent and symptomatic renal stones in PHPT.

AIMS

To characterize patients with PHPT with nephrolithiais and to compare patients with silent and symptomatic stones.

MATERIALS AND METHODS

We reviewed clinical data of 186 patients with PHPT managed at our center from January 1996 to December 2017. Silent renal stones were defined as ultrasonography finding of renal stones without symptoms. Symptomatic renal stones were defined as those with symptoms or a history of graveluria or any procedure for nephrolithiasis. A 5-mm diameter was set as the cut-off between micro- and macrolithiasis. We compared those with (n = 95) and without (n = 91) stones, and, among stone formers, those with symptoms (n = 66) and silent (n = 29) were compared.

RESULTS

There was no significant difference between stone formers and nonstone formers with respect to biochemical parameters. Patients with silent renal stones had significantly lower serum calcium and higher phosphate, than those with symptomatic stones. Most (75%) patients with silent renal stones had microlithiais, while only a fifth (22%) with symptomatic renal stones had microlithiasis.

CONCLUSION

Nephrolithiasis is a common complication of PHPT. Most patients with silent renal stones had microlithiasis and biochemical features of less severe disease. Patients with silent renal stones may represent early mild stage of PHPT.

Non-surgical management of primary hyperparathyroidism

The purpose of this chapter is to discuss the options available for patients with primary hyperparathyrodism (PHPT) not undergoing parathyroidectomy (PTx). Adequate hydration should be recommended in all patients. Calcium intake should not be restricted and vitamin D deficiency should be corrected aiming at a serum concentration of 25OHD of >20 ng/mL or even higher (>30 ng/mL according to some opinion leaders). Pharmacologic therapy is not an alternative to PTx and could be considered in patients who meet the surgical criteria but unwilling to undergo PTx, as well as in patients with an increased risk of surgery or failed surgery. Targeted therapy includes antiresorptive drugs for skeletal protection and cinacalcet for lowering serum calcium. Combined therapy can be an option when appropriate. Pregnant women should be treated conservatively (hydration) and surgery, if needed, performed in the second trimester of pregnancy. Severe hypercalcemia is a life-threatening condition and requires immediate intensive treatment.

Primary Hyperparathyroidism

Background

Primary hyperparathyroidism (PHPT), the most common cause of hypercalcemia, is most often identified in postmenopausal women. The clinical presentation of PHPT has evolved over the past 40 years to include three distinct clinical phenotypes, each of which has been studied in detail and has led to evolving concepts about target organ involvement, natural history, and management.

Methods

In the present review, I provide an evidence-based summary of this disorder as it has been studied worldwide, citing key concepts and data that have helped to shape our concepts about this disease.

Results

PHPT is now recognized to include three clinical phenotypes: overt target organ involvement, mild asymptomatic hypercalcemia, and high PTH levels with persistently normal albumin-corrected and ionized serum calcium values. The factors that determine which of these clinical presentations is more likely to predominate in a given country include the extent to which biochemical screening is used, vitamin D deficiency is present, and whether parathyroid hormone levels are routinely measured in the evaluation of low bone density or frank osteoporosis. Guidelines for parathyroidectomy apply to all three clinical forms of the disease. If surgical guidelines are not met, parathyroidectomy can also be an appropriate option if no medical contraindications are present. If either the serum calcium or bone mineral density is of concern and surgery is not an option, pharmacological approaches are available and effective.

Conclusions

Advances in our knowledge of PHPT have guided new concepts in diagnosis and management.

Occult urolithiasis in asymptomatic primary hyperparathyroidism

OBJECTIVE

Recent international guidelines suggest renal imaging to detect occult urolithiasis in all patients with asymptomatic primary hyperparathyroidism (PHPT), but data regarding their prevalence and associated risk factors are limited. We evaluated the prevalence and risk factors for occult urolithiasis.

METHODS

Cross-sectional analysis of 96 asymptomatic PHPT patients from a university hospital in the United States with and without occult nephrolithiasis.

RESULTS

Occult urolithiasis was identified in 21% of patients. Stone formers had 47% higher 24-hour urinary calcium excretion (p = 0.002). Although available in only a subset of patients (n = 28), activated vitamin D [1,25(OH)₂D] was 29% higher (p = 0.02) in stone formers. There was no difference in demographics, BMI, calcium or vitamin D intake, other biochemistries, renal function, BMD, or fractures. Receiver operating characteristic curves indicated that urinary calcium excretion and 1,25(OH)₂D had an area under the curve of 0.724 (p = 0.003) and 0.750 (p = 0.04), respectively. A urinary calcium threshold of >211mg/day provided a sensitivity of 84.2% and a specificity of 55.3% while a 1,25(OH)₂D threshold of >91pg/mL provided a sensitivity and specificity of 62.5% and 90.0% respectively for the presence of stones.

CONCLUSION

Occult urolithiasis is present in about one-fifth of patients with asymptomatic PHPT and is associated with higher urinary calcium and 1,25(OH)₂D. Given that most patients will not have occult urolithiasis, targeted imaging in those most likely to have occult stones rather than screening all asymptomatic PHPT patients may be useful. The higher sensitivity of urinary calcium versus 1,25(OH)₂D suggests screening those with higher urinary calcium may be an appropriate approach.

Communicating Hydrocephalus in a Case of Long-Term Primary Hyperparathyroidism

We present the rare case of a 47-year-old woman with protracted primary hyperparathyroidism complicated by communicating hydrocephalus and cerebellar tonsillar herniation secondary to calvarial thickening. The parathyroid glands remained elusive, despite the use of advanced preoperative imaging modalities and three neck explorations. The serum calcium was optimally controlled with cinacalcet and alfacalcidol. Awareness of this rare complication is essential for early diagnosis and prompt intervention to prevent fatal posterior brain herniation.

Characteristics, management, and outcome of primary hyperparathyroidism at a single clinical center from 2005 to 2016

This study presents the clinical and biochemical profiles of patients with PHPT between 2005 and 2016 at our center. Most PHPT patients in China show symptomatic features. The number of symptomatic and asymptomatic patients increased during that time, and the number of individuals with parathyroid carcinoma is now increasing.

INTRODUCTION

Over the last decade, the prevalence of primary hyperparathyroidism (PHPT) has increased sharply, and the number of individuals with parathyroid cancer is still trending upward. Little is known about the clinical outlook of the disease over the last decade in China. The aim of this study was to describe the clinical characteristics of PHPT patients at our center from January 2005 to December 2016.

METHODS

Two hundred sixty patients with PHPT visiting Shanghai Jiao Tong University Affiliated Sixth People's Hospital were enrolled retrospectively. The clinical manifestations and biochemical abnormalities of these patients were analyzed.

RESULTS

Among all patients, 73.1% had symptomatic PHPT, while the number of symptomatic and asymptomatic patients increased 1 to 2.5 times and 1.5 to 3 times, respectively, from 2005 to 2016. Bone pain and single adenoma were the most frequent signs and pathological results. The patients with parathyroid carcinoma over the last 5 years accounted for 90% (9/10) of all parathyroid carcinoma patients from 2005 to 2016, and parathyroid carcinoma patients had higher levels of serum calcium, parathyroid hormone (PTH), and serum creatinine (P < 0.05) than parathyroid hyperplasia and parathyroid adenoma patients.

CONCLUSIONS

Most patients with PHPT in China still exhibit classic clinical and biochemical features. Both symptomatic and asymptomatic patients have increased over the last 12 years. Although the proportion of parathyroid carcinoma was small, a noticeable upward tendency was observed at our center.

Primary hyperparathyroidism

In this Review, we describe the pathogenesis, diagnosis and management of primary hyperparathyroidism (PHPT), with a focus on recent advances in the field. PHPT is a common endocrine disorder that is characterized by hypercalcaemia and elevated or inappropriately normal serum levels of parathyroid hormone. Most often, the presentation of PHPT is asymptomatic in regions of the world where serum levels of calcium are routinely measured. In addition to mild hypercalcaemia, PHPT can manifest with osteoporosis and hypercalciuria as well as with vertebral fractures and nephrolithiasis, both of which can be asymptomatic. Other clinical forms of PHPT, such as classical disease and normocalcaemic PHPT, are less common. Parathyroidectomy, the only curative treatment for PHPT, is recommended in patients with symptoms and those with asymptomatic disease who are at risk of progression or have subclinical evidence of end-organ sequelae. Parathyroidectomy results in an increase in BMD and a reduction in nephrolithiasis. Various medical therapies can increase BMD or reduce serum levels of calcium, but no single drug can do both. More data are needed regarding the neuropsychological manifestations of PHPT and the pathogenetic mechanisms leading to sporadic PHPT, as well as on risk factors for complications of the disorder. Future work that advances our knowledge in these areas will improve the management of the disorder.

Clinical profile of juvenile primary hyperparathyroidism: a prospective study

INTRODUCTION

Juvenile primary hyperparathyroidism is uncommon and more symptomatic than the adult counterpart. The aim of this prospective monocentric study, conducted in a tertiary referral center, was to evaluate the clinical, biochemical, and densitometric data, and the outcome of a series of patients with juvenile primary hyperparathyroidism.

MATERIAL AND METHODS

The study group included 154 patients with sporadic and familial juvenile primary hyperparathyroidism, aged ≤40 years. Relative frequency of sporadic and familial forms, comparison of the clinical and biochemical characteristics, rate of cure after parathyroidectomy and the outcome of patients not undergoing surgery were evaluated.

RESULTS

Familial cases (n = 42) were younger, less frequently females, and had milder disease compared to sporadic cases (n = 112). No difference was observed in biochemical and densitometric parameters. Among patients undergoing parathyroidectomy (n = 116), familial cases had a higher rate of multigland disease and a higher persistence/relapse rate compared to sporadic cases (73 vs. 3.6% and 48.1 vs. 5.7%, respectively). Patients who did not undergo parathyroidectomy had stable clinical, biochemical, and densitometric parameters during follow-up (median 27 months). Using the cut-off age of 25 years, there was no difference in clinical, biochemical and densitometric parameters between younger and older patients, with the exception of parathyroid hormone and phosphate, which were significantly lower and higher, respectively, in patients <25 years.

CONCLUSIONS

In conclusion, this prospective study shows that juvenile primary hyperparathyroidism is frequently a sporadic disease, with no difference in the biochemical phenotype between sporadic and familial forms. Patients with familial juvenile primary hyperparathyroidism have a milder clinical phenotype and higher rate of persistence/recurrence after PTx than those with sporadic juvenile primary hyperparathyroidism.

Sex Difference in the Clinical Presentation of Primary Hyperparathyroidism: Influence of Menopausal Status

CONTEXT

Female-to-male ratio in primary hyperparathyroidism (PHPT) is 3:1, but data on sex impact on the clinical presentation are limited.

DESIGN

We evaluated, retrospectively, sex difference in biochemistry and clinical presentation at diagnosis in a monocentric series of 417 patients with PHPT: 93 men (58.6 ± 14.5 years), and 324 women (61.7 ± 12.8 years), of whom 54 were premenopausal (pre-F) and 270 postmenopausal (post-F).

RESULTS

Men were significantly younger (P = 0.046) and more frequently symptomatic than women (62.3% vs 47%, P = 0.016). No sex difference was found in serum parathyroid hormone, calcium, creatinine, 25-hydroxy-vitamin D, and urinary calcium levels, whereas serum phosphate was higher in women. Nephrolithiasis (detected by imaging or history of passing stones) was more frequent in men (50.5% vs 33% in women, P = 0.003) and osteoporosis (T-score <-2.5 at any site) was more frequent in women (52.2% vs 35.5% in men, P = 0.0066). Symptomatic patients were 43.3%, 64.8%, and 62.3% in post-F women, pre-F women, and men, respectively. Kidney stones were less frequent and osteoporosis more frequent in post-F women than in pre-F women (28.1% vs 59.2% and 58.9% vs 18.5%, respectively). After combining symptomatic and asymptomatic patients meeting surgical criteria recommended by current guidelines, no sex difference was observed in the proportion of patients to be referred for surgery (84.6% in men vs 84.9% in women).

CONCLUSION

Biochemical activity of PHPT seems to be independent of sex, but clinical presentation is different, mostly due to menopausal state. However, surgical referral was indicated equally in men and women.

MECHANISMS IN ENDOCRINOLOGY: Kidney involvement in patients with primary hyperparathyroidism: an update on clinical and molecular aspects

Primary hyperparathyroidism (PHPT) is the third most common endocrine disease. Kidney is a target of both chronic elevated PTH and calcium in PHPT. The classic PHPT complications of symptomatic kidney stones and nephrocalcinosis have become rare and the PHPT current presentation is asymptomatic with uncertain and long-lasting progression. Nonetheless, the routine use of imaging and of biochemical determinations have revealed the frequent occurrence of asymptomatic kidney stones, hypercalciuria and reduced kidney function in asymptomatic PHPT patients. Though the pathogenesis is far from being elucidated, PHPT is associated with reduced renal function, in terms of estimated glomerular filtration rate, and related increased morbidity and mortality. In the last decade, the effort of the Kidney Disease: Improving Global Outcomes (KDIGO) panel of experts highlighted that even mild reduction of kidney function is associated with increased risk of cardiovascular disease. These considerations provided the basis for the Fourth Workshop recommendations of a more extensive diagnostic workout about kidney features and of wider criteria for parathyroid surgery including asymptomatic kidney disease. Moreover, kidney involvement in PHPT is likely to be affected by variants of genes coding the key molecules regulating the calcium and ions renal handling; these features might have clinical relevance and should be considered both during diagnostic workout and follow-up. Finally, the effects of parathyroid surgery and of medical treatment on kidney involvement of PHPT are reviewed.

Parathyroidectomy: is vitamin D a player for a good outcome?

Background: The field of parathyroidectomy (PTx) is complex and brings together many specialists. Even if the surgical approaches changed from classical to minimally invasive PTx, a good outcome is correlated with an adequate localization before and during PTx, while blood assays, such as parathormone (PTH) or 25-hydroxyvitamin D, become useful additional markers. Aim. Specific aspects related to parathyroidectomy and vitamins D (VD) were introduced. Material and Method. The article represents a PubMed-based narrative review. Results. The growing evidence regarding the high prevalence of hypovitaminosis D and early detection of primary hyperparathyroidism (HPT) requires a particular attention to the association of these two disorders, which may be incidental, but some common pathogenic links are displayed. Low VD stimulates PTH production as a secondary or even tertiary type of HPT diagnosis. VD deficiency is associated with larger parathyroid adenomas and higher levels of PTH before and after surgery for primary HPT. Asymptomatically and normocalcemic forms of primary HPT, which are not immediately referred to PTx, require a normalization of the VD levels. VD supplements are safe under some serum calcium cutoffs and offer a better outcome after PTx. However, primary HPT is cured by surgery and, if the indication is well established, this should not be delayed too long to replace VD. Up to half of PTx cases may experience increased PTH levels after surgery, but most of these are transitory if rapid VD correction is done and only a few remaining cases will eventually develop persistent / recurrent primary HPT. Conclusion. A close following of 25-hydroxivitamin D represents one of the keys for a good outcome in the field of parathyroid surgery. Abbreviations: HPT = hyperparathyroidism, MEN = Multiple Endocrine Neoplasia Syndrome, PTx = parathyroidectomy, PTH = parathormone, VD = Vitamin D.