"Incipient" primary hyperparathyroidism: a "forme fruste" of an old disease

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 Eucalcemic Patient With Elevated Parathyroid Hormone Levels

Primary hyperparathyroidism (PHPT) is classically characterized by hypercalcemia with elevated or inappropriately normal parathyroid hormone (PTH) levels. Elevated PTH levels in the presence of normal calcium levels are not infrequently found during the evaluation of metabolic bone disorders or kidney stone disease. This can be caused by secondary hyperparathyroidism (SHPT) or normocalcemic primary hyperparathyroidism (NPHPT). NPHPT is due to autonomous parathyroid function whereas SHPT is caused by a physiologic stimulation to PTH secretion. Many medical conditions and medications can contribute to SHPT, and differentiation between SHPT and NPHPT may be difficult. Cases are presented to illustrate examples. In this paper, we review the distinction between SHPT and NPHPT as well as end organ effects of NPHPT and outcomes of surgery in NPHPT. We suggest that the diagnosis of NPHPT be made only after careful exclusion of causes of SHPT and consideration of medications that can increase PTH secretion. Further, we advise a conservative approach to surgery in NPHPT.

Surgery for primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a hypercalcemic disorder that occurs when one or more parathyroid glands produces excessive parathyroid hormone (PTH). PHPT is typically treated with surgery, and it remains the only definitive therapy, whose techniques have evolved over previous decades. Advances in preoperative localization exams and the intraoperative PTH monitoring have become the cornerstones of recent parathyroidectomy techniques, as minimally invasive techniques are appropriate for most patients. Nevertheless, these techniques, are not suitable for PHPT patients who are at risk for multiglandular disease, especially in those who present with familial forms of PHPT that require bilateral neck exploration. This manuscript also explores other conditions that warrant special consideration during surgical treatment for PHPT: normocalcemic primary hyperparathyroidism, pregnancy, reoperation for persistent or recurrent PHPT, parathyroid carcinoma, and familial and genetic forms of hyperparathyroidism.

Comparisons Between Normocalcemic Primary Hyperparathyroidism and Typical Primary Hyperparathyroidism

BACKGROUND

Normocalcemic primary hyperparathyroidism (NPHPT) was first described in 2008. It is defined as consistently elevated serum parathyroid hormone (PTH) levels with normal serum calcium (sCa) concentration, after excluding secondary causes of PTH elevation. However, the exact definition and management strategy for NPHPT remain controversial. We retrospectively investigated the clinicopathological features and short-term outcomes of NPHPT patients.

METHODS

A total of 280 patients who were surgically indicated for primary hyperparathyroidism (PHPT) at the Yonsei Severance Medical Center between 2015 and 2019 were included. Patients were classified according to preoperative PTH, corrected sCa, and ionized calcium (iCa) levels as follows: typical primary hyperparathyroidism (TPHPT, elevated PTH, sCa, and iCa, n = 158) and NPHPT (elevated PTH, normal sCa, n = 122).

RESULTS

NPHPT was commonly seen in younger individuals (aged < 50 years, P = 0.025); nephrolithiasis and bone fractures were common. Preoperative PTH level was higher in the TPHPT group (P < 0.001). The NPHPT group had higher numbers of multiple parathyroid lesions (P = 0.004) that were smaller (P = 0.011). NPHPT patients were further divided into two subgroups according to iCa levels: the elevated (n = 95) and normal iCa (n = 27) groups. There was no significant difference between the two subgroups regarding symptoms and multiplicity of lesions.

CONCLUSION

We found that NPHPT may be a heterogeneous disease entity of PHPT with high rates of multi-gland disease, which appears to be biochemically milder but symptomatic. Intraoperative PTH monitoring might help increase the surgery success rate. Moreover, the short-term outcomes of NPHPT after surgery did not differ from that of TPHPT.

Correlation of Preoperative Imaging Findings and Parathyroidectomy Outcomes Support NICE 2019 Guidance

CONTEXT

Preoperative localization studies are standard practice in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). The most common modalities are neck ultrasound (US) and sestamibi scanning. However, the nature of pHPT is changing, with imaging increasingly yielding negative results. Numerous studies suggest unlocalized disease is associated with poor outcomes, calling into question whether such patients are best treated conservatively.

OBJECTIVE

This study aims to correlate parathyroidectomy outcomes with preoperative imaging in a single, high-volume institution.

METHODS

Data from a prospectively maintained departmental database of operations performed from 2017 to 2019 were analyzed. All patients undergoing first-time surgery for sporadic pHPT were included. Data collected included patient demographics, preoperative imaging, surgical strategy, and postoperative outcomes.

RESULTS

A total of 609 consecutive parathyroidectomies were included, with a median age of 59 years (range 20-87 years). The all-comer cure rate was 97.5%; this was 97.9% in dual localized patients (those with positive US and sestamibi), compared to 95.8% in the dual unlocalized group (those with negative US and sestamibi) (P = 0.33). Unilateral neck exploration was the chosen approach in 59.9% of patients with double-positive imaging and 5.7% of patients with double-negative imaging (otherwise, bilateral parathyroid visualization was performed). There was no significant difference in postoperative complications between patients undergoing unilateral or bilateral neck exploration.

CONCLUSIONS

Patients with negative preoperative imaging who undergo parathyroidectomy are cured in almost 96% of cases, compared to 98% when the disease is localized. This difference does not reach statistical or clinical significance. These findings therefore support current recommendations that all patients with pHPT who are likely to benefit from operative intervention should be considered for parathyroidectomy, irrespective of preoperative imaging findings.

European Expert Consensus on Practical Management of Specific Aspects of Parathyroid Disorders in Adults and in Pregnancy: Recommendations of the ESE Educational Program of Parathyroid Disorders

This European expert consensus statement provides recommendations for the diagnosis and management of primary hyperparathyroidism (PHPT), chronic hypoparathyroidism in adults (HypoPT), and parathyroid disorders in relation to pregnancy and lactation. Specified areas of interest and unmet needs identified by experts at the second ESE Educational Program of Parathyroid Disorders (PARAT) in 2019, were discussed during two virtual workshops in 2021, and subsequently developed by working groups with interest in the specified areas. PHPT is a common endocrine disease. However, its differential diagnosing to familial hypocalciuric hypercalcemia (FHH), the definition and clinical course of normocalcemic PHPT, and the optimal management of its recurrence after surgery represent areas of uncertainty requiring clarifications. HypoPT is an orphan disease characterized by low calcium concentrations due to insufficient PTH secretion, most often secondary to neck surgery. Prevention and prediction of surgical injury to the parathyroid glands are essential to limit the disease-related burden. Long-term treatment modalities including the place for PTH replacement therapy and the optimal biochemical monitoring and imaging surveillance for complications to treatment in chronic HypoPT, need to be refined. The physiological changes in calcium metabolism occurring during pregnancy and lactation modify the clinical presentation and management of parathyroid disorders in these periods of life. Modern interdisciplinary approaches to PHPT and HypoPT in pregnant and lactating women and their newborns children are proposed. The recommendations on clinical management presented here will serve as background for further educational material aimed for a broader clinical audience, and were developed with focus on endocrinologists in training.

A Diagnosis of Normocalcemic Primary Hyperparathyroidism Prompted by “Salt and Pepper” Lesions of the Calvarium

Background

We report a case of normocalcemic primary hyperparathyroidism, a diagnosis prompted by radiographic “salt and pepper” calvarial lesions, typically described in hypercalcemic primary hyperparathyroidism or secondary hyperparathyroidism.

Case Report

A 60-year-old woman noticed indentations of her scalp and presented to her primary care provider. Radiography of the calvarium demonstrated granular “salt and pepper” lesions, prompting investigation. The patient was found to have an elevated parathyroid hormone (PTH) level of 79 pg/mL (reference range, 14-54 pg/mL) and a normal albumin-corrected calcium level of 9.8 mg/dL (reference range, 8.6-10.4 mg/dL). She was referred to our endocrine clinic and described having bone aches, fevers, leg cramps, and a remote history of nephrolithiasis. Her physical examination revealed hypertension. Repeat laboratory evaluation confirmed elevated PTH and normal albumin-corrected calcium. Secondary causes of hyperparathyroidism were ruled out. Her 25-hydroxyvitamin D level was 35 ng/mL (reference range, 30-100 ng/mL), with a normal creatinine level (0.73 mg/dL; reference range, 0.5-0.99 mg/dL). The patient underwent ultrasound and sestamibi scintigraphy, with uptake in the right inferior thyroid pole. She was found to have a 6-mm parathyroid adenoma and underwent a targeted parathyroidectomy, with normalization of serum PTH.

Discussion

Many cases of normocalcemic primary hyperparathyroidism are diagnosed in asymptomatic patients presenting with low bone mass; however, imaging prompted this patient's evaluation. Ultimately, the calvarial lesions were thought secondary to bone resorption from increased osteoclast activity.

Conclusion

This case highlights an atypical presentation of normocalcemic primary hyperparathyroidism in that the evaluation was precipitated by unexpected radiographic evidence of metabolic bone disease, rather than by symptoms or biochemical studies.

What happens to the bone structure after normocalcemic primary hyperparathyroidism surgery?

BACKGROUND

Bone disease in primary hyperparathyroidism is a clear indication for surgical treatment. However, it is not known whether surgery benefits hypercalcemic primary hyperparathyroidism and normocalcemic primary hyperparathyroidism equally. The aim of our study was to evaluate the bone changes in patients undergoing parathyroidectomy based on the biochemical profile 1 and 2 years after surgery.

METHODS

This prospective study included 87 consecutive patients diagnosed with primary hyperparathyroidism who underwent surgery between 2016 and 2018. Bone densitometry (1/3 distal radius, lumbar, and femur) and bone remodeling markers (osteocalcin, type 1 procollagen [P1NP], β-cross-linked telopeptide of type I collagen [BCTX]) were performed preoperatively and postoperatively. Postoperative changes in bone mineral density and bone markers were compared and evaluated according to the clinical characteristics and the individual biochemical profile.

RESULTS

One year after surgery, all patients showed an increase in bone mineral density at the lumbar site (mean, 0.029 g/cm²; range, 0.017-0.04; P < .001) and femur neck (mean, 0.025 g/cm²; range, 0.002-0.05; P < .001); however, there were no changes in the distal third of the radius (mean, -0.003 g/cm²; range, -0.008 to 0.002; P = NS). There were no significant differences when comparing normocalcemic primary hyperparathyroidism and hypercalcemic primary hyperparathyroidism. Serum osteocalcin (37 ± 17.41), P1NP (67.53 ± 31.81) and BCTX (0.64 ± 0.37) levels were elevated before surgery. One year after the surgery, we observed a significant decrease in P1NP (33.05 ± 13.16, P = .001), osteocalcin (15.80 ± 6.19, P = .001), and BCTX (0.26 ± 0.32, P < .001) levels.

CONCLUSION

Our findings indicate that parathyroidectomy has similar benefits for normocalcemic primary hyperparathyroidism and hypercalcemic primary hyperparathyroidism in terms of bone improvement. Although the most substantial improvement occurred during the first postoperative year in both groups, we consider that studies with longer follow-up are warranted.

[The clinical practice guidelines for primary hyperparathyroidism, short version]

Primary hyperparathyroidism (PHPT) is an endocrine disorder of parathyroid glands characterized by excessive secretion of parathyroid hormone (PTH) with an upper normal or elevated blood calcium level. Classical PHPT refers to a symptomatic, multi-system disorder, wich can lead to a significant decrease in the quality of life, disability of patients, and even an increased risk of premature death. Hypercalcemia and the catabolic effect of PTH on various cells are considered as the main pathogenetic mechanisms of the PHPT associated complications. In the last two decades, there has been an increase in the incidence of PHPT, mainly due to the mild forms of the disease, primarily due to the routine calcium screening in North America, Western Europe and, Asia. High prevalence of the disease, as well as the variety of clinical manifestations, cause the attention of different specialists - physicians, rheumatologists, urologists, nephrologists, cardiologists and other doctors. This review cover the main issues of Russian guidelines for the management of PHPT, approved in 2020, including laboratory and instrumental methods, differential diagnosis, surgical and conservative approach, short-term and long-term follow-up. This guidelines also include the recommendations for special groups of patients with hereditary forms of PHPT, parathyroid carcinoma, PHPT during pregnancy.

Normocalcemic Primary Hyperparathyroidism: Need for a Standardized Clinical Approach

Since normocalcemic primary hyperparathyroidism (NHPT) was first defined at the Third International Workshop on the Management of Asymptomatic Primary Hyperparathyroidism in 2008, many papers have been published describing its prevalence and possible complications. Guidelines for the management of this condition are still lacking, and making the diagnosis requires fulfillment of strict criteria. Recent studies have shown that intermittent oscillations of serum calcium just below and slightly above the normal limits are very frequent, therefore challenging the assumption that serum calcium must be consistently normal to make the diagnosis. There is debate if these variations in serum calcium outside the normal range should be included under the rubric of NHPT or, rather, a milder form of classical primary hyperparathyroidism. Innovative approaches to define NHPT have been proposed that still need to be validated in prospective studies. Non-classical complications, especially cardiovascular complications, have been associated with NHPT, indicating that hyperparathyroidism may be a cardiovascular risk factor. New associations between parathyroid hormone (PTH) and several other comorbidities have also been reported from observational studies, suggesting that excessive PTH secretion might cause tissue dysfunction independent of serum calcium. Heterogeneous studies using different definitions of NHPT, however, make it difficult to draw definitive conclusions regarding the role of PTH excess when complications other than osteoporosis or kidney stones are described. This review will focus on clinical aspects and suggest an approach to NHPT.

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

Primary hyperparathyroidism (PHPT) is classically associated with both an elevated or 'inappropriately normal' parathyroid hormone (PTH) level and raised serum calcium. However, in clinical practice, increasing numbers of patients present with raised PTH but normal serum calcium, renal function and vitamin D; this is known as normocalcaemic PHPT (nPHPT). Studies investigating the clinical presentation of this condition have shown that patients may present with hypertension, nephrolithiasis, impaired glucose tolerance, osteoporosis and fragility fractures. The prevalence of such complications in nPHPT is similar to that in classical hypercalcaemic PHPT (hPHPT). Although the National Institute for Health and Care Excellence (NICE) have developed guidelines for the management of PHPT generally, a consensus is yet to be reached on the optimal management of nPHPT specifically. A review of the literature on parathyroidectomy in the treatment of nPHPT revealed that nPHPT patients were more likely to present with multi-glandular disease and significantly less nPHPT patients had an intra-operative PTH fall of >50% compared with those with hPHPT. These findings demonstrate that patients with nPHPT are more likely to receive bilateral neck explorations and require remedial surgery compared with hPHPT patients. Following surgery, improvements in bone mineral density (BMD) and renal stones are generally observed in those with nPHPT. Where surgery is not possible, medical management with alendronate has been shown to be effective in nPHPT patients. Given the higher incidence of multi-gland disease and greater possibility of remedial surgery in nPHPT, careful consideration of risks and benefits should be made on an individualised basis and surgery should be performed by surgeons experienced in four gland exploration.

Normocalcaemic primary hyperparathyroidism: An update on diagnostic and management challenges

Normocalcaemic primary hyperparathyroidism is a condition that can present with intermittent hypercalcemia or may evolve into hypercalcemic primary hyperparathyroidism. This milder biochemical entity remains incompletely understood because of a lack of long-term health outcomes regarding both medical and surgical approaches to its management. Medical therapies have shown some efficacy. A limited number of studies have found that bisphosphonates increase bone mineral density, and calcimimetics may decrease the risk of nephrolithiasis in patients with normocalcaemic primary hyperparathyroidism. Studies have also described patient outcomes after applying the same surgical criteria used for patients with hypercalcaemic primary hyperparathyroidism to those with the normocalcaemic form of the disease. These studies suggest that parathyroid surgery appears to be effective in normalizing elevated serum parathyroid hormone concentrations and decreasing adverse renal and skeletal outcomes in patients with normocalcaemic hyperparathyroidism. Given the available data and overall lack of consensus regarding the optimal management of these patients, a reasonable approach is to tailor treatment to the individual patient by considering their risk factors for new or accelerated bone loss, kidney stones, diminished quality of life, and cardiovascular disease.

Normocalcemic primary hyperparathyroidism: an update

Normocalcemic primary hyperparathyroidism (NPHPT) is diagnosed in the setting of elevated PTH concentrations with consistently normal albumin-adjusted and ionized serum calcium levels, in absence of secondary causes for elevated PTH concentrations. In order to confirm persistence of the hyperparathyroid state, PTH levels should be elevated on at least two occasions over a 3 to 6 months period. The prevalence of NPHPT depends on the population studied. Data from different studies are often not comparable; indeed, different criteria have been used to exclude secondary hyperparathyroidism. Notwithstanding such limits, the prevalence of NPHPT in studies including ionized calcium dosage was between 0.5% and 0.7%. Available data suggest that patients with NPHPT are likely to have more skeletal, kidney and metabolic complications compared to healthy subjects, but almost all studies suffer from possible misclassification of patients due to lack of ionized calcium dosage. The management of NPHPT is controversial in part due to lack of solid data about the natural history. However, surgical treatment is currently performed more frequently than in the past, although studies do not show, so far, a clear benefit from intervention.

Normocalcemic Hyperparathyroidism: A Heterogeneous Disorder Often Misdiagnosed?

Normocalcemic primary hyperparathyroidism (NHPT) was first described over 10 years ago, but uncertainties still remain about its definition, prevalence, and rates of complications. As a result, consensus management guidelines for this condition have not yet been published. Several hypotheses have been proposed for the pathophysiology of NHPT, but it may be a heterogeneous disorder with multiple causes, rather than a single etiology that explains this biochemical phenotype. A common clinical concern is whether NHPT should be treated surgically when complications are already present at first recognition of the disorder, rather than following patients clinically over time. The literature on NHPT is based mostly on larger studies of population‐based cohorts and smaller studies from referral centers. Lack of rigorous diagnostic criteria and selection bias inherent in populations seen at tertiary referral centers may explain the heterogeneity of reported rates of bone and renal complications in relation to consistently mild laboratory alterations. Unresolved questions remain about the significance of NHPT when it is diagnosed biochemically without evident bone or kidney complications. Moreover, its natural history remains to be elucidated because a proportion of what is classified as NHPT may revert to normal spontaneously, thus revealing previously unrecognized secondary hyperparathyroidism. These issues indicate that caution should be used in recommending surgery for NHPT. This review will focus on recent issues regarding the pathophysiology, evaluation, and management of NHPT. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Clinical, Biochemical, and Radiological Profile of Normocalcemic Primary Hyperparathyroidism

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.

Re-operative Parathyroidectomy in Patients With Mild Primary Hyperparathyroidism

BACKGROUND

Surgery is the definitive management of primary hyperparathyroidism and the only curative therapy. However, many surgeons are hesitant to operate on individuals with mild primary hyperparathyroidism, with an even greater reluctance to operate on those who underwent a previous parathyroidectomy. We hypothesize that patients with mild primary hyperparathyroidism who undergo a re-operation have equivalent outcomes compared with those who undergo a first-time (FT) operation.

METHODS

We reviewed a prospective database of 459 patients with mild primary hyperparathyroidism who underwent surgery by one endocrine surgeon. Of these patients, 59 had a re-operative (RE-OP) parathyroid surgery. We compared these patients to those with mild primary hyperparathyroidism who had FT surgery (n = 400) using either the Pearson chi-square, Fisher's exact test, or Student's t-test where appropriate.

RESULTS

The mean age of our cohort was 60 ± 14 y, with 86% females. Patients in the RE-OP group had similar preoperative calcium and parathyroid hormone levels compared with those in the FT group. Most patients who underwent a RE-OP surgery had four gland hyperplasia on pathology (49.2%). Patients in the RE-OP and FT groups both had high and similar cure rates (100% versus 99.8%, P = 0.70). RE-OP patients had a higher rate of recurrent hyperparathyroidism (10.3% versus 3.3%, P = 0.025).

CONCLUSIONS

In patients with mild primary hyperparathyroidism, those who undergo RE-OP parathyroidectomy have a high cure rate that is similar to FT surgery. Therefore, we recommend that these patients with recurrence of mild hyperparathyroid disease be considered for parathyroidectomy.

The calcium-to-phosphorous (Ca/P) ratio in the diagnosis of primary hyperparathyroidism and hypoparathyroidism: a multicentric study

PURPOSE

The diagnosis of primary hyperparathyroidism (PHPT) and chronic hypoparathyroidism (HypoPT) is still challenging, especially in patients asymptomatic or with non-classical phenotypes and for physicians not skilled in calcium-phosphorous (Ca-P) disorders. The serum calcium/phosphorous (Ca/P) ratio has been proposed as accurate index to identify PHPT, while it has never been tested in HypoPT. The aim of this study is to investigate the diagnostic power of the serum Ca/P ratio in the diagnosis of primary parathyroid dysfunctions (both PHPT and HypoPT) in a large series of data.

METHODS

A multicentric, retrospective, cross-sectional study (ClinicalTrials.gov: NCT03747029) was carried out including 432 PHPT patients and 217 HypoPT patients compared with 389 controls. Serum Ca, P, creatinine, parathyroid hormone and 25OH-vitamin D were collected. Serum Ca and P were expressed in mmol/L. Ca/P diagnostic performance was evaluated by receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy.

RESULTS

The Ca/P ratio was significantly higher in PHPT and lower in HypoPT patients than controls (p < 0.0001). At ROC curve analysis, the Ca/P ratio above 2.55 was defined to identify PHPT patients (sensitivity 85.7%, specificity 85.3%) and below 1.78 to identify HypoPT patients (sensitivity 88.2%, specificity 87.9%).

CONCLUSIONS

The Ca/P ratio is a highly accurate index to identify PHPT when Ca/P is above 2.55 and HypoPT when it is below 1.78. These results demonstrate the reliability of this index to rule in/out primary parathyroid dysfunctions and remark the importance of measuring serum P in clinical practice.

Normocalcemic Hyperparathyroidism: Study of its Prevalence and Natural History

CONTEXT

Normocalcemic hyperparathyroidism (NPHPT) is characterized by persistently normal calcium levels and elevated parathyroid hormone (PTH) values, after excluding other causes of secondary hyperparathyroidism. The prevalence of the disease varies greatly and the data on the natural history of this disease are sparse and inconclusive.

OBJECTIVES

The objectives of this study are to describe the prevalence of NPHPT and its natural history in a referral population and to compare the variability of serum calcium with a group of patients with primary hyperparathyroidism (PHPT).

DESIGN

A retrospective study was conducted over 5 years.

SETTING

The setting for this study was a metabolic bone referral center.

PATIENTS

A total of 6280 patients were referred for a bone mineral density measurement (BMD).

MAIN OUTCOME MEASURES

The prevalence and natural history of NPHPT and variability of calcium were the main outcome measures.

RESULTS

We identified NPHPT patients using data from the day of the BMD measurement. We excluded patients with low estimated glomerular filtration rate (eGFR) or vitamin D, or with no measurements available. Based on the evaluation of their medical files, we identified 11 patients with NPHPT (prevalence 0.18%). Only 4 patients had consistent normocalcemia throughout their follow-up, with only 2 also having consistently high PTH. None had consistently normal eGFR or vitamin D.Intermittent hypercalcemia was present in 7 of the 11 NPHPT patients. The mean adjusted calcium was found to be significantly lower in the NPHPT group compared with the PHPT group but higher than the control group. PTH was similar for NPHPT and PHPT. These 2 groups had similar variability in serum calcium.

CONCLUSIONS

NPHPT patients often have episodes of hypercalcemia. We believe that NPHPT is a mild form of PHPT.

Comparative prospective study on the presentation of normocalcemic primary hyperparathyroidism. Is it more aggressive than the hypercalcemic form?

BACKGROUND

Some patients with primary hyperparathyroidism (PHPT) have an elevated PTH that does not always correlate with high blood calcium levels. We aimed to compare the clinical presentation between normocalcaemic and hypercalcaemic forms using ionized calcium levels as an inclusion criterion.

METHODS

We included all patients referred for surgery for PHPT between January 2015 and December 2017. Patients were divided into 2 groups (hypercalcaemic (hPHTP)/normocalcaemic (nPHPT)).

RESULTS

104 patients were included.64% of the patients who were initially classified as normocalcaemic had high ionized calcium levels. There were no differences between groups except in terms of bone resorption parameters:patients with hypercalcaemia had higher osteocalcin (37.4vs23.5 ng/mL,P = .02), collagen amino-terminal propeptide (73.5vs49.2 ng/mL,P = .005), and beta-CTX levels (0.68vs0.38 ng/mL,P = .001). Bone involvement as measured by densitometry was similar.

CONCLUSSIONS

When these patients' diagnosis and classification is accurate, their clinical presentation and symptoms are similar to those of the classical form. Since the only difference is in terms of bone resorption parameters, in most cases it seems to be an attenuated form or even similar to the classical presentation. The improvement in diagnostic sensitivity supports the use of ionized calcium levels in patients suspected to have nPHPT.

Do Symptoms and Serum Calcium Levels Affect the Results of Surgical Treatment of Primary Hyperparathyroidism?

Introduction

The purpose of this study was to investigate the difference in surgical outcomes between symptomatic and asymptomatic patients with primary hyperparathyroidism (PHPT) and between patients with high serum calcium and those with normal blood calcium, as well as to explore the epidemiological trend of PHPT in northern China.

Methods

Clinicopathologic data of 197 patients (50 men and 147 women) with PHPT who underwent surgery at the First Affiliated Hospital of Harbin Medical University from 2008 to 2017 were analyzed. Changes in clinicopathology were compared among different subgroups of patients. Patients were categorized into subgroups based on serum calcium levels, whether or not they presented with symptoms, and admission time.

Results

Of the total patients, 82.23% had hypercalcemic primary hyperparathyroidism (HCPHPT), 17.77% had normocalcemic primary hyperparathyroidism (NCPHPT), 45.18% had symptomatic primary hyperparathyroidism (SPHPT), and 54.82% had asymptomatic primary hyperparathyroidism (ASPHPT). Seventy-seven cases of PHPT involved thyroid nodules, with 22 confirmed as papillary thyroid carcinoma, and 29 confirmed as nodular goiter. There was no significant difference in the success rate of surgery, postoperative recurrence rate, and the symptoms of temporary hypocalcemia between the HCPHPT and NCPHPT groups, and between the SPHPT and ASPHPT groups. The incidence of PHPT has increased threefold since 2013.

Conclusions

Symptoms and serum calcium levels did not affect the results of surgical treatment for PHPT. The incidence of PHPT in northern China is increasing. Moreover, PHPT manifestation has shifted from the symptomatic to the asymptomatic form. Thyroid surgery should be performed in PHPT patients with thyroid nodules.

Asymptomatic and normocalcemic hyperparathyroidism, the silent attack: a combo-endocrinology overview

Asymptomatic primary hyperparathyroidism (PHPT) and the new variant of PHPT, normocalcemic PHPT, are considered by many physicians as mild, innocuous forms of disease, requiring nothing more than monitoring. Although this may be true in some cases in which the disease does not progress or cause complications, deterioration with more or less severe manifestations may occur. In the present review, we discuss the existing evidence of both the classic (skeletal and renal) and non-classic (cardiovascular, gastrointestinal, and psychiatric) features that have been attributed to asymptomatic and normocalcemic PHPT and the treatment effect on them.

Proceedings of the 2018 Santa Fe Bone Symposium: Advances in the Management of Osteoporosis

The Santa Fe Bone Symposium is an annual meeting devoted to clinical applications of recent advances in skeletal research. The 19th Santa Fe Bone Symposium convened August 3-4, 2018, in Santa Fe, New Mexico, USA. Attendees included physicians of many specialties, fellows in training, advanced practice providers, clinical researchers, and bone density technologists. The format consisted of lectures, case presentations by endocrinology fellows, and panel discussions, with all involving extensive interactive discussions. Topics were diverse, including an evolutionary history of calcium homeostasis, osteoporosis treatment in the very old, optimizing outcomes with orthopedic surgery, microbiome and bone, new strategies for combination and sequential therapy of osteoporosis, exercise as medicine, manifestations of parathyroid hormone excess and deficiency, parathyroid hormone as a therapeutic agent, cell senescence and bone health, and managing patients outside clinical practice guidelines. The National Bone Health Alliance conducted a premeeting on development of fracture liaison services. A workshop was devoted to Bone Health TeleECHO (Bone Health Extension for Community Healthcare Outcomes), a strategy of ongoing medical education for healthcare professions to expand capacity to deliver best practice skeletal healthcare in underserved communities and reduce the osteoporosis treatment gap.

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.

Brown tumor of multiple facial bones associated with primary hyperparathyroidism: A clinical case report

RATIONALE

Only 4.5% of brown tumors involve facial bones; of these, solitary bone involvement is usual. Brown tumors of multiple facial bones are extremely rare. Here, we report the case of a brown tumor of multiple facial bones initially misdiagnosed as an odontogenic cyst.

PATIENT CONCERNS

A pregnant 26-year-old woman was referred to our hospital with painful swelling of multiple facial bones, anemia, urinary calculi, marasmus, and a history of multiple bone fractures. Laboratory examination revealed an elevated serum calcium level of 3.09 mmol/L (normal range: 2.0-2.8 mmol/L) and a low phosphorus level of 0.62 mmol/L (normal range: 0.81-1.65 mmol/L). The serum alkaline phosphatase concentration was 397 IU/L (normal range: 24-82 IU/L) and parathyroid hormone level was 267 pg/mL (normal range: 14-72 pg/mL). Cone beam computed tomography revealed multiple ossifying fibromas of the maxilla and mandible. Incisional biopsy revealed abundant spindle cells with areas of hemorrhage and haphazardly arranged diffuse multinucleated giant cells.

DIAGNOSES

The patient was diagnosed with primary hyperparathyroidism (HPT).

INTERVENTIONS

She was treated by parathyroidectomy.

OUTCOMES

The multiple osteitis fibrosa cystica gradually resolved as bone re-mineralized. The patient has been followed up for 2 years without evidence of tumor recurrence.

LESSONS

As multiple osteolytic lesions of facial bones can be caused by primary HPT, serum calcium and parathyroid hormone assays should be performed routinely when investigating these lesions.

Normocalcaemic primary hyperparathyroidism: a pragmatic approach

It is well recognised that over the past three to four decades the incidence of asymptomatic primary hyperparathyroidism has increased significantly. However, more recently this pattern has further evolved into a presentation with normocalcaemia and raised parathyroid hormone (PTH) level without the presence of a recognised stimulus for its rise, in the form of vitamin D deficiency or renal impairment. A diagnostic label of normocalcaemic hyperparathyroidism (NPHPT) has been given to this phenotype and in most such individuals, the initial PTH measurement is driven by the presence of metabolic bone disease. The reported prevalence, degree of end-organ involvement and the rate of progression vary considerably and are related to patients studied and the biochemical cut-offs used in its definition. A majority of patients are diagnosed during assessment of metabolic bone disease of varying degrees. Once the diagnosis is confirmed by excluding confounding factors, the patient should undergo full assessment of end-organ involvement, which is the main determinant of further therapeutic decisions. Surgery, with prior localisation, is considered in patients with significant end-organ involvement in keeping with the guidance for hypercalcaemic patients. If a patient does not meet these criteria, annual clinical and biochemical surveillance is recommended to identify progression to hypercalcaemia or worsening end-organ involvement. It is less clear if patients identified during 'routine' requests for evaluation of unrelated symptoms require similar close monitoring. In conclusion, in this review on NPHPT we focus on its definition, planning of further investigations, selection of patients for intervention and devising an appropriate follow-up strategy.

Parathyroid hormone: Data mining for age-related reference intervals in adults

OBJECTIVE

Age-related changes in parathyroid hormone (PTH) have been previously documented in adults. However, because of the limitations of traditional approaches to establishing reference intervals, age-related reference intervals have not been defined. We sought to use a data mining approach to derive age-related PTH reference intervals.

DESIGN AND PARTICIPANTS

Results from patients undergoing PTH testing over a 4-year period were extracted from the database of a private pathology laboratory in New South Wales, Australia. Patients were included in the study if they were 18 years or older and had simultaneous determination of PTH, serum calcium, estimated glomerular filtration rate and 25-hydroxyvitamin D (25-OHD). Patients with abnormalities of serum calcium or renal function were excluded.

MEASUREMENTS

Bhattacharya analysis of log-transformed data was used to derive age-related PTH reference intervals across adulthood.

RESULTS

Results were available for 33 652 subjects. Among patients with optimal 25-OHD status, older age was associated with higher PTH concentrations. Age-related reference intervals were derived and showed a 63% increase in the upper and lower reference limits between the youngest (18-29 years of age) and the oldest (80 years of age or older) age partitions. The appropriateness of using a single reference interval for patients of all ages was evaluated against objective criteria and was found to be unsatisfactory.

CONCLUSIONS

Data mining was demonstrated to be a useful tool for establishing age-related PTH reference intervals. The technique demonstrated that increasing age is associated with higher PTH concentrations and that age-related reference intervals are important for accurate result interpretation.

Normocalcemic primary hyperparathyroidism associated with progressive cortical bone loss - A case report

The existence of normocalcemic primary hyperparathyroidism (NPHP) was acknowledged at the Third and Fourth International Proceedings on primary hyperparathyroidism PHPT but data relating to its clinical presentation, natural history, and skeletal status were limited and there was no information nor guidelines as to definitive therapy. Herein are reported biochemical, hormonal, and densitometry data in a postmenopausal woman seen initially for osteoporosis who was found to have increased serum PTH levels and normal serum total and ionized calcium levels without evidence of secondary hyperparathyroidism. Over a seven year period, the patient exhibited continuing preferential cortical bone loss at the one-third site of the radius in the face of relatively stable readings at the lumbar spine and hip that led to a subtotal parathyroidectomy for parathyroid hyperplasia with resultant normalization of serum PTH.

Parathyroid hormone reflects adiposity and cardiometabolic indices but not bone density in normal men

Hyperparathyroidism may be associated with skeletal and cardiovascular abnormalities, but it is unclear whether these associations exist for high-normal levels of parathyroid hormone (PTH). We assessed relationships between PTH and anthropometric, skeletal and cardiometabolic indices in normal men. Body composition, blood pressure, biochemistry and bone mineral density (BMD) were evaluated in 151 healthy men. BMD was reassessed at 2 years, and coronary artery calcium (CAC) was measured at 3.5 years. Relationships between PTH and other baseline characteristics, CAC scores and change in BMD were evaluated. PTH correlated positively with baseline body mass index, fat mass, diastolic blood pressure, triglycerides, total and low-density lipoprotein (LDL) cholesterol, (r=0.19-0.25, P=0.02-0.002), and with category of CAC score. Relationships between PTH and cardiometabolic indices remained significant after adjustment for age, 25-hydroxyvitamin D and estimated glomerular filteration rate. Men in the top PTH tertile (⩾4.4 pmol l^-1, n=51) were more likely to have LDL cholesterol ⩾3.5 mmol l^-1, diastolic blood pressure ⩾85 mm Hg, and CAC score >0 than men in lower tertiles. PTH was not associated with history of fracture, baseline BMD, or change in BMD over 2 years. In summary, in this cohort of healthy men, PTH levels are linearly related to adiposity and to cardiometabolic indices, but not to BMD or bone loss. These findings suggest that adiposity should be considered as an independent cause of secondary hyperparathyroidism, and they may be relevant to patients with normocalcemic hyperparathyroidism, in whom high PTH levels may be a marker of adiposity and cardiometabolic risk rather than always indicating parathyroid autonomy.

Elevated PTH with normal serum calcium level: a structured approach

Normocalcaemic hyperparathyroidism is a common biochemical finding, usually identified during an assessment of bone or renal health. Hypercalcaemia must be considered by calculation of adjusted calcium, and a careful history taken to assess dietary calcium intake and for the possibility of a malabsorption syndrome. 25-hydroxyvitamin D (25OHD) should be measured and replaced if indicated. The management plan for the patient is influenced by the context in which calcium and PTH were measured. In this brief review we describe the assessment of a patient with normocalcaemic hyperparathyroidism.

Normocalcemic hyperparathyroidism is associated with complications similar to those of hypercalcemic hyperparathyroidism

Normocalcemic primary hyperparathyroidism (NC-PHPT) is a variant of hyperparathyroidism, characterized by normal serum calcium levels, high parathyroid hormone (PTH) and normal 25-OH vitamin D status. The present study aimed to compare complications related to hyperparathyroidism in patients with NC-PHPT and hypercalcemic PHPT (HC-PHPT). We retrospectively evaluated the records of 307 PHPT patients between January 2010 and March 2013. We excluded patients with impaired renal function and liver failure. All patients underwent a biochemical and hormonal examination including serum glucose, albumin, total calcium, phosphorus, creatinine, lipoproteins, PTH and 25-OH vitamin D. Nephrolithiasis and bone mineral density were documented based on a review of the medical records. The study population consisted of 36 (12 %) males and 271 (88 %) females with a mean age of 53.3 ± 9.5 years (29-70 years). Twenty-three of the patients were diagnosed with NC-PHPT (group 1) and 284 were diagnosed with HC-PHPT (group 2). There were no significant differences in terms of age, gender, prevalence of hypertension, low bone mineral density and kidney stones between the groups. The mean thyroid-stimulating hormone (TSH) and low-density lipoprotein (LDL) levels were significantly higher in group 1 than in group 2. Our study found that patients with NC-PHPT have similar several complications as patients with HC-PHPT. NC-PHPT patients have higher TSH levels despite being within the normal range, and higher LDL-C levels than patients with HC-PHPT. However, this relationship needs to be clarified in future studies with larger cohorts.

PTH and Vitamin D

PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.

Patients with normocalcemic primary hyperparathyroidism may have similar metabolic profile as hypercalcemic patients

Primary hyperparathyroidism is well known to be associated with cardiovascular morbidity and mortality. However, it is unclear whether normocalcemic primary hyperparathyroidism (NC-PHPT) and hypercalcemic primary hyperparathyroidism (HC-PHPT) share the same risk factors. We aimed to determine prevalence of metabolic syndrome in NC-PHPT and compare metabolic syndrome parameters and insulin resistance in NC-PHPT subjects with those in HC-PHPT and control subjects. After excluding patients with secondary hyperparathyroidism, the study enrolled 25 patients with NC-PHPT, 24 patients with HC-PHPT and 30 age-gender matched controls. All participants were evaluated using the International Diabetes Federation (IDF)-2006 metabolic syndrome criteria. Compared with HC-PHPT patients, NC-PHPT patients had similar prevalence of metabolic syndrome, glucose intolerance, and previous history of hypertension/anti-hypertensive medications, but compared with controls, NC-PHPT patients had significantly higher prevalence of glucose intolerance and previous history of hypertension/anti-hypertensive medications. Not serum calcium but PTH concentration was found to be significantly higher in those with glucose intolerance. Serum fasting triglyceride concentration and waist circumference were found to be positively correlated only with serum PTH concentration. In conclusion, patients with NC-PHPT may be prone to similar metabolic disturbances linked to higher cardiovascular risk like patients with HC-PHPT. Although NC-PHPT is thought to occur early in the development of the classical disease, it should be monitored regularly because of its metabolic consequences.

An overview of normocalcemic primary hyperparathyroidism

PURPOSE OF REVIEW

Normocalcemic primary hyperparathyroidism (PHPT) received special attention in the publication of the conference proceedings from the Fourth International Workshop on the Management of Asymptomatic PHPT, although much remains unknown about the disorder.

RECENT FINDINGS

Observational studies have found that despite maintaining normocalcemia, patients with normocalcemic PHPT have a high incidence of kidney stones and osteoporosis. Small studies focusing on the cardiovascular implications of normocalcemic PHPT have shown a possible association with hypertension and an atherogenic lipid profile, but not insulin resistance. Recent data from small cohorts show that subjects with normocalcemic PHPT respond to medical therapy and have a positive densitometric response following parathyroid surgery.

SUMMARY

The available evidence suggests that patients with normocalcemic PHPT develop complications of PHPT, despite having normal calcium levels. Most data come from referral populations and information regarding a mild, asymptomatic form of the disease is lacking. Future research requires a standardized approach to the diagnostic criteria of normocalcemic PHPT.

Normocalcemic primary hyperparathyroidism: a survey in a small village of Southern Italy

We investigated the prevalence of normocalcemic primary hyperparathyroidism (NPHPT) in the adult population living in a village in Southern Italy. All residents in 2010 (n=2045) were invited by calls and 1046 individuals accepted to participate. Medical history, calcium intake, calcium, albumin, creatinine, parathyroid hormone (PTH) and 25OHD were evaluated. NPHPT was defined by normal albumin-adjusted serum calcium, elevated plasma PTH, and exclusion of common causes of secondary hyperparathyroidism (SHPT) (serum 25OHD <30 ng/ml, estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m(2) and thiazide diuretics use), overt gastrointestinal and metabolic bone diseases. Complete data were available for 685 of 1046 subjects. Twenty subjects did not meet the inclusion criteria and 341 could not be evaluated because of thawing of plasma samples. Classical PHPT was diagnosed in four women (0.58%). For diagnosing NPHPT the upper normal limit of PTH was established in the sample of the population (n=100) who had 25OHD ≥30 ng/ml and eGFR ≥60 ml/min per 1.73 m(2) and was set at the mean+3s.d. Three males (0.44%) met the diagnostic criteria of NPHPT. These subjects were younger and with lower BMI than those with classical PHPT. Our data suggest, in line with previous studies, that NPHPT might be a distinct clinical entity, being either an early phenotype of asymptomatic PHPT or a distinct variant of it. However, we cannot exclude that NPHPT might also represent an early phase of non-classical SHPT, since other variables, in addition to those currently taken into account for the diagnosis of NPHPT, might cumulate in a normocalcemic subject to increase PTH secretion.

In vitro diagnostic company recalls and medical laboratory practices: an Italian case

Introduction

In vitro human diagnostic (IVD) company recalls are a common practice aimed to either minimize a potential error or eliminate an existing failure. In this case report, we aim to provide a critical analysis of a recent IVD recall and to provide a practical framework about what to do when an IVD company recalls product(s) based on the International Organization for Standardization - ISO 15189:2012 standard.

Case report

In 2014, Abbott Laboratories® (Green Oaks, IL) published an urgent field safety notice regarding a product recall (Architect Intact parathyroid hormone (PTH) Assay List Number 8K25) with immediate action required. The IVD company explained the reasons for the recall as follows: i) Abbott has confirmed that a performance shift in the Architect Intact PTH assay has the potential to generate falsely elevated results on patient samples; ii) results generated with impacted lots may demonstrate a positive shift relative to those generated with previous reagent and/or calibrator lots. This issue may also impact established Architect Intact PTH reference ranges; iii) the magnitude of shift averages approximately 13% to 45%; iv) Abbott Architect Intact PTH controls do not detect the shift; and v) all current reagent, calibrator, and control inventory are impacted. The recall could have resulted in ~40,000 inaccurate laboratory tests reported by 18 laboratories from Italy (Lombardy region).

Conclusion

IVD company recalls have a serious impact on the patient safety and require a thorough investigation and responsible approach to minimize the possible damage. Medical laboratories accredited according to the ISO 15189 standard have procedures in place to manage such situations and ensure that patient safety is maintained when such recalls are issued.

A step towards cinacalcet testing for the diagnosis of primary hyperparathyroidism: comparison with the standardized intravenous calcium loading. A pilot study

OBJECTIVE

A calcium load to suppress parathyroid hormone (PTH) secretion can help to perform the diagnosis in some case of primary hyperparathyroidism (PHPT) with atypical presentation. A similar test with calcimimetic, which avoids hypercalcaemia, would be of interest. Our proof of concept study was conducted to compare firstly the results of a single-dose cinacalcet testing with those of the standardized short-time calcium load in healthy control (HC) and secondly the results of the single-dose cinacalcet testing in HC and in PHPT.

METHODS

Twelve HCs received in a random order, at a 2-week interval, either 0·33 mmol/kg calcium gluconate intravenously for 3 h, or a single oral dose of 30 mg or 60 mg cinacalcet. Twelve PHPTs received 30 mg cinacalcet and twelve other PHPTs 60 mg cinacalcet orally. Calcaemia and serum PTH levels were measured basally and then hourly for 6 h.

RESULTS

In HC, plasma calcium did not significantly change after cinacalcet intake, whereas calcaemia rose up to 3·47 ± 0·05 mmol/l (mean ± SEM) at the end of the calcium load. PTH dropped from basal level to a similar extend (≥80%) with 60 mg cinacalcet and calcium load, whereas the decrease was significantly lesser (P < 0·01) with 30 mg cinacalcet. In PHPT, serum PTH levels dropped by 44·8 ± 6·9% and 58·2 ± 5·3% 1 h after the respective intake of 30 and 60 mg cinacalcet. One hour after the oral intake of 60 mg cinacalcet, serum PTH levels were <8 ng/l in HC and ≥8 ng/l in PHPT.

CONCLUSION

Sixty milligrams of cinacalcet provides similar results as the standardized calcium load test; PHPT patients have a lower response to 60 mg cinacalcet than HC.

Effects of alendronate and vitamin D in patients with normocalcemic primary hyperparathyroidism

No data on the pharmacological treatment of normocalcemic hyperparathyroidism (NPHPT) are available. We treated 30 NPHPT postmenopausal women with alendronate/cholecalciferol (treated group) or vitamin D alone (control group). Over 1 year, bone mineral density (BMD) increased significantly in treated group, but not in control group. Both treatments did not affect serum or urinary calcium.

INTRODUCTION

Normocalcemic primary hyperparathyroidism (NPHPT) is defined by normal serum calcium and consistently elevated PTH levels after ruling out the causes of secondary hyperparathyroidism. It is likely that subjects with NPHPT may develop kidney and bone disease. As no data on the pharmacological treatment of NPHPT are available, we aimed to investigate the effects of alendronate and cholecalciferol on both BMD and bone biochemical markers in postmenopausal women with NPHPT. Safety of vitamin D was evaluated as secondary endpoint.

METHODS

The study was a prospective open label randomized trial comparing 15 postmenopausal women with NPHPT (PMW-NPHPT), treated with oral alendronate plus cholecalciferol (treated group) and 15 PMW-NPHPT treated only with cholecalciferol (control group). Blood samples were obtained at baseline and after 3, 6, and 12 months. Bone turnover markers (BTM) were measured at baseline, 3, and 6 months, respectively. BMD was assessed at baseline and after 12 months.

RESULTS

After 1 year of treatment, BMD increased significantly at the lumbar, femoral neck, and hip level in the treated group, but not in the control group (p = 0.001). No differences were found between or within groups in serum calcium, PTH, and urinary calcium levels. BTM significantly decreased in the treated group but not in the control group, at 3 and 6 months (p < 0.001), respectively. No cases of hypercalcemia or hypercalciuria were detected during the study.

CONCLUSION

The results of this study indicate that alendronate/cholecalciferol increases BMD in postmenopausal women with NPHPT. Alendronate/cholecalciferol or vitamin D alone does not affect serum or urinary calcium.

Impact of vitamin D replacement in patients with normocalcaemic and hypercalcaemic primary hyperparathyroidism and coexisting vitamin D deficiency

Background

Vitamin D deficiency is increasingly recognized in patients with primary hyperparathyroidism but some clinicians are reluctant to replace vitamin D due to concerns with aggravating hypercalcaemia. We investigated the impact of vitamin D repletion in asymptomatic patients with normocalcaemic and hypercalcaemic primary hyperparathyroidism.

Methods

This is a retrospective analysis of 111 patients with elevated parathyroid hormone concentrations (>6.4 pmol/L) referred to our endocrine clinic between January and December 2012; we identified 39 patients with primary hyperparathyroidism and vitamin D deficiency, i.e. 25 hydroxy vitamin D <20  µg/L. Patients were categorized into normocalcaemic (n = 23) and hypercalcaemic (n = 16) groups and the impact on biochemical parameters was recorded after at least six months treatment with either 1600 or 3200 units daily of cholecalciferol.

Results

Both normocalcaemic and hypercalcaemic groups showed a rise in 25 hydroxy vitamin D concentrations after replacement (p <0.0001). Parathyroid hormone concentrations fell in the normocalcaemic group (p = 0.08) but individually, five patients showed a rise (8–38% of baseline). In the hypercalcaemic group, parathyroid hormone remained static but the adjusted calcium concentration fell significantly (p = 0.006) except in two patients who showed mild rises (3 and 6%, respectively). There was no deterioration in renal function or calcium-related adverse events in any of the groups.

Conclusions

Our study supports the safety of vitamin D replacement in patients with mild asymptomatic primary hyperparathyroidism and coexistent vitamin D deficiency. Repletion does not aggravate hypercalcaemia and may limit disease progression. Patients with normocalcaemic primary hyperparathyroidism need further characterization from longitudinal studies.

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

OBJECTIVE

To conduct a literature review on the diagnosis and management of primary hyperparathyroidism including the classical hipercalcemic form as well as the normocalcemic variant.

MATERIALS AND METHODS

This scientific statement was generated by a request from the Brazilian Medical Association (AMB) to the Brazilian Society for Endocrinology as part of its Clinical Practice Guidelines program. Articles were identified by searching in PubMed and Cochrane databases as well as abstracts presented at the Endocrine Society, Brazilian Society for Endocrinology Annual Meetings and the American Society for Bone and Mineral Research Annual Meeting during the last 5 years. Grading quality of evidence and strength of recommendation were adapted from the first report of the Oxford Centre for Evidence-based Medicine. All grades of recommendation, including "D", are based on scientific evidence. The differences between A, B, C and D, are due exclusively to the methods employed in generating evidence.

CONCLUSION

We present a scientific statement on primary hyperparathyroidism providing the level of evidence and the degree of recommendation regarding causes, clinical presentation as well as surgical and medical treatment.

Mild primary hyperparathyroidism: a literature review

The biochemical profile of classic primary hyperparathyroidism (pHPT) consists of both elevated calcium and parathyroid hormone levels. The standard of care is parathyroidectomy unless prohibited by medical comorbidities. Because more patients are undergoing routine bone density evaluation and neck imaging studies for other purposes, there is a subset of people identified with a biochemically mild form of the pHPT that expresses itself as either elevated calcium or parathyroid hormone levels. These patients often do not fall into the criteria for operation based on the National Institutes of Health consensus guidelines, and they can present a challenge of diagnosis and management. The purpose of this paper is to review the available literature on mild pHPT in an effort to better characterize this patient population and to determine whether patients benefit from parathyroidectomy. Evidence suggests that there are patients with mild pHPT who have overt symptoms that are found to improve after parathyroidectomy. There is also a group of patients with biochemically mild pHPT who are found to progress to classic pHPT over time; however, it is not predictable which group of patients this will be. Early intervention for this group with mild pHPT may prevent progression of bone, psychiatric, and renal complications, and parathyroidectomy has proven safe in appropriately selected patients at high volume centers.

Bone disease in primary hyperparathyroidism

Bone disease in severe primary hyperparathyroidism (PHPT) is described classically as osteitis fibrosa cystica (OFC). Bone pain, skeletal deformities and pathological fractures are features of OFC. Bone mineral density is usually extremely low in OFC, but it is reversible after surgical cure. The signs and symptoms of severe bone disease include bone pain, pathologic fractures, proximal muscle weakness with hyperreflexia. Bone involvement is typically characterized as salt-and-pepper appearance in the skull, bone erosions and bone resorption of the phalanges, brown tumors and cysts. In the radiography, diffuse demineralization is observed, along with pathological fractures, particularly in the long bones of the extremities. In severe, symptomatic PHPT, marked elevation of the serum calcium and PTH concentrations are seen and renal involvement is manifested by nephrolithiasis and nephrocalcinosis. A new technology, recently approved for clinical use in the United States and Europe, is likely to become more widely available because it is an adaptation of the lumbar spine DXA image. Trabecular bone score (TBS) is a gray-level textural analysis that provides an indirect index of trabecular microarchitecture. Newer technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), have provided further understanding of the microstructural skeletal features in PHPT.

Individual site-specific bone mineral density gain in normocalcemic primary hyperparathyroidism

In this study, we show that successful parathyroidectomy is followed at 1 year by a significant individual bone mineral density (BMD) gain in nearly half of normocalcemic PHPT patients with reduced bone mass. Alkaline phosphatase levels above median were identified as an independent predictor of individual BMD gain in normocalcemic PHPT patients.

INTRODUCTION

The aims of this study were to assess bone mineral density (BMD) gains after parathyroidectomy (PTX) in normocalcemic primary hyperparathyroidism (PHPT) at the individual level and to identify predictors of BMD gain after PTX in this context.

METHODS

Longitudinal cohort study of 55 PHPT patients referred for low bone mass and mild abnormalities of calcium/phosphorus metabolism, and successfully treated by PTX. BMD gain at 1 year was considered significant if ≥0.030 g/cm(2) at one site or more, without any equivalent BMD loss at another site. A logistic regression analysis was performed to identify predictive factors of individual BMD gain.

RESULTS

Among the 55 PHPT patients included, 29 patients with hypercalcemia, 36 patients with normocalcemic PHPT, defined by normal pre-PTX serum total (albumin-corrected) calcium (tCa), including 15 patients with normal ionized calcium (iCa), were identified. At 1 year of PTX, an individual BMD gain was observed in 73.7 % of hypercalcemic, 44.4 % of normocalcemic, and 46 % of PHPT patients with both normal tCa and iCa. Site-specific BMD gains were most important at the spine and hip in all subgroups including patients with normal iCa. Alkaline phosphatase activity above median, which reflects high bone turnover, was predictive of individual BMD gain, both in the overall cohort (OR = 4.9, 95 % CI 1.3-18.9), and in the normocalcemic group: OR = 8.4, 95 % CI 1.4-56.6.

CONCLUSIONS

Successful PTX is followed at 1 year by a significant individual BMD gain in nearly half of normocalcemic PHPT patients with osteoporosis. ALP levels above median could contribute to the therapeutic decision in this context.