Oral alendronate increases bone mineral density in postmenopausal women with primary hyperparathyroidism

Phosphate: An underrated component of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a systemic disease that affects all the systems of the body, specifically the bones and the kidneys. Its main action is on calcium homeostasis. It tries to preserve the body's calcium level at the cost of phosphate. The criteria for surgery in asymptomatic PHPT patients revolve around raised serum calcium levels, renal dysfunction or nephrolithiasis, and bone health. It does not take into account the serum phosphate levels. Depending on the serum level, Hypophosphatemia is divided into mild, moderate, and severe categories. In PHPT, several studies have suggested that asymptomatic PHPT patients with moderate hypophosphatemia may warrant surgical intervention. Treatment of hypophosphatemia in PHPT is based upon the degree of hypophosphatemia, and treatment is given according to that oral or intravenous route; after surgical and medical treatment of PHPT, phosphate levels gradually normalized. But even after these considerations, phosphate levels in PHPT are not given much importance.

Primary hyperparathyroidism

Primary hyperparathyroidism (PHPT), the most common cause of hypercalcemia, is most often identified in postmenopausal women with hypercalcemia and parathyroid hormone (PTH) levels that are either frankly elevated or inappropriately normal. The clinical presentation of PHPT includes three phenotypes: target organ involvement of the renal and skeletal systems; mild asymptomatic hypercalcemia; and more recently, high PTH levels in the context of persistently normal albumin-corrected and ionized serum calcium values. The factors that determine which of these three clinical presentations is more likely to predominate in a given country include the extent to which biochemical screening is employed, the prevalence of vitamin D deficiency, and whether a medical center or practitioner tends to routinely measure PTH levels in the evaluation of low bone density or frank osteoporosis. When biochemical screening is common, asymptomatic primary hyperparathyroidism is the most likely form of the disease. In countries where vitamin D deficiency is prevalent and biochemical screening is not a feature of the health care system, symptomatic disease with skeletal abnormalities is likely to predominate. Finally, when PTH levels are part of the evaluation for low bone mass, the normocalcemic variant is seen. Guidelines for surgical removal of hyperfunctioning parathyroid tissue apply to all three clinical forms of the disease. If guidelines for surgery are not met, parathyroidectomy can also be an appropriate option if there are no medical contraindications to surgery. In settings where either the serum calcium or bone mineral density is of concern, and surgery is not an option, pharmacological approaches are available and effective. Referencing in this article the most current published articles, we review the different presentations of PHPT, with particular emphasis on recent advances in our understanding of target organ involvement and management.

A Systematic Review Supporting the Endocrine Society Clinical Practice Guideline on the Treatment of Hypercalcemia of Malignancy in Adults

CONTEXT

Hypercalcemia is a common complication of malignancy that is associated with high morbidity and mortality.

OBJECTIVE

To support development of the Endocrine Society Clinical Practice Guideline for the treatment of hypercalcemia of malignancy in adults.

METHODS

We searched multiple databases for studies that addressed 8 clinical questions prioritized by a guideline panel from the Endocrine Society. Quantitative and qualitative synthesis was performed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess certainty of evidence.

RESULTS

We reviewed 1949 citations, from which we included 21 studies. The risk of bias for most of the included studies was moderate. A higher proportion of patients who received bisphosphonate achieved resolution of hypercalcemia when compared to placebo. The incidence rate of adverse events was significantly higher in the bisphosphonate group. Comparing denosumab to bisphosphonate, there was no significant difference in the rate of patients who achieved resolution of hypercalcemia. Two-thirds of patients with refractory/recurrent hypercalcemia of malignancy who received denosumab following bisphosphonate therapy achieved resolution of hypercalcemia. Addition of calcitonin to bisphosphonate therapy did not affect the resolution of hypercalcemia, time to normocalcemia, or hypocalcemia. Only indirect evidence was available to address questions on the management of hypercalcemia in tumors associated with high calcitriol levels, refractory/recurrent hypercalcemia of malignancy following the use of bisphosphonates, and the use of calcimimetics in the treatment of hypercalcemia associated with parathyroid carcinoma. The certainty of the evidence to address all 8 clinical questions was low to very low.

CONCLUSION

The evidence summarized in this systematic review addresses the benefits and harms of treatments of hypercalcemia of malignancy. Additional information about patients' values and preferences, and other important decisional and contextual factors is needed to facilitate the development of clinical recommendations.

Treatment of Hypercalcemia of Malignancy in Adults: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Hypercalcemia of malignancy (HCM) is the most common metabolic complication of malignancies, but its incidence may be declining due to potent chemotherapeutic agents. The high mortality associated with HCM has declined markedly due to the introduction of increasingly effective chemotherapeutic drugs. Despite the widespread availability of efficacious medications to treat HCM, evidence-based recommendations to manage this debilitating condition are lacking.

OBJECTIVE

To develop guidelines for the treatment of adults with HCM.

METHODS

A multidisciplinary panel of clinical experts, together with experts in systematic literature review, identified and prioritized 8 clinical questions related to the treatment of HCM in adult patients. The systematic reviews (SRs) queried electronic databases for studies relevant to the selected questions. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make recommendations. An independent SR was conducted in parallel to assess patients' and physicians' values and preferences, costs, resources needed, acceptability, feasibility, equity, and other domains relevant to the Evidence-to-Decision framework as well as to enable judgements and recommendations.

RESULTS

The panel recommends (strong recommendation) in adults with HCM treatment with denosumab (Dmab) or an intravenous (IV) bisphosphonate (BP). The following recommendations were based on low certainty of the evidence. The panel suggests (conditional recommendation) (1) in adults with HCM, the use of Dmab rather than an IV BP; (2) in adults with severe HCM, a combination of calcitonin and an IV BP or Dmab therapy as initial treatment; and (3) in adults with refractory/recurrent HCM despite treatment with BP, the use of Dmab. The panel suggests (conditional recommendation) the addition of an IV BP or Dmab in adult patients with hypercalcemia due to tumors associated with high calcitriol levels who are already receiving glucocorticoid therapy but continue to have severe or symptomatic HCM. The panel suggests (conditional recommendation) in adult patients with hypercalcemia due to parathyroid carcinoma, treatment with either a calcimimetic or an antiresorptive (IV BP or Dmab). The panel judges the treatments as probably accessible and feasible for most recommendations but noted variability in costs, resources required, and their impact on equity.

CONCLUSIONS

The panel's recommendations are based on currently available evidence considering the most important outcomes in HCM to patients and key stakeholders. Treatment of the primary malignancy is instrumental for controlling hypercalcemia and preventing its recurrence. The recommendations provide a framework for the medical management of adults with HCM and incorporate important decisional and contextual factors. The guidelines underscore current knowledge gaps that can be used to establish future research agendas.

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.

Efficacy of antiresorptive agents bisphosphonates and denosumab in mitigating hypercalcemia and bone loss in primary hyperparathyroidism: A systematic review and meta-analysis

PURPOSE

Primary hyperparathyroidism (PHPT) is characterized by increased bone remodeling and hypercalcemia. Parathyroidectomy (PTX), the current standard of care, is recommended in all symptomatic and some groups of asymptomatic patients. Anti-resorptive therapies (bisphosphonates and denosumab) have been used in patients where PTX is refused or contraindicated. In this meta-analysis, we investigated the effectiveness of anti-resorptives in preventing/treating PHPT-induced bone loss and mitigating hypercalcemia.

METHOD

PubMed, Scopus, and Cochrane Library databases were searched for articles with keywords containing PHPT, bisphosphonates, and denosumab in various combinations. We extracted and tabulated areal BMD (aBMD), serum mineral, and bone turnover parameters from the qualified studies and used comprehensive meta-analysis software for analysis.

RESULTS

Of the 1,914 articles screened, 13 were eligible for meta-analysis. In the pooled analysis, 12 months of anti-resoptives (bisphosphonates and denosumab) therapy significantly increased aBMD at the lumbar spine (Standard difference in means (SDM)=0.447, 95% CI=0.230 to 0.664, p=0.0001), femoral neck (SDM=0.270, 95% CI=0.049 to 0.491, p=0.017) and increased serum PTH (SDM=0.489, 95% CI=0.139 to 0.839, p=0.006), and decreased serum calcium (SDM=-0.545, 95% CI=-0.937 to -0.154, p=0.006) compared with baseline. 12 months of bisphosphonate use significantly increased aBMD only at the lumbar spine (SDM=0.330, 95% CI=0.088 to 0.571, p=0.007) with a significant increased in serum PTH levels (SDM=0.546, 95% CI= 0.162 to 0.930, p=0.005), and a decreased in serum calcium (SDM=-0.608, 95% CI=-1.048 to -0.169, p=0.007) and bone-turnover markers (BTMs) compared with baseline. Denosumab use for 12 months significantly increased aBMD at both the lumbar spine (SDM=0.828, 95% CI=0.378 to 1.278, p=0.0001) and femur neck (SDM=0.575, 95% CI=0.135 to 1.015, p=0.010) compared with baseline. Mean lumbar spine aBMD (SDM=0.350, 95% CI=0.041 to 0.659, p=0.027) and serum PTH (SDM=0.602, 95% CI= 0.145 to 1.059, p=0.010) were significantly increased after 12 months of alendronate use compared with placebo. When compared with baseline, alendronate significantly decreased BTMs after 12 months and increased aBMD without altering the PTH and calcium levels after 24 months.

CONCLUSION

Anti-resorptives are effective in mitigating bone loss and hypercalcemia in PHPT while maintaining or increasing aBMD. PTX reversed all changes in PHPT and normalized PTH levels.

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Medical management of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is an endocrine disorder resulting from the hyperfunction of one or more parathyroid glands, with hypersecretion of parathyroid hormone (PTH). It can be managed by parathyroidectomy (PTX) or non-surgically. Medical therapy with pharmacological agents is an alternative for those patients with asymptomatic PHPT who meet guidelines for surgery but are unable or unwilling to undergo PTX. In this review, we focus upon these non-surgical aspects of PHPT management. We emphasize the most studied and widely used pharmacological alternatives: bisphosphonates, denosumab, cinacalcet and hormone therapy, in addition to combined therapy. We also address the relevant aspects of perioperative management.

Management of Primary Hyperparathyroidism

Since the last international guidelines were published in 2014 on the evaluation and management of primary hyperparathyroidism (PHPT), new information has become available with regard to evaluation, diagnosis, epidemiology, genetics, classical and nonclassical manifestations, surgical and nonsurgical approaches, and natural history. To provide the most current summary of these developments, an international group, consisting of over 50 experts in these various aspects of PHPT, was convened. This paper provides the results of the task force that was assigned to review the information on the management of PHPT. For this task force on the management of PHPT, two questions were the subject of systematic reviews using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) methodology. The full report addressing surgical and nonsurgical management of PHPT, utilizing the GRADE methodology, is published separately in this series. In this report, we summarize the results of that methodological review and expand them to encompass a much larger body of new knowledge that did not specifically fit the criteria of the GRADE methodology. Together, both the systematic and narrative reviews of the literature, summarized in this paper, give the most complete information available to date. A panel of experts then considered the last set of international guidelines in light of the newer data and assessed the need for their revision. This report provides the evidentiary background to the guidelines report. In that report, evidence from all task forces is synthesized into a summary statement and revised guidelines for the evaluation and management of PHPT. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Primary hyperparathyroidism in the geriatric population: A case report and mini literature review

We report a case of a 93‐year‐old woman with PHPT secondary to a left inferior parathyroid adenoma. The patient met criteria to be a surgical candidate; however, literature about parathyroidectomy in the elderly was limited and controversial. The patient remained stable through medical management for the next 5 years.

Diagnosis and management of PHPT in the geriatric population remains challenging. Although parathyroidectomy is the definitive treatment in the general population, medical management can be strongly considered in the geriatric population with PHPT.

The Efficacy and Safety of Medical and Surgical Therapy in Patients With Primary Hyperparathyroidism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Both medical and surgical therapy represent potential management options for patients with asymptomatic primary hyperparathyroidism (PHPT). Because uncertainty remains regarding both medical and surgical therapy, this systematic review addresses the efficacy and safety of medical therapy in asymptomatic patients or symptomatic patients who decline surgery and surgery in asymptomatic patients. We searched Medline, Embase, Cochrane Central Register of Controlled Trials, and PubMed from inception to December 2020, and included randomized controlled trials in patients with PHPT that compared nonsurgical management with medical therapy versus without medical therapy and surgery versus no surgery in patients with asymptomatic PHPT. For surgical complications we included observational studies. Paired reviewers addressed eligibility, assessed risk of bias, and abstracted data for patient-important outcomes. We conducted random-effects meta-analyses to pool relative risks and mean differences with 95% confidence intervals and used Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) to assess quality of evidence for each outcome. For medical therapy, 11 trials reported in 12 publications including 438 patients proved eligible: three addressed alendronate, one denosumab, three cinacalcet, two vitamin D, and two estrogen therapy. Alendronate, denosumab, vitamin D, and estrogen therapy all increased bone density. Cinacalcet probably reduced serum calcium and parathyroid hormone (PTH) levels. Cinacalcet and vitamin D may have a small or no increase in overall adverse events. Very-low-quality evidence raised the possibility of an increase in serious adverse events with alendronate and denosumab. The trials also provided low-quality evidence for increased bleeding and mastalgia with estrogen therapy. For surgery, six trials presented in 12 reports including 441 patients proved eligible. Surgery achieved biochemical cure in 96.1% (high quality). We found no convincing evidence supporting an impact of surgery on fracture, quality of life, occurrence of kidney stones, and renal function, but the evidence proved low or very low quality. Surgery was associated with an increase in bone mineral density. For patients with symptomatic and asymptomatic PHPT, who are not candidates for parathyroid surgery, cinacalcet probably reduced serum calcium and PTH levels; anti-resorptives increased bone density. For patients with asymptomatic PHPT, surgery usually achieves biochemical cure. These results can help to inform patients and clinicians regarding use of medical therapy and surgery in PHPT. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Evaluation and Management of Primary Hyperparathyroidism: Summary Statement and Guidelines from the Fifth International Workshop

The last international guidelines on the evaluation and management of primary hyperparathyroidism (PHPT) were published in 2014. Research since that time has led to new insights into epidemiology, pathophysiology, diagnosis, measurements, genetics, outcomes, presentations, new imaging modalities, target and other organ systems, pregnancy, evaluation, and management. Advances in all these areas are demonstrated by the reference list in which the majority of listings were published after the last set of guidelines. It was thus, timely to convene an international group of over 50 experts to review these advances in our knowledge. Four Task Forces considered: 1. Epidemiology, Pathophysiology, and Genetics; 2. Classical and Nonclassical Features; 3. Surgical Aspects; and 4. Management. For Task Force 4 on the Management of PHPT, Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) methodology addressed surgical management of asymptomatic PHPT and non-surgical medical management of PHPT. The findings of this systematic review that applied GRADE methods to randomized trials are published as part of this series. Task Force 4 also reviewed a much larger body of new knowledge from observations studies that did not specifically fit the criteria of GRADE methodology. The full reports of these 4 Task Forces immediately follow this summary statement. Distilling the essence of all deliberations of all Task Force reports and Methodological reviews, we offer, in this summary statement, evidence-based recommendations and guidelines for the evaluation and management of PHPT. Different from the conclusions of the last workshop, these deliberations have led to revisions of renal guidelines and more evidence for the other recommendations. The accompanying papers present an in-depth discussion of topics summarized in this report. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Sporadic Primary Hyperparathyroidism

Sporadic primary hyperparathyroidism is a common endocrinopathy, particularly afflicting postmenopausal women and both African American men and women. Although classic signs and symptoms of the disease are well appreciated and described, because of the ease and availability and low threshold for screening, the disorder often is diagnosed in patients who are minimally symptomatic or asymptomatic. Surgery conducted by experienced endocrine surgeons has a high cure rate, particularly if guided by concordant imaging. In patients who cannot safely undergo surgery or who fail to be cured, medical therapy with the oral calcimimetic cinacalcet is a validated option for controlling serum calcium levels.

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.

Efficacy and Safety of Intravenous Pamidronate for Parathyroid Hormone-dependent Hypercalcemia in Hospitalized Patients

CONTEXT

Bisphosphonates are effective for hypercalcemia of malignancy (HOM). Efficacy and safety data for bisphosphonates in parathyroid hormone-related hypercalcemia (PTHRH) are rare, including pamidronate (Pam), which is not indicated for this condition.

OBJECTIVE

This work aims to evaluate the efficacy and safety of Pam for moderate-to-severe PTHRH.

METHODS

This retrospective case-control study was conducted at a tertiary care medical center. Patients included adults hospitalized with serum calcium levels greater than 12 mg/dL, from October 29, 2013 to December 17, 2019. Etiology was categorized as PTHRH or PTH-independent. Clinical and laboratory data of PTHRH patients treated with Pam (PTHRH-Pam+) were compared to Pam-untreated counterparts (PTHRH-Pam-).

RESULTS

Thirty-four patients with 37 hospitalizations for PTHRH (Pam-treated and -untreated) met the inclusion criteria. Pam was given in 24 of 37 cases (64.8%). Admission serum calcium levels for the PTHRH-Pam+ group were higher than for PTHRH-Pam- group (14.4 mg/dL vs 13.0 mg/dL, P = .005). Median total Pam dose was 60 mg (range, 30-180 mg) in the treated group. Serum calcium decreased 3.5 mg/dL for PTHRH-Pam+ vs 1.6 mg/dL for PTHRH-Pam- (P = .003). No PTHRH-Pam+ patients developed hypocalcemia or acute kidney injury. Nadir serum phosphorus levels were lower in the PTHRH-Pam+ vs PTHRH-Pam- group (1.7 mg/dL vs 2.4 mg/dL, respectively, P = .004). Three PTHRH-Pam+ patients developed severe hypophosphatemia; all resolved with intravenous and oral supplementation. Seventeen patients underwent parathyroidectomy, of whom 10 received Pam within 28 days preoperatively. Postoperatively, 4 developed hypocalcemia and 3 hypophosphatemia.

CONCLUSION

This study demonstrates that Pam is effective and safe for treating PTHRH, while ensuring close laboratory monitoring of calcium and phosphorus metabolism. Larger, prospective studies are needed to establish the role of Pam and other potent bisphosphonates in moderate-to-severe PTHRH.

Hypercalcaemia in primary hyperparathyroidism: a rare cause of recurrent acute pancreatitis

Hyperparathyroidism leading to hypercalcaemia is a rare cause of acute pancreatitis with debatable association. The diagnosis of hyperparathyroidism is frequently overlooked or delayed as symptoms are non-specific and serum calcium is not routinely measured in acute pancreatitis. Early diagnosis and treatment of hyperparathyroidism may reduce the chances of complications. We report a 35-year-old woman, who was admitted with recurrent episodes of acute pancreatitis. She was previously diagnosed with gall-stone induced acute pancreatitis, had undergone laparoscopic cholecystectomy, but the recurrence of acute pancreatitis suggested an alternative aetiology and provoked extensive investigations. Serum calcium was found to be elevated. No additional risk factor for pancreatitis was found. Further workup revealed primary hyperparathyroidism, which was due to a functioning parathyroid adenoma. She has undergone parathyroidectomy followed by an uneventful recovery. She subsequently conceived and is now in her first trimester, without any recurrence of acute pancreatitis since her surgery.

Biochemical bone turnover markers in hormonal disorders in adults: a narrative review

BACKGROUND

Hormonal disorders are often associated with abnormal levels of bone turnover markers (BTMs). N-terminal propeptide of type I procollagen (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) are the reference markers of bone formation and bone resorption, respectively.

METHODS

A comprehensive literature search within the MEDLINE and Web of Science databases was performed.

RESULTS

Acromegaly is associated with higher BTM levels, which decrease during the remission after treatment. Adult-onset growth hormone deficiency is often associated with decreased BTM levels. Growth hormone replacement therapy stimulates bone turnover and increases BTM levels. Hypothyroidism is characterized by general slowing of bone metabolism which is reflected by lower BTM levels. The replacement thyroid hormone therapy increases the bone turnover rate and BTM levels increase. Patients with thyroid cancer receive a suppressive dose of thyroid hormones and may have slightly elevated BTM levels. Patients with overt hyperthyroidism had higher BTM levels and anti-thyroid therapy induces a rapid decrease in the BTM levels. Patients with overt primary hyperparathyroidism have higher BTM levels, whereas those with asymptomatic and normocalcemic hyperparathyroidism usually have normal BTM levels. Hypoparathyroidism is characterized by slightly decreased BTM levels. Cushing's syndrome is characterized consistently by markedly decreased osteocalcin concentration, whereas data on other BTMs are discordant.

CONCLUSIONS

BTMs help us to better understand mechanisms of the impact of hormonal disorders and their treatment on bone metabolism. However, it is unknown whether BTMs may be used to monitor the effect of their treatments on bone in the clinical practice.

Denosumab and cinacalcet for primary hyperparathyroidism (DENOCINA): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Medical treatment options for primary hyperparathyroidism are scarce. We aimed to assess the efficacy of denosumab and combined with cinacalcet in patients with primary hyperparathyroidism.

METHODS

In this randomised, single-centre, proof-of-concept, double-blind trial, patients aged at least 18 years with primary hyperparathyroidism were recruited from the Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark. Key eligibility criteria were a T-score between -1·0 and -3·5 at the lumbar spine, femoral neck, or total hip. Patients were assigned (1:1:1) via permuted block randomisation to receive 30 mg cinacalcet per day plus 60 mg denosumab subcutaneously every 6 months (n=14; combination group) for 1 year, denosumab plus placebo (n=16; denosumab group) for 1 year, or placebo plus placebo injection (n=15; placebo group) for 1 year. Primary outcomes were changes in bone mineral density (BMD) measured by dual x-ray absorptiometry at the lumbar spine, total hip, femoral neck, and distal forearm after 1 year. Additionally, effects on bone-metabolic biochemistry were explored. Patients and investigators were masked. All enrolled patients were included in efficacy analyses. The trial was done in an outpatient setting and is registered at ClinicalTrials.gov, NCT03027557, and has been completed.

FINDINGS

Between March 14, 2017, and March 16, 2018 we recruited 285 participants. 16 patients were randomly allocated to the denosumab group, 15 to the combination group, and 15 to the placebo group. Dropout was limited to one patient in the combination group. Compared with placebo, BMD improved in groups receiving denosumab: lumbar spine (combination group 5·4% [95% CI 2·7-8·1], denosumab group 6·9% [95% CI 4·2-9·6]; p<0·0001), total hip (combination group 5·0% [3·0-6·9], denosumab group 4·1% [2·5-5·8]; p<0·0001), and femoral neck (combination group 4·5% [1·9-7·9]; p=0·0008, denosumab group 3·8% [1·4-6·3]; p=0·0022]). Changes in BMD at the third distal forearm were borderline significant. Six non-fatal serious adverse events occurred (combination group [n=2], denosumab group [n=1], placebo group [n=3]). The overall prevalence of adverse events did not differ between treatment groups, and no fatal adverse events occurred.

INTERPRETATION

Evidence suggested denosumab was effective in improving BMD and lowering bone turnover in patients with primary hyperparathyroidism irrespective of cinacalcet treatment and might be a valid option for patients in which surgery is undesirable.

FUNDING

Aalborg University Hospital and Aalborg University, Denmark.

Mild primary hyperparathyroidism-to treat or not to treat?

INTRODUCTION

The presentation of primary hyperparathyroidism (PHPT) has shifted from a disease characterized by renal and skeletal complications to a mild or asymptomatic condition. Modern imaging allows localization of a surgical target in the majority of cases.

SOURCES OF DATA

Data were collected from literature searches of online databases including PUBMED, MEDLINE and Cochrane. A narrative review was performed.

AREAS OF AGREEMENT

Parathyroidectomy is the only therapy with curative potential with good outcomes and low risk of complications in experienced hands. Current guidelines advocate that surgery is offered in all symptomatic cases and in those who meet criteria depending on age, serum calcium concentration, skeletal and renal parameters. A structured monitoring approach should be offered to those who do not undergo surgery.

AREAS OF CONTROVERSY

Thresholds for intervention to improve skeletal and renal outcomes are debatable. In addition, controversy persists over the benefit of surgery for non-skeletal/renal outcomes.

GROWING POINTS

The role of medical management of PHPT using agents such as bisphosphonates, denosumab and cinacalcet are discussed.

AREAS TIMELY FOR DEVELOPING RESEARCH

In summary, further data on the natural history and effects of treatment of mild and asymptomatic PHPT are required to determine thresholds for surgery. In particular, further investigations of non-skeletal and non-renal parameters, such as neurocognitive quality of life and cardiovascular disease are required. Data on normocalcaemic PHPT are lacking. Large-scale randomized controlled trials would be welcome in these areas, however in view of the cost implications a more pragmatic approach may be to develop collaborative multi-centre registries.

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.

Primary hyperparathyroidism

Primary hyperparathyroidism (PHPT), the most common cause of hypercalcemia, is most often identified in postmenopausal women with hypercalcemia and parathyroid hormone (PTH) levels that are either frankly elevated or inappropriately normal. The clinical presentation of PHPT includes three phenotypes: target organ involvement of the renal and skeletal systems; mild asymptomatic hypercalcemia; and more recently, high PTH levels in the context of persistently normal albumin-corrected and ionized serum calcium values. The factors that determine which of these three clinical presentations is more likely to predominate in a given country include the extent to which biochemical screening is employed, the prevalence of vitamin D deficiency, and whether a medical center or practitioner tends to routinely measure PTH levels in the evaluation of low bone density or frank osteoporosis. When biochemical screening is common, asymptomatic primary hyperparathyroidism is the most likely form of the disease. In countries where vitamin D deficiency is prevalent and biochemical screening is not a feature of the health care system, symptomatic disease with skeletal abnormalities is likely to predominate. Finally, when PTH levels are part of the evaluation for low bone mass, the normocalcemic variant is seen. Guidelines for surgical removal of hyperfunctioning parathyroid tissue apply to all three clinical forms of the disease. If guidelines for surgery are not met, parathyroidectomy can also be an appropriate option if there are no medical contraindications to surgery. In settings where either the serum calcium or bone mineral density is of concern, and surgery is not an option, pharmacological approaches are available and effective. Referencing in this article the most current published articles, we review the different presentations of PHPT, with particular emphasis on recent advances in our understanding of target organ involvement and management.

Bone disease in primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a disease of high bone turnover, decreased bone mineral density (BMD) especially at cortical sites, and increased risk of fractures at all skeletal sites. Early diagnosis during the last decades resulted in milder forms of bone involvement. New methods of imaging and validation such as high resolution peripheral quantitative computed tomography and trabecular bone score provide evidence of disturbed bone microarchitecture and explain further the increased risk of fractures at both cortical and trabecular skeletal sites. Parathyroidectomy has a long-term beneficial effect on the skeleton and is probably prudent to refer PHPT patients for surgery in all cases where increased bone fragility is suspected. Bisphosphonates (BPs), mainly alendronate, have been proved as reasonable choices for BMD improvement while cinacalcet has no effect on bone strength in PHPT. Combination of BPs and cinacalcet, is a valid therapeutic approach from a pathophysiological point of view at least in terms of bone health, however, an adequately powered study to prove it is lacking. Adequate dietary calcium intake and vitamin D supplementation is advised as in the general population for the skeletal integrity of PHPT patients albeit with a close monitoring of serum and urinary calcium levels.

Hyperparathyroidism

Primary hyperparathyroidism is a common endocrine disorder of calcium metabolism characterised by hypercalcaemia and elevated or inappropriately normal concentrations of parathyroid hormone. Almost always, primary hyperparathyroidism is due to a benign overgrowth of parathyroid tissue either as a single gland (80% of cases) or as a multiple gland disorder (15-20% of cases). Primary hyperparathyroidism is generally discovered when asymptomatic but the disease always has the potential to become symptomatic, resulting in bone loss and kidney stones. In countries where biochemical screening tests are not common, symptomatic primary hyperparathyroidism tends to predominate. Another variant of primary hyperparathyroidism has been described in which the serum calcium concentration is within normal range but parathyroid hormone is elevated in the absence of any obvious cause. Primary hyperparathyroidism can be cured by removal of the parathyroid gland or glands but identification of patients who are best advised to have surgery requires consideration of the guidelines that are regularly updated. Recommendations for patients who do not undergo parathyroid surgery include monitoring of serum calcium concentrations and bone density.

Contemporary Medical Management of Primary Hyperparathyroidism: A Systematic Review

INTRODUCTION

Primary hyperparathyroidism is increasingly an asymptomatic disease at diagnosis, but the recognized guidelines for management are based on evidence obtained from studies on patients with symptomatic disease, and surgery is not always indicated. Other patients are unable to undergo surgery, and thus a medical treatment is warranted. This systematic review provides an overview of the existing literature on contemporary pharmaceutical options available for the medical management of primary hyperparathyroidism.

METHODS

Databases of medical literature were searched for articles including terms for primary hyperparathyroidism and each of the included drugs. Data on s-calcium, s-parathyroid hormone, bone turnover markers, bone mineral density (BMD) and hard endpoints were extracted and tabulated, and level of evidence was determined. Changes in s-calcium were estimated and a meta-regression analysis was performed.

RESULTS

The 1,999 articles were screened for eligibility and 54 were included in the review. Weighted mean changes calculated for each drug in s-total calcium (mean change from baseline ± SEM) were pamidronate (0.31 ± 0.034 mmol/l); alendronate (0.07 ± 0.05 mmol/l); clodronate (0.20 ± 0.040 mmol/l); mixed bisphosphonates (0.16 ± 0.049 mmol/l); and cinacalcet (0.37 ± 0.013 mmol/l). The meta-analysis revealed a significant decrease of effect on s-calcium with time for the bisphosphonates (Coef. -0.049 ± 0.023, p = 0.035), while cinacalcet proved to maintain its effect on s-calcium over time. Bisphosphonates improved BMD while cinacalcet had no effect.

DISCUSSION

The included studies demonstrate advantages and drawbacks of the available pharmaceutical options that can prove helpful in the clinical setting. The great variation in how primary hyperparathyroidism is manifested requires that management should rely on an individual evaluation when counseling patients. Combining resorptive agents with calcimimetics could prove rewarding, but more studies are warranted.

Primary hyperparathyroidism: review and recommendations on evaluation, diagnosis, and management. A Canadian and international consensus

The purpose of this review is to assess the most recent evidence in the management of primary hyperparathyroidism (PHPT) and provide updated recommendations for its evaluation, diagnosis and treatment. A Medline search of "Hyperparathyroidism. Primary" was conducted and the literature with the highest levels of evidence were reviewed and used to formulate recommendations. PHPT is a common endocrine disorder usually discovered by routine biochemical screening. PHPT is defined as hypercalcemia with increased or inappropriately normal plasma parathyroid hormone (PTH). It is most commonly seen after the age of 50 years, with women predominating by three to fourfold. In countries with routine multichannel screening, PHPT is identified earlier and may be asymptomatic. Where biochemical testing is not routine, PHPT is more likely to present with skeletal complications, or nephrolithiasis. Parathyroidectomy (PTx) is indicated for those with symptomatic disease. For asymptomatic patients, recent guidelines have recommended criteria for surgery, however PTx can also be considered in those who do not meet criteria, and prefer surgery. Non-surgical therapies are available when surgery is not appropriate. This review presents the current state of the art in the diagnosis and management of PHPT and updates the Canadian Position paper on PHPT. An overview of the impact of PHPT on the skeleton and other target organs is presented with international consensus. Differences in the international presentation of this condition are also summarized.

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.

Is surgery necessary for 'mild' or 'asymptomatic' hyperparathyroidism?

A large majority of the currently diagnosed patients with hyperparathyroidism (PHPT) are mild or asymptomatic, mainly women after menopause. Following the debate held at the 16th European Congress of Endocrinology in Wroclaw (Poland) from May 3-7, 2014, arguments are here presented by a surgeon and a medical practitioner considering these situations rather have to profit from surgery, or simply from survey. For the trained endocrine surgeon, it is evident that parathyroidectomy confirms the diagnosis and undoubtedly reduces the discomfort felt by certain patients, prevents all risks of complications, removes patients and medical teams from the monitoring and represents a real individual financial benefit. On the other hand, the medical practitioner considers that mild or asymptomatic PHPT is commonly stable, and very rare are the subjects at risk of complications, particularly of fractures; prevention of vascular and metabolic disorders, nephrolithiasis and bone rarefaction justify regular physical exercise, a safe alimentation, a sufficient calcium and high water intake, the correction of the frequent deficit in vitamin D; finally has also to be considered the impossibility to refer to specialized (endocrine) surgeons, the enormous cohort of subjects more than 50 years with 'mild' or 'asymptomatic' PHPT. The surgeon and the medical practitioner agree to consider that in patients with 'mild' or 'asymptomatic' disease, there is no place for medical treatments, in particular calcimimetics and bisphophonates. Both agree that further studies are needed to clarify the long-term prognosis of operated and non-operated PHPT in term of fractures, cardiovascular risk and mortality. Individual and collective cost/benefit ratios of surgery or survey are also still imperfectly evaluated.

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.

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.

Comparison of alendronate and raloxifene for the management of primary hyperparathyroidism

AIM

To evaluate and compare the efficacy of alendronate sodium (ALN) and raloxifene (RLX) for the management of primary hyperparathyroidism (PHPT) in postmenopausal female patients (pts) with osteoporosis.

METHODS

Twenty-four postmenopausal women with osteoporosis who were diagnosed with PHPT, but refused the option of surgery, were enrolled. Participants were sequentially randomized into two groups: an ALN-group of 12 pts (70 mg/week) and a RLX-group of 12 pts (60 mg/day). The control group consisted of 10 pts with PHPT who did not have any indications for surgery.

RESULTS

The decrease in ionized calcium levels was significantly more pronounced in the ALN group compared to the RLX and control groups (p<0.001). In terms of difference from baseline in bone mineral density (BMD) of the lumbar area in percentages over a period of 12 months, pts in the ALN and RLX groups both showed statistically significant improvements compared to pts in the control group (control vs ALN, p<0.001; control vs RLX, p<0.001). BMD measurements of the femoral and radial areas were comparable in all three groups.

CONCLUSIONS

ALN and RLX may improve bone density in the lumbar area of osteoporotic post-menopausal women with PHPT. The more significant decrease in serum calcium levels which was observed in the ALN group compared to both RLX and control groups, suggests that ALN could be used for the short-term control of calcium levels in patients awaiting surgery.

Subclinical and asymptomatic parathyroid disease: implications of emerging data

Primary hyperparathyroidism, a disorder in which there is a tendency for hypercalcaemia caused by autonomous overproduction of parathyroid hormone, is common, especially in postmenopausal women. Although parathyroidectomy is indicated for symptomatic patients, most individuals with the disorder are asymptomatic and without classic complications, such as renal stones and osteoporosis, at diagnosis. Consensus guidelines suggest which individuals might be suitable for medical follow-up rather than parathyroidectomy, but there are no long-term randomised controlled trials to support the safety of medical surveillance, and some patients progress with time. Data from observational studies suggest that cardiovascular morbidity and mortality are increased in patients with primary hyperparathyroidism, and might be predicted by parathyroid hormone concentrations, even in individuals with asymptomatic primary hyperparathyroidism. Whether parathyroidectomy improves cardiovascular outcomes in patients with asymptomatic primary hyperparathyroidism is unproven, but data suggest that surgery decreases fracture risk and might improve neuropsychological symptoms. Studies also show that patients with normocalcaemic (subclinical) hyperparathyroidism and hypoparathyroidism have a low risk of progression to overt disease, but their long-term risks are not defined. In this Review, we explore the increasing range of asymptomatic parathyroid disorders, focusing on current evidence about their natural history and potential complications, with a particular emphasis on primary hyperparathyroidism.

When would I use medical therapies for the treatment of primary hyperparathyroidism?

Although there may be controversy surrounding the indications for parathyroidectomy in primary hyperparathyroidism, it remains the only accepted definitive therapy. However, even if parathyroidectomy is indicated, some patients refuse surgery, are medically unfit or have residual or recurrent disease inaccessible to further surgery. Some of these patients may be suitable for long-term observation but others require intervention for management of symptomatic or moderate to severe hypercalcaemia, loss of bone mineral density or renal calculi. The selection of a suitable therapy for each patient should be individualized.

Pathology, pathophysiology, and treatment strategies of endocrine disorders and their cardiac complications

The cardiovascular system is affected by a multitude of endocrine disorders, including dysfunction of the thyroid, calcium, glucocorticoids, insulin/glucose, and growth hormone axes. Since most of these changes in the cardiovascular system are reversible when treated, early diagnosis is important, as if left untreated, they may become fatal. This review focuses on the pathophysiology, clinical presentation, pathology, and treatment of patients with these endocrine diseases who present with a variety of cardiovascular manifestations. Neuroendocrine tumors presenting with the carcinoid syndrome and their cardiovascular manifestations are also discussed.

Primary hyperparathyroidism

OBJECTIVE

To review primary hyperparathyroidism and the key issues that are relevant to the practicing endocrinologist.

METHODS

The latest information on the presentation, diagnosis, and traditional and nontraditional aspects of primary hyperparathyroidism is reviewed.

RESULTS

The diagnosis of primary hyperparathyroidism is straightforward when the traditional hypercalcemic patient is documented to have an elevated parathyroid hormone (PTH) level. Commonly, patients are identified who have normal serum calcium levels but elevated PTH levels in whom no secondary causes for hyperparathyroidism can be confirmed. Traditional target organs of primary hyperparathyroidism-the skeleton and the kidneys-continue to be a focus in the patient evaluation. Bone mineral density shows a typical pattern of involvement with the distal one-third radius being selectively reduced compared with the lumbar spine in which bone mineral density is generally well maintained. Neurocognitive and cardiovascular aspects of primary hyperparathyroidism, while a focus of recent interest, have not been shown to definitively aid in the decision for or against surgery. The recommendation for surgery in primary hyperparathyroidism is based on guidelines that focus on the serum calcium level, renal function, bone mineral density, and age. In patients who do not meet guidelines, a nonsurgical management approach has merit.

CONCLUSIONS

Primary hyperparathyroidism is continuing to show changes in its clinical profile, with normocalcemic primary hyperparathyroidism being a topic of great interest. Skeletal and renal features of primary hyperparathyroidism drive, in most cases, the decision to recommend surgery. In patients who do not meet any criteria for surgery, a conservative approach with appropriate monitoring is acceptable.

Medical management of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the outpatient population. It is diagnosed in most individuals in the Western world at an asymptomatic stage without signs or symptoms of parathyroid hormone (PTH) calcium excess. Nonspecific symptoms include weakness, malaise, fatigue, and possible mood disturbances, which may be present at the time of diagnosis. The diagnosis of PHPT is confirmed in the presence of hypercalcemia and a normal or elevated PTH level in the absence of conditions that mimic PHPT. Indications for surgery have recently been revised based on international consensus, and surgery is advised in the presence of significant hypercalcemia, impaired renal function, and osteoporosis and in individuals younger than 50yr. The classical complications of PHPT are skeletal fragility, nephrolithiasis, and nephrocalcinosis. Surgery is always appropriate in an individual with confirmed PHPT after excluding conditions that can mimic PHPT and in the absence of contraindications. Individuals with asymptomatic PHPT not meeting the guidelines for surgery or those with contraindications for surgery may be followed and considered for medical management. For those at an increased risk of fragility fracture, antiresorptive therapy may be considered with close monitoring of biochemical data and bone densitometry. Targeted therapy with a calcimimetic agent may be of value in lowering serum calcium and PTH. There are currently no fracture data for the medical options available, and prospective randomized controlled trials are required to confirm the effects of medical therapy on fracture risk reduction in those with asymptomatic PHPT.

Bone turnover markers in primary hyperparathyroidism

Primary hyperparathyroidism is an endocrine disorder characterized by elevated or inappropriate normal levels of parathyroid hormone in a setting of hypercalcemia. The inclusion of calcium on the basic metabolic bone panel has allowed this disorder to be diagnosed even in the absence of symptoms. Nevertheless, the skeleton can be a target of excess parathyroid hormone activity even during its asymptomatic presentation. Bone turnover markers a surrogate index of the process of the remodeling process at the level of bone, and thus can be useful to monitor skeleton involvement in primary hyperparathyroidism.

Asymptomatic primary hyperparathyroidism

The clinical profile of primary hyperparathyroidism (PHPT) as it is seen in the United States and most Western countries has evolved significantly over the past half century. The introduction of the multichannel serum autoanalyzer in the 1970s led to the recognition of a cohort of individuals with asymptomatic hypercalcemia, in whom evaluation led to the diagnosis of PHPT. The term "asymptomatic primary hyperparathyroidism" was introduced to describe patients who lack obvious signs and symptoms referable to either excess calcium or parathyroid hormone. Although it was expected that asymptomatic patients would eventually develop classical symptoms of PHPT, observational data suggest that most patients do not evolve over time to become overtly symptomatic. In most parts of the world, the asymptomatic phenotype of PHPT has replaced classical PHPT. This report is a selective review of data on asymptomatic PHPT: its demographic features, presentation and natural history, as well as biochemical, skeletal, neuromuscular, psychological, and cardiovascular manifestations. In addition, we will summarize available information on treatment indications and options for those with asymptomatic disease.

Nonsurgical management of mild primary hyperparathyroidism - a reasonable option

Primary hyperparathyroidism (PHPT) is a relatively common disorder which is often diagnosed incidentally and characterized in the majority of those affected by mild stable biochemical abnormalities and lack of symptoms. Nephrolithiasis and bone loss leading to an increased risk of fracture are generally accepted complications of PHPT. Some epidemiological studies report associations between PHPT and a wide range of common diseases, but these relationships may be confounded by the increased body weight observed in PHPT. Because there is a dearth of controlled clinical trial evidence in PHPT, optimal management is controversial. For individuals with mild stable PHPT, low fracture risk and no renal stones, observation without intervention is reasonable. Surgical treatment is clearly indicated for patients at risk of severe hypercalcaemia or with nephrolithiasis. For individuals with increased risk of fracture, antiresorptive therapies improve bone mineral density to a similar degree to surgical treatment. Calcimimetic agents may have a role in managing patients with symptomatic PHPT who cannot undergo, or fail, surgical treatment. There is a need for additional randomized clinical trials to inform management of PHPT.