Alendronate in the treatment of primary hyperparathyroid-related osteoporosis: a 2-year study

Secondary Hyperparathyroidism

Secondary hyperparathyroidism (SHPT) does not initiate as a primary dysfunction of parathyroid glands resulting from an intrinsic defect or disease but is the physiologic response of parathyroids to metabolic changes elsewhere in the body occurring over time. SHPT is a manifestation of a chronic condition that classically occurs from chronic kidney disease. In fact, given the relatively recent transition of populations from outside (agrarian) to indoor (industrial, information technology, and so forth) employment and a consequent reduction in sun exposure, combined with diets of highly processed food, vitamin D and calcium deficiencies are now the leading causes of SHPT.

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.

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.

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.

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.

Modulation of bone turnover aberration: A target for management of primary osteoporosis in experimental rat model

Osteoporosis is a skeletal degenerative disease characterised by abnormal bone turnover with scant bone formation and overabundant bone resorption. The present approach was intended to address the potency of nanohydroxyapatite (nHA), chitosan/hydroxyapatite nanocomposites (nCh/HA) and silver/hydroxyapatite nanoparticles (nAg/HA) to modulate bone turnover deviation in primary osteoporosis induced in the experimental model. Characterisation techniques such as TEM, zeta-potential, FT-IR and XRD were used to assess the morphology, the physical as well as the chemical features of the prepared nanostructures. The in vivo experiment was conducted on forty-eight adult female rats, randomised into 6 groups (8 rats/group), (1) gonad-intact, (2) osteoporotic group, (3) osteoporotic + nHA, (4) osteoporotic + nCh/HA, (5) osteoporotic + nAg/HA and (6) osteoporotic + alendronate (ALN). After three months of treatment, serum sclerostin (SOST), bone alkaline phosphatase (BALP) and bone sialoprotein (BSP) levels were quantified using ELISA. Femur bone receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL) and cathepsin K (CtsK) mRNA levels were evaluated by quantitative RT-PCR. Moreover, alizarin red S staining was applied to determine the mineralisation intensity of femur bone. Findings in the present study indicated that treatment with nHA, nCh/HA or nAg/HA leads to significant repression of serum SOST, BALP and BSP levels parallel to a significant down-regulation of RANKL and CtsK gene expression levels. On the other side, significant enhancement in the calcification intensity of femur bone has been noticed. The outcomes of this experimental setting ascertained the potentiality of nHA, nCh/HA and nAg/HA as promising nanomaterials in attenuating the excessive bone turnover in the primary osteoporotic rat model. The mechanisms behind the efficacy of the investigated nanostructures involved the obstacle of serum and tissue indices of bone resorption besides the strengthening of bone mineralisation.

Primary hyperparathyroidism: should surgery be performed on all patients? Current evidence and residual uncertainties

Primary hyperparathyroidism (pHPT) is the third most common endocrine disease and is characterized by hypercalcaemia and elevated or inappropriately 'normal' levels of the parathyroid hormone (PTH). The main target organs of PTH are the skeletal system and the kidneys. Before the 1970s, pHPT was a rarely detected disease associated with notable morbidity and premature mortality. Introduction of biochemical screening, allowing for a wide range of indications, has contributed to the detection of the full spectrum of the disease. A new entity with an isolated elevation of PTH, normocalcaemic HP, has emerged and is currently being explored. The highest incidence of pHPT, 3-5%, is observed amongst women, and the prevalence increases with age. The female-to-male ratio is 3-4 : 1 except in younger patients where distribution is equal and known hereditary causes account for approximately 10% of the cases. In the last few decades, it has become evident that fewer patients than previously believed are truly asymptomatic. The cause of pHPT is often a benign tumour, a parathyroid adenoma, and the only definite treatment is parathyroidectomy (PTX). No medical treatment, single or combined, can achieve a curing of pHPT. Recent data indicate that PTX, despite being proven to be cost-effective compared to conservative treatment, is underutilized, especially in elderly pHPT patients. The decision of PTX should always be based on a safe diagnosis, and the potential benefits of curative treatment should not be outweighed by the risks of surgery or anaesthesia.

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.

Current Indications for Surgical Treatment of Primary Hyperparathyroidism in the Elderly

This study presents the results of surgery in the elderly for primary hyperparathyroidism (PHPT) from a single institution's experience. We retrospectively analyzed 898 cases of surgically treated PHPT, divided into two groups: 135 elderly patients (A) and 763 patients younger than 65 years (B). PHPT was symptomatic in 68.8 per cent patients in group A and in 81.6 per cent in group B. Unilateral temporary recurrent laryngeal nerve palsy was observed in 0.9 per cent in group A and 0.1 per cent in group B (P > 0.05). No cervical hematomas, mortality or major cardiovascular, neurological, respiratory or metabolic postoperative complications were registered. All the patients evaluated at one year had improvement in the quality of life, with increase of bone mineral density (BMD) in 85.6 per cent and 79.8 per cent of patients in groups A and B, with no significant differences between symptomatic and asymptomatic patients. Parathyroidectomy in elderly PHPT patients is safe, with rate of morbidity similar to what observed in younger individuals. Further investigations are recommended to confirm the role of surgery as an effective approach in elderly PHPT patients.

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.

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.

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.

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.

Parathyromatosis: a rare yet problematic etiology of recurrent and persistent hyperparathyroidism

Recurrent or persistent hyperparathyroidism is an uncommon yet challenging clinical problem, and parathyromatosis is one of its very rare causes. In this minireview, we review causes of recurrent hyperparathyroidism and all cases of parathyromatosis available in the literature. The clinical course of a case of parathyromatosis with the longest follow-up (1977-2011) is described. Similar cases reported between 1975 and the present are reviewed and analyzed to characterize the clinical presentation, course, and management of this rare condition. Parathyromatosis, which is benign parathyroid tissue seeding, has been detailed in 35 patients in the English literature. The majority were female subjects, with end-stage renal disease, in their fifth to sixth decade of life. In most cases, the diagnosis was made intraoperatively; and the condition was often refractory to surgery. A calcimimetic agent was used in 5 cases with end-stage renal disease; serum calcium and/or parathyroid hormone levels decreased in 4 subjects, but only one was reported to experience increments in bone density. Medical management combining a calcimimetic with a bisphosphonate may therefore be a preferred alternative.

Cinacalcet for the treatment of primary hyperparathyroidism

The objective of this article is to review the literature regarding the treatment of primary hyperparathyroidism (PHPT) with a focus on cinacalcet. A MEDLINE (1965-June 2009) and bibliographic search of the English-language literature was conducted using the search terms cinacalcet, calcimimetics, primary hyperparathyroidism, and treatment. All articles identified in the search were included. Parathyroidectomy is curative for patients with PHPT; however, there are few options for patients who are not surgical candidates, who refuse surgery, or those with refractory PHPT after parathyroidectomy. Possible treatment options include estrogens, raloxifene, bisphosphonates, calcitonin, and cinacalcet. Cinacalcet has been shown to decrease serum calcium and parathyroid hormone serum levels in patients with PHPT. These trials, however, have not studied the effect of cinacalcet on patient-oriented outcomes such as bone mineral density, nephrolithiasis, or other complications of PHPT. Cinacalcet may be considered to reduce serum calcium and parathyroid hormone serum levels in patients with PHPT who cannot or will not undergo surgery and those with refractory PHPT after parathyroidectomy. Because the effects of cinacalcet on bone mineral density are uncertain, more frequent monitoring of bone mineral density may be required along with a medication proven to improve bone mineral density. Future studies should evaluate the effect of cinacalcet on complications of PHPT.

Primary hyperparathyroidism: Skeletal and non-skeletal effects, diagnosis and management

Primary hyperparathyroidism (PHPT) is the third most common endocrinopathy seen today, and is most frequently found in the 6th to 7th decade of life. PHPT can present with various degrees of symptoms, and can affect many organ systems, including the skeletal, renal, central nervous system and cardiovascular system. Despite this, the most common presentation of hyperparathyroidism is "asymptomatic" with the diagnosis being made incidentally with the initial finding of hypercalcemia on routine laboratory studies, leading to further investigation. Surgical versus medical management is usually based on factors such as age and complications related to hyperparathyroidism (i.e. the presence of renal stones, renal insufficiency and bone loss and significant increases in serum calcium). Treatment options include parathyroidectomy, bisphosphonates, calcitonin and calcimimetics. In this review, we discuss primary hyperparathyroidism in detail with a focus on clinical manifestations particularly in the elderly population. We highlight the indications for surgical versus medical management and compare some of the uses of newer therapeutic agents relative to traditional ones.

Long-term effects of neridronate and its discontinuation in patients with primary hyperparathyroidism

In patients with primary hyperparathyroidism (PHPT) not suitable for surgical correction, a skeletal protection with bisphosphonates is considered a reasonable option, but the long-term effects after treatment discontinuation are not well known. Sixty postmenopausal women with PHPT were given 400-600 IU vitamin D(3) daily and 100 mg neridronate IV every 2 months for 2 years with 2 additional years of follow-up without antiresorptive therapies. Bone mineral density (BMD) progressively rose by 6.7 ± 7.6% (SD) and by 2.9 ± 4.5% at the spine and femoral neck, respectively. During follow-up, mean BMD progressively fell, but after 2 years it was still 3.9 ± 5.5% higher than baseline values at the spine. Bone alkaline phosphatase and serum C-telopeptide of type I collagen decreased significantly within 6 months (28 and 49% versus baseline, respectively) and rose to baseline values within 6-12 months during follow-up. Serum PTH significantly rose from baseline during treatment, but it remained significantly higher than baseline during follow-up. The PTH changes were significantly correlated with serum 25-hydroxyvitamin D (25OHD) levels. In conclusion, in this study we observed that in patients with mild PHPT treatment with bisphosphonates is associated with the expected changes in bone-turnover markers and that the significant increases of both hip and spine BMD are partially maintained for at least 2 years after treatment discontinuation at the vertebral site. The marked increases in serum PTH levels, particularly in subjects with low 25OHD levels, persist after treatment discontinuation and this raises the suspicion that this might reflect a worsening of PHPT.

Primary hyperparathyroidism: an overview

Primary hyperparathyroidism is a common condition that affects 0.3% of the general population. Primary and tertiary care specialists can encounter patients with primary hyperparathyroidism, and prompt recognition and treatment can greatly reduce morbidity and mortality from this disease. In this paper we will review the basic physiology of calcium homeostasis and then consider genetic associations as well as common etiologies and presentations of primary hyperparathyroidism. We will consider emerging trends in detection and measurement of parathyroid hormone as well as available imaging modalities for the parathyroid glands. Surgical indications and approach will be reviewed as well as medical management of primary hyperparathyroidism with bisphosphonates and calcimimetics.

New perspectives in the management of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a biochemical syndrome caused by the inappropriate or unregulated overproduction of parathyroid hormone, Leading to hypercalcae-mia. It was previously considered a relatively rare disorder, with clinical manifestations dominated by renal and/or bone disease. However, in modern times the diagnosis is most frequently recognized coincidentally on biochemical testing in patients evaluated for unrelated complaints. Parathyroidectomy is the only curative treatment for PHPT, with improved outcomes in symptomatic patients following this procedure. However, surgical intervention in patients with no clear clinical features remains controversial. The National Institutes for Health (NIH) have developed consensus guidelines giving specific indications for when surgery is recommended in patients with asymptomatic PHPT. This article examines the impact of treatment on asymptomatic PHPT, focusing on bone disease, neurocognitive function, quality of Life, cardiovascular disease and mortality. Medical treatment options, including bisphospho-nates and cinacalcet, are also discussed.

Effect of alendronate on bone metabolic indices and bone mineral density in patients treated with high-dose glucocorticoid: a prospective study

SUMMARY

This prospective study, in the very early phase after initiation of glucocorticoid (GC) treatment, showed that alendronate was effective in suppressing accelerated bone resorption and subsequent decrease in bone mineral density (BMD) at the lumbar spine of patients with high-dose GC treatment.

INTRODUCTION

How bisphosphonates affect bone metabolism and BMD of patients with high-dose GC in the early phase, especially within 1 month is unclear.

METHODS

We examined the prospective effects of daily 5 mg alendronate on bone metabolism and BMD in 20 patients with high-dose GC (at least 40 mg prednisolone/day) and compared them to 34 high-dose GC-treated patients without alendronate.

RESULTS

Serum levels of calcium decreased at day 28 in the alendronate group. Urinary calcium excretion significantly increased after day 7 in both groups. The increase in serum parathyroid hormone (PTH) level at day 7 in the control group was not observed in the alendronate group, but PTH levels increased at day 28 and month 3 in the alendronate group. As for the bone turnover markers, the serum osteocalcin level decreased in both alendronate and control groups, but serum bone-type alkaline phosphatase levels did not show significant changes. Although the urinary type I collagen cross-linked N-telopeptide (NTX) level showed significant increases on days 7 and 28 in the control group; such early increases in urinary NTX were not observed in the alendronate group. Thereafter, the urinary NTX levels fell slowly in the alendronate group significantly. BMD at the lumbar spine significantly decreased from month 1 in the control group, whereas in the alendronate group, BMD at the lumbar spine maintained almost the same level at all time points observed.

CONCLUSION

Alendronate was effective in suppressing bone resorption and subsequent BMD decrease at the lumbar spine in patients with high-dose GC treatment.

Skeletal effects of interventions in mild primary hyperparathyroidism: a meta-analysis

CONTEXT

Uncertainty exists as to the optimal management and monitoring of the skeletal consequences of mild primary hyperparathyroidism (PHPT).

OBJECTIVE

The aim of this study was to determine the effects of surgical treatment, medical treatment and no treatment on bone mineral density (BMD) in mild PHPT.

DATA SOURCES

Our sources were Medline, EMBASE, and Cochrane CENTRAL prior to January 2009, and abstracts from meetings of international bone and mineral societies from 1987-2008.

STUDY SELECTION

Eligible studies were of at least 1-yr duration and included more than 10 participants with mild PHPT (serum calcium < 12 mg/dl) who had BMD measured by dual-energy x-ray absorptiometry while being observed without intervention, or treated with antiresorptive therapy or surgery. Primary analysis was of studies of up to 2-yr duration. Secondary analysis was of studies with follow-up beyond 2 yr.

DATA EXTRACTION

Data were extracted from the text of the retrieved articles or conference abstracts.

DATA SYNTHESIS

Increases in BMD in response to surgical intervention were comparable to those induced by antiresorptive therapies. Significant bone loss was observed in untreated subjects, but the rates of loss ranged from 0.6-1.0%/yr. Analysis of studies reporting data beyond 2 yr of follow-up demonstrated stable increases in BMD after surgery and stable BMD or slow loss (0.1-0.3%/yr) in untreated PHPT.

CONCLUSIONS

Surgical treatment and antiresorptive therapies increase BMD in mild PHPT to a similar degree, and each represents a reasonable option in a patient with mild PHPT and low BMD. Rapid bone loss does not occur in untreated mild PHPT, such that monitoring of BMD less frequently than every 1-2 yr is reasonable in individuals for whom intervention is not immediately required.

Alendronate therapy in men with primary hyperparathyroidism

OBJECTIVE

To determine the skeletal effects of alendronate therapy in men with primary hyperparathyroidism (PHPT) in comparison with those in postmenopausal women.

METHODS

There essentially are no published data on the effects of bisphosphonate therapy in men with PHPT. We previously conducted a double-blind, randomized, single- crossover trial of alendronate, 10 mg daily, in PHPT and reported that alendronate significantly increases bone mineral density (BMD) at 12 months relative to baseline values. That study sample included both women (n = 28) and men (n = 9) and both premenopausal (n = 4) and postmenopausal (n = 24) women. Study subjects were randomly assigned to receive either alendronate or placebo during the first year, and all subjects received alendronate during the second year. Among the men, 3 received alendronate and 6 received placebo during the first year. The current analysis focuses on the skeletal effects of alendronate therapy in the 9 men during their first year of treatment versus the 6 men during their first year while receiving placebo as well as the 24 postmenopausal women during their first year of alendronate therapy. Paired t tests comparing baseline and 12-month data were performed for the 9 treated men and the 6 control subjects; unpaired t tests were used to compare the 9 treated men and the 24 treated women.

RESULTS

Alendronate therapy for 1 year (n = 9) resulted in a 4.8% increase in BMD at the lumbar spine (P = .1) in comparison with the men who received 1 year of placebo (n = 6). Relative to baseline, men receiving alendronate showed a significant 4.4% gain in BMD at the lumbar spine (P = .009) and a 2.95% gain in total hip BMD (P =.027). A 47% decline in serum levels of bone-specific alkaline phosphatase activity was also noted with alendronate therapy (P = .003). Changes in BMD in the male population were similar to previously reported effects of alendronate therapy in postmenopausal women with PHPT.

CONCLUSION

Alendronate therapy in men with PHPT is associated with improvements in BMD and reductions in bone turnover. These data, similar to the findings in postmenopausal women with PHPT, suggest that aminobisphosphonates may be of value in providing skeletal protection for men with PHPT. Further study is needed to confirm skeletal protection and fracture efficacy in this population.

Biochemical effects of calcifediol supplementation in mild, asymptomatic, hyperparathyroidism with concomitant vitamin D deficiency

It has been proposed to cautiously supplement with vitamin D to any patient with asymptomatic primary hyperparathyroidism (PHTP) and a plasma 25-hydroxyvitamin D [25(OH)D] concentration <50 nmol/l. Evidence about the safeness of this intervention is limited to two studies. Our aim was to prospectively assess the biochemical effects of one-year 25(OH)D supplementation in this context. Twenty-seven patients were included in this study. Calcifediol was started at a dose of 480-960 IU/24 h (8-16 microg/24 h) and adjusted up to a maximum of 960 IU/24 h (16 microg/24 h). Basal calcium, phosphate, albumin, total alkaline phosphatase (ALP), creatinine, 24 h calcium urinary excretion, intact PTH (iPTH) and 25(OH)D were measured before and during vitamin D supplementation. The mean basal 25(OH)D was 28.7 +/- 8.0 nmol/l, and at 12 months was 71.5 +/- 32.5 nmol/l (P = 0.00 vs. baseline). After 3, 6 and 12 months iPTH levels were 141.7 +/- 108.4 ng/l (P = 0.00 vs. baseline), 131.1 +/- 95.7 ng/l (P = 0.03 vs. baseline) and 162.2 +/- 139.3 ng/l (P = ns vs. baseline). Mean calcium did not change. Mean urinary calcium excretion increased significantly (basal: 5.7 +/- 2.9 mmol/24 h, 12 months: 7.9 +/- 4.9 mmol/24 h, P = 0.02). Cautious calcifediol supplementation significantly increased mean 25(OH)D and temporarily reduced mean iPTH. It did not change mean serum calcium, but urinary calcium excretion increased significantly. We suggest that serum calcium and 24 h calciuria be measured at regular intervals in patients with PHTP, while on calcifediol supplementation.

Hyperparathyroidism

Hyperparathyroidism is due to increased activity of the parathyroid glands, either from an intrinsic abnormal change altering excretion of parathyroid hormone (primary or tertiary hyperparathyroidism) or from an extrinsic abnormal change affecting calcium homoeostasis stimulating production of parathyroid hormone (secondary hyperparathyroidism). Primary hyperparathyroidism is the third most common endocrine disorder, with the highest incidence in postmenopausal women. Asymptomatic disease is common, and severe disease with renal stones and metabolic bone disease arises less frequently now than it did 20-30 years ago. Primary hyperparathyroidism can be cured by surgical removal of an adenoma, increasingly by minimally invasive parathyroidectomy. Medical management of mild disease is possible with bisphosphonates, hormone replacement therapy, and calcimimetics. Vitamin D deficiency is a common cause of secondary hyperparathyroidism, particularly in elderly people. However, the biochemical definition of vitamin D deficiency and its treatment are subject to much debate. Secondary hyperparathyroidism as the result of chronic kidney disease is important in the genesis of renal bone disease, and several new treatments could help achieve the guidelines set out by the kidney disease outcomes quality initiative.

[Medical treatment of primary hyperparathyroidism: role of calcimimetics]

Primary hyperparathyroidism (PHPT) is a common endocrinological process, characterized by chronic elevation of serum concentrations of calcium and parathyroid hormone (PTH). The only intervention able to cure the disease is parathyroidectomy. However, there are few valid medical alternatives for patients whose PHPT is unresolved by surgery, or in those with contraindications for surgery or who refuse the procedure. The discovery of calcium-sensing receptors (CaSRs), which regulate PTH secretion according to extracellular calcium concentrations, has allowed specific anti-parathyroid drugs called calcimimetics to be designed. Cinacalcet is an allosteric modulator of CaSR that has demonstrated safety and efficacy in controlling serum calcium values and in reducing PTH levels in patients with PHPT. The exact role of calcimimetics in the overall management of PHPT is promising and should be considered in future clinical practice guidelines.

Medical management of asymptomatic primary hyperparathyroidism: proceedings of the third international workshop

BACKGROUND

Primary hyperparathyroidism (PHPT) is a common endocrine disorder that is frequently asymptomatic. The 2002 International Workshop on Asymptomatic PHPT addressed medical management of asymptomatic PHPT and summarized the data on nonsurgical approaches to this disease. At the Third International Workshop on Asymptomatic PHPT held in May 2008, this subject was reviewed again in light of data that have since become available. We present the results of a literature review of advances in the medical management of PHPT.

METHODS

A series of questions was developed by the International Task Force on PHPT. A comprehensive literature search for relevant studies evaluating the management of PHPT with bisphosphonates, hormone replacement therapy, raloxifene, and calcimimetics was conducted. Existing guidelines and recent unpublished data were also reviewed. All selected relevant articles were reviewed, and the questions developed by the International Task Force were addressed by the Consensus Panel.

RESULTS

Bisphosphonates and hormone replacement therapy are effective in decreasing bone turnover in patients with PHPT and improving bone mineral density (BMD). Fracture data are not available with either treatment. Raloxifene also lowers bone turnover in patients with PHPT. None of these agents, however, significantly lowers serum calcium or PTH levels. The calcimimetic cinacalcet reduces both serum calcium and PTH levels and raises serum phosphorus. Cinacalcet does not, however, reduce bone turnover or improve BMD.

CONCLUSIONS

Bisphosphonates and hormone replacement therapy provide skeletal protection in patients with PHPT. Limited data are available regarding skeletal protection in patients with PHPT treated with raloxifene. Calcimimetics favorably alter serum calcium and PTH in PHPT but do not significantly affect either bone turnover or BMD. Medical management of asymptomatic PHPT is a promising option for those who are not candidates for parathyroidectomy.

Analysis of factors affecting increase in bone mineral density at lumbar spine by bisphosphonate treatment in postmenopausal osteoporosis

Bisphosphonate is an effective drug to reduce fracture risk in osteoporotic patients; however, factors affecting the efficacy of bisphosphonate treatment are not fully known, especially in Japanese patients. In the present study, we examined the relationships between an increase in lumbar spine bone mineral density (BMD) by bisphosphonates and several pretreatment parameters, including biochemical, bone/mineral, and body composition indices, in 85 postmenopausal osteoporotic patients treated with alendronate or risedronate. BMD increase was measured by dual-energy X-ray absorptiometry at the lumbar spine before and 2 years after treatment. BMD increase at the lumbar spine was observed as independent of age, height, weight, body mass index, and fat mass, although lean body mass seemed slightly related. On the other hand, fasting plasma glucose (FPG) levels were significantly and positively related to BMD increase at the lumbar spine. In multiple regression analysis, FPG levels were not significantly related to BMD increase at the lumbar spine when lean body mass was considered. As for bone/mineral parameters, BMD increase at the lumbar spine was not significantly related to serum levels of calcium, parathyroid hormone (PTH), and alkaline phosphatase or urinary levels of deoxypiridinoline and calcium excretion. As for BMD parameters, Z-scores of BMD at any site and bone geometry parameters obtained by forearm peripheral quantitative computed tomography were not significantly related to BMD increase at the lumbar spine. BMD increases at the lumbar spine were similar between groups with or without vertebral fractures. In conclusion, BMD increase at the lumbar spine by bisphosphonate treatment was not related to any pretreatment parameters, including body size, body composition, and bone/mineral metabolism in postmenopausal Japanese women with primary osteoporosis, although FPG correlated partly to BMD through lean body mass.

Percutaneous ethanol injection therapy: a surgery-sparing treatment for primary hyperparathyroidism

OBJECTIVE

To describe our 3-year experience in the long-term efficacy and safety of percutaneous ethanol injection therapy (PEIT), as an alternative to surgery for the management of patients with primary hyperparathyroidism (p-HPT).

DESIGN

Prospective study with a mean follow-up of 19.6 +/- 10.6 months.

PATIENTS

Our study population included 19 consecutive high risk patients with p-HPT, who met the criteria for surgery.

MEASUREMENTS

Under ultrasonic guidance, ethanol (95%) was injected into parathyroid glands with a volume of >or= 0.15 cm(3). With the aim of normalizing intact parathormone (iPTH) values, repeated ethanol injections were carried out, in an interval of 2 weeks, until normalization of iPTH was reached or until no residual blood supply was detected by ultrasound in the gland. Biochemical parameters were monitored throughout the study.

RESULTS

At 6-month follow-up, normalization of iPTH levels (10-65 ng/l) was achieved in 11 (58%) patients (responders). Of the eight remaining patients (nonresponders), six patients had reduced (but not normalized) iPTH levels and two patients required parathyroid surgery. Seventeen (11 responders and 6 nonresponders) of the 19 patients (89.5%) became normocalcaemic (serum Ca <or= 2.57 mmol/l) and remained so for a mean follow-up of 21 months (8-39 months). The odds ratio (P < 0.05) of response vs. no response to PEIT was 16.7-fold for pretreatment iPTH < 200 vs. > 200 ng/l. The only complication was a transient dysphonia noticed in three patients.

CONCLUSIONS

PEIT is a safe and effective nonsurgical treatment for patients with p-HPT, who are unsuitable for surgical intervention.

Primary hyperparathyroidism and the skeleton

Today, primary hyperparathyroidism (PHPT) in the developed countries is typically a disease with few or no obvious clinical symptoms. However, even in the asymptomatic cases the endogenous excess of PTH increases bone turnover leading to an insidious reversible loss of cortical and trabecular bone because of an expansion of the remodelling space and an irreversible loss of cortical bone due to increased endocortical resorption. In contrast trabecular bone structure and integrity to a large extent is maintained and there may be a slight periosteal expansion. Most studies have reported decreased bone mineral density (BMD) in PHPT mainly located at cortical sites, whereas sites rich in trabecular bone only show a modest reduction or even a slight increase in BMD. The frequent occurrence of vitamin D insufficiency and deficiency in PHPT and increased plasma FGF23 levels may also contribute to the decrease in BMD. The effect of smoking is unsolved. Epidemiological studies have shown that the relative risk of spine and nonspine fractures is increased in untreated PHPT starting up to 10 years before the diagnosis is made. Successful surgery for PHPT normalizes bone turnover, increases BMD and decreases fracture risk based on larger epidemiological studies. However, 10 years after surgery fracture risk appears to increase again due to an increase in forearm fractures. There are no randomized controlled studies (RCTs) demonstrating a protective effect of medical treatment on fracture risk in PHPT. Less conclusive studies suggest that vitamin D supplementation may have a beneficial effect on plasma PTH and BMD in vitamin D deficient PHPT patients. Hormone replacement therapy (HRT) and maybe SERM appear to reduce bone turnover and increase BMD. However, their nonskeletal side-effects preclude their use for this purpose. Bisphosphonates reduce bone turnover and increase BMD in PHPT as in osteoporosis and may be a therapeutical option in selected patients with low BMD. Obviously, there is a need for larger RCTs with fractures as end-points that appraise this possibility. Calcimimetics reduce plasma calcium and PTH in PHPT but has no beneficial effect on bone turnover or BMD. In symptomatic hypercalcaemic PHPT with low BMD where curative surgery is impossible or contraindicated a combination of a calcimimetic and a bisphosphonate may be an undocumented therapeutical option that needs further evaluation.

Cinacalcet for the treatment of primary hyperparathyroidism

Primary hyperparathyroidism (HPT) is the leading cause of hypercalcemia in the outpatient setting, and it is treated primarily by parathyroidectomy. There are few nonsurgical treatment options for patients who do not wish to have surgery, who have failed surgery, or who have contraindications to surgery. Cinacalcet increases the sensitivity of parathyroid calcium-sensing receptors to extracellular calcium, thereby reducing serum calcium levels. We conducted a retrospective chart review from 2004 to 2006 to investigate the efficacy of cinacalcet in reducing serum total calcium, ionized calcium, and parathyroid hormone (PTH) in patients with primary HPT. Patients were started on cinacalcet if they met at least one indication for parathyroidectomy, which includes T score less than -2.5 standard deviations from the mean, serum calcium 1 mg/dL above the upper limit of normal, 24-hour urine calcium above 400 mg/dL, age less than 50 years, or a creatinine clearance that is 30% below age- and sex-matched controls. The primary outcome was normalization of serum calcium. A total of 18 patients with primary HPT were started on cinacalcet: 16 men and 2 women with a mean age of 70 years. Mean baseline serum calcium was 10.60 +/- .53 mg/dL; ionized serum calcium, 1.45 +/- .07 mmol/L; and serum PTH, 141 +/- 78 pg/mL. After treatment with cinacalcet, the mean serum calcium decreased to 9.46 +/- .34 mg/dL, ionized calcium decreased to 1.26 +/- .06 mmol/L, and PTH decreased to 108 +/- 64.5 pg/mL. Ninety-four percent of the patients on cinacalcet had normal total serum calcium, 81% had normal serum ionized calcium, whereas only 25% had a normal serum PTH level. Cinacalcet normalizes serum calcium in most patients while only modestly reducing serum PTH levels.

Asymptomatic hyperparathyroidism--need for multicentre studies

Long-term follow-up is initially considered appropriate for the majority of patients with primary hyperparathyroidism (PHPT) having small increases in calcium levels (< 2.8 mmol/l) and lacking the 'classical' symptoms of PHPT. The supportive reasoning is that many such patients never progress to more severe biochemical or clinical disease. There are, however, arguments in favour of early surgical treatment of such patients but adequately powered studies have not been carried out in this subgroup of patients to asses the impact of PHPT on their quality of life, cardiovascular risk and bone density. Progressive loss in bone mineral density and an increased risk of bone fracture become increasingly significant in an ageing population. Left ventricular hypertrophy, an increased risk of arrhythmia and/or myocardial infarction in addition to changes in atherogenic lipid profile and impaired glucose tolerance may translate into an increased risk of premature death in this group of patients. Changes in the quality of life identified using standardized questionnaires are sometimes recognized by patients only in retrospect (i.e. after resolution of symptoms following successful parathyroidectomy). In addition, many series fail to assess and record accurately such symptoms. Multicentre cohort studies of patients with asymptomatic PHPT randomized to immediate or delayed surgical treatment could address some of the debated issues highlighted in this review. Until such studies are set up, most surgeons would consider that parathyroid surgery should represent the first choice of treatment for all patients, but many physicians would favour a long-term follow-up. Nevertheless, the threshold for referral for surgical treatment has been lowered since the introduction of scan-directed minimally invasive parathyroidectomy, which enables the experienced parathyroid surgeon to successfully treat patients with PHPT with a minimum of complications as a day-case operation. In the context of improved surgical treatment, we need more data on the benefits or otherwise in so-called asymptomatic patients with a thorough assessment of their bone quality, cardiovascular risk and quality of life.

Nonsurgical management of primary hyperparathyroidism

Primary hyperparathyroidism is the most common cause of hypercalcemia in the outpatient setting and is typically caused by a single benign parathyroid adenoma. Most patients with hyperparathyroidism are postmenopausal women. Patients can be asymptomatic or minimally symptomatic. Parathyroidectomy is the definitive cure for primary hyperparathyroidism, and no medical therapies have been approved by the Food and Drug Administration for this disorder. Guidelines for surgery have been established by a National Institutes of Health consensus panel, but many patients do not meet these guidelines or have comorbid conditions that prohibit surgery. This review describes alternative treatment options for patients who decide against or are unable to proceed with surgery.