Raloxifene reverses bone loss in postmenopausal women with mild asymptomatic primary hyperparathyroidism

Primary Hyperparathyroidism: A Narrative Review of Diagnosis and Medical Management

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

Recent Advances on Magnetic Sensitive Hydrogels in Tissue Engineering

Tissue engineering is a promising strategy for the repair and regeneration of damaged tissues or organs. Biomaterials are one of the most important components in tissue engineering. Recently, magnetic hydrogels, which are fabricated using iron oxide-based particles and different types of hydrogel matrices, are becoming more and more attractive in biomedical applications by taking advantage of their biocompatibility, controlled architectures, and smart response to magnetic field remotely. In this literature review, the aim is to summarize the current development of magnetically sensitive smart hydrogels in tissue engineering, which is of great importance but has not yet been comprehensively viewed.

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.

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.

Raloxifene improves skeletal properties in an animal model of cystic chronic kidney disease

Patients with chronic kidney disease (CKD) have an increased risk of fracture. Raloxifene is a mild antiresorptive agent that reduces fracture risk in the general population. Here we assessed the impact of raloxifene on the skeletal properties of animals with progressive CKD. Male Cy/+ rats that develop autosomal dominant cystic kidney disease were treated with either vehicle or raloxifene for five weeks. They were assessed for changes in mineral metabolism and skeletal parameters (microCT, histology, whole-bone mechanics, and material properties). Their normal littermates served as controls. Animals with CKD had significantly higher parathyroid hormone levels compared with normal controls, as well as inferior structural and mechanical skeletal properties. Raloxifene treatment resulted in lower bone remodeling rates and higher cancellous bone volume in the rats with CKD. Although it had little effect on cortical bone geometry, it resulted in higher energy to fracture and modulus of toughness values than vehicle-treated rats with CKD, achieving levels equivalent to normal controls. Animals treated with raloxifene had superior tissue-level mechanical properties as assessed by nanoindentation, and higher collagen D-periodic spacing as assessed by atomic force microscopy. Thus, raloxifene can positively impact whole-bone mechanical properties in CKD through its impact on skeletal material properties.

Strategies to improve physical activity by exercise training in patients with chronic kidney disease

Decreased physical activity resulting in muscle loss is often observed in patients with chronic kidney disease and is one of the main predictors of mortality in these patients. Exercise training may improve physical activity and prevent muscle loss in patients with chronic kidney disease. Efforts to introduce exercise training to these patients may be clinically beneficial by reducing their mortality rates.

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.

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.

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.

Cinacalcet as alternative treatment for primary hyperparathyroidism: achievements and prospects

Primary hyperparathyroidism (pHPT), which most frequently occurs asymptomatically, is a common endocrine disease associated with increased morbidity and mortality. The newly introduced management guidelines as well as the recent availability of the first calcimimetic offer a highly promising therapeutic option for patients with pHPT. Cinacalcet, the first available calcimimetic, increases the sensitivity of the calcium-sensing receptor (CaR) to circulating serum calcium, thereby safely reducing serum calcium and PTH concentrations in patients with mild-to-moderate pHPT, intractable disease, and also parathyroid carcinoma. Cinacalcet has proved efficient in short- and long-term controls of hypercalcemia and, though bone mineral density was not improved, the available data point to cinacalcet as the treatment of choice in non-operable patients with pHPT. These results encompass a wide spectrum of disease severity. Results are pending as to whether cinacalcet decreases mortality and morbidity in pHPT, confirmation of which would conclusively recommend this drug as a valid alternative to surgery.

Management of skeletal health in patients with asymptomatic primary hyperparathyroidism

Asymptomatic primary hyperparathyroidism (PHPT) may cause adverse skeletal effects that include high bone remodeling, reduced bone mineral density (BMD), and increased fracture risk. Parathyroid surgery, the definitive treatment for PHPT, has been shown to increase BMD and appears to reduce fracture risk. Current guidelines recommend parathyroid surgery for patients with symptomatic PHPT or asymptomatic PHPT with serum calcium >1mg/dL above the upper limit of normal, calculated creatinine clearance <60 mL/min, osteoporosis, previous fracture, or age <50 yr. The type of operation performed (parathyroid exploration or minimally invasive procedure) and localizing studies to identify the abnormal parathyroid glands preoperatively should be individualized according to the skills of the surgeon and the resources of the institution. In patients who choose not to be treated surgically or who have contraindications for surgery, medical therapy should include a daily calcium intake of at least 1200 mg and maintenance of serum 25-hydroxyvitamin D levels of at least 20 ng/mL (50 nmol/L). Bisphosphonates and estrogens have been shown to provide skeletal benefits that appear to be similar to parathyroid surgery. Cinacalcet reduces serum calcium in PHPT patients with intractable hypercalcemia but has not been shown to improve BMD. It is not known whether any medical intervention reduces fracture risk in patients with PHPT. There are insufficient data on the natural history and treatment of normocalcemic PHPT to make recommendations for management of this disorder.

Cinacalcet reduces serum calcium concentrations in patients with intractable primary hyperparathyroidism

CONTEXT

Patients with persistent primary hyperparathyroidism (PHPT) after parathyroidectomy or with contraindications to parathyroidectomy often require chronic treatment for hypercalcemia.

OBJECTIVE

The objective of the study was to assess the ability of the calcimimetic, cinacalcet, to reduce serum calcium in patients with intractable PHPT.

DESIGN

This was an open-label, single-arm study comprising a titration phase of variable duration (2-16 wk) and a maintenance phase of up to 136 wk.

SETTING

The study was conducted at 23 centers in Europe, the United States, and Canada.

PATIENTS

The study included 17 patients with intractable PHPT and serum calcium greater than 12.5 mg/dl (3.1 mmol/liter).

INTERVENTION

During the titration phase, cinacalcet dosages were titrated every 2 wk (30 mg twice daily to 90 mg four times daily) for 16 wk until serum calcium was 10 mg/dl or less (2.5 mmol/liter). If serum calcium increased during the maintenance phase, additional increases in the cinacalcet dose were permitted.

MAIN OUTCOME MEASURE

The primary end point was the proportion of patients experiencing a reduction in serum calcium of 1 mg/dl or greater (0.25 mmol/liter) at the end of the titration phase.

RESULTS

Mean +/- sd baseline serum calcium was 12.7 +/- 0.8 mg/dl (3.2 +/- 0.2 mmol/liter). At the end of titration, a 1 mg/dl or greater reduction in serum calcium was achieved in 15 patients (88%). Fifteen patients (88%) experienced treatment-related adverse events, none of which were serious. The most common adverse events were nausea, vomiting, and paresthesias.

CONCLUSIONS

In patients with intractable PHPT, cinacalcet reduces serum calcium, is generally well tolerated, and has the potential to fulfill an unmet medical need.

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 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.

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.

Asymptomatic primary hyperparathyroidism

Primary hyperparathyroidism is a common disorder of mineral metabolism characterized by incompletely regulated, excessive secretion of parathyroid hormone from one or more of the parathyroid glands. In adults with the disease, a single, benign adenoma is seen approximately 80 percent of the time, with multiple gland involvement comprising most of the remaining patients. Very rarely, a parathyroid cancer is responsible but it is seen in less than 0.5 percent of patients with primary hyperparathyroidism. In this article, we will review important clinical and diagnostic features of asymptomatic primary hyperparathyroidism as well as considerations for surgical or medical management of the disease.

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.

Current Pharmacological Options for the Management of Primary Hyperparathyroidism

Drugs for treating primary hyperparathyroidism can be divided into two main groups: (i) antiresorptive drugs that inhibit the increased bone turnover, which can be divided into estrogen-like compounds (estrogen, oral contraceptives and selective estrogen receptor modulators [SERMs]), bisphosphonates and calcitonin; and (ii) drugs that interfere with parathyroid hormone (PTH) secretion (currently only cinacalcet is available). No drugs that interfere with PTH action are currently available. Available studies suggest that all classes of drugs are able to lower serum calcium levels. However, calcitonin does so only temporarily. Estrogen-containing compounds (hormone replacement therapy) may be less attractive because of the potential risk of breast cancer, cardiovascular disease and deep vein thromboembolism. Oral contraceptives have not been shown to be able to prevent fractures in the general population, and no data are available on their effect in women with primary hyperparathyroidism. The only SERM marketed for hyperparathyroidism is raloxifene and this has not been associated with an increased risk of breast cancer and cardiovascular diseases, and has been shown to be able to prevent vertebral fractures in postmenopausal women with osteoporosis. Two small trials suggest that raloxifene may increase bone mineral density (BMD) and decrease serum calcium levels in patients with primary hyperparathyroidism. Bisphosphonates have been shown to decrease serum calcium and increase BMD in patients with primary hyperparathyroidism, but PTH levels may increase. Cinacalcet effectively induces a sustained decrease in serum calcium and PTH for up to 1 year. However, BMD does not seem to increase. No data on hard endpoints such as fractures, kidney stones, cardiovascular disease etc. are available for any of the drugs available for the treatment of primary hyperparathyroidism.

Persistent and recurrent hyperparathyroidism

More than 95% of patients with primary hyperparathyroidism (HPT) will be cured at initial operation by an experienced surgeon. Despite this success rate, persistent and recurrent HPT remain challenging clinical entities. The most cost effective and safest treatment for persistent and recurrent HPT is avoidance by successful first operation. The contributors to treatment failure can be categorized into factors related to the initial surgical procedure, anatomic variability, and the biology of disease. An understanding of the factors that commonly contribute to treatment failure can help prevent persistent and recurrent disease and plays an integral role in planning subsequent surgical approaches. Once a biochemical diagnosis of persistent or recurrent HPT is confirmed, a thorough evaluation of previous operative, pathology, and radiology reports is essential. Localization procedures supplement this information and help direct the reoperative approach. When complementary noninvasive studies, such as ultrasound, sestamibi, and magnetic resonance imaging are negative, equivocal, or discordant, invasive tests (eg, selective venous sampling for parathyroid hormone levels) are warranted. Intraoperative ultrasound and gamma-probe localization are of questionable value, but intraoperative parathyroid hormone assays help facilitate these challenging repeat dissections. Repeat parathyroid exploration is associated with more complications and fewer cures compared to the initial explorations and should only be undertaken by an experienced surgeon in a center that can provide expert preoperative localization, adjunctive intraoperative tools, and cryopreservation of parathyroid tissue when necessary. Although controversy exists regarding indications for reoperative treatment for persistent or recurrent HPT, parathyroidectomy remains the only curative treatment option. Surgery should be considered first-line treatment in most circumstances.

Significance of primary hyperparathyroidism in the management of osteoporosis

Primary hyperparathyroidism (HPT) has catabolic effects on cortical bone and anabolic effects on cancellous bone with overall deleterious effects on skeleton. Primary HPT is associated with increased fracture risk both at the cancellous bone-enriched spine and the cortical bone-enriched distal one third of the radius. This risk is reversed by parathyroidectomy.

Update on genetic and clinical aspects of primary hyperparathyroidism

Primary hyperparathyroidism (pHPT) is a common endocrine disorder that predominantly affects postmenopausal women. It is mostly caused by solitary tumours within the parathyroid glands. Although the pathophysiology of pHPT is still incompletely understood, recent studies provide new clues on the development and cellular growth of tumours within the parathyroids associated with hypersecretion of parathyroid hormone and hypercalcaemia. The natural course of pHPT is rather benign. Nowadays, it has become an oligo- or asymptomatic disease often only detected by routine blood tests. These facts raise the question whether to perform parathyroidectomy on oligo- and asymptomatic patients with pHPT or whether it is possible to monitor these patients without surgery. The aim of this article is to review the literature as regards (i) the pathophysiological mechanisms that underlie parathyroid neoplasia and (ii) the defective calcium-sensing in patients with pHPT (iii) environmental and/or genetic risk factors that predispose to or promote parathyroid neoplasia, as well as (iv) alternative approaches to treat oligo- and asymptomatic patients with pHPT medically.

Raloxifene lowers serum calcium and markers of bone turnover in postmenopausal women with primary hyperparathyroidism

Estrogen replacement therapy (ERT) decreases total serum calcium by about 0.5 mg/dl in postmenopausal women with primary hyperparathyroidism (PHPT). We investigated the ability of raloxifene, which has skeletal antiresorptive properties similar to those of ERT, to decrease serum calcium concentrations and markers of bone turnover in PHPT. Eighteen postmenopausal women with asymptomatic PHPT were randomized to 8 wk of raloxifene (60 mg/d) or placebo, followed by a 4-wk washout. At baseline, the groups were well matched. The calcium concentration decreased significantly by 8 wk of raloxifene administration (10.8 +/- 0.2 to 10.4 +/- 0.2 mg/dl; P < 0.05), as did markers of bone resorption and formation [osteocalcin, 11.4 +/- 1.6 to 9.9 +/- 1.6 nmol/liter (P < 0.05); serum N-telopeptide, 21.2 +/- 3.4 to 17.3 +/- 2.8 nmol bone collagen equivalents/liter (P < 0.05)]. Four weeks after raloxifene was discontinued, indices were indistinguishable from baseline. Raloxifene administration did not affect serum PTH, 1,25-dihydroxyvitamin D, total alkaline phosphatase, or urinary calcium excretion. Calcium and bone marker changes were therefore similar to those observed with ERT in PHPT. This short-term study suggests that raloxifene may be a useful approach to the treatment of postmenopausal women with mild PHPT.

Ultrasound guided laser ablation of a parathyroid adenoma

We present a case of primary hyperparathyroidism with severe hypercalcaemia, treated successfully with ultrasound (US) guided percutaneous interstitial laser photocoagulation (ILP) of a single parathyroid tumour. To our knowledge, this is the first reported case of ILP applied in primary hyperparathyroidism. US guided thermic tissue coagulation with ILP may be a non-surgical alternative in patients with symptomatic hypercalcaemia due to a parathyroid tumour when surgery is contraindicated.