Normocalcemic primary hyperparathyroidism

Quality appraisal of clinical practice guidelines for the evaluation and management of primary hyperparathyroidism

PURPOSE

Multiple groups have created clinical practice guidelines (CPGs) for the management of primary hyperparathyroidism (PHPT). This report provides a rigorous quality assessment using the Appraisal of Guidelines for Research & Evaluation Instrument (AGREE II) to identify high-performing guidelines and areas for improvement.

METHODS

A systematic review was conducted to isolate CPGs addressing the management of PHPT. Guideline data was extracted and quality ratings were assigned by four independent reviewers. Intraclass correlation coefficients (ICC) were calculated to ensure interrater reliability.

RESULTS

Twelve guidelines were assessed. The American Association of Endocrine Surgeons (AAES) guideline had the highest mean scaled score across all domains (73.6 ± 31.4%). No other published guideline achieved a "high" quality designation. The highest scoring domain was "clarity of presentation" (mean 60.5 ± 26.5%). The lowest scoring domain was "applicability" (mean 19.8 ± 18.2%). Scoring reliability was excellent, with ICC ≥ 0.89 for all AGREE II 6 domains.

CONCLUSION

Although several working groups have developed guidelines to address PHPT management, only those published by the AAES meet all methodologic quality criteria necessary to ensure incorporation of recommendations into clinical practice. Future guidelines would benefit from the development of tools, resources, monitoring criteria that enhance applicability.

Imaging Recommendations for Diagnosis and Management of Primary Parathyroid Pathologies: A Comprehensive Review

Parathyroid pathologies are suspected based on the biochemical alterations and clinical manifestations, and the predominant roles of imaging in primary hyperparathyroidism are localisation of tumour within parathyroid glands, surgical planning, and to look for any ectopic parathyroid tissue in the setting of recurrent disease. This article provides a comprehensive review of embryology and anatomical variations of parathyroid glands and their clinical relevance, surgical anatomy of parathyroid glands, differentiation between multiglandular parathyroid disease, solitary adenoma, atypical parathyroid tumour, and parathyroid carcinoma. The roles, advantages and limitations of ultrasound, four-dimensional computed tomography (4DCT), radiolabelled technetium-99 (99mTc) sestamibi or dual tracer 99mTc pertechnetate and 99mTc-sestamibi with or without single photon emission computed tomography (SPECT) or SPECT/CT, dynamic enhanced magnetic resonance imaging (4DMRI), and fluoro-choline positron emission tomography (18F-FCH PET) or [11C] Methionine (11C -MET) PET in the management of parathyroid lesions have been extensively discussed in this article. The role of fluorodeoxyglucose PET (FDG-PET) has also been elucidated in this article. Management guidelines for parathyroid carcinoma proposed by the American Society of Clinical Oncology (ASCO) have also been described. An algorithm for management of parathyroid lesions has been provided at the end to serve as a quick reference guide for radiologists, clinicians and surgeons.

Natural history and complications of normocalcemic hyperparathyroidism: a retrospective cohort study

Normocalcemic hyperparathyroidism (NHPT) is variably defined, and information regarding complications and natural history are scarce. We aimed to describe the phenotype of NHPT in relation to hypercalcemic hyperparathyroidism (PHPT) and controls, to determine risk of progression, and to develop a predictive model for progression to PHPT. This is a retrospective chart review of 232 patients at a tertiary medical center, comparing 75 controls, 73 patients with NHPT, and 84 with PHPT. NHPT was intermediate in biochemical profile between controls and PHPT with respect to cCa, iPTH, intraindividual coefficient of variant of cCa, phosphorus, and 25(OH)D. NHPT patients had an increased adjusted risk of urolithiasis (OR 5.34, 95%CI, 2.41-12.71, P < .001) and fragility fractures (OR 4.53, 95%CI, 1.63-14.84, P = .006) versus controls, after adjustment for age, sex, and BMI. Fewer NHPT compared with PHPTH patients achieved cure with parathyroidectomy (P = .001). NHPT more often had nonlocalizing imaging or polyglandular disease (P = .005). Parathyroidectomy improved biochemical but not BMD parameters in NHPT. Over a median follow-up of 4.23 (IQR 1.76-5.31) years, NHPT patients managed expectantly experienced no change in iPTH, and progression to PHPT occurred in 9%. An XGBoost model combining 6 factors for progression (mean index 2 iPTH, mean index 2 cCa, 24-h urinary calcium, age, 25(OH)D, and presence of urolithiasis) had an area under the curve 1.00 (95%CI, 1.00-1.00, P < .001) for predicting combined progression. NHPT is a mild variant of PHPT at intermediate risk of urolithiasis and fragility fractures. Cure was less often achieved with parathyroidectomy, which did not improve BMD parameters. Progression was infrequent with conservative management. Because only a minority progressed to PHPT, in addition to lower surgical success rates, we suggest conservative management for the majority of NHPT unless risk factors for progression are identified.

Normocalcaemic primary hyperparathyroidism: is nephrolithiasis more common than osteoporosis?

BACKGROUND

Normocalcaemic primary hyperparathyroidism (NPHPT) is often under-recognised in clinical practice.

AIM

To determine the prevalence and clinical significance of NPHPT in an unselected sample in an acute hospital setting.

METHODS

Patients aged >18 years who had measurement of an elevated serum parathyroid hormone (PTH ≥ 7 pmol/L) during 12 months from 1 January 2017 to 31 December 2017 were retrospectively studied. NPHPT was defined by the presence of elevated serum PTH with normal albumin-corrected serum calcium on two or more occasions after excluding secondary causes. Patients were followed up for 2 years. Relevant data were collected by review of electronic medical records.

RESULTS

Of the 2593 patients who had PTH measured during the study period, 1278 had serum PTH ≥ 7 pmol/L. Hypercalcaemic primary hyperparathyroidism (PHPT) was diagnosed in 174 patients. Secondary causes for elevated serum PTH were identified in 993 patients: 815 (chronic kidney disease - estimated glomerular filtration rate < 60 mL/min/1.73 m² or renal transplant), 98 (vitamin D deficiency - 25(OH)D < 50 nmol/L), 28 (gastric bypass surgery), 38 (medications), 13 (malabsorption or post-thyroidectomy) and 1 (hypercalciuria). Data were incomplete for 80 patients. The prevalence of NPHPT with and without the exclusion of hypercalciuria was 0.19% (5) and 0.39% (10) respectively. The prevalence of nephrolithiasis in NPHPT was higher than PHPT (100% vs 15% among five patients (P < 0.001) and 50% vs 15% among 10 patients (P = 0.014)). The prevalence of osteoporosis was not significantly different between NPHPT and PHPT (20% vs 45% among five patients (P = 0.389) and 30% vs 45% among 10 patients (P = 0.518)).

CONCLUSION

These findings give further credence to the diagnosis of NPHPT as a clinical entity. Nephrolithiasis may be a greater problem than osteoporosis in NPHPT compared with PHPT. This needs prospective evaluation.

Asymptomatic elevated parathyroid hormone level due to immunoassay interference

BACKGROUND

Parathyroid hormone (PTH) measurement using immunoassays is inherently vulnerable to interferences due to the presence of different proteins such as heterophile antibodies, human anti-animal antibodies, auto-analyte antibodies, the rheumatoid factor, and others. The frequency of immunoassay interference can be as high as 6%. We report the case of a patient showing persistent high levels of PTH without impact on calcium and bone metabolism.

CASE PRESENTATION

The patient was a 59-year-old asymptomatic woman who consistently showed elevated PTH levels (385-482 pg/ml) using the Roche Elecsys (Cobas e-411) and ADVIA Centaur assays, with normal calcium, phosphorus, vitamin D, and renal function parameters. She had no history of fractures, nephrolithiasis, gastrointestinal complaints, renal insufficiency, or autoimmune diseases. Her physical examination revealed no abnormalities. Biomarkers of bone metabolism were within the reference range. To rule out falsely elevated PTH levels, we initially performed serial dilutions using both assays, which revealed nonlinearity. After a polyethylene glycol precipitation test, less than 10% of PTH was recovered from the supernatant. These results suggested the presence of heterophile antibodies as the cause of the falsely elevated PTH levels.

CONCLUSION

Physicians should be aware of this issue in order to avoid unnecessary clinical investigations and inappropriate treatments.

Association of Serum Parathyroid Hormone Levels With All-Cause and Cause-Specific Mortality Among U.S. Adults

OBJECTIVE

To examine whether parathyroid hormone (PTH) is associated with mortality among U.S. adults.

METHODS

This study included 8286 U.S. adults aged ≥20 years with a measurement of serum intact PTH from the National Health and Nutrition Examination Survey 2003-2006 linked to national mortality data through 2015. Multivariable Cox proportional hazard regression models were employed to estimate the adjusted hazard ratio (aHR) of all-cause and cause-specific (cardiovascular and cancer) mortality according to intact PTH levels (low or low-normal, <38; middle-normal, 38-56; high-normal, 57-74; high, >74 pg/mL). We also stratified the analyses by serum albumin-adjusted calcium and 25-hydroxy vitamin D (25OHD) levels.

RESULTS

During a median follow-up of 10.1 years, the mean age was 49 years, and 48% were men. After adjusting for potential confounders, both the high-normal and high PTH groups showed higher risks of all-cause mortality than the low or low-normal PTH group (high-normal PTH, aHR, 1.28; 95% confidence interval [CI], 1.10-1.48; high PTH, aHR, 1.42; 95% CI, 1.19-1.69]. When stratified by calcium and 25OHD levels, the association between high PTH and mortality was also found among participants with albumin-adjusted calcium levels of ≥9.6 mg/dL (aHR, 1.53; 95% CI, 1.17-2.01) and those with 25OHD levels of ≥20 ng/mL (aHR, 1.46, 95% CI, 1.17-1.82). We found no evidence of the increased cause-specific mortality risks in the high PTH group.

CONCLUSION

Higher PTH levels were associated with an increased risk of all-cause mortality, particularly among participants with albumin-adjusted calcium levels of ≥9.6 mg/dL or 25OHD levels of ≥20 ng/mL.

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

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

The role of unhenanced CT in a ruptured parathyroid adenoma: A case report

Acute bleeding is a rare and potentially life-threatening complication of a Parathyroid Adenoma described in just a few cases in literature. We describe the case of a healthy 53-years-old female patient without prior history of parathyroid pathology who presented with acute onset of neck and mediastinal hemorrhage. Ultrasound (US), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) combined with laboratory tests led to the diagnosis of a bleeding Parathyroid adenoma. This case is presented to sensitize both Radiologists and Clinicians about this rare presentation that should be put into differential diagnosis of acute neck swelling and pain.

Pediatric hyperparathyroidism: review and imaging update

Hyperparathyroidism, due to increased secretion of parathyroid hormones, may be primary, secondary or tertiary. Most pediatric patients with sporadic primary hyperparathyroidism will be symptomatic, presenting with either end-organ damage or nonspecific symptoms. In younger patients with primary hyperparathyroidism, there is a higher prevalence of familial hyperparathyroidism including germline inactivating mutations of the calcium-sensing receptor genes that result in either neonatal severe hyperparathyroidism or familial hypocalciuric hypercalcemia. Parathyroid scintigraphy and ultrasound are complementary, first-line imaging modalities for localizing hyperfunctioning parathyroid glands. Second-line imaging modalities are multiphase computed tomography (CT) and magnetic resonance imaging. In pediatrics, multiphase CT protocols should be adjusted to optimize radiation dose. Although, the role of these imaging modalities is better established in preoperative localization of hyperfunctioning parathyroid glands in primary hyperparathyroidism, the same principles apply in secondary and tertiary hyperparathyroidism. In this manuscript, we will review the embryology, anatomy, pathophysiology and preoperative localization of parathyroid glands as well as several subtypes of primary familial hyperparathyroidism. While most of the recent imaging literature centers on adults, we will focus on the issues that are pertinent and applicable to pediatrics.

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

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

ECHOCARDIOGRAPHIC FINDINGS IN PATIENTS WITH NORMOCALCEMIC PRIMARY HYPERPARATHYROIDISM COMPARED WITH FINDINGS IN HYPERCALCEMIC PRIMARY HYPERPARATHYROID PATIENTS AND CONTROL SUBJECTS

OBJECTIVE

There are no data regarding echocardiographic parameters in patients with normocalcemic primary hyperparathyroidism (NCPHPT). We compared the echocardiographic findings in postmenopausal women with NCPHPT with those in patients with hypercalcemic primary hyperparathyroidism (PHPT) and controls.

METHODS

Seventeen consecutive Caucasian postmenopausal women with NCPHPT were compared with 20 women with hypercalcemic PHPT and 20 controls. Obesity, diabetes, kidney failure, and previous cardiovascular diseases were considered exclusion criteria. Each patient underwent biochemical evaluation, bone mineral density scan, and echocardiographic measurements. Patients with parathyroid disorders underwent kidney ultrasound evaluation.

RESULTS

Patients with PHPT had significantly higher mean total serum calcium, ionized calcium, 24-hour urinary calcium, and parathyroid hormone and lower mean phosphorus levels compared with those in the controls (all P < .05). The only differences between patients with NCPHPT and PHPT were significantly lower mean total serum calcium, ionized calcium, and 24-hour urinary calcium and higher phosphorus levels in patients with NCPHPT (all P < .05). The only biochemical difference between patients with NCPHPT and the controls was a higher level of mean parathyroid hormone in patients with NCPHPT. There were no differences in cardiovascular risk factors between patients with NCPHPT and PHPT and the controls. Hypertension was the most frequent cardiovascular risk factor, diagnosed in 65% of patients with PHPT. This high prevalence was not statistically significant compared with that observed in patients with NCPHPT (59%) and in the controls (30%). Echocardiography parameters were not different between patients with NCPHPT and PHPT and the controls when subdivided according to the presence of hypertension (ANOVA followed by Bonferroni correction).

CONCLUSION

In a population with a low cardiovascular risk, we found no differences in cardiovascular risk factors and echocardiographic parameters between patients with NCPHPT and PHPT and the controls.

OCCULT PRIMARY HYPERPARATHYROIDISM: A CASE REPORT AND REVIEW OF PARATHYROID ULTRASONOGRAPHY

Objective

To discuss the diagnosis and management of occult primary hyperparathyroidism.

Methods

We present the biochemical and radiologic evaluation, treatment, and outcome of a woman with occult primary hyperparathyroidism which presented as an unusual neck mass on ultrasound. We also present a relevant literature review.

Results

A 52-year-old female presented with Hashimoto thyroiditis and a 1.2-cm, hypoechoic oval nodule in the left upper lateral portion of the thyroid. She returned a decade later with a 2.2-cm, hypervascular mass on ultrasound. Parathyroid hormone was mildly elevated at 90 pg/mL (reference range is 15 to 65 pg/mL), but she had persistently normal levels of total serum calcium at 9.9 mg/dL (reference range is 8.7 to 10.3 mg/dL), phosphorus at 3.5 mg/dL (reference range is 2.1 to 4.5 mg/dL), and albumin at 4.4 g/dL (reference range is 3.6 to 4.8 g/dL). She had elevated ionized calcium of 5.9 mg/dL (reference range is 4.5 to 5.6 mg/dL). Computed tomography with contrast of the neck revealed an enhancing oval lesion abutting the superior pole of the left thyroid with attenuation characteristics similar though slightly different from the thyroid. 99mTc-Sestamibi scan showed increased uptake posterior to the superior aspect of the left thyroid. Bone densitometry showed osteoporosis of the left distal radius and osteopenia of the left femoral neck. Minimally invasive radio-guided parathyroidectomy was performed with normalization of parathyroid hormone. Pathology confirmed a 1.715-g parathyroid adenoma.

Conclusion

Despite normal total calcium levels, clinically significant primary hyperparathyroidism may present as a large adenoma which could appear as a hypervascular neck mass on ultrasound. A high index of suspicion based on ultrasound features and measurement of ionized calcium may be helpful in diagnosing occult, but clinically relevant primary hyperparathyroidism.

Hyperparathyroidism in men - morbidity and mortality during 21 years' follow-up

Hyperparathyroidism (HPT), including normocalcaemic, vitamin D sufficient (Serum (S)-25(OH)D ≥ 50 nmol/L) hyperparathyroidism (nHPT), has increasingly been diagnosed in the last few decades due to the more common use of the serum parathyroid hormone (S-PTH) assay. We investigated if men with HPT had higher morbidity and mortality than men without HPT during 21 years' follow-up.A random population sample of 750 men, all 50 years of age, was examined in 1993. Endpoints were retrieved 21 years later at 71 years of age.Albumin-corrected serum (S) calcium, S-25-hydroxyvitamin D and S-PTH were assessed along with data on cardiovascular risk factors and medication. Outcome data on fractures, stroke, myocardial infarction, cancer and death were retrieved in 2014; 21 years after primary assessment. The prevalence of HPT at 50 years of age was 9.3%; nHPT 2.8%, primary HPT 0.4%, secondary HPT 0.4%, and HPT with vitamin D insufficiency 6%. Fracture rate, myocardial infarction, stroke, cancer and death occurred similarly in men with or without HPT, as well as in men with nHPT as compared with men without calcium/PTH aberrations during 21 years' follow-up. S-PTH was evenly distributed in the univariable analyses for each outcome. Cox regression analyses showed no increase in serious morbidity or in mortality in men with HPT, irrespective of cause, compared with men with normal S-PTH over a 21-year period. None had HPT at a S-25(OH)D level of 100 nmol/L.

Investigating patients with normocalcemic hyperparathyroidism: When is a parathyroid scintigraphy indicated?

In clinical practice, physicians often encounter patients with persistent elevated serum parathyroid hormone levels and normal serum calcium levels, a state known as normocalcemic hyperparathyroidism (NHPT). The investigation of NHPT cases can lead to unnecessary use of parathyroid scintigraphy (PS) and consequently unnecessary health-care costs. In this clinical review, the most common causes of NHPT and the possible indications for PS performance in such cases are mainly presented and discussed.

Parathyroid adenoma presenting as genu valgum in a child: A rare case report

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Primary hyperparathyroidism is a rare disease in children and adolescents.

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Genu valgum is a rare presentation in children with PHPT.

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Primary hyperparathyroidism may present as normocalcemic primary hyperparathyroidism if associated with vit. D deficiency.

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Technetium99 M-sestamibi scan is most sensitive and specific for localization of parathyroid adenoma.

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Surgery is the only curative treatment for PHPT and post-operative management for features of hypocalcemia is crucial.

Introduction

Parathyroid adenoma is the most common cause of primary hyperparathyroidism (PHPT). Patients typically present with elevated serum calcium levels and elevated serum parathyroid hormone levels. The incidence and prevalence is higher in adults but is rare in pediatric age group.

Case presentation

A 12-year-old, pre-pubertal female presented with pain in bilateral knee joints and gait abnormality since one year. Her past medical history and family history were insignificant. On general examination, no other congenital bony deformities were observed besides genu valgum. Laboratory tests showed hypocalcemia and elevated serum levels of intact parathyroid hormone. Radiograph of bilateral both knee joints was suggestive of genu valgum. Ultra sonogram of neck revealed enlarged parathyroid gland and a Technetium (99mTc) sestamibi scan was suggestive of right inferior parathyroid adenoma. Surgical resection was performed and post-operative hypocalcemia was seen. After necessary treatment was given and the patient was discharged when asymptomatic.

Discussion and conclusion

Parathyroid adenoma causing primary hyperparathyroidism is a rare disease in children. They typically present with nonspecific symptoms involving gastrointestinal, musculoskeletal, renal and neurological symptoms due to hypercalcemia. Moreover, Genu valgum is a rare presentation in children with parathyroid adenoma.

Parathyroidectomy improves cardiovascular risk factors in normocalcemic and hypercalcemic primary hyperparathyroidism

BACKGROUND

Parathyroidectomy has ameliorated cardiovascular risk factors in patients with hypercalcemic primary hyperparathyroidism (PHPT), but the effect of parathyroidectomy on normocalcemic PHPT is not exactly known. This case-controlled study aimed to investigate the effect of parathyroidectomy on cardiovascular risk factors in patients with normocalcemic and hypercalcemic PHPT.

METHODS

Subjects with normocalcemic PHPT (n = 35), age- and sex-matched hypercalcemic PHPT (n = 60) and age- and sex-matched control (n = 60) were included. Cardiometabolic disorders were investigated with traditional cardiometabolic risk factors and the Framingham cardiovascular risk score (CRS) before and 6 months after parathyroidectomy.

RESULTS

Diabetes, dyslipidemia, hypertension, obesity, insulin resistance, osteoporosis, having fractures were similarly increased in the hypercalcemic and normocalcemic PHPT groups (p > 0.05) compared with the controls (p < 0.05). Blood pressures, glucose metabolism (glucose, insulin, HOMA-IR) and lipid profiles were similarly increased in the PHPT groups (p > 0.05) compared with the controls (p < 0.05). After parathyroidectomy, blood pressures, serum total cholesterol, and HOMA-IR were decreased in both PHPT groups (p < 0.05). CRS was lower in the controls (5.74 ± 3.24, p < 0.05). After parathyroidectomy, CRS was decreased in the normocalcemic (11.98 ± 10.11 vs. 7.37 ± 4.48) and hypercalcemic (14.62 ± 11.06 vs. 8.05 ± 7.72) PHPT groups. Increased blood pressures were independent predictors of serum iPTH.

CONCLUSION

The normocalcemic and hypercalcemic PHPT groups had similarly increased cardiovascular risk factors, even independently of serum calcium. Parathyroidectomy ameliorated the increased cardiovascular risk factors in both normocalcemic and hypercalcemic PHPT.

PETC/CT with 18F-Choline localizes hyperfunctioning parathyroid adenomas equally well in normocalcemic hyperparathyroidism as in overt hyperparathyroidism

PURPOSE

Identification of pathologic parathyroid glands in primary hyperparathyroidism, traditionally based on neck ultrasound (US) and/or ^99mTc-Sestamibi scintigraphy, can be challenging. PET/CT with ¹⁸F-Fluorocholine (¹⁸F-FCH) might improve the detection of pathologic parathyroid glands. We aimed at comparing the diagnostic performance of ¹⁸F-FCH-PET/CT with that of dual-phase dual-isotope parathyroid scintigraphy and neck US.

METHODS

Thirty-four consecutive patients with primary hyperparathyroidism were prospectively enrolled, 7 had normocalcemic hyperparathyroidism, and 27 had classic hypercalcemic hyperparathyroidism. All patients underwent high-resolution neck US, dual-phase dual-isotope ^99mTc-Pertechnetate/^99mTc-Sestamibi scintigraphy, and ¹⁸F-FCH-PET/CT.

RESULTS

In the whole patients' group, the detection rates of the abnormal parathyroid gland were 68% for neck US, 71% for ¹⁸F-FCH-PET/CT, and only 15% for ^99mTc-Sestamibi scintigraphy. The corresponding figures in normocalcemic and hypercalcemic hyperparathyroidism were 57 and 70% for neck US, 70 and 71% for ¹⁸F-FCH-PET/CT, and 0 and 18% for ^99mTc-Sestamibi scintigraphy, respectively. In the 17 patients in whom the abnormal parathyroid gland was identified, either at surgery or at fine needle aspiration cytology/biochemistry, the correct detection rate was 82% for neck US, 89% for ¹⁸F-FCH-PET/CT, and only 17% for ^99mTc-Sestamibi scintigraphy.

CONCLUSIONS

¹⁸F-FCH-PET/CT can be considered a first-line imaging technique for the identification of pathologic parathyroid glands in patients with normocalcemic and hypercalcemic hyperparathyroidism, even when the parathyroid volume is small.

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.

Degree of hypercalcemia correlates with parathyroidectomy but not with symptoms

BACKGROUND

Primary hyperparathyroidism (HPT) is an undertreated disease. This study's purpose is to determine if the calcium levels correlate with prevalence of symptoms and surgical treatment in patients with primary HPT.

METHOD

Patients treated in 2006-2015 with serum calcium≥10.0 mg/dL and PTH>65 pg/mL were identified and stratified based on calcium level: 10.0-10.3 (normocalcemia), 10.4-11.2 (moderate), and ≥11.3 (severe) mg/dL. Clinical variables and rates of surgery were compared between the three groups.

RESULTS

A total of 2266 patients were identified: 303 with normocalcemia, 1513 with moderate hypercalcemia, and 450 with severe hypercalcemia. All three groups had similar rates of nephrolithiasis (p = 0.10), osteoporosis (p = 0.82), and reduced GFR (p = 0.06). Most patients (85%) had at least one surgical indication, but only 29% underwent parathyroidectomy. Higher calcium levels were correlated with higher surgical rates: 12% for Ca 10.0-10.3, 27% for Ca 10.4-11.2, and 46% for Ca≥11.3 (p < 0.01).

CONCLUSION

Prevalence of symptoms does not correlate with calcium levels. Patients with normocalcemia and moderate hypercalcemia were equally likely to have a surgical indication, but normocalcemic patients are less likely to receive surgery.

Diagnosis, management, histology and genetics of sporadic primary hyperparathyroidism: old knowledge with new tricks

Primary hyperparathyroidism (pHPT) is a common endocrinopathy resulting from inappropriately high PTH secretion. It usually results from the presence of a single gland adenoma, multiple gland hyperplasia or rarely parathyroid carcinoma. All these conditions require different management, and it is important to be able to differentiate the underlined pathology, in order for the clinicians to provide the best therapeutic approach. Elucidation of the genetic background of each of these clinical entities would be of great interest. However, the molecular factors that control parathyroid tumorigenesis are poorly understood. There are data implicating the existence of specific genetic pathways involved in the emergence of parathyroid tumorigenesis. The main focus of the present study is to present the current optimal diagnostic and management protocols for pHPT as well as to review the literature regarding all molecular and genetic pathways that are to be involved in the pathophysiology of sporadic pHPT.

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

OBJECTIVE

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

DESIGN AND PARTICIPANTS

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

MEASUREMENTS

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

RESULTS

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

CONCLUSIONS

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

Parathyroidectomy for tertiary hyperparathyroidism: A systematic review

OBJECTIVE

Analyze the efficacy and indications for parathyroidectomy as an intervention for tertiary hyperparathyroidism.

DATA SOURCES

PubMed, MEDLINE, and Cochrane Library databases.

REVIEW METHODS

A systematic literature search was performed using the. Original research articles in English were retrieved using the search terms ("tertiary hyperparathyroidism" OR "3HPT") AND "parathyroidectomy". Articles were analyzed in regards to their surgical indications, operative endpoints, comparison between different surgical interventions, characterization of disease recurrence rates, and evaluation of alternative medical management.

RESULTS

Thirty studies met the criteria for inclusion. Among the studies that report indications for parathyroidectomy, persistent hypercalcemia as well as clinical manifestations of hypercalcemia despite medical therapy predicted which patients would eventually need surgical intervention. The majority of studies comparing the extent of parathyroidectomy recommended a more focused approach to parathyroidectomy when warranted. All studies found that parathyroidectomy was an effective treatment for 3HPT. Three studies discussed alternative conservative approaches.

CONCLUSION

Interestingly, hyperparathyroidism alone is not an indication for surgery without other findings; rather, symptomatic hypercalcemia appears to be the main indication. Most studies recommend limited or subtotal parathyroidectomy for 3HPT. The operative endpoint of surgery is not necessarily a return of PTH to normal, but a >50% drop in PTH level even if PTH remains above normal. Additionally, "success" or "cure" is defined as normal calcium levels regardless of whether or not PTH is elevated. It appears the goal of surgery for 3HPT is not a normal PTH value, but a normal calcium level at least six months postoperatively.

Evaluation of coronary calcium score in patients with normocalcemic primary hyperparathyroidism

RATIONALE

Given that the diagnosis of primary hyperparathyroidism (PHPT) is given at an increasingly less-symptomatic phase, and the literature data on the cardiovascular risk of patients with normocalcemic primary hyperparathyroidism (NPHPT) are controversial, the coronary calcium score (CCS), which is correlated with coronary artery disease, may be useful for clarifying the association between cardiovascular risk and NPHPT.

OBJECTIVE

This research aims to describe the CCS and the clinical and laboratory variables of patients with NPHPT compared with a control group and to verify the presence of an association between NPHPT and CCS.

STUDY POPULATION AND METHODS

A questionnaire on anthropometric data (weight, height, waist circumference, and blood pressure) was used, laboratory examinations (estimations of glucose, glycated hemoglobin [HbA1c], total cholesterol [TC] and its fractions, triglycerides, creatinine, calcium, parathyroid hormone, and 25-OH vitamin D) were conducted, and computerized tomography was carried out to measure the CCS in 13 patients diagnosed with NPHPT and 16 controls.

RESULTS

There was no association between NPHPT and altered CCS (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.05-1.26; p=0.095). Differences between the case and control groups were found in terms of body mass index (BMI) (26.97 kg/m² vs 31.53 kg/m², respectively; p=0.044), HbA1c (5.59% vs 6.62%; p=0.000), and TC (188.07 mg/dL vs 220.64 mg/dL; p=0.088). After adjustment for potential confounders, no statistical significance was observed for the association between changes in CCS and presence of NPHPT (adjusted OR: 1.64; 95% CI: 0.1-26.43; p=0.726).

CONCLUSION

No association was found between the CCS and the presence of NPHPT.

Hypocalcemia development in patients operated for primary hyperparathyroidism: Can it be predicted preoperatively?

OBJECTIVE

Primary hyperparathyroidism (PHP) is a common endocrine disease, and its most effective treatment is surgery. Postoperative hypocalcemia is a morbidity of parathyroid surgeries, and it may extend hospitalization durations. The purpose of this study is to determine the predictive factors related to the development of hypocalcemia and hungry bone syndrome (HBS) in patients who underwent parathyroidectomy for PHP.

MATERIALS AND METHODS

Laboratory data comprising parathyroid hormone (PTH), calcium, phosphate, 25-OHD, albumin, magnesium, alkaline phosphatase (ALP), blood urea nitrogen (BUN), and thyroid stimulating hormone (TSH) of the patients were recorded preoperatively, on the 1st and 4th days postoperatively, and in the 6th postoperative month, and their neck ultrasound (US) and bone densitometry data were also recorded.

RESULTS

Hypocalcemia was seen in 63 patients (38.4%) on the 1st day after parathyroidectomy. Ten patients (6.1%) had permanent hypocalcemia in the 6th month after surgery. Out of the patients who underwent parathyroidectomy for PHP, 22 (13.4%) had HBS. The incidence of postoperative hypocalcemia was higher in patients who underwent parathyroidectomy for PHP, who had parathyroid hyperplasia, and who had osteoporosis. Preoperative PTH, ALP, and BUN values were higher in those patients who developed HBS. Furthermore, HBS was more common in patients who had osteoporosis, who had parathyroid hyperplasia, and who underwent thyroidectomy simultaneously with parathyroidectomy.

CONCLUSIONS

As a result, patients who have the risk factors for development of hypocalcemia and HBS should be monitored more attentively during the perioperative period.

Experience with a third-generation parathyroid hormone assay (BIO-PTH) in the diagnosis of primary hyperparathyroidism in a Brazilian population

OBJECTIVE

To evaluate the usefulness of a third-generation PTH assay in the diagnosis of primary hyperparathyroidism (PHPT).

SUBJECTS AND METHODS

Forty-one PHPT patients (4 men and 37 women) with 61.2 ± 10.9 (mean ± SD) years, were studied and had PTH levels measured with two different methods using the same immunochemiluminescent assay plataform (Elecsys 2010 System, Roche). We compared a second-generation assay (I-PTH) with a third-generation PTH assay (Bio-PTH). Two populations of 423 and 120 healthy adults with serum 25OHD levels above 25 ng/mL were used to define normal values in the I-PTH and Bio-PTH assays respectively.

RESULTS

Normal PTH values based in the healthy adults population were 24.2-78.0 pg/mL for the I-PTH assay and 19.9-58.5 pg/mL for Bio-PTH assay. In PHPT patients, PTH values ranged from 67 to 553 pg/mL (median: 168 pg/mL) using the I-PTH assay and from 55 to 328 pg/mL (median: 111 pg/mL) using the Bio-PTH assay. Results obtained with the Bio-PTH assay were significantly lower (p < 0.0001, Wilcoxon). In general I-PTH and Bio-PTH showed highly significant correlation (r = 0.952, p < 0.0001). Passing-Bablok analysis gave a regression equation of Bio PTH = 13.44 + 0.59 x intact PTH. PHPT patients had 25OHD levels ranging from 4 to 36 ng/mL (mean 16.2 ng/mL); 35 subjects (85.3%) had values bellow 25 ng/mL.

CONCLUSION

Our results demonstrate that both second and third generation PTH methods are strongly correlated in PHPT patients and control subjects. Lower results with Bio-PTH tests are expected in function of the assay specificity determined by the amino-terminal antibody used.

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

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

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

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

An overview of normocalcemic primary hyperparathyroidism

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Expanding the net: The re-evaluation of the multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) in the setting of secondary hyperparathyroidism and the development of the MultIdimensional Predictive hyperparaTHyroid model (Mi-PTH)

BACKGROUND

The multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) model identifies a personalized upper limit of normal parathyroid hormone (PTH) and successfully predicts classical primary hyperparathyroidism (PHP). We aimed to assess whether maxPTH can distinguish normocalcemic PHP (NCPHP) from secondary hyperparathyroidism (SHP), including subjects who underwent bariatric surgery (BrS).

METHODS

A total of 172 subjects with 359 complete datasets of serum calcium (Ca), 25-OH vitamin D, and intact PTH from Oregon were analyzed: 123 subjects (212 datasets) with PHP and 47 (143) with SHP, including 28 (100) with previous BrS. An improved prediction model, MultIdimensional evaluation for Primary hyperparaTHyroidism (Mi-PTH), was created with the same variables as maxPTH by the use of a combined cohort (995 subjects) including participants from previous studies.

RESULTS

In the Oregon cohort, maxPTH's sensitivity was 100% for classical PHP and 89% for NCPHP, but only 50% for normohormonal PHP (NHPHP) and 40% specific for SHP. In comparison, although sensitivity for NCPHP was similar (89%), Mi-PTH vastly improved SHP specificity (85%). In the combined cohort, Mi-PTH had better sensitivity of 98.5% (vs 95%) and specificity 97% (vs 85%).

CONCLUSION

MaxPTH was sensitive in detecting PHP; however, there was low specificity for SHP, especially in patients who underwent BrS. The creation of Mi-PTH provided improved performance measures but requires further prospective evaluation.

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

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

Normocalcaemic, vitamin D-sufficient hyperparathyroidism - high prevalence and low morbidity in the general population: A long-term follow-up study, the WHO MONICA project, Gothenburg, Sweden

OBJECTIVE

There is limited knowledge about the natural history of normocalcaemic, vitamin D-sufficient hyperparathyroidism (nHPT). The aim was to study the prevalence of nHPT and its relation to morbidity.

DESIGN

Cross-sectional and retrospective study at the Sahlgrenska University Hospital, Gothenburg, Sweden.

SUBJECTS

A random population of 608 men and women, age 25-64 years, was studied in 1995 as part of the WHO MONICA study and reinvestigated in 2008 (n = 410, of whom 277 were vitamin D sufficient).

MEASUREMENTS

A serum intact parathyroid hormone (S-PTH) ≥60 ng/l was considered as HPT, S-calcium 2·15-2·49 mmol/l as normocalcaemia and S-25(OH)D ≥ 50 nmol/l as vitamin D sufficiency. Data on fractures, stroke and myocardial infarction were retrieved until 2013, that is a 17-year follow-up.

RESULTS

The prevalence of nHPT was 2·0% in 1995 (age 25-64) and 11·0% in 2008 (age 38-79). S-PTH was positively correlated with age and BMI. After adjustment for these variables, a high S-PTH level (≥60 ng/l) at follow-up was associated with previously low S-25(OH)D, high osteocalcin, S-PTH and both past and presently treated hypertension. No relation was seen with creatinine, cystatin C, malabsorption markers, thyroid function, glucose, insulin, lipids, calcaneal quantitative ultrasound, fractures, myocardial infarction, stroke or death at follow-up.

CONCLUSIONS

This small random population study showed that nHPT was common, 11% at follow-up. Only one individual developed mild hypercalcaemia in 13 years. Previous S-PTH was predictive of nHPT and hypertension was prevalent, but no increase in hard end-points was seen over a 17-year period.

Clinicopathological correlates of hyperparathyroidism

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Characteristics of hyperparathyroid states in the Canadian multicentre osteoporosis study (CaMos) and relationship to skeletal markers

CONTEXT

PTH is an essential regulator of mineral metabolism; PTH hypersecretion may result in hyperparathyroidism including normocalcaemic, primary and secondary hyperparathyroidism.

OBJECTIVE

To examine the characteristics of participants with hyperparathyroid states and the relationship to bone mineral density (BMD).

DESIGN AND PARTICIPANTS

A cross-sectional study of 1872 community-dwelling men and women aged 35+ years (mostly Caucasian) with available serum PTH from Year 10 Canadian Multicentre Osteoporosis Study follow-up (2005-07). PTH was determined using a second-generation chemiluminescence immunoassay.

OUTCOME MEASURES

L1-L4, femoral neck and total hip BMD.

RESULTS

We established a PTH reference range (2·7-10·2 pmol/l) based on healthy participants (i.e. normal serum calcium, serum 25-hydroxyvitamin D, kidney function and body mass index, who were nonusers of antiresorptives, glucocorticoids and diuretics and not diagnosed with diabetes or thyroid disease). Participants with PTH levels in the upper reference range (5·6-10·2 pmol/l), representing a prevalence of 10·7%, had lower femoral neck and total hip BMD, by 0·030 g/cm(2) [95% confidence interval: 0·009; 0·051] and 0·025 g/cm(2) (0·001; 0·049), respectively, than those with levels 2·7-5·6 pmol/l. Participants with normocalcaemic and secondary hyperparathyroidism also had lower total hip BMD than those with levels 2·7-5·6 pmol/l, and CaMos prevalences of normocalcaemic, primary and secondary hyperparathyroidism were 3·3%, 1·4% and 5·2%, respectively.

CONCLUSION

We found reduced BMD in participants with accepted hyperparathyroid states but also a notable proportion of other participants that might benefit from having lower PTH levels.

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

Background

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

Methods

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

Results

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

Conclusions

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

Mild primary hyperparathyroidism: a literature review

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

Bone disease in primary hyperparathyroidism

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

Normocalcemic primary hyperparathyroidism: long-term follow-up associated with multiple adenomas

Normocalcemic primary hyperparathyroidism (NPHPT) is a condition characterized by elevation of the parathyroid hormone (PTH) in the presence of normal serum calcium and the absence of secondary causes. The case described illustrates the long-term follow-up of a postmenopausal woman with NPHPT patient who progressed with multiple adenomas. This case reports a 77-year-old female who has chronic generalized pain and osteoporosis. Her initial serum PTH was 105 pg/mL, with total serum calcium of 9.6 mg/dL, albumin 4.79 g/dL, phosphorus 2.8 mg/dL, and 25OHD after supplementation was 34.6 ng/mL. The bone densitometry (BMD) results were as follows: lumbar spine: T-score -3.0, femoral neck: T-score -2.6 and distal radius: -4.2. Other causes of secondary hyperparathyroidism were ruled out and cervical ultrasound and Tc-99-Sestamibi scan were negative. She used oral alendronate and three infusions of zoledronic acid for treatment of osteoporosis. In the 10th year of follow-up, after successive negative cervical imaging, ultrasound showed a nodule suggestive of an enlarged right inferior parathyroid gland. PTH levels in fluid which was obtained during fine-needle aspiration (FNA) were over 5,000 pg/mL and a Sestamibi scan was negative. The patient underwent parathyroidectomy, and a histological examination confirmed parathyroid adenoma. Post-operatively serum PTH remained elevated in the presence of normal serum calcium levels. A follow-up cervical ultrasound showed a new solid nodule suggestive of an enlarged right superior parathyroid gland. PTH levels in the aspiration fluid were remarkably high. A second parathyroidectomy was performed, with the excision of a histologically confirmed parathyroid adenoma. In conclusion, this is an unusual presentation of NPHPT and highlights the long-term complications.

Diagnosis and clinico-radiological presentation in an aggressive maxillary brown tumour

Brown's tumour is an uncommon focal giant cell lesion which arises as a result of the effect of increased parathyroid hormone on bone tissues in hyperparathyroidism. The mandible is the predominantly affected site in the maxillofacial area and a maxillary involvement is rare. The severity of the lesion, caused by a Brown's tumour, may lead to evident osteolysis and gross deformity in the maxillofacial region, which suggests the need for making an early diagnosis and giving prompt treatment. We are reporting a male patient who presented with a massive painful swelling in the right maxilla as the first manifestation of primary hyperparathyroidism, caused by a parathyroid adenoma.

Sporadic primary hyperparathyroidism: medical and surgical updates

This review discusses recent findings on the clinical presentation, evaluation, medical and surgical management of primary hyperparathyroidism. Medical management includes the use of cinacalcet and bisphosphonates for bone loss and correction of vitamin D deficiency. Surgical updates reviewed recent studies on the preoperative localization of the disease, specifically, sestamibi scans, 4DCT and MRI. Focused parathyroidectomy continues to be the preferred surgical approach for a select group of patients, guided by intraoperative use of PTH and new technology, such as endoscopic and robotic platforms; however, there appears to be no difference in long-term success compared to the traditional approach.

Primary hyperparathyroidism in pregnancy

Primary hyperparathyroidism (PHPT) is rarely diagnosed during pregnancy but is associated with significant maternal and fetal morbidity and mortality. Information on appropriate management is limited. We reviewed the medical literature through December 2012 for key articles on PHPT during pregnancy, focusing on large series. Clinical knowledge in this area is restricted to isolated case reports and a few retrospective studies. Diagnosis can be difficult, owing to the non-specific nature of signs and symptoms of hypercalcemia during pregnancy. Pregnant women with a calcium level over 2.85 mmol/L (11.4 mg/dL) and prior pregnancy loss are at a particularly high risk of maternal complications (hypercalcemic crisis, nephrolithiasis, pancreatitis, etc.) and fetal loss. Around one-half of neonates born to mothers with untreated PHPT have hypocalcemia and tetany. Algorithms proposed for the management of the pregnant woman with PHPT are not evidence based, reflecting the paucity of data. Treatment should thus be individually tailored. Gestational age and the severity of hypercalcemia should be taken into account when assessing the risk-benefit balance of a conservative approach (hyperhydration and vitamin D supplementation) versus parathyroid surgery. Current evidence supports parathyroidectomy as the main treatment, performed preferably during the second trimester, when the serum calcium is above 2.75 mmol/L (11 mg/dL). In the patients with mild forms of PHPT, which are nowadays the most frequent, a conservative management is generally preferred.

Adjustment of ionized calcium concentration for serum pH is not a valid marker of calcium homeostasis: implications for identifying individuals at risk of calcium metabolic disorders

BACKGROUND

Ionized calcium (iCa) is the biologically active form of this micronutrient. Serum determination of iCa is measured via ion-electrode potentiometry (IEP) and reporting iCa relative to pH 7.4 is normally utilized to avoid the potential confounding effects of ex vivo changes to serum pH. Adjustment of iCa for pH has not been adequately justified.

METHODS

In this study, utilizing carefully standardized protocols for blood collection, the preparation of serum and controlling time of collection-to-analysis, we determined serum iCa and pH utilizing an IEP-analyser hosted at an accredited diagnostic laboratory.

RESULTS

Regression analysis of unadjusted-iCa (iCa(raw)) concentration versus pH was described by linear regression and accounted for 37% of serum iCa(raw) variability. iCa(raw) was then expressed at pH 7.4 by either adjusting iCa(raw) based on the linear regression equation describing the association of iCa with serum pH (iCa(regr)) or using IEP coded published normative equations (iCa(pub)). iCa(regr) was comparable to iCa(raw), indicating that blood collection and processing methodologies were sound. However, iCa(pub) yielded values that were significantly lower than iCa(raw). iCa(pub) did not identify 15% subjects who had greater than desirable serum concentration of iCa based on iCa(raw). Sixty percent of subjects with low levels of iCa(raw) were also not detected by iCa(pub). Determination of the kappa value measure of agreement for iCa(raw) versus iCa(pub) showed relatively poor concordance (κ = 0.42).

CONCLUSIONS

With simple protocols that avoid sampling artefacts, expressing iCa(raw) is likely to be a more valid and physiologically relevant marker of calcium homeostasis than is iCa(pub).

Reduced parathyroid hormone-stimulated 1,25-dihydroxyvitamin d production in vitamin d sufficient postmenoposual women with low bone mass and idiopathic secondary hyperparathyroidism

OBJECTIVE

Distinguishing secondary hyperparathyroidism (sHPT) from eucalcemic primary hyperparathyroidism (EC-pHPT) is important. The objective of this study was to measure parathyroid hormone (PTH)-stimulated production of 1α,25-dihydroxyvitamin D (1,25[OH]2D) in early postmenopausal patients with idiopathic sHPT, who also fit the criteria for EC-pHPT, compared to age-matched controls.

METHODS

In this pilot case-control study, postmenopausal women aged 44 to 55 years with normal serum calcium (Ca), glomerular filtration rate (GFR) ≥65 mL/min, and 25-hydroxyvitamin D (25[OH]D) ≥75 nmol/L (30 ng/mL) were given an 8 hour infusion of PTH(1-34), 12 pmol/kg/h. Patients (n = 5) had elevated PTH, normal 1,25(OH)2D, and no hypercalciuria. Controls (n = 5) had normal PTH. At baseline, 4, and 8 hours, serum Ca, creatinine (Cr), phosphorus (P), 1,25(OH)2D, fibroblast growth factor (FGF23), and 24,25(OH)2D as well as urine Ca, P, Cr, and cAMP/GFR were measured. The fractional excretion of calcium (FeCa) and tubular reabsorption of phosphorus (TMP)/GFR were calculated.

RESULTS

Patients had lower 1,25(OH)2D levels (± SD) than controls at 4 (39.8 ± 6.9 versus 58.8 ± 6.7; P = .002) and 8 hours (56.4 ± 9.2 versus 105 ± 2.3; P = .003) of PTH infusion, attenuated after adjusting for higher body mass index (BMI) in patients (P = .05, .04), respectively. The 24,25(OH)2D levels were lower in patients than controls (1.9 ± 0.6 versus 3.4 ± 0.6, respectively; P = .007). No differences were seen in serum Ca or P, urine cAMP/GFR, TRP/GFR, FeCa, or PTH suppression at 8 hours (patients 50%, controls 64%).

CONCLUSION

Vitamin D sufficient patients who fit the criteria for EC-pHPT had reduced PTH-stimulated 1,25(OH)2D compared to controls, partially attributable to their higher BMI. Other causes of reduced 1,25(OH)2D production ruled out were excessive catabolism of vitamin D metabolites, elevated FGF23, and CYP27B1 mutation. Elevated BMI and idiopathic reduced PTH-stimulated 1,25(OH)2D production should be considered in the differential of sHPT.

[Normocalcemic primary hyperparathyroidism: a growing problem]

Normocalcemic primary hyperparathyroidism is at present one of the most common reasons for consultation in bone metabolism units. It is characterized by increased levels of intact parathyroid hormone in the presence of normal serum calcium (total and ionized) in generally asymptomatic individuals. The differential diagnosis should be considered in all situations that occur with secondary hyperparathyroidism. Its natural history is not well known, and it does not always progress to hypercalcemia. As a recently recognized entity, there are still no specific recommendations for its management. In this review we discuss some aspects of this entity, emphasizing the importance of a proper laboratory diagnosis, assessing possible signs or symptoms associated such as kidney stones or osteoporosis, which can help the clinician to take a conservative or interventionist attitude.

Osteoporosis in men: recent progress

As osteoporosis in men has been recognized as an important clinical problem, new information is being accumulated on its scope, pathophysiology, evaluation, and treatment. Fracture risk calculators, such as FRAX, identify a large proportion of the older male population to be at heightened risk for fracture. The classification of osteoporosis into primary and secondary forms, while still useful, is affected by the fact that many men have multiple contributing factors to their fracture risk. The role of sex steroids is being better defined as other risk factors for fracture are delineated. As longevity continues to increase in men and until osteoporotic fracture is truly recognized as a potentially fatal disorder, many men will be undiagnosed and untreated. Two recent studies provide more evidence that treatments which decrease fracture risk in women do the same in men. With the publication of guidelines and increasing strength of evidence for treatment efficacy, it is hoped that more men will be evaluated and treated for this often neglected disorder.

Normocalcemic hyperparathyroidism and hypoparathyroidism in two community-based nonreferral populations

CONTEXT

Normocalcemic primary hyperparathyroidism is typically identified after referral to a specialty clinic. At diagnosis, patients demonstrate features seen in hypercalcemic primary hyperparathyroidism. Normocalcemic hypoparathyroidism has been discovered after hypocalcemia unmasked after bisphosphonate administration.

OBJECTIVE

We hypothesized that screening unselected, nonreferral populations, such as The Osteoporotic Fractures in Men (MrOS) study and Dallas Heart Study (DHS), would identify asymptomatic subjects with normocalcemic hyperparathyroidism and hypoparathyroidism.

METHODS

Normocalcemic hyperparathyroidism was defined as serum PTH greater than the upper reference range with normal albumin-adjusted serum calcium, excluding common secondary causes (renal failure [estimated glomerular filtration rate <60 mL/min], 25-hydroxyvitamin D <20 ng/mL, and thiazide use), and normocalcemic hypoparathyroidism as PTH below the reference range with normocalcemia. Cross-sectional data were obtained from MrOS, and longitudinal data (baseline and 8 years) from DHS.

RESULTS

In 2364 men from MrOS, we identified 9 with normocalcemic hyperparathyroidism (prevalence 0.4%) and 26 with normocalcemic hypoparathyroidism (1.1%). In 3450 men and women from DHS, we identified 108 with normocalcemic hyperparathyroidism (3.1%) and 68 with normocalcemic hypoparathyroidism (1.9%). Of the 108 normocalcemic hyperparathyroid subjects, 64 had follow-up data. Hypercalcemic primary hyperparathyroidism developed in 1 subject whereas 13 (0.6% of the follow-up cohort) showed persistently elevated PTH levels with normocalcemia. Of the 26 normocalcemic hypoparathyroid subjects with follow-up data, none developed overt hypoparathyroidism and 2 (0.09%) had persistent evidence of normocalcemic hypoparathyroidism.

CONCLUSIONS

This study documents normocalcemic primary hyperparathyroidism and hypoparathyroidism identified among community-dwelling individuals. Larger studies are needed to determine the true prevalence and natural history of these parathyroid disorders.

Differences between sporadic and MEN related primary hyperparathyroidism; clinical expression, preoperative workup, operative strategy and follow-up

Background

Primary hyperparathyroidism (PHPT) is most commonly sporadic (sPHPT). However, sometimes PHPT develops as part of multiple endocrine neoplasia (MEN) type 1 or 2A. In all, parathyroidectomy is the only curative treatment. Nevertheless, there are important differences in clinical expression and treatment.

Methods

We analyzed a consecutive cohort of patients treated for sporadic, MEN1-related, and MEN2A-related PHPT and compared them regarding clinical and biochemical parameters, differences in preoperative workup, operative strategies, findings, and outcome.

Results

A total of 467 patients with sPHPT, 52 with MEN1- and 16 with MEN2A-related PHPT were analyzed. Patients with sPHPT were older, more often female and had higher preoperative calcium and parathyroid hormone levels, when compared with MEN1 and MEN2A patients. Minimally invasive parathyroidectomy (MIP) was performed in 367 of 467 sPHPT patients (79%). One abnormal parathyroid was found in 426 patients (91%). Two or more in 35 patients (7%). In six patients (1%) no abnormal parathyroid gland was retrieved. Of 52 MEN1 patients, eight (15%) underwent a MIP and 44 patients (85%) underwent conventional neck exploration (CNE); with resection of fewer than 3½ enlarged glands in 21 patients (40%), subtotal parathyroidectomy (SPTX, 3-3½ glands) in seventeen (33%) and total parathyroidectomy with autotransplantation (TPTX) in six (12%). Eleven patients (21%) had persistent disease, 29 (56%) recurrent PHPT and nine (17%) permanent hypoparathyroidism, mostly after TPTX. Of 16 MEN2A patients, six (38%) underwent MIP, four (25%) CNE and six (38%) selective resection of the enlarged gland(s) during total thyroidectomy. Three patients (19%) suffered from persistent PHPT and two (13%) developed recurrent disease.

Conclusions

Sporadic PHPT, MEN1- and MEN2A-related PHPT are three distinct entities as is reflected preoperatively by differences in gender, age at diagnosis and calcium and PTH levels.

MEN2A patients are very similar to sPHPT with respect to operative approach and findings. MIP is the treatment of choice for both. MIP has low rates of persistent and recurrent PHPT and a low complication rate. The percentage of multiglandular disease and recurrences are significantly higher in MEN1 patients, demonstrating the need for a different approach. We advocate treating these patients with CNE and SPTX.