The diagnosis and management of asymptomatic primary hyperparathyroidism

Bilateral exploration in primary hyperparathyroidism: Double adenoma distribution and biochemical patterns over two decades

BACKGROUND

We investigated if anatomic patterns of abnormal parathyroid glands have ch anged for primary hyperparathyroidism (pHPT) as atypical biochemical presentation (normohormonal and normocalcemic) has increased.

METHODS

Retrospective review of patients with pHPT who underwent routine bilateral neck exploration.

RESULTS

2762 patients were included. The "late" cohort (2014-2020) exhibited lower preoperative calcium (10.8 vs 11.1 ​mg/dL; P ​= ​0.001) and PTH levels (101 vs. 146 ​pg/mL; P ​= ​0.001) compared to the "early" cohort (2000-2006). Patients with atypical biochemical profiles increased from 25.5% to 31.3% (P ​< ​0.001). The prevalence of single adenoma (SA) decreased (66.1% vs 58.9%, P ​= ​0.02) while the proportion of double adenoma (DA) increased (17.3% vs. 22.6%, P ​< ​0.01). Upper parathyroid adenoma(s) remained the most common finding for SA and DA in both time points.

CONCLUSIONS

Despite changes in patient characteristics, single upper adenoma and bilateral double upper adenomas remain the most common findings for patients with pHPT.

Differences in Primary Hyperparathyroidism Between Pre- and Postmenopausal Women in India

OBJECTIVE

Primary hyperparathyroidism (PHPT) is a common endocrine disorder in women which becomes more prevalent after menopause. In this study, we compared the demographic, clinical, and biochemical variables between premenopausal (pre-M) and postmenopausal (post-M) women with PHPT.

METHODS

A retrospective analysis (from 2005 to 2019) of enrolled women PHPT patients from an online Indian PHPT registry.

RESULTS

Of the women with PHPT, 232 and 122 were pre-M and post-M, respectively. The number of post-M PHPT cases registered had a 3.3-fold increase in 2015-2019 from 2005-2009 compared with only a 2.5-fold increase in pre-M cases in the same duration. The majority were symptomatic (90%), although pre-M had a higher proportion of symptomatic than post-M (92% vs 85%; P = .04). Pre-M women showed more prevalence of osteitis fibrosa cystica than post-M women (28% vs 13%; P = .03), although hypertension and gallstone disease were seen more frequently in post-M PHPT women. Pre-M women had a significantly higher median PTH (403 vs 246 pg/mL; P = .02) and median alkaline phosphatase (202 vs 145 pg/mL; P = .02) than post-M women, and vitamin D deficiency was more common in pre-M women (58% vs 45%; P = .03). Gland localization, tumor weight, and disease cure rates did not differ according to menopausal status.

CONCLUSION

PHPT was more prevalent in pre-M women, although the number of post-M cases had significantly increased in the last 10 years. Pre-M women had generally more severe clinical and biochemical variables than post-M PHPT women.

Progressive rise in the prevalence of asymptomatic primary hyperparathyroidism in India: Data from PHPT registry

INTRODUCTION

Primary hyperparathyroidism (PHPT), a third common endocrine disorder, varies from asymptomatic disease, mostly seen in the West where routine biochemical screening is practiced, to the classical symptomatic disease mostly seen in the Eastern countries. We aimed to compare the demographic, clinical, biochemical measurements in patients with asymptomatic and symptomatic PHPT from the Indian PHPT registry.

MATERIAL AND METHODS

Data of PHPT patients from the last 25 years (1995-2019) were analyzed for demographic, clinical presentation and biochemical measurements, and compared these characteristics between asymptomatic and symptomatic PHPT patients.

RESULTS

Of the 554 patients, 54 (10%) patients had asymptomatic PHPT. There was a sharp rise in the proportion of asymptomatic PHPT patients of 3% in the first decade to 13% in the second decade of the century (p = 0.003). Patients with asymptomatic PHPT were significantly older (50 vs. 42 years; p < 0.0001) and had higher mean body mass index (27.8 vs. 23.5 kg/m²; p < 0.0001) compared to the symptomatic PHPT group. In addition, asymptomatic PHPT patients had significantly lower median plasma iPTH (180 vs. 370 pg/mL; p < 0.0001), serum alkaline phosphatase (119 vs. 172 IU/L; p < 0.0001), and parathyroid adenoma weight (1.0 vs. 2.62 g; p = 0.006) compared to the symptomatic PHPT group.

CONCLUSION

Although symptomatic PHPT is still most prevalent (> 90%) in India with higher indices of the disease and tumor weights, there is a progressive rise in the prevalence of asymptomatic PHPT patients in the last decade. Improvements in calcium and vitamin D nutrition might account for this change as in the Western series.

Severe hypercalcaemia of primary hyperparathyroidism: Could giant adenoma be the real culprit rather than carcinoma?

INTRODUCTION

Hypercalcaemic crisis is a rare manifestation of hyperparathyroidism and occurs in 1.6-6% of patients with primary hyperparathyroidism (pHPT). Although such high serum calcium levels (>14mg/dl) are attributed to malignancy, it is also associated with benign disease of the parathyroid glands. The aim of this study was to evaluate the clinical features and treatment modalities of patients with severe hypercalcaemia who underwent surgery for pHPT.

METHODS

The medical records of 537 patients who underwent parathyroidectomy in our department for pHPT between 2005 and 2019 were reviewed retrospectively. Twenty-four (4.4%) of the patients were described as having severe hypercalcaemia.

RESULTS

Among 24 patients, 71% were female and the mean age was 55.7 years (range: 40-71 years). The mean serum calcium level at time of diagnosis was 15.9mg/dl (range: 14-22.7mg/dl). According to postoperative pathology reports, solitary adenoma, parathyroid cancer and parathyromatosis were diagnosed with the rates of 87.5%, 8.3% and 4.1% respectively. The mean weight of the solitary parathyroid lesions was 14.9g (standard deviation: 8.9g, range: 4-38g). The mean longest diameter was 2.87cm (standard deviation: 1.4cm, range: 1-5.5cm). Serum calcium levels were within the normal range on the first postoperative day in 75% of the cases.

CONCLUSIONS

Severe hypercalcaemia is a rare but urgent condition of pHPT and requires prompt management. Accelerated surgery after adequate medical treatment should be performed. It is important to emphasise that giant adenoma, which is a benign disease, may be a more common cause of severe hypercalcaemia than carcinoma, unlike previously thought.

A clinical perspective of parathyroid hormone related hypercalcaemia

There are many causes of hypercalcaemia including hyperparathyroidism, drugs, granulomatous disorders and malignancy. Parathyroid hormone (PTH) related hypercalcaemia is most commonly caused by primary hyperparathyroidism (PHPT) and more rarely by familial hypocalciuric hypercalcaemia (FHH). Algorithms for diagnosis of PTH related hypercalcaemia require assessment of a 24-h urinary calcium and creatinine excretion to calculate calcium/creatinine clearance ratio and radiological investigations including ultrasound scan and ^99mTc-sestamibi-SPECT/CT. To illustrate investigations and management of parathyroid-related hypercalcaemia, we present a selection of distinct cases of PHPT due to eutopic and ectopic parathyroid adenomas, as well as a case with a syndromic form of PHPT (multiple endocrine neoplasia type 1), and a case with FHH type 1 due to a CASR inactivating mutation. Additional cases with normocalcaemic hyperparathyroidism and secondary hyperparathyroidism are included for completeness of differential diagnosis. The common eutopic parathyroid adenomas are easily treated with parathyroidectomy while the less common ectopic parathyroid adenomas require more complex investigations and operative procedures such as video-assisted thoracoscopic surgery. On the other hand, the much less common FHH does not require treatment. Assessment of kin with FHH is important to identify members with this inherited condition in order to prevent unnecessary interventions.

Hypercalcaemic Crisis Due to Primary Hyperparathyroidism: Report of Two Cases

INTRODUCTION

A hypercalcaemic crisis, also called para thyrotoxicosis, hyper parathyroid crisis or parathyroid storm, is a complication of primary hyperparathyroidism (PHPT) and an endocrinology emergency that can have dramatic or even fatal consequences if it is not recognised and treated in time.

CASE PRESENTATION

Two cases presented in the emergency department with critical hypercalcaemic symptoms and severe elevation of serum calcium and parathyroid hormone levels, consistent with a hypercalcaemic crisis. The first case, a 16-year-old female patient, had imaging data that highlighted a single right inferior parathyroid adenoma and a targeted surgical approach was used. The second case, a 35-year-old man was admitted for abdominal pain, poor appetite, nausea and vomiting. Laboratory tests revealed severe hypercalcaemia, hypophosphatemia and an increased serum iPth level. There was no correlation between scintigraphy and ultrasonography, and a bilateral exploration of the neck was preferred, resulting in the exposure of two parathyroid adenomas. The patients were referred for surgery and recovery in both cases was uneventful.

CONCLUSION

These cases support the evidence that surgery remains the best approach for patients with a hypercalcaemic crisis of hyperparathyroidism origin, ensuring the rapid improvement of both the symptomatology and biochemical alterations of this critical disease.

Management of familial hyperparathyroidism syndromes: MEN1, MEN2, MEN4, HPT-Jaw tumour, Familial isolated hyperparathyroidism, FHH, and neonatal severe hyperparathyroidism

While primary hyperparathyroidism (PHPT) generally represents a common endocrine disorder, being the more frequent cause of hypercalcemia in outpatients, familial forms of PHPT (FPHPT) account for no more than 2-5% of the overall PHPT. In the last decades, many technical progresses in both molecular and biochemical-radiological evaluation have been made, and substantial advancements in understanding these disorders have been reached. Differences both in the pathogenesis and clinical presentation exist among the various hyperparathyroid syndromic forms, and, since FPHPT is frequently associated to other endocrine, proliferative and/or functional disorders, as also non-endocrine tumours, with varying clinical spectrum of occurrence in each syndrome, its early clinically detection for appropriately preventing complications (i.e. kidney and bone disorders) is strictly advised. In this review, the clinical-biochemical features and diagnostic procedures of each FPHPT form will be summarized and a general overview on surgical and pharmacological approaches to FPHPT has been also considered.

Multimodality Imaging in Patients with Secondary Hypertension: With a Focus on Appropriate Imaging Approaches Depending on the Etiologies

Although the causes of hypertension are usually unknown, about 10% of the cases occur secondary to specific etiologies, which are often treatable. Common categories of secondary hypertension include renal parenchymal disease, renovascular stenosis, vascular and endocrinologic disorders. For diseases involving the renal parenchyma and adrenal glands, ultrasonography (US), computed tomography (CT) or magnetic resonance (MR) imaging is recommended. For renovascular stenosis and vascular disorders, Doppler US, conventional or noninvasive (CT or MR) angiography is an appropriate modality. Nuclear imaging can be useful in the differential diagnosis of endocrine causes. Radiologists should understand the role of each imaging modality and its typical findings in various causes of secondary hypertension. This article focuses on appropriate imaging approaches in accordance with the categorized etiologies leading to hypertension.

GCM2-Activating Mutations in Familial Isolated Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disease characterized by parathyroid hormone excess and hypercalcemia and caused by hypersecreting parathyroid glands. Familial PHPT occurs in an isolated nonsyndromal form, termed familial isolated hyperparathyroidism (FIHP), or as part of a syndrome, such as multiple endocrine neoplasia type 1 or hyperparathyroidism-jaw tumor syndrome. The specific genetic or other cause(s) of FIHP are unknown. We performed exome sequencing on germline DNA of eight index-case individuals from eight unrelated kindreds with FIHP. Selected rare variants were assessed for co-segregation in affected family members and screened for in an additional 32 kindreds with FIHP. In eight kindreds with FIHP, we identified three rare missense variants in GCM2, a gene encoding a transcription factor required for parathyroid development. Functional characterization of the GCM2 variants and deletion analyses revealed a small C-terminal conserved inhibitory domain (CCID) in GCM2. Two of the three rare variants were recurrent, located in the GCM2 CCID, and found in seven of the 40 (18%) kindreds with FIHP. These two rare variants acted as gain-of-function mutations that increased the transcriptional activity of GCM2, suggesting that GCM2 is a parathyroid proto-oncogene. Our results demonstrate that germline-activating mutations affecting the CCID of GCM2 can cause FIHP.

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.

Primary hyperparathyroidism and vitamin D deficiency

Primary hyperparathyroidism (PHPT) and vitamin D (VD) deficiency are frequent conditions due to the widespread application of assays for calcium and VD. PHPT presentation is dominated by diversity in its expression and the current predominance of asymptomatic forms. VD, which plays a major role in calcium and phosphate homeostasis, is also involved in many physiological processes in this disease, such as lipid and glucose metabolism, and in the signalling pathways and functioning of many cell types. The bone and cardiometabolic complications described in PHPT are exacerbated by vitamin D deficiency, the prevalence of which varies according to many parameters (environment, skin pigmentation, associated chronic diseases, liver and kidney function, assay kit used, etc.). In response to this observation, experts in field from medical societies validated the indication for systematic assay of VD occurring with PHPT and the need for replacement in case of deficiency. Several epidemiological studies have confirmed that replacement with natural vitamin D is well tolerated and safe in subjects with PHPT and VD deficiency. This supplementation reduces hyperparathormonemia, does not have symptomatic effects on calciuria, and especially improves the bone and functional condition of patients.

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.

Endocrine scintigraphy with hybrid SPECT/CT

Nuclear medicine imaging of endocrine disorders takes advantage of unique cellular properties of endocrine organs and tissues that can be depicted by targeted radiopharmaceuticals. Detailed functional maps of biodistributions of radiopharmaceutical uptake can be displayed in three-dimensional tomographic formats, using single photon emission computed tomography (CT) that can now be directly combined with simultaneously acquired cross-sectional anatomic maps derived from CT. The integration of function depicted by scintigraphy and anatomy with CT has synergistically improved the efficacy of nuclear medicine imaging across a broad spectrum of clinical applications, which include some of the oldest imaging studies of endocrine dysfunction.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

CONCLUSION

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

Risk of nephrolithiasis in primary hyperparathyroidism is associated with two polymorphisms of the calcium-sensing receptor gene

AIMS

Two single-nucleotide polymorphisms (SNPs) at the calcium-sensing receptor (CASR) gene were previously associated with kidney stones in patients with primary hyperparathyroidism (PHPT): rs1501899, likely associated with a decrease in CASR expression, and Arg990Gly, causing a gain of CASR function. To evaluate the interaction of these two SNPs in the stone risk, we tested the association of stones with the genotype at both SNPs in PHPT patients and the association of rs1501899 with CASR expression as messenger RNA (mRNA) in human kidney samples.

METHODS AND RESULTS

Two hundred and ninety-six PHPT patients were genotyped at the rs1501899 and Arg990Gly SNPs. Minor allele frequency at tested SNPs was higher in PHPT stone formers relative to non-stone forming patients. PHPT patients carrying one or two copies of the minor allele at both rs1501899 and Arg990Gly (n = 16) had the maximal risk of stones (odds ratio, OR 8.3) and higher serum ionized calcium compared with homozygous patients for the wild-type allele at both SNPs. CASR expression as mRNA was measured by real time polymerase chain reaction (PCR) in normal kidney medulla samples from 109 subjects. CASR mRNA was significantly lower in medulla samples from homozygotes for the minor allele at rs1501899 than in subjects with other genotypes.

CONCLUSIONS

We conclude that the simultaneous presence of the minor allele at rs1501899 and Arg990Gly may amplify the kidney stone risk in PHPT patients, despite their apparently opposite effects on CASR function in the kidney.

Elevated parathyroid hormone after parathyroidectomy delays symptom improvement

BACKGROUND

Curative parathyroidectomy for primary hyperparathyroidism (PHPT) resolves various nonspecific symptoms related to the disease. Between 8% and 40% of patients with normocalcemia after parathyroidectomy have persistently elevated parathyroid hormone (ePTH) levels at follow-up. We investigated whether ePTH in the early postoperative period was associated with the timing of symptom improvement.

MATERIALS AND METHODS

This prospective study included adult patients with PHPT who underwent curative parathyroidectomy from November 2011 to September 2012. Biochemical testing at 2 wk postoperatively identified ePTH (defined as PTH>72 pg/mL) versus normal PTH (nPTH). A questionnaire administered pre- and post-operatively at 6 wk and 6 mo asked patients to rate the frequency of 18 symptoms of PHPT on a five-point Likert scale. Student t-tests were used to compare pre- with postoperative changes in scores for individual symptoms.

RESULTS

Of 194 patients who underwent parathyroidectomy, 129 (66%) participated in the study. Preoperatively, all patients were symptomatic, with a mean of 13±4 symptoms. Two weeks postoperatively, 20 patients (16%) had ePTH. The percentage of patients with postoperative improvement for individual symptoms was compared between groups. At the early time point (6 wk), the ePTH group showed less improvement in 14 of 18 symptoms. This difference reached statistical significance for four symptoms: anxiety, constipation, thirst, and polyuria. By the 6-mo time point, these differences had resolved, and symptom improvement was similar between groups.

CONCLUSIONS

ePTH after curative parathyroidectomy may result in a delay in symptom improvement 6 wk postoperatively; however, this difference resolves in 6 mo.

Primary hyperparathyroidism masquerading as rickets: diagnostic challenge and treatment outcomes

Primary hyperparathyroidism (PHPT) is extremely uncommon among children and is more likely to be associated with genetic syndromes, multiglandular involvement, and more severe symptoms. Rickets can very rarely be the presenting feature of PHPT in children. Rickets was diagnosed in a 12-year-old girl presenting with short stature, genu valgum, eversion deformity at the ankle joints, and flat feet. Radiograms showed generalized osteopenia, widening of the distal ends of the long bones along with splaying, cupping and fraying. Biochemical evaluation revealed low serum calcium (7.8 mg/dL), low phosphorus (1.4 mg/dL), vitamin-D deficiency [25-hydroxy-vitamin-D (25(OH)D): 8.7 ng/mL], and elevated intact parathyroid hormone (PTH, 811 pg/mL). Re-evaluation due to lack of clinical improvement following vitamin-D and calcium supplementation revealed hypercalcemia 11.9 mg/dL, normal 25(OH)D 41 ng/mL, persistence of elevated PTH 632 pg/mL. A 99mTc-sestamibi scan showed increased uptake at the lower pole of the right lobe of the thyroid. A right inferior parathyroidectomy was performed. Histopathology revealed chief cell type parathyroid adenoma. Last evaluated 4 months after surgery, the bone pains and proximal weakness had resolved, with significant improvement in the patient's quality of life. Rickets in the setting of PHPT often masks the classical phenotype of PHPT. In a child with rickets, lack of improvement following vitamin-D supplementation, hypercalcemia at presentation or following vitamin-D supplementation are warning signs which necessitate further evaluation to rule out PHPT.

Characteristics, management and outcome of primary hyperparathyroidism in South Africa: a single-centre experience

INTRODUCTION

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterised by hypercalcaemia and elevated parathyroid hormone (PTH) levels. However, it remains a relatively underdiagnosed disease in the developing world primarily due to a lack of routine blood chemistry screening. The aim of this analysis was to evaluate the characteristics, management and outcome of patients with PHPT at a tertiary referral clinic in South Africa.

METHODS

A retrospective analysis was undertaken on all patients with a diagnosis of PHPT attending the endocrinology clinic at a tertiary referral hospital in Durban, South Africa, between January 2003 and June 2009. Information on clinical presentation, past medical history, biochemistry, radiology, histology and surgical notes were recorded. Patients with multiple endocrine neoplasia were excluded.

RESULTS

A total of 28 case records of PHPT were reviewed. The mean age at presentation was 60±14.5 years with a female preponderance (78.6%). The mode of presentation included referral for investigation of an abnormal serum calcium (n: 23), referral from urologist with nephrolithiasis (n: 3) and for investigation of bone disease (n: 2). Symptomatic disease was found in 26 patients (92.9%), including bone pain (75%), fatigue (46.4%) and abdominal pain (32.1%). Mean serum calcium was 3.0+0.39 (normal 2.08-2.65) mmol/L, serum intact PTH 34.7±41.5 (normal 1.2-8.5) pmol/L and serum alkaline phosphatase 206.3±340.2 (normal 53-141) mIU/L. Sestamibi scan was performed on 24 patients and an adenoma was identified in 83.3%. Of the 19 (68%) patients who had parathyroidectomy, an adenoma was identified as the cause in all cases where histology was available (n:18). Surgery was successful in 18 patients with only one patient requiring repeat parathyroidectomy for persistent hypercalcaemia. Postoperative hypocalcaemia developed in eight patients (42.1%) including four patients who required intravenous calcium infusion for symptomatic hypocalcaemia.

CONCLUSIONS

PHPT is a treatable disorder with good surgical success. Asymptomatic disease was uncommon in this group of patients. This is compatible with the symptomatic pattern of presentation reported in other developing countries.

Asymptomatic primary hyperparathyroidism

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

Nonsurgical management of mild primary hyperparathyroidism - a reasonable option

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

The importance of measuring ionized calcium in characterizing calcium status and diagnosing primary hyperparathyroidism

CONTEXT

Serum total calcium (tCa) is routinely measured for diagnosing calcium disorders but may not reflect levels of biologically active ionized calcium (iCa) in disease or detect all cases of primary hyperparathyroidism.

OBJECTIVE

We investigated the utility of measuring iCa and tCa for diagnosing primary hyperparathyroidism.

DESIGN

This was an observational, retrospective, cross-sectional study.

PATIENTS

We studied a biochemistry cohort of consecutive ambulatory outpatients with suspected bone or calcium metabolism disorders referred for calcium metabolism biochemistry panels and a surgical cohort of consecutive tertiary hospital patients whose parathyroid specimens were submitted to a single center, and consecutive parathyroidectomy patients of a single surgeon with specimens submitted to a different center.

RESULTS

In 5490 biochemistry cohort patients, discordance between iCa and tCa in classifying calcium status occurred in 12.6% of cases overall but was worse in hypercalcemic (whether defined by tCa and/or iCa) cases (49%) and hypocalcemic cases (92%). Reliance on tCa alone would miss 45% with ionized hypercalcemia. In 315 biochemistry cohort cases with PTH-dependent hypercalcemia, 130 (41%) had isolated ionized hypercalcemia at diagnosis. In 143 patients with histologically proven parathyroid disease, 24% had isolated ionized hypercalcemia at diagnosis. These patients were younger (P = 0.022) with milder ionized hypercalcemia and better renal function (both P ≤ 0.001) than patients presenting with concurrently elevated iCa and tCa.

CONCLUSION

In abnormal calcium states, tCa frequently disagrees with iCa in classifying calcium status. Histologically proven parathyroid disease can present with isolated ionized hypercalcemia. Measurement of iCa is required to accurately assess calcium status and improve diagnostic accuracy.

Total parathyroidectomy in a large cohort of cases with hyperparathyroidism associated with multiple endocrine neoplasia type 1: experience from a single academic center

Most cases of sporadic primary hyperparathyroidism present disturbances in a single parathyroid gland and the surgery of choice is adenomectomy. Conversely, hyperparathyroidism associated with multiple endocrine neoplasia type 1 (hyperparathyroidism/multiple endocrine neoplasia type 1) is an asynchronic, asymmetrical multiglandular disease and it is surgically approached by either subtotal parathyroidectomy or total parathyroidectomy followed by parathyroid auto-implant to the forearm. In skilful hands, the efficacy of both approaches is similar and both should be complemented by prophylactic thymectomy. In a single academic center, 83 cases of hyperparathyroidism/ multiple endocrine neoplasia type 1 were operated on from 1987 to 2010 and our first surgical choice was total parathyroidectomy followed by parathyroid auto-implant to the non-dominant forearm and, since 1997, associated transcervical thymectomy to prevent thymic carcinoid. Overall, 40% of patients were given calcium replacement (mean intake 1.6 g/day) during the first months after surgery, and this fell to 28% in patients with longer follow-up. These findings indicate that several months may be needed in order to achieve a proper secretion by the parathyroid auto-implant. Hyperparathyroidism recurrence was observed in up to 15% of cases several years after the initial surgery. Thus, long-term follow-up is recommended for such cases. We conclude that, despite a tendency to subtotal parathyroidectomy worldwide, total parathyroidectomy followed by parathyroid auto-implant is a valid surgical option to treat hyperparathyroidism/multiple endocrine neoplasia type 1. Larger comparative systematic studies are needed to define the best surgical approach to hyperparathyroidism/multiple endocrine neoplasia type 1.

Current evidence for recommendation of surgery, medical treatment and vitamin D repletion in mild primary hyperparathyroidism

Management of patients with mild primary hyperparathyroidism (PHPT) has been widely discussed because most patients today do not have specific symptoms. While surgery is always an option, the recommendations for treatment have shifted, which mostly reflects changes in clinical practice. In this study, we aimed to evaluate evidence for the current recommendations concerning operation vs observation, repletion with vitamin D (VitD) and alternative medical management. Surgery is followed by normalisation of calcium and parathyroid hormone (PTH) and a decrease in bone turnover followed by an increase in bone mass. It is not known what the consequences would be for the frequency of fractures. Randomised studies have indicated beneficial effects of operation on quality of life (QoL), but the effects have been minor and inconsistent. Operation seems not to be superior to observation for cardiovascular risk factors. Although PHPT patients in average have slightly decreased plasma 25OH VitD, severe symptomatic VitD deficiency seems not to be a characteristic of PHPT patients in Europe. However, if present, we recommend VitD substitution before final decision on surgical treatment. It is unknown whether routine VitD supplementation should be offered preoperatively to all patients with mild PHPT or as part of long-term medical treatment. Targeted medical management could be an option for patients with contraindications to surgery. Antiresorptive therapy might be appropriate for patients with a low bone mass to prevent further bone loss. Calcimimetics could be tried to control serum calcium levels although there is no evidence of an effect on the hypercalcaemic symptoms or the QoL. Combined therapy with calcimimetics and alendronate could be considered for patients with hypercalcaemia and overt bone disease.

[Recurrence prevention of kidney stone disease]

In each urolithiasis patient the individual risk for recurrence determines the need for specific medical treatment. Therefore, a brief evaluation of the risk status after stone passage is mandatory to define patients at high risk for recurrence. Only one quarter of all urolithiasis patients are at high risk or suffer from severe metabolic disorders, which both demand further metabolic work-up prior to medical therapy. However, the other three quarters benefit sufficiently from general preventive measures, such as high fluid intake, well-balanced mixed diet and lifestyle changes. This article summarizes the recent recommendations for stone-specific recurrence prevention, discusses the different pharmacological treatment options and sketches the follow-up concept for high risk patients with ongoing medication.

Management and surgical treatment of parathyroid crisis secondary to parathyroid tumors: report of four cases

Parathyroid crisis, also known as a parathyroid storm, is a rare and serious complication of primary hyperparathyroidism. Four cases are reported here in which patients presented to hospital with general complaints due to hypercalcemia secondary to hyperparathyroidism. Blood test results upon admission showed high levels of serum calcium and parathyroid hormone, and medical treatment initiated to lower the calcium level was ineffective. After relevant investigations, each patient underwent surgical exploration of the parathyroid glands, followed by excision of a pathological parathyroid tumor. There was a prompt decrease in parathyroid hormone level immediately after surgery. Histology reports revealed that patients had parathyroid adenoma. All patients recovered after surgery, with serum calcium levels restored back to normal and with resolution of all symptoms of hypercalcemia. This report illustrates how often this disease is initially misdiagnosed, and how prompt appropriate surgical treatment provides the best outcome for the patient.

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.

Parathyroid cancer

Parathyroid cancer is an uncommon malignancy and rare cause of primary hyperparathyroidism (HPT) with a high morbidity and patient death in advanced cases usually resulting from intractable hypercalcemia. Inactivation of the HRPT2/CDC73 gene, encoding the putative tumor-suppressor protein parafibromin and discovered in the context of the hyperparathyroidism-jaw tumor (HPT-JT) syndrome, is a common, somatic event in most parathyroid cancers. Approximately 25% of patients with apparently sporadic parathyroid cancer carry germline HRPT2/CDC73 mutation. Germline DNA analysis for HRPT2/CDC73 mutation is recommended in all patients with parathyroid cancer because of the potential benefit for first-degree relatives, who should nevertheless undergo serum calcium screening. The histopathologic diagnosis of parathyroid cancer is nonspecific unless vascular, lymphatic, capsular, or soft tissue invasion is seen, or metastases are clinically evident. Immunohistochemical analysis of parathyroid tumors for loss of parafibromin expression offers promise as a diagnostic tool. En bloc tumor resection offers the highest chance of cure in patients with suspected parathyroid carcinoma. No adjuvant chemotherapy regimen has yet proven effective, and the role of local adjuvant radiotherapy is being evaluated. Metastatic disease can be palliated with surgical debulking. Medical therapy with the calcimimetic cinacalcet and bisphosphonates can ameliorate hypercalcemia in patients with inoperable disease.

The regulation of parathyroid hormone secretion and synthesis

Secondary hyperparathyroidism classically appears during the course of chronic renal failure and sometimes after renal transplantation. Understanding the mechanisms by which parathyroid hormone (PTH) synthesis and secretion are normally regulated is important in devising methods to regulate overactivity and hyperplasia of the parathyroid gland after the onset of renal insufficiency. Rapid regulation of PTH secretion in response to variations in serum calcium is mediated by G-protein coupled, calcium-sensing receptors on parathyroid cells, whereas alterations in the stability of mRNA-encoding PTH by mRNA-binding proteins occur in response to prolonged changes in serum calcium. Independent of changes in intestinal calcium absorption and serum calcium, 1α,25-dihydroxyvitamin D also represses the transcription of PTH by associating with the vitamin D receptor, which heterodimerizes with retinoic acid X receptors to bind vitamin D-response elements within the PTH gene. 1α,25-Dihydroxyvitamin D additionally regulates the expression of calcium-sensing receptors to indirectly alter PTH secretion. In 2°HPT seen in renal failure, reduced concentrations of calcium-sensing and vitamin D receptors, and altered mRNA-binding protein activities within the parathyroid cell, increase PTH secretion in addition to the more widely recognized changes in serum calcium, phosphorus, and 1α,25-dihydroxyvitamin D. The treatment of secondary hyperparathyroidism by correction of serum calcium and phosphorus concentrations and the administration of vitamin D analogs and calcimimetic agents may be augmented in the future by agents that alter the stability of mRNA-encoding PTH.

Current concepts in the management of primary hyperparathyroidism

Primary hyperparathyroidism is the commonest cause of hypercalcemia in the ambulatory setting. Widespread use of routine laboratory screening has resulted in a large number of patients presenting with subclinical disease. In truly asymptomatic patients, consensus guidelines have been developed to determine which patients need definitive treatment. The most common pathologic finding is parathyroid adenoma, followed by hyperplasia, double adenomas and parathyroid carcinoma. The mainstay of treatment is surgery. While there is still an important role for four gland exploration and evaluation, there is now considerable interest in a more focused surgical approach. This paradigm shift is based on localizing studies that combine sestamibi scanning with anatomic imaging, most commonly ultrasound scanning. A range of minimally invasive approaches have been developed to treat parathyroid adenomas, including unilateral and single gland explorations as well as a number of different endoscopic techniques. Intra-operative rapid parathormone assay has replaced histologic examination as a more effective method to confirm the adequacy of surgery in most cases. Functional localization and exploration using a gamma probe has also been described. The management of patients with persistent or recurrent hyperparathyroidism is difficult and requires a multidisciplinary approach.

Early-onset, progressive, frequent, extensive, and severe bone mineral and renal complications in multiple endocrine neoplasia type 1-associated primary hyperparathyroidism

Differences in bone mineral density (BMD) patterns have been recently reported between multiple endocrine neoplasia type 1-related primary hyperparathyroidism (HPT/MEN1) and sporadic primary HPT. However, studies on the early and later outcomes of bone/renal complications in HPT/MEN1 are lacking. In this cross-sectional study, performed in a tertiary academic hospital, 36 patients cases with uncontrolled HPT from 8 unrelated MEN1 families underwent dual-energy X-ray absorptiometry (DXA) scanning of the proximal one-third of the distal radius (1/3DR), femoral neck, total hip, and lumbar spine (LS). The mean age of the patients was 38.9 ± 14.5 years. Parathyroid hormone (PTH)/calcium values were mildly elevated despite an overall high percentage of bone demineralization (77.8%). In the younger group (<50 years of age), demineralization in the 1/3DR was more frequent, more severe, and occurred earlier (40%; Z-score -1.81 ± 0.26). The older group (>50 years of age) had a higher frequency of bone demineralization at all sites (p < .005) and a larger number of affected bone sites (p < .0001), and BMD was more severely compromised in the 1/3DR (p = .007) and LS (p = .002). BMD values were lower in symptomatic (88.9%) than in asymptomatic HPT patients (p < .006). Patients with long-standing HPT (>10 years) and gastrinoma/HPT presented significantly lower 1/3DR BMD values. Urolithiasis occurred earlier (<30 years) and more frequently (75%) and was associated with related renal comorbidities (50%) and renal insufficiency in the older group (33%). Bone mineral- and urolithiasis-related renal complications in HPT/MEN1 are early-onset, frequent, extensive, severe, and progressive. These data should be considered in the individualized clinical/surgical management of patients with MEN1-associated HPT.

Recurrent pancreatitis induced by hyperparathyroidism in pregnancy

Introduction

As primary hyperparathyroidism affects mainly middle-aged and elderly women, it is an infrequent finding during gestation and breastfeeding. To date, less than 200 pregnant patients with primary hyperparathyroidism diagnosed during pregnancy have been described. Like in other disorders of the parathyroid gland, the recognition of primary hyperparathyroidism during pregnancy and lactation may be difficult, as clinical symptoms are not specific, while laboratory findings may be masked by some typical pregnancy-induced changes in calcium and phosphate homeostasis. If remains untreated, the disease may result in serious clinical implications for the mother and fetus. Most authors consider surgery within the second trimester of pregnancy as the treatment of choice in this group of patients.

Case report

In our paper, we discuss the case of a 35-year-old female with a history of recurrent acute pancreatitis and recurrent abortions. As the patient declined surgery, conservative management with calcitonin was started and continued throughout the rest of pregnancy, and led to giving birth to the infant whose only health problem was transient hypocalcemia.

Conclusion

The described case shows that conservative management, if started respectively early and conducted on the basis of a patient’s condition, may effectively reduce increased perinatal and maternal morbidity and mortality in pregnant women declining surgery.

Clinical pharmacokinetic and pharmacodynamic profile of cinacalcet hydrochloride

Cinacalcet hydrochloride (cinacalcet) is a calcimimetic approved for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) receiving dialysis and for the treatment of hypercalcaemia in patients with parathyroid carcinoma. Following oral administration, peak plasma concentrations of cinacalcet occur within 2-6 hours. The absolute bioavailability is 20-25%, and administration of cinacalcet with low- or high-fat meals increases exposure (area under the plasma concentration-time curve from time zero to infinity [AUC(infinity)]) 1.5- to 1.8-fold. Cinacalcet has no significant interaction with calcium carbonate or sevelamer hydrochloride, phosphate binders commonly used in the treatment of patients with CKD receiving dialysis. The terminal elimination half-life is 30-40 hours, and steady-state concentrations are achieved within 7 days. The pharmacokinetics of cinacalcet are dose proportional over the dose range of 30-180 mg. The pharmacokinetic profile of cinacalcet is not notably affected by varying degrees of renal impairment. The pharmacokinetics of cinacalcet are comparable between healthy subjects, patients with primary hyperparathyroidism and patients with secondary hyperparathyroidism with reduced renal function (including those patients with secondary hyperparathyroidism receiving dialysis). Additionally, the pharmacokinetics of cinacalcet are similar in patients with secondary hyperparathyroidism receiving haemodialysis and patients with secondary hyperparathyroidism receiving peritoneal dialysis. Mild hepatic impairment does not affect the pharmacokinetics of cinacalcet, whereas moderate or severe hepatic impairment increases the exposure (AUC(infinity)) by approximately 2- and 4-fold, respectively. Age, sex, bodyweight and race do not notably affect the pharmacokinetics of cinacalcet. Cinacalcet is extensively metabolized by multiple hepatic cytochrome P450 (CYP) enzymes (primarily 3A4, 2D6 and 1A2) with <1% of the parent drug excreted in the urine. Dose adjustments of cinacalcet may be necessary, and parathyroid hormone (PTH) and serum calcium concentrations should be closely monitored if a patient initiates or discontinues therapy with a strong CYP3A4 inhibitor (e.g. ketoconazole, erythromycin, itraconazole). Cinacalcet is a strong inhibitor of CYP2D6; therefore, dose adjustment of concomitant medications that are predominantly metabolized by CYP2D6 and have a narrow therapeutic index (e.g. flecainide, vinblastine, thioridazine and most tricyclic antidepressants) may be required. Cinacalcet does not appreciably inhibit or induce the activities of CYP3A4, 1A2, 2C9 or 2C19. An inverse relationship exists between plasma PTH and cinacalcet concentrations. PTH concentrations are greatest before dose administration when the cinacalcet concentration is lowest (24 hours after the previous day's dose). Nadir PTH levels occur approximately 2-3 hours after dosing.

Parathyroid surgery in pregnancy: review of the literature and localization by aspiration for parathyroid hormone levels

OBJECTIVE

To review the management of primary hyperparathyroidism in pregnant women by focusing on the use of preoperative localization procedures and minimally invasive parathyroid surgery during pregnancy.

STUDY DESIGN

We report the clinical course of two pregnant women with severe hypercalcemia due to primary hyperparathyroidism, as well as review the literature.

RESULTS

Primary hyperparathyroidism in pregnant women is associated with high prevalence of maternal and neonatal complications. In women, with severe hypercalcemia, parathyroid surgery during pregnancy reduces fetal and maternal morbidities. Preoperative localization of parathyroid adenomas during pregnancy remains challenging. In selected cases aspiration of nodules suspected of being parathyroid adenomas with the measurement of the parathyroid hormone (PTH) from the aspirate can localize the adenoma, and allow the surgeon to carry out a minimally invasive parathyroidectomy.

CONCLUSION

Localization of a suspected parathyroid adenoma by ultrasound-guided aspiration of a lesion and the measurement of the PTH has previously been described in non-pregnant women. Our review of the literature did not identify any previous case of a pregnant woman with primary hyperparathyroidism, where preoperative localization of a parathyroid adenoma was accomplished by aspiration of a suspected lesion followed by a successful minimally invasive parathyroidectomy carried out during pregnancy.

Effect of surgery on cardiovascular risk factors in mild primary hyperparathyroidism

CONTEXT

Mild primary hyperparathyroidism (pHPT) seems to have a good prognosis, and indications for active treatment (surgery) are widely discussed. The extraskeletal effects of PTH, such as insulin resistance, arterial hypertension, and cardiovascular (CV) risk, may however be reversible by operation.

OBJECTIVE

Our aim was to study biochemical markers of bone turnover, indices of the metabolic syndrome, and various risk markers for CV disease in patients with mild pHPT randomized to observation without surgery or operative treatment and followed for 2 yr.

DESIGN/SETTING/PATIENTS

A total of 116 patients (mean age, 63 +/- 8 yr; 19 men and 97 women) who on May 1, 2008, had performed the 2-yr visit in a randomized study on mild pHPT (serum calcium at baseline, 2.69 +/- 0.11 mmol/liter) and where frozen samples were available from baseline and follow-up participated in the study.

RESULTS

Calcium and PTH levels were normalized after surgery, and biochemical markers of bone turnover decreased by 35%, followed by a significant increase in BMD in the spine (2.7%; P < 0.01) and femoral neck (1.1%; P < 0.02) compared with the observation group. No significant differences were observed between the groups for blood pressure, markers of insulin resistance, detailed cholesterol metabolism, adipokines, or parameters of inflammation and CV surrogate markers.

CONCLUSIONS

We observed expected effects on biochemical markers of bone turnover and bone mass after surgical treatment of mild pHPT, with stable values in the group randomized to observation. For a variety of measures of the metabolic syndrome, adipokines, and CV risk factors, no benefit of operative treatment could be demonstrated. Neither did we observe any deleterious effects of conservative management in the 2-yr perspective.

Nuclear imaging and minimally invasive surgery in the management of hyperparathyroidism

Primary hyperparathyroidism is the most common cause of hypercalcemia, and the treatment is primarily surgical. Because of biochemical screening, more patients now present with asymptomatic primary hyperparathyroidism, and consensus guidelines have been developed for the treatment of these patients. There is now considerable interest in minimally invasive approaches to the treatment of hyperparathyroidism. Sestamibi scanning as a localizing study, used in combination with anatomic imaging and intraoperative rapid parathyroid hormone assays, has enabled focused surgical approaches. Patients with localizing studies that indicate a single parathyroid adenoma are candidates for such approaches, including unilateral neck exploration, minimally invasive single-gland exploration, or endoscopic exploration instead of the traditional approach of bilateral neck exploration. Nuclear imaging is also critical to the successful management of patients with persistent or recurrent hyperparathyroidism.

New strategies for the treatment of hyperparathyroidism incorporating calcimimetics

BACKGROUND

Hyperparathyroidism (HPT), characterised by increased parathyroid hormone (PTH) secretion and parathyroid hyperplasia, can be caused by physiologic defects in the parathyroid gland (primary HPT [PHPT]) or as a consequence of declining renal function (secondary HPT [SHPT]).

OBJECTIVE

To review the safety and efficacy of cinacalcet in the treatment of SHPT and PHPT.

METHODS

Studies indexed in NLM/PubMed investigating the safety, efficacy, and pharmacokinetics of cinacalcet for PHPT and SHPT and supporting preclinical evidence.

RESULTS/CONCLUSION

Recent evidence has demonstrated the efficacy of the calcimimetic cinacalcet in the treatment of PHPT and SHPT. Compared with traditional therapies such as vitamin D sterols and phosphate binders, cinacalcet treatment can allow an increased proportion of patients with SHPT to improve Kidney Disease Outcomes Quality Initiative (KDOQI) Bone Metabolism and Disease laboratory parameter target attainment. Recent evidence suggests that improvements in these biochemical parameters with cinacalcet can translate into improved morbidity and mortality. Cinacalcet lowers PTH and calcium in patients following renal transplantation, and also normalises serum calcium in patients with PHPT. Ongoing studies are focusing and future studies are likely to focus on the effect of cinacalcet on clinical outcomes and on novel strategies for the integration of cinacalcet with traditional therapies to improve serum PTH and mineral metabolism control.

Development of Transgenic Chickens Expressing Human Parathormone Under the Control of a Ubiquitous Promoter by Using a Retrovirus Vector System

Transgenic chickens, ubiquitously expressing a human protein, could be a very useful model system for studying the role of human proteins in embryonic development as well as for efficiently producing pharmaceutical drugs as bioreactors. Human parathormone (hPTH) secreted from parathyroid glands plays a significant role in calcium homeostasis and is an important therapeutic agent for the treatment of osteoporosis in humans. Here, by using a robust replication-defective Moloney murine leukemia virus-based retrovirus vector encapsidated with vesicular stomatitis virus G glycoprotein, we generated transgenic chickens expressing hPTH under the control of a ubiquitous Rous sarcoma virus promoter. The recombinant retrovirus was injected into the subgerminal cavity of freshly laid eggs at the blastodermal stage. After 21 d of incubation, 42 chicks hatched from 473 retrovirus-injected eggs. All 42 living chicks were found to express the vector-encoded hPTH gene in diverse organs, as revealed by PCR and reverse transcription-PCR analysis by using primer pairs specific for hPTH. Four days after hatching, 6 chicks died and 14 chicks showed phenotypic deformities. At 18 wk of age, only 3 G(0) chickens survived. They also released the hPTH hormone in their blood and transmitted the hPTH gene to G(1) embryos. However, although the embryos were alive at d 18 of incubation, none hatched. An electrochemiluminescence immunoassay further showed that the hPTH expression level was markedly elevated in mammalian cells infected by the retrovirus vector. Thus, we demonstrated that transgenic chickens, expressing a human protein under the control of a ubiquitous promoter, not only could be an efficient bioreactor for the production of pharmaceutical drugs, but also could be useful for studies on the role of human proteins in embryonic development. To our knowledge, this is the first report on the production of a human protein (hPTH) in transgenic chickens under the control of a ubiquitous promoter by using a replication-defective Moloney murine leukemia virus-based retrovirus vector system.

Surgery or surveillance for mild asymptomatic primary hyperparathyroidism: a prospective, randomized clinical trial

CONTEXT

It is unclear whether patients with asymptomatic primary hyperparathyroidism (PHPT) do better with parathyroidectomy (PTx) as compared with conservative medical management.

OBJECTIVE

The aim of the study was to evaluate the beneficial effect of PTx vs. conservative management in patients with mild asymptomatic PHPT.

DESIGN

We conducted a prospective, randomized study.

SETTING

The study took place at a referral center.

PATIENTS

We studied 50 patients who did not meet any guidelines for parathyroid surgery as recommended by the National Institutes of Health Consensus Development Conference on Asymptomatic PHPT.

INTERVENTION

Patients were randomly assigned to PTx or no PTx and were evaluated at 6 months and at 1 yr.

MAIN OUTCOME MEASURES

We compared changes (percentage of basal) of lumbar spine bone mineral density (BMD) between the two groups at 1 yr.

RESULTS

The change in BMD at lumbar spine was greater after PTx (+4.16 +/- 1.13 for PTx vs. -1.12 +/- 0.71 for no PTx; P = 0.0002). The change in BMD at the total hip was also significantly greater in the PTx group (+2.61 +/- 0.71 for PTx vs. -1.88 +/- 0.60 for no PTx; P = 0.0001). There was no difference in BMD after 1 yr between both groups at the one-third radius site. In comparison with those who did not undergo surgery, the PTx subjects, after 1 yr, showed significant differences in four quality of life measures as determined by the 36-item short form health survey scale: bodily pain (P = 0.001), general health (P = 0.008), vitality (P = 0.003), and mental health (P = 0.017).

CONCLUSIONS

In patients with mild asymptomatic PHPT, successful PTx is followed by an improvement in BMD and quality of life. Most patients followed without surgery did not show evidence of progression.

[Surgical resection of the thyroid and parathyroid glands]

The main indication for surgery of the thyroid gland is the resection of nodular, suspicious or hyperfunctioning tissue. Following thyroidectomy, L-thyroxine therapy is initiated adjusted to the remnant thyroid function. To prevent recurrence of a multinodular goiter, supplementation with iodine is strongly recommended. The management of patients with differentiated thyroid cancer depends on risk stratification. Although large prospective studies are missing, low-risk patients probably do not benefit from total thyroid ablation and lifelong thyroxine suppression therapy. As a result of impaired parathyroid function or resection of the parathyroid glands for hyperparathyroidism, acute or chronic hypocalcaemia can develop. If treatment with oral calcium is insufficient, the addition of a vitamin D analogue is necessary. This requires close monitoring to avoid renal or other hypercalcaemic complications.

[Hypercalcemia of double origin: association of multiple myeloma and ectopic parathyroidal adenoma]

INTRODUCTION

Multiple myeloma and primary hyperparathyroidism are two causes of hypercalcemia. This association has already been described to be not casual, despite their link is still unknown.

OBSERVATION

We describe a 68 years old woman, without notable background, was admitted for low back pain. Biology showed an IgG Kappa multiple myeloma (stade 3) and an hypercalcemia without renal failure. Hypercalcemia was difficult to control with bisphosphonate and calcitonin. At first, there was also an hypophosphoremia and a high parathormone level (287 pg/ml). Imaging showed spread myeloma impairment and a right paramediastinal tissular mass. Biopsy diagnosed an ectopic parathyroidal adenoma.

DISCUSSION

Multiple myeloma and primary hyperparathyroidism can be associated. They are often revealed by an hypercalcemia difficult to control or refractory to the treatment. Hypophosphoremia can suggest the diagnosis of hyperparathyroidism. Both this observation and litterature (about twenty case reports) suggest that this double diagnosis should be systematicly evoked and explored by an assay of parathormone and a seric proteins electrophoresis in all hypercalcemia.

CONCLUSION

Multiple myeloma and parathyroidal adenoma should be both explored in all hypercalcemia, because they can be associated.