Skeletal effects of primary hyperparathyroidism

A 15-year experience: intraoperative parathyroid hormone assay for the management of primary hyperparathyroidism in a UK endocrine surgical unit

PURPOSE

This study aims to evaluate the outcomes of first-time parathyroidectomy for primary hyperparathyroidism using intraoperative PTH (IOPTH) assay in the light of the UK National Institute for Health and Care Excellence (NICE) guidelines for the management of primary hyperparathyroidism.

METHOD

This is a retrospective cohort analysis of a prospectively maintained database of endocrine surgery in a tertiary centre. Preoperative radiological localisation (concordance and accuracy), intraoperative PTH parameters and adjusted serum calcium at minimum 6-month follow-up were analysed. The accuracy of IOPTH to predict post-operative normocalcaemia and the number needed to treat (NNT) within the cohort when IOPTH was utilised were determined. Differences between groups were evaluated with Chi-squared and Fisher's exact test.

RESULTS

Between January 2004 and September 2018, 849 patients (75.4% women), median age 64 years (IQR 54-72), were analysed. The median preoperative adjusted serum calcium was 2.80mmol/l (IQR 2.78-2.90), and the median preoperative PTH was 14.20pmol/l (IQR 10.70-20.25). The overall first-time cure (normocalcaemia) rate was 96.4%. The sensitivity, specificity, positive predictive value and negative predictive values of IOPTH were 96.8%, 83.2%, 97.6% and 78.8%, respectively, with an accuracy of 95.1%. For patients with concordant scans (48.3%), a targeted approach without IOPTH would have achieved a cure rate of 94.1% compared with 98.0% using IOPTH (p<0.01) CONCLUSION: The use of IOPTH assay significantly improved the rate of normocalcaemia at 6 months. The low NNT to benefit from IOPTH, particularly those patients with a single positive scan, and the inevitable reduction in the potential costs incurred from failure and reoperation justify its utilisation.

Management of Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is the unregulated overproduction of parathyroid hormone (PTH) resulting in abnormal calcium homeostasis. The disease profile has evolved over the last century from symptomatic hyperparathyroidism to asymptomatic hyperparathyroidism. Primary hyperparathyroidism is a biochemical diagnosis. Parathyroidectomy is the only established cure for this disease. Every effort is made to localize the offending gland preoperaively with various imaging modalities. These localization studies along with intraoperative parathormone monitoring will direct the surgeon to either a focused parathyroidectomy or a four gland exploration. All symptomatic patients and asymptomatic patients who meet the criteria for surgery should undergo parathyroidectomy if no medical contraindications exist. Pharmacologic approaches are reserved for those patients unfit or unwilling to undergo surgery.

Primary Hyperparathyroidism in the Common Orthopaedic Practice

An extensive review of the publications on primary hyperparathyroidism (pHPT) is presented in this report. It has strongly been emphasized in the literature that patients with pHPT may present either with the classical symptomatology or with asymptomatic disease, emerged due to biochemical screening. The clinical and epidemiological presentation of pHPT in western countries has changed profoundly during the past few decades, and bone disease is nowadays a distinct rarity. The introduction of serum calcium screening for osteoporosis and the technological advances in the laboratory assessment of parathyroid hormone have played important roles in early diagnosis. Subsequently, the disease is increasingly being detected as asymptomatic hypercalcaemia without guiding signs or symptoms. A third type of disease, the normocalcaemic variant, has been recently described in the literature. However, the potential diagnosis of pHPT should always be on the orthopaedics’ list of differential diagnoses in female or elderly patients with vertebral fractures and nephrolithiasis, either symptomatic or asymptomatic, as well as when solitary or multiple osteolytic lesions are encountered on the radiographs.

Additionally, a middle aged woman with parathyroid adenoma and subsequent brown tumors detected on the pelvic radiographs is reported. Her initial laboratory findings indicated a minimal increase of the serum calcium, a mild increase of the erythrocyte sedimentation rate, and a significant increase in total serum alkaline phosphatase. Finally, the detection of elevated parathyroid hormone levels indicated the diagnosis of pHPT and necessitated imaging studies of the parathyroid glands, which indicated a parathyroid adenoma. Following successful excision of the parathyroid adenoma, the patient suffered from the hungry bone syndrome. After a follow-up of 20 years, the patient had normal calcium, vitamin D, and parathyroid hormone serum levels, while a pelvic radiograph indicated no significant changes in the appearance of the brown tumors.

Primary Hyperparathyroidism in the Common Orthopaedic Practice

An extensive review of the publications on primary hyperparathyroidism (pHPT) is presented in this report. It has strongly been emphasized in the literature that patients with pHPT may present either with the classical symptomatology or with asymptomatic disease, emerged due to biochemical screening. The clinical and epidemiological presentation of pHPT in western countries has changed profoundly during the past few decades, and bone disease is nowadays a distinct rarity. The introduction of serum calcium screening for osteoporosis and the technological advances in the laboratory assessment of parathyroid hormone have played important roles in early diagnosis. Subsequently, the disease is increasingly being detected as asymptomatic hypercalcaemia without guiding signs or symptoms. A third type of disease, the normocalcaemic variant, has been recently described in the literature. However, the potential diagnosis of pHPT should always be on the orthopaedics’ list of differential diagnoses in female or elderly patients with vertebral fractures and nephrolithiasis, either symptomatic or asymptomatic, as well as when solitary or multiple osteolytic lesions are encountered on the radiographs.

Additionally, a middle aged woman with parathyroid adenoma and subsequent brown tumors detected on the pelvic radiographs is reported. Her initial laboratory findings indicated a minimal increase of the serum calcium, a mild increase of the erythrocyte sedimentation rate, and a significant increase in total serum alkaline phosphatase. Finally, the detection of elevated parathyroid hormone levels indicated the diagnosis of pHPT and necessitated imaging studies of the parathyroid glands, which indicated a parathyroid adenoma. Following successful excision of the parathyroid adenoma, the patient suffered from the hungry bone syndrome. After a follow-up of 20 years, the patient had normal calcium, vitamin D, and parathyroid hormone serum levels, while a pelvic radiograph indicated no significant changes in the appearance of the brown tumors.

Primary Hyperparathyroidism in Pregnancy: Literature Review of the Diagnosis and Management

Background: Parathyroid disease is uncommon in pregnancy. During pregnancy, multiple changes occur in the calcium regulating hormones which may make the diagnosis of primary hyperparathyroidism more challenging. Close monitoring of serum calcium during pregnancy is necessary in order to optimize maternal and fetal outcomes. In this review, we will describe the diagnosis and management of primary hyperparathyroidism during pregnancy. Methods: We searched MEDLINE, CINAHL, EMBASE and Google scholar bases from 1 January 1990 to 31 December 2020. Case reports, case series, book chapters and clinical guidelines were included in this review. Conclusions: Medical management options for primary hyperparathyroidism during pregnancy are severely limited due to inadequate safety data with the various potential therapies available, and surgery is advised during the 2nd trimester of pregnancy in the presence of severe hypercalcemia (calcium adjusted for albumin greater than 3.0 mmol/L (12.0 mg/dL)). Hypercalcemia should be avoided during pregnancy in order to minimize maternal and fetal complications.

Primary Hyperparathyroidism: A Narrative Review of Diagnosis and Medical Management

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

Minimally invasive parathyroid carcinoma-A missing entity between parathyroid adenoma and carcinoma: Scintigraphic and histological features

PURPOSE

Minimally invasive parathyroid carcinoma (MIPC) is clinically and biochemically comparable with parathyroid adenoma (PA) though histopathologically differ from PA. MIPC is an intermediate of PA and parathyroid carcinoma (PC). In literature, there is no definite criterion to diagnose MIPC. Our aim was to evaluate and characterize the imaging and biochemical parameters with histological characteristics of MIPC.

METHODOLOGY

Ten patients with MIPC were recruited from (single centre) Indian PHPT registry (www.indianphptregistry.com) from January 2014 to July 2018. Clinical, biochemical, imaging and histological features of MIPC patients were reviewed.

RESULTS

The mean age of MIPC patients (n = 10; 3 males) was 39.9 ± 11.3 years (range: 17-50). All patients had an elevated preoperative parathyroid hormone (iPTH) level ranging from 427 to 2138 pg/mL (median: 1328). MIBI scan showed intensely avid and enlarged parathyroid tumours in all patients; LIPT in 6, RIPT in 3 and ectopic mediastinal in 1 with mean size of the tumours was 2.8 ± 1.1 cm. The mean of maximum standardized uptake value (SUVmax) of MIPC in F-18 fluorocholine PET/CT was 6.7 ± 1.1 (range 6.0-8.3). The mean tumour weight was 12 ± 9.5 g (range: 1.09-28). All MIPC patients had identified capsular invasion in 80% and vascular invasion in 50% only but there was no local invasion, lymph nodal or distant metastasis. The mean Ki-67 labelling index was 3.2 ± 2.7 (range 1.1-10).

CONCLUSION

The study concluded that MIPC patients are less aggressive (on the basis of imaging and histopathological findings) and should be differentiated from parathyroid adenoma and carcinoma.

Prevalence and Risk of Vertebral Fractures in Primary Hyperparathyroidism: A Nested Case-Control Study

Prevalence of vertebral fractures (VFx) in primary hyperparathyroidism (PHPT) remains uncertain. We aimed to estimate the prevalence of VFx, investigate potential risk factors associated with VFx, and whether bone mineral density (BMD) differs between PHPT and osteoporotic patients with VFx. Through the Danish National Patient Register, we identified patients diagnosed with PHPT from 2005 to 2015. The diagnosis was verified by reviewing biochemical findings, and X-ray reports were reviewed by two investigators. Osteoporotic patients with VFx were identified from our outpatient clinic and matched on age and sex with PHPT patients with VFx. We identified 792 PHPT patients among whom spine X-ray was available from 588 patients. VFx were present in 122 (21%) patients and were equally frequent among sexes (77% females). Fractured patients were older (70 versus 63 years) and had lower heights (163 versus 166 cm) compared with nonfractured patients (p all < 0.02). After stratification by age groups, the prevalence of VFx differed significantly between sexes (p < 0.01). Ionized calcium and parathyroid hormone did not differ between groups. BMD at total hip and forearm were lower in fractured compared with nonfractured patients (p < 0.03 for both) after adjusting for age, sex, and body mass index (BMI). Compared with osteoporotic patients with VFx (n = 108), BMD at the lumbar spine was higher in PHPT patients with VFx (n = 108) (p < 0.01). This did not change by excluding patients with lumbar VFx (p < 0.01). The severity of PHPT assessed by biochemistry does not seem to be associated with risk of VFx. Compared with osteoporosis, VFx seems to occur at a higher BMD in PHPT. © 2018 American Society for Bone and Mineral Research.

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

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

The effect of endogenous parathyroid hormone in iliac bone structure and turnover in healthy postmenopausal women

Little is known about the effect of endogenous parathyroid hormone (PTH) on the skeleton in postmenopausal women without hyperparathyroidism. In this study, the effects of PTH on bone were investigated in iliac crest biopsies obtained from 37 healthy white postmenopausal women aged 50-73 years. The results showed that neither cancellous nor cortical bone structure changed with serum PTH levels. In cancellous bone, bone formation (wall thickness, osteoid surface, osteoblast surface, mineralizing surface, and mineral apposition rate) and turnover (bone formation rate at the surface, volume levels, and activation frequency) variables increased with increasing serum PTH levels (all p < 0.05) in univariate analysis. Multiple linear regressions, adjusted for serum 25-OHD, calcium, alkaline phosphatase, age, and BMI, showed that serum PTH level was independently associated with wall thickness, osteoid surface, osteoblast surface, mineralizing surface, and bone formation rate (all p < 0.05). In cortical bone, no histomorphometric variable was correlated with PTH levels. On the endosteal surface, some of the bone formation (osteoid surface, osteoblast surface, mineralizing surface) and turnover (bone formation rate at the bone surface levels and activation frequency) variables were positively correlated with PTH levels (all p < 0.05). None of these variables could be independently predicted by PTH status. We conclude that in healthy postmenopausal women endogenous PTH has a positive effect on bone formation on the cancellous surface. The effects of PTH on the endosteal surface are probably confounded by other factors.

Primary hyperparathyroidism with brown tumor mimicking metastatic bone malignancy

Bone and joint pain are commonly encountered conditions in daily practice. In the elderly, when osteolytic lesions are identified in imaging studies, metastatic bone tumor is the first impression that comes to the clinician's mind. Although the worst-case scenario should be ruled in, other differential diagnoses such as metabolic bone disease should be considered as well. We report a case of brown tumor caused by parathyroid adenoma. The patient had initial presentation of diffuse bone pain and multiple osteolytic lesions on imaging studies similar to metastatic bone tumor. With a systematic approach and awareness of metabolic bone disease, an accurate diagnosis was finally reached. Appropriate treatments, including preventive internal fixation of the impending femoral fracture and surgical excision of the parathyroid adenoma were performed accordingly. The key treatment for the condition was surgical excision of the parathyroid adenoma. After normalization of serum intact-parathyroid hormone level, the bony lesions resolved and required no further orthopedic surgery. The patient is now symptom-free. In addition to suspecting malignancy, the clinician should be highly alert to other possible causes of bony lesions. Brown tumor should be kept in mind during daily practice.

Secondary osteoporosis: a review of the recent evidence

OBJECTIVE

To review several causes of secondary osteoporosis as well as screening recommendations for underlying disorders.

METHODS

We conducted a review of the literature on many of the causes of osteoporosis that have been published during the past 15 years, focusing on those sources available from 2000 through the present. Indeed, more than two-thirds of the articles that we reviewed were printed during the past 6 years. These reports examined secondary osteoporosis in general, as well as many of the specific causes.

RESULTS

Secondary osteoporosis occurs in almost two-thirds of men, more than half of premenopausal and perimenopausal women, and about one-fifth of postmenopausal women. Its causes are vast, and they include hypogonadism, medications, hyperthyroidism, vitamin D deficiency, primary hyperparathyroidism, solid organ transplantation, gastrointestinal diseases, hematologic diseases, Cushing's syndrome, and idiopathic hypercalciuria. These causes have their own pathogenesis, epidemiologic features, and effect on the skeleton.

CONCLUSION

The causes of secondary osteoporosis are numerous, and an understanding of their characteristics with respect to bone density and potential fracture risk is essential in the management of osteoporosis. A heightened awareness of the possibility of their existence is necessary to provide optimal care.

Standards for performing DXA in individuals with secondary causes of osteoporosis

This document addresses skeletal health assessment in individuals with secondary causes of osteoporosis. Recommendations are based on consensus of the Canadian Panel of the International Society for Clinical Densitometry and invited international experts. Bone mineral density (BMD) testing in these populations is performed in conjunction with careful evaluation of the disease state contributing to bone loss and increased fragility fracture risk, as well as assessment of other contributing risk factors for fracture. The presence of secondary causes of bone loss may further increase the risk of fracture independently of BMD and may necessitate earlier pharmacologic intervention. Dual-energy X-ray absorptiometry is indicated in the initial workup of secondary causes of osteoporosis. The BMD fracture risk relationship is not known for individuals with chronic renal failure (CRF). The BMD testing in this population may be normal in the presence of skeletal fragility, and quantitative bone histomorphometry is better at evaluating skeletal status than BMD in CRF. Dual-energy X-ray absorptiometry is a valuable tool in assessing skeletal health in individuals with secondary causes of osteoporosis.

Primary hyperparathyroidism in north India: a description of 52 cases

BACKGROUND

Primary hyperparathyroidism (PHPT) has a variable clinical expression. Symptomatic PHPT is still the predominant form of the disease in many parts of the world, especially developing countries. Because the clinical profile of the disease has changed from that described in the past, we sought to improve our understanding of the disease in patients in north India.

METHODS

We summarized the clinical presentation, biochemical and radiological features, and operative findings from the case records from the last 13 years of 52 patients at a tertiary care centre in north India who had documented PHPT.

RESULTS

The male: female ratio was 1: 3.3 with ages ranging from 6 to 60 years (mean +/- SD, 36.38 +/- 12.73). Bone disease (46%), recurrent renal stones (21%) and body aches and pains (21%) were the most common modes of presentation. The lag time varied ranged from 1 month to 16 years. Common clinical manifestations included bone pain (67%), weakness/fatigue (56%), fracture of the long bones (48%), abdominal pain (39%), polyuria (37%) and psychiatric manifestations (23.1%). Hypertension was observed in 42% and a palpable nodule in the neck in 19%. Biochemical features included hypercalcemia (86.5%), hypophosphatemia (65.4%) and hyperphosphatasia (67.3%). Mean intact PTH ( +/- SD) was 809.0 +/- 696.3 ng/L with levels significantly lower in patients who had only kidney stone disease as compared with those with bone disease (P = 0.017). A single parathyroid adenoma was localized in 50 (98%) patients. Hungry bone disease was seen in 59% patients.

CONCLUSION

PHPT in India continues to be a symptomatic disorder with skeletal and renal manifestations at a much younger age.

Recovery pattern of patients with osteitis fibrosa cystica in primary hyperparathyroidism after successful parathyroidectomy

BACKGROUND

After parathyroidectomy, recovery of osteitis fibrosa cystica, which continues to dominate presentation of primary hyperparathyroidism in India has not been documented objectively.

METHODS

We followed up clinical recovery, biochemic markers of bone turnover, bone mineral density, and skeletal radiology in 51 patients with primary hyperparathyroidism and osteitis fibrosa cystica for 9 to 124 months (median, 32 months).

RESULTS

After parathyroidectomy, 46 patients had hypocalcemia. During postoperative week 1, bone pain improved in 71%. During 3 months, appendicular fractures healed in all 33 such patients, and 6 of 7 patients who were bedridden could walk. Mean bone mineral density increments (percent change/y) seen at various sites at 1 week, 3, 6, and 12 months were distal forearm--37, 28, 23, 21; lumbar spine--165, 104, 101, 106; and total hip--168, 157, 166, 133. Follow-up radiographs demonstrated prompt recovery though disorderly remineralization. Brown tumors and fractures showed hyperdensities within 3 months. Brown tumors regressed partially in 6 of 27 patients after 6 months.

CONCLUSIONS

After parathyroidectomy, patients with primary hyperparathyroidism have early, marked, and sustained recovery of osteitis fibrosa cystica. Early (1 week) bone mineral density increments of > 100%/y hint at the skeleton's ability to promptly restore itself. Densitometric recovery is prompt at cancellous (lumbar spine), but not at cortical (forearm) bone sites. Contour defects and bony tumors persist, and may need corrective osteotomies.

Bone densitometry: applications and limitations

Osteoporosis is clinically diagnosed in its advanced stages, usually following a fracture. Accurate, precise, and noninvasive skeletal assessment is now possible for early detection of osteoporosis at a preclinical stage. Currently, the gold standard in bone mass measurement and fracture prediction is dual energy X-ray absorptiometry (DEXA) of the hip and spine. Exponential increases in fracture risk have been observed with small decreases in bone mineral density. Bone mineral density (BMD) should be considered in conjunction with independent clinical risk factors for fracture, including: low body weight, history of postmenopausal fracture, family history of fracture, and poor neuromuscular function. The World Health Organization (WHO) diagnostic criteria for osteoporosis and osteopenia are appropriate for postmenopausal Caucasian women and are applicable to DEXA assessments at the hip, spine, or forearm. This review explores the relationship between BMD and fracture risk, the principles of bone densitometry interpretation, and the applications as well as the limitations of DEXA technology, and presents cases illustrating common errors seen in the interpretation of DEXA studies.

The spectrum of radiographic findings in primary hyperparathyroidism

The aim of this study was to assess the spectrum of radiographic findings in primary hyperparathyroidism (PHPT). The study group consisted of 16 women and 7 men whose Ca levels were at least two or three times higher than normal. The average age was 55.3 in women and 49.4 in men. We detected carcinoma in 1, hyperplasia in 1, multiple adenomas in 4, single adenoma in 17 patients. The most common finding in the skeletal system was the decreased bone mineral density (BMD) and the complete loss of the lamina durae dentium. BMD was found lower in women than in men. This result attributed the increased number of postmenopausal patients in our study group. The second most common finding in our study group was subperiosteal bone resorption. Brown tumors (BTs) were located at maxilla in one, widespread in one, mandibula in two, long tubular bones in four patients. Renal stone disease was found in five, spastic colon in two, gastric ulcer in one, mitral valve calcification in one patients. We demonstrated no pathologic changes consistent with PHPT in remaining seven patients.

Association among age, height, weight, and body mass index with discordant regional bone mineral density

Patients with osteoporosis have a body mass index (BMI) that is significantly lower than patients with normal bone mineral density (BMD). This study was conducted to examine the associations among age, height, weight, and BMI in patients with discordant regional BMD. For the purpose of this study, discordant regional BMD was defined as having a BMD result that is in the osteoporotic range at one site while being normal at the other sites. Data from 7513 qualifying bone densitometry scans from a suburban Detroit osteoporosis testing center were analyzed. A patient was classified as having generalized osteoporosis if the T-score was < 2.5 at the lumbar spine, femoral neck, and distal radius and normal if the T-score was > 1 at the same three sites. Patients were determined to have discordant low BMD when the T-score was < 2.5 at one site while the T-score was > 1 at the other two sites. Patients with generalized osteoporosis were older (mean age: 72.2 vs 54.7 yr; p < 0.001), shorter (height: 153.1 vs 161.7 cm; p < 0.001) and had lower BMI (23.7 vs 28.5 kg/m(2); p < 0.001) compared with patients with normal BMD. The distal radius was the site where discordant osteoporosis was most prevalent (70 patients, 0.9%). Patients with isolated low distal radius BMD were similar in age (mean age: 70.4 vs 72.2. yr; p = NS), but were taller (height: 158.6 vs 153.1 cm; p < 0.001) and had BMI values that were significantly higher (BMI: 28.7 vs 23.7 kg/m(2); p < 0.001) than patients with generalized osteoporosis. Patients with discordant BMD at the distal radius had anthropometric characteristics that were significantly different from patients with generalized osteoporosis. These differences may represent differences in the etiology of osteoporosis and differential effects on cortical vs trabecular bone.