Preoperative normal level of parathyroid hormone signifies an early and mild form of primary hyperparathyroidism

Relationship between parathyroid adenoma size, weight and histological subtypes with perioperative serum levels

AIMS

This study aims to identify associations between parathyroid adenoma (PTA) characteristics (histology, weight and size) with the change in parathyroid hormone (PTH) and calcium levels.

METHODS

A historical cohort study was conducted on adult patients with solitary PTA removed in the Gold Coast Health Precinct, Australia, between 2017 and 2022.

RESULTS

PTA weight is correlated with the change in day 1 PTH level (r=0.26, p=0.036), the change in day 1 corrected calcium level (r=0.20, p=0.033), and the change in follow-up corrected calcium level (r=0.47, p<0.001). The largest dimension (size) of PTA is also correlated with the change in day 1 PTH (r=0.30, p=0.011) and the change in follow-up corrected calcium level (r=0.40, p<0.001). Adjusted for age and gender, a statistically significant negative correlation was found between day 1 PTH level and adenoma size, resulting in a 0.5% change in size for every percentage change in PTH level (equating to a 5.0% increase in variance explained, p=0.038). Similarly, a negative correlation was identified in day 1 corrected calcium levels and weight, with a 4.7% change in weight for every percentage of change in day 1 corrected calcium level (an increase of 5.6% variance explained, p=0.010). In addition, a negative correlation was identified, where every 3.1% change in size (an increase of 17.4% variance explained, p<0.001) and 7.6% change in weight (an increase of 22.7% variance explained, p<0.001) was seen with every percentage change in follow-up corrected calcium levels. Clear-cell PTA had the most significant percentage fall in day 1 corrected calcium levels compared with other PTA subtypes (p=0.007).

CONCLUSIONS

Preoperative calcium and PTH levels correlate with PTA weight and size. The degree of change in postoperative corrected calcium levels behaved differently in the clear-cell subtype.

Intraoperative Parathyroid Hormone Monitoring In Normohormonal Primary Hyperparathyroidism: How Low Do You Go?

OBJECTIVE

The primary goal of this study was to determine in patients with normohormonal primary hyperparathyroidism (NHHPT) what percent reduction in post-excision intraoperative parathyroid hormone (IOPTH) from baseline would yield a rate of cure comparable to that in patients with classical primary hyperparathyroidism (PHPT).

METHODS

This is a retrospective cohort study of patients who underwent parathyroidectomy between July 2013 and February 2020. Demographic data, preoperative, intraoperative, and postoperative metrics were collected. Patients with NHHPT were compared to those with classical PHPT. Subgroup analyses were performed.

RESULTS

Of the 496 patients included in the study, 66 (13.3%) were of the normohormonal variant based on preoperative intact parathyroid hormone (PTH) levels and 28 (5.6%) based on baseline IOPTH levels. The cure rates in the two normohormonal groups were not significantly different from their classical counterparts (98.4% and 100.0% vs. 97.1%, p = 1.000). The median percent decline in post-excision IOPTH from baseline that achieved cure in the normohormonal groups were 82.6% and 80.4% compared to their respective controls at 87.3%, p = 0.011 and p = 0.001. Although the rate of multiglandular disease was higher in one of the normohormonal variant groups, this difference was due to a higher rate of double adenomas, not four-gland hyperplasia.

CONCLUSION

Patients with NHHPT undergoing parathyroidectomy can expect cure rates similar to that in patients with classical PHPT. The results of this study indicate that achieving an 80% drop or more in IOPTH levels predicts a high likelihood of cure. This is true irrespective of whether the patient is deemed normohormonal based on preoperative or intraoperative testing.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2480-2484, 2024.

Normohormonal primary hyperparathyroidism: A systematic review and meta-analysis

OBJECTIVE

We aim to evaluate the body of evidence reporting on normohormonal primary hyperparathyroidism (NHpHPT) patients to help guide their diagnosis, characterization and treatment.

BACKGROUND

Normohormonal primary hyperparathyroidism is a term used to describe patients with a normal PTH and elevated calcium levels. There is limited understanding regarding the presentation and appropriate management of these patients.

METHODS

A systematic review was conducted: abstract and full-text screening were independently conducted by 2 investigators. Odds ratios (OR), standard mean differences (SMD) and 95% confidence intervals were calculated.

RESULTS

Twenty-two studies were identified. Patients with NHpHPT were more likely to present with lower PTH (p < 0.00001) and calcium (p < 0.00001) levels. Intraoperatively, the NHpHPT group was 1.8 times more likely to undergo bilateral neck exploration (BNE) and harbor multigland disease. The rates of surgical cure were 93% in the NHpHPT and 96% in the pHPT groups (p = 0.0003).

CONCLUSION

Symptomatic patients with NHpHPT benefit from parathyroidectomy with prolonged intraoperative PTH monitoring, and a low threshold for conversion to BNE.

Hypercalcemia with a parathyroid hormone level of ≤50 pg/mL: Is this primary hyperparathyroidism?

BACKGROUND

Primary hyperparathyroidism is characterized by hypercalcemia with inappropriately normal or elevated parathyroid hormone. However, the absolute parathyroid hormone value that is defined as inappropriately normal is unclear. We reviewed our experience with parathyroidectomy in patients with hypercalcemia and parathyroid hormone of ≤50.0 pg/mL (normal range 12.0-88.0 pg/mL).

METHODS

A total of 2,349 patients underwent parathyroidectomy for primary hyperparathyroidism between 2000 and 2021. Of these, 149 patients had preoperative parathyroid hormone ≤50.0 pg/mL (parathyroid hormone ≤50). The biology and outcomes were compared to patients with parathyroid hormone >50.0 pg/mL (parathyroid hormone >50).

RESULTS

Of the parathyroid hormone ≤50 patients, the median parathyroid hormone was 40.0 pg/mL (range 11.6-50.0 pg/mL). All patients were found to have abnormal hypercellular parathyroid glands with a cure rate of 96.7%. When compared to the parathyroid hormone >50 group, the parathyroid hormone ≤50 group was younger (56 ± 15 vs 60 ± 14 years, P < .001) with a lower body mass index (28.7 ± 7.0 kg/m² vs 31.2 ± 7.9 kg/m², P < .001), higher rate of fatigue (73.2% vs 63.0%, P = .033), and higher rate of multiglandular disease (58.9% vs 31.9%, P < .001). There was no difference between the groups with respect to patient demographics, rate of previous parathyroidectomy, surgical cure, or postoperative complications (persistent or recurrent hyperparathyroidism and hypocalcemia).

CONCLUSION

Patients with hypercalcemia and parathyroid hormone ≤50 pg/mL have a similar clinical presentation and rate of surgical cure to other primary hyperparathyroidism patients and should be considered for parathyroidectomy. Most of these patients have multiglandular disease and thus should be considered for bilateral parathyroid exploration.

Primary hyperparathyroidism: Disease of diverse genetic, symptomatic, and biochemical phenotypes

Genetic, symptomatic, and biochemical heterogeneity of patients with primary hyperparathyroidism (PHPT) has become apparent in recent years. An in-depth, evidence-based review of the phenotypes of PHPT was conducted. This review was intended to provide the resulting information to surgeons who operate on patients with hyperparathyroidism. This review revealed that the once relatively clear distinction between familial and sporadic PHPT has become more challenging by the finding of various germline mutations in patients with seemingly sporadic PHPT. On the one hand, the genetic and clinical characteristics of some syndromes in which PHPT is an important component are now better understood. On the other hand, knowledge is emerging about novel syndromes, such as the rare multiple endocrine neoplasia type IV (MEN4), in which PHPT occurs frequently. It also revealed that, currently, the classical array of symptoms of PHPT is seen rarely upon initial presentation for evaluation. More common are nonspecific, nonclassical symptoms and signs of PHPT. In areas of the world where serum calcium levels are checked routinely, most patients today are "asymptomatic" and they are diagnosed after an incidental finding of hypercalcemia; however, some of them have subclinical involvement of bones and kidneys, which is demonstrated on radiographs, ultrasound, and modern imaging techniques. Last, the review points out that there are three distinct biochemical phenotypes of PHPT. The classical phenotype in which calcium and parathyroid hormone levels are both elevated, and other disease presentations in which the serum levels of calcium or intact parathyroid hormone are normal. Today several, distinct phenotypes of the disease can be identified, and they have implications in the diagnostic evaluation and treatment of patients, as well as possible screening of relatives.

Surgical management of MILD hyperparathyroidism

INTRODUCTION

There is no consensus for management of Mild primary hyperparathyroidism (MILD-pHP). Specific management has been suggested by some authors. We have compared the surgical management of the patients with MILD-pHP to those with Classic primary hyperparathyroidism (C-pHP) treated by surgery according to The Fourth International Workshop on pHP.

MATERIALS AND METHODS

Data of 173 patients who underwent a parathyroidectomy were reviewed and retrospectively analysed. Management of 32 patients with MILD-pHPT (18.5%) patients were compared to that of 141 (81.5%) patients with C-pHPT.

RESULTS

MILD-pHP group was more often discovered after non-fractured osteoporosis (21.9% vs 7.1%, p = 0.02) and surgery for chondrocalcinosis was more often carried out (6.3% vs 0%, p = 0.03) in the MILD-pHP group. A Mini-Invasive Parathyroidectomy (MIP) was carried out in 81.3% of cases, and 87.5% of patients had a single adenoma. The rate of multiglandular pathology was not different. Same day discharge was significantly higher in MILD-pHP group (37.5% vs 17.7%, p = 0.01). Success was obtained in 87.5% in the MILD-pHP group, there was no significant difference with the C-pHP group (92.9%, p = 0.48). There was no significant difference in the imaging performances. Imaging discordance was observed in 18.8% of cases in MILD-pHP and 33.6% in C-pHP (p = 0.38) without correlation with surgical failure.

CONCLUSION

This study suggests that, by selecting patients on the basis of concordant imaging and international recommendations, there is no difference in outcome between MILD-pHP and C-pHP treated surgically.

Biochemical bone turnover markers in hormonal disorders in adults: a narrative review

BACKGROUND

Hormonal disorders are often associated with abnormal levels of bone turnover markers (BTMs). N-terminal propeptide of type I procollagen (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) are the reference markers of bone formation and bone resorption, respectively.

METHODS

A comprehensive literature search within the MEDLINE and Web of Science databases was performed.

RESULTS

Acromegaly is associated with higher BTM levels, which decrease during the remission after treatment. Adult-onset growth hormone deficiency is often associated with decreased BTM levels. Growth hormone replacement therapy stimulates bone turnover and increases BTM levels. Hypothyroidism is characterized by general slowing of bone metabolism which is reflected by lower BTM levels. The replacement thyroid hormone therapy increases the bone turnover rate and BTM levels increase. Patients with thyroid cancer receive a suppressive dose of thyroid hormones and may have slightly elevated BTM levels. Patients with overt hyperthyroidism had higher BTM levels and anti-thyroid therapy induces a rapid decrease in the BTM levels. Patients with overt primary hyperparathyroidism have higher BTM levels, whereas those with asymptomatic and normocalcemic hyperparathyroidism usually have normal BTM levels. Hypoparathyroidism is characterized by slightly decreased BTM levels. Cushing's syndrome is characterized consistently by markedly decreased osteocalcin concentration, whereas data on other BTMs are discordant.

CONCLUSIONS

BTMs help us to better understand mechanisms of the impact of hormonal disorders and their treatment on bone metabolism. However, it is unknown whether BTMs may be used to monitor the effect of their treatments on bone in the clinical practice.

Intraoperative parathyroid hormone (PTH) testing in patients with primary hyperparathyroidism and PTH levels in the normal range

Background

Primary hyperparathyroidism is a common endocrine disorder. Hypercalcemia with normal PTH levels is very unusual and can lead to diagnostic difficulties. There are very few very few studies in the literature and all with limited numerical samples. The goal of the present study was to determine the real incidence and characteristics of primary hyperparathyroidism with normal PTH and to evaluate if intraoperative PTH testing is useful in these patients.

Methods

We performed a retrospective review of 314 patients who had undergone parathyroidectomy to treat primary hyperparathyroidism between January 2002 and December 2016. Patients were divided in two groups according to biochemical preoperative findings: in Group A were included patients with normal serum PTH, in Group B those with increased serum PTH.

Results

Nine patients (3.7%) were included in group A and 235 in group B. Patients in group A were younger (51.5 ± 12.9 years vs 59.6 ± 12.5); preoperative serum calcium and the incidence of coexisting thyroid disease were similar between the two groups. Symptomatic patients were more frequent in Group A (77.8% vs 39.1%; p = 0.048). There were no significant differences regarding preoperative localization studies and surgical procedure. Intraoperative PTH determination demonstrated sensitivity of 86% in group A and 97% in group B, specificity and positive predictive value of 100% in both the groups, negative predictive value of 67% in group A and 79% in group B. Histopathological examination demonstrated a single gland disease in 8 (88.9%) patients in group A and a multi gland disease in 1 (11.1%), in group B single gland disease was found in 218 (92.8%) patients and multi gland disease in 17 (7.2%). Unsuccessful surgery with persistent or recurrent hyperparathyroidism occurred in 1 (11.1%) patient in group A and 4 (1.7%) in group B.

Conclusions

Primary hyperparathyroidism with normal PTH is rare but physicians should be aware of this possibility in patients with hypercalcaemia. Patients with normal PTH levels are younger and more frequently symptomatic. Intraoperative PTH testing plays an important role in the operative management even in such patients.

Classic Primary Hyperparathyroidism Versus Normocalcemic and Normohormonal Variants: Do They Really Differ?

BACKGROUND

Normocalcemic (NCpHPT) and normohormonal (NHpHPT) variants have been recognized primary hyperparathyroidism entities that pose serious challenges. We sought to define the differences among them in a series of surgically treated patients.

PATIENTS AND METHODS

Between 2011 and 2015, 149 patients were enrolled into three groups: CpHPT (Ca > 10.2 mg/dL, PTH > 65 pg/mL), NCpHPT (normal Ca, PTH > 65 pg/mL) and NHpHPT (Ca > 10.2 mg/dL, normal PTH). Descriptive statistics and inter-group differences were computed, whereas multiple logistic/linear regression tests were used for further analysis.

RESULTS

Of these patients 125 were female and 24 male, mean age 56.3 years (range 8-83). A total of 115 (77.2%) patients presented with CpHPT, 23 (15.4%) with NCpHPT and 11 (7.4%) with NHpHPT. MGD was found in 25 (16.8%) patients and SGD in 124 (83.2%); multivariate analysis failed to reveal statistically significant association of MGD with any pHPT variant (CpHPT 16.5% vs NCpHPT 21.7% vs NHpHPT 9.1%, p = 0.726). Conversely, NCpHPT patients exhibited statistically significant smaller adenoma weight (p = 0.023). Moreover, U/S in these patients had smaller positive predictive value (p = 0.278), whereas concordance between U/S and MIBI was also lower (p = 0.669). The utility of MIBI and U/S differed significantly (p < 0.001); more frequent use of U/S was observed for all groups. However, their predictive values did not differ significantly (p = 0.832).

CONCLUSIONS

NCpHPT is more similar than different to CpHPT. NCpHPT constitutes the most challenging entity: it is associated with smaller adenoma weight, whereas U/S exhibited lower positive predictive value and lower concordance rate with MIBI. A trend for higher MGD presence in this group of patients was observed, though without statistical significance.

Case report: incidental parathyroid adenoma in a Chinese diabetic patient with hypercalcemia and normal parathyroid hormone levels

RATIONALE

Parathyroid hormone PTH) levels are the main parameters to differentiate primary hyperparathyroidism (PHPT) from non-PTH-dependent hypercalcemia. We report a case of hypercalcemia with normal PTH levels due to a parathyroid adenoma.

PATIENT CONCERNS

A 52-year-old female patient presented with 2-year history of documented sustained high-normal serum calcium and hypercalcemia (2.51-3.03 mmol/L) with normal serum intact PTH levels (21.95-40.15 pg/ mL).

DIAGNOSES

A parathyroid tumor was localized by ultrasonography and 99mTc-sestamibi dual-phase fusion imaging with single-photon emission computed tomography/computed tomography.

INTERVENTIONS

Parathyroidectomy was performed to excise the tumor completely.

OUTCOMES

A 1.2-cm-sized parathyroid adenoma was removed surgically. The serum calcium was declined to normal level immediately after resection, as well as in 4- month follow-ups. The immunohistological diagnosis proved to be a PTH positive parathyroid adenoma.

LESSONS

In case of hypercalcemia, serum intact PTH and parathyroid imaging should be monitored to evaluate the presence of parathyroid adenoma with care because PHPT could present with inappropriate normal PTH.

Minimally elevated preoperative parathyroid hormone level influences the management of primary hyperparathyroidism

OBJECTIVES/HYPOTHESIS

To determine the effect of preoperative parathyroid hormone (PTH) level on the extent of surgery and the accuracy of parathyroid imaging in primary hyperparathyroidism.

STUDY DESIGN

Retrospective cohort.

METHODS

Final diagnosis of single-gland adenoma and its location versus multigland disease was established in this retrospective cohort study. Positive predictive value, negative predictive value, and accuracy of imaging were analyzed in relation to preoperative PTH levels.

RESULTS

Eighty-seven percent of the 218 patients enrolled in the study underwent unilateral targeted operation and had a 97.9% (95% confidence interval: 95.8%-100%) success rate. However, in patients with PTH <65 pg/mL, 28.6% had bilateral exploration compared to 10.3% in those with PTH ≥65 pg/mL (P = .042). In patients with PTH <65 pg/mL, 7/21 (33.3%) had inaccurate sestamibi findings compared to 24/174 (13.8%) in patients with PTH ≥65 pg/mL (P = .047).

CONCLUSIONS

Accuracy of sestamibi drops significantly, by threefold, in patients with mild primary hyperparathyroidism and PTH <65 pg/mL. Patients with PTH < 65 pg/mL have a 2.5-fold higher rate of bilateral operation to identify the hypersecreting gland(s) compared to patients with PTH ≥65 pg/mL.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1016-1021, 2018.

Mild primary hyperparathyroidism: a literature review

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

Multigland disease and slower decline in intraoperative PTH characterize mild primary hyperparathyroidism

BACKGROUND

Many patients with primary hyperparathyroidism (PHPT) present with less severe biochemical parameters. The purpose of this study was to compare the presentation, operative findings, and outcomes of these patients with "mild" PHPT to patients with "overt" disease.

METHODS

A retrospective review of a prospectively collected parathyroid database was performed to identify cases of PHPT undergoing an initial neck operation. Patients were classified as mild when either the preoperative calcium or PTH was within the normal limits. Comparisons were made with the Student's t test, Chi-squared test, or Wilcoxon rank-sum test where appropriate. Kaplan-Meier estimates were plotted for disease-free survival and compared by the log-rank test.

RESULTS

Of the 1,429 patients who met inclusion criteria, 1,049 were classified as overt and 388 (27.1 %) were mild. Within the mild group, 122 (31.4 %) presented with normocalcemic PHPT and 266 (68.6 %) had a normal PTH. The two groups had similar demographics and renal function. Interestingly, the mild group had more than double the rate of kidney stones (3.1 vs. 1.3 %, p = 0.02). The mild group was less likely to localize on sestamibi scan (62.4 vs. 78.7 %, p < 0.01). Intraoperatively, more mild patients exhibited multigland disease (34.3 vs. 14.1 %, p < 0.01). When examining intraoperative PTH (IoPTH) kinetics where single adenomas were excised, the IoPTH fell at a rate of 6.9 pg/min in mild patients compared with 11.5 pg/min in the overt group (p < 0.01). Accordingly, 62.2 % of patients in the overt group and 53.3 % in the mild group were cured at 5 min postexcision (p < 0.01). There was no difference in the rates of persistence or recurrence between the groups, and disease-free survival estimates were identical (p = 0.27).

CONCLUSIONS

Patients with mild PHPT were more likely to have multigland disease and a slower decline in IoPTH, but these patients can be successfully treated with surgery.

What predicts adverse outcomes in untreated primary hyperparathyroidism? The Parathyroid Epidemiology and Audit Research Study (PEARS)

OBJECTIVE

This study aims to identify the best biochemical risk factors alongside other factors for predicting adverse outcomes seen in untreated primary hyperparathyroidism (PHPT).

DESIGN

Population-based cohort study, 1997-2006.

SETTING

Tayside, Scotland, UK.

PATIENTS

Patients with untreated diagnosed PHPT. OUTCOME MEASURES AND METHODS: Outcomes considered were all-cause mortality, fatal and nonfatal cardiovascular disease (CVD). Models were derived using survival analysis. Potential biochemical predictors tested were baseline serum calcium, parathyroid hormone (PTH), creatinine and alkaline phosphatase (ALP), and other covariates considered were gender, age at diagnosis, deprivation, previous comorbidities and bisphosphonates usage.

RESULTS

From 1997 to 2006, 2097 patients (mean age, 68·4 years; 69·9% women) with untreated PHPT were identified with a total follow-up of 7338 person years, in the population of Tayside, Scotland. The median baseline calcium was 2·61 mm, and PTH was 7·2 pm. PTH was the only statistically significant risk factor in all outcomes observed adjusting for other covariates. Serum creatinine and ALP predicted mortality outcomes in the short term (≤3 years), but not long term. Calcium was associated with increased risk of all-cause mortality in the short term but had no significant impact on other outcomes.

CONCLUSION

Baseline PTH, rather than calcium, best predicts long-term outcomes in untreated PHPT.

Normal PTH levels in primary hyperparathyroidism: still the same disease?

PURPOSE

Previous studies have suggested that primary hyperparathyroidism (pHPT) with only normal parathyroid hormone (PTH) levels is a milder, less symptomatic form of pHPT. This study investigates symptoms, laboratory values, imaging, and outcomes of sporadic pHPT patients with normal PTH values.

METHODS

We reviewed our prospectively collected database of 861 patients with sporadic pHPT who underwent parathyroidectomy between December 1999 and June 2010. Patients with only normal PTH values for 6 months before surgery were compared to a randomized control group of sporadic pHPT patients with elevated PTH, matched 1:2 for age and gender.

RESULTS

Fifty-eight (7%) patients had only normal PTH values within 6 months of surgery. The mean PTH was 55.1 pg/ml in the normal PTH group and 151.3 pg/ml in the control group (n=116). There was no difference in preoperative calcium values, subjective symptoms, bone health, or the frequency of single-gland disease (SGD; 88% vs. 91%) between the two groups, but the normal PTH group had higher preoperative vitamin D values (30.8 vs. 21.4 ng/ml; P<0.001), smaller adenomas (405 vs. 978 mg, P<0.001), and more frequently underwent bilateral neck exploration (57% vs. 49%). There was a trend toward lower sensitivity of preoperative imaging in the normal PTH group.

CONCLUSIONS

Patients with pHPT and either elevated or normal PTH levels present with similar symptoms and calcium levels. The majority of patients with normal PTH have SGD, although adenomas are smaller. This may explain why patients with normal PTH values have less sensitive imaging and more frequently require four-gland exploration.

Severe obesity is associated with symptomatic presentation, higher parathyroid hormone levels, and increased gland weight in primary hyperparathyroidism

CONTEXT

A relationship between primary hyperparathyroidism (PHPT) and obesity has been observed but is incompletely understood. Furthermore, obesity has been associated with vitamin D deficiency, suggesting that the three conditions may be linked.

OBJECTIVE

We hypothesized that PHPT in morbidly obese patients is more severe and that the difference may be explained by vitamin D deficiency. DESIGN AND SETTING, PARTICIPANTS, AND OUTCOME MEASURES: Records of 196 patients with surgically treated PHPT and known body mass index (BMI) were examined. Patients were stratified into three BMI groups: group I (nonobese), BMI < 25 kg/m(2) (n = 54); group II (non-severely obese), BMI 25-34 kg/m(2) (n = 102); and group III (severely obese), BMI 35 kg/m(2) or greater (n = 40).

RESULTS

Preoperative PTH levels were higher in group ΙΙΙ compared with group Ι (181 ± 153 vs. 140 ± 80 pg/ml, p = 0.04). Group III patients had larger tumors on average compared with group I (1.8 ± 1.5 vs. 1.04 ± 1.5 g, P = 0.0002). In group III, BMI positively correlated with parathyroid tumor weight (r = 0.5, P = 0.002). Postoperative PTH was higher in group III compared with group Ι (61 ± 41 vs. 44 ± 28 pg/ml, P = 0.02). There was higher frequency of depression, musculoskeletal symptoms, weakness, and gastroesophageal reflux disease in group III patients.

CONCLUSIONS

BMI positively correlated with parathyroid tumor weight independent of vitamin D. Severely obese patients have larger parathyroid tumor weight, higher pre- and postoperative PTH, and greater symptoms.

Cardiac function in mild primary hyperparathyroidism and the outcome after parathyroidectomy

OBJECTIVE

Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity. The extent of cardiovascular abnormalities in patients with mild-asymptomatic disease is unclear. Using sensitive echocardiographic methods, we compared cardiac structure and function in patients with mild PHPT and in healthy controls, and evaluated the changes after parathyroidectomy (PTX).

METHODS

In a prospective case-control design, we studied 51 PHPT patients without any cardiovascular risk factors/diseases and 51 healthy matched controls. Cardiac structure, and systolic and diastolic function were evaluated by echocardiography and Doppler tissue imaging (DTI). Blood pressure (BP) and heart rate were measured.

RESULTS

We observed no differences in systolic or diastolic function or in cardiac morphology between the PHPT patients and the age-matched healthy controls. The regional peak systolic myocardial velocities (S') measured with DTI decreased at all sites (P<0.05) after PTX (tricuspid annulus 14.23+/-1.85 to 13.48+/-1.79, septal 8.48+/-0.96 to 7.97+/-0.85, and lateral 9.61+/-2.05 to 8.87+/-1.63 cm/s, part of the mitral annulus). At baseline, systolic BP was higher in patients compared to controls (127.6+/-17.1 vs 119.6+/-12.6 mmHg, P<0.05). After PTX, both systolic (127.6+/-17.1 vs 124.6+/-16.6 mmHg, P<0.05) and diastolic (80.3+/-9.6 vs 78.4+/-8.6 mmHg, P<0.05) BP decreased.

CONCLUSIONS

Our results indicate that patients with PHPT without cardiovascular risk factors have a normal global systolic and diastolic function and cardiac morphology. BP and the systolic velocities were marginally reduced after PTX, but reflected the values of the control group. Our findings warrant further investigation of the clinical and prognostic significance of these possibly disease-related inotropic effects.

Substernal oxyphil parathyroid adenoma producing PTHrP with hypercalcemia and normal PTH level

Background

Parathyroid adenoma is the most common cause of primary hyperparathyroidism. Preoperative serum calcium and intact-parathyroid hormone levels are the most useful diagnostic parameters that allow differentiating primary hyperparathyroidism from non-parathyroid-dependent hypercalcemia. Parathyroidectomy is the definitive treatment for primary hyperparathyroidism. Approximately 5% of patients who underwent parathyroidectomy present with persistent or recurrent hyperparathyroidism due to ectopic localization of the adenoma. Functioning oxyphil parathyroid adenoma is an uncommon histological form, seldom causing primary hyperparathyroidism. Parathyroid adenoma with hypercalcemia exhibiting normal parathyroid hormone level is rare. An incidence of 5% to 33% has been documented in the literature; no etiologic explanation has been given. In 1987, parathyroid-hormone-related peptide was isolated as a causative factor of humeral hypercalcemia of malignancy. The presence of parathyroid-hormone-related peptide in parathyroid tissue under normal and pathological conditions has been described in the literature; however, its role in causing hyperparathyroidism has not yet been defined.

Case presentation

We present a case of persistent hypercalcemia with a normal level of intact-parathyroid hormone due to a substernal parathyroid adenoma, treated with radioguided parathyroidectomy. The final histological diagnosis was oxyphil adenoma, positive for parathyroid-hormone-related peptide antigens.

Conclusion

In clinical practice, this atypical biochemical presentation of primary hyperparathyroidism should be considered in the differential diagnosis of hypercalcemia. The parathyroid-hormone-related peptide should be considered not only in the presence of malignancy.

Disturbances of calcium homeostasis consistent with mild primary hyperparathyroidism in premenopausal women and associated morbidity

CONTEXT

Primary hyperparathyroidism (PHPT) and associated morbidity are comprehensively assessed in elderly females; however, less is known of the disease in younger women.

OBJECTIVES

Our objectives were to estimate the prevalence of mild disturbances in calcium homeostasis, which could be analogous with early PHPT, in a premenopausal population, and determine the potential presence of associated morbidity.

DESIGN

Initial results from this longitudinal study are from 2002-2004.

SETTING

We conducted a population-based screening of serum (s)-calcium in conjunction with routine mammography.

PARTICIPANTS

Participants included premenopausal women, 40-50 yr of age (n = 1900). Cases fulfilling previously evaluated biochemical criteria for PHPT (n=214) were matched to controls (n = 214).

MAIN OUTCOME MEASUREMENTS

All participants underwent investigation, including screening of parameters of calcium homeostasis, dual x-ray absorptiometry, and body mass index assessment, and filled out extensive health and quality of life (SF-36) questionnaires. Participants were divided into four groups depending on the relation between s-calcium/intact PTH. Statistical comparisons between cases and controls as well as among the four groups were performed to evaluate morbidity.

RESULTS

The prevalence of assumed mild PHPT, i.e. inappropriate intact PTH value in relation to total s-calcium, was estimated to be 5.1% (n = 96). Women with mild disturbances in calcium homeostasis had statistically significant lower bone mineral density in the proximal femur and femoral neck, higher body mass index, and lower scores for vitality and general health in the analysis of SF-36.

CONCLUSIONS

Mild disturbances in calcium homeostasis in premenopausal women were more prevalent than previously thought and were associated with obesity, lower bone mineral density, and decreased quality of life.

Impact of intraoperative parathyroid hormone monitoring on the prediction of multiglandular parathyroid disease

Optimal interpretation of the results of intraoperative parathyroid hormone (IOPTH) monitoring during neck exploration for primary hyperparathyroidism (pHPT) is still controversial. The reliability of the "50% rule" in multiglandular disease (MGD) is often disputed, mostly because of competing pathophysiologic paradigms. The aim of this study was to ascertain and corroborate the ability of IOPTH monitoring to detect MGD in a practice, combining conventional and alternative parathyroidectomy techniques. This is a retrospective single institution analysis of 69 consecutive patients undergoing cervical exploration for pHPT by various approaches. The IOPTH measurements were performed after induction of anesthesia but prior to skin incision and 10 minutes after excision of the first visualized enlarged parathyroid gland. In this series, 55 patients (80%) had single adenomas, and 14 patients (20%) had MGD. In 8 of the 14 patients with MGD, IOPTH levels were obtained sequentially after removal of every enlarged gland. Of these 8 patients, 6 (75%) had a false-positive decrease (decrease below 50% of baseline value in presence of another enlarged gland) failing to predict the presence of a second enlarged gland. In 2 cases IOPTH monitoring provided a true-negative result, correctly predicting MGD. If MGD is defined by gross morphologic criteria, IOPTH monitoring fails to predict the presence of MGD reliably. However, if MGD is defined by functional criteria, the course of these patients does not seem significantly affected. The importance of these findings must be further investigated, especially with regard to the outcome of minimally invasive parathyroid procedures.