Preoperative Serum Parathyroid Hormone Research Articles

Self-assembled nanobody-DNA nanomachine conjugate for parathyroid glands intraoperative imaging and parathyroid hormone detection

During thyroidectomy, inadvertent parathyroid damage commonly occurs owing to the varying location of the parathyroid glands and their similarity to adipose tissue, lymph nodes, and thyroid nodules. Therefore, in this study, we aimed to develop a novel self-assembled nanobody-DNA nanomachine conjugate probe (PTH-Nb-HCR) for precisely identifying the parathyroid glands and monitoring parathyroid hormone (PTH) levels in patient blood. The probe consists of two components: the first component is the nanobody (Nb)-nucleic acid conjugate PTH-Nb-Trigger, acting as a recognition unit for PTH and capable of initiating the hybridization chain reaction (HCR), whereas the second component comprises the HCR hairpin probes HP1-FAM (with a modified FAM signal molecule at the 5′ end) and HP2. The assembly of the PTH-Nb-HCR fluorescent probe takes only 20 min. Using the probe, the serum PTH level was quantitatively detected in the 0.1–1000 pg/mL range, and the parathyroid glands were rapidly distinguished from adipose, lymphoid, and thyroid tissues within 5 min. We also used this probe for imaging parathyroid glands with hyperparathyroidism. Considering the strong correlation between fluorescence intensity and preoperative serum PTH levels in patients, we anticipate the use of this probe to distinguish normal and hyperfunctional tissues during hyperparathyroidism surgery.

The Nexus of Hyperparathyroidism and Thyroid Carcinoma: Insights into Pathogenesis and Diagnostic Challenges-A Narrative Review.

This review investigates the intricate relationship between hyperparathyroidism (HPT) and thyroid carcinoma (TC), aiming to elucidate their coexistence, potential pathogenetic mechanisms, and clinical implications. A systematic search strategy, employing the MeSH terms 'Hyperparathyroidism' and 'Thyroid Carcinoma', spanned publications from 2013 to 2023 across the PubMed, Web of Science, and Scopus databases. Fifteen selected articles were analyzed. Studies unanimously confirm the notable association between primary hyperparathyroidism (PHPT) and thyroid nodules/cancer, with incidences ranging from 2.8% to 47.1%. Key findings reveal a predilection for papillary thyroid carcinoma (PTC) in this association, showcasing varying tumor characteristics and gender disparities. Lower preoperative serum parathyroid hormone (PTH) levels are a potential risk factor for thyroid cancer in PHPT patients. Diverse surgical approaches and tumor characteristics between PHPT and secondary hyperparathyroidism (SHPT) cases were noted. Moreover, this review underscores the scarcity of definitive guidelines in managing concurrent PHPT and thyroid conditions, advocating for comprehensive assessments to enhance diagnostic accuracy and refine therapeutic interventions. Rare coincidental associations, as highlighted by case reports, shed light on unique clinical scenarios. In essence, this review amalgamates evidence to deepen the understanding of the interplay between HPT and TC, emphasizing the need for further research to elucidate underlying mechanisms and guide clinical management.

Comparison of frequency of Hypoparathyroidism in Total Thyroidectomy (TT) versus Near-Total Thyroidectomy (NTT) patients

BACKGROUND & OBJECTIVE: Hypoparathyroidism in total thyroidectomy and near-total thyroidectomy is debatable. This study will determine the procedure of choice. Our objective is to compare the frequency of hypoparathyroidism in total thyroidectomy versus near-total thyroidectomy patients.
 METHODOLOGY: Prospective observational study was conducted at the Department of Surgery, Allied Hospital, Faisalabad. The study duration was six months. A total of 140 patients having multinodular goiter, 30-70 years of age, were selected. Patients were divided into two groups. In group A; patients underwent total thyroidectomy while in group B; patients were offered near-total thyroidectomy. All the parathyroid glands were preserved. In all patients, serum calcium levels and parathyroid hormone (PTH) levels were checked on 1st & the 2nd day after surgery.
 RESULTS: Mean age in group A was 48.06±8.21 years & in group B was 48.83 ± 7.0 years. The majority of patients, 88 (62.86%) were between 30 to 50 years of age. Out of these 140 patients, 37 (26.43%) were males & 103 (73.57%) were females, with the ratio of 1:2.8. Mean pre-operative serum Parathyroid hormone was 25.67±9.87 pg/mL. The mean postoperative serum Parathyroid hormone was 16.87±2.43 pg/mL. Mean pre-operative serum calcium levels were 11.32 ± 4.52 mg/dl and mean postoperative serum calcium levels were 9.4 ±0.45mg/dl. In this study, the frequency of Hypoparathyroidism in the total thyroidectomy group (28.57%) was significantly higher than near-total thyroidectomy (8.57%) (p=0.002).
 CONCLUSION: Hypoparathyroidism is more common after total thyroidectomy as compared to near-total thyroidectomy.

Parathyroid Carcinoma with Low Values of Elevated Parathyroid Hormone: A Case Report

Parathyroid Carcinoma (PC) is a rare endocrine malignancy, accounting for <1% of sporadic Primary Hyperparathyroidism (PHPT) cases. A preoperative and even intraoperative diagnosis of PC is rarely reported due to its close resemblance to parathyroid adenoma with respect to symptoms- hypercalcaemia, renal stones and/or failure, osteoporosis, and cardiac/neurocognitive dysfunction. The mean serum calcium in PC is reported to be greater than 14 mg/dL along with serum Parathyroid Hormone (PTH) levels often above 1000 pg/mL. When serum PTH levels are 10 times the upper limit of the normal, it is considered diagnostic of PC. Surgical en-bloc resection without capsular breach is the only definitive cure for PC. The present case report included two patients who presented with features of single parathyroid glandular enlargement, hypercalcaemia, its consequences and with normal ionised calcium, but relatively low levels of elevated serum PTH (<300 pg/mL). They were operated and identified postoperatively as having PC. This rare presentation of PC where the preoperative serum PTH values were lower than usually seen in carcinoma, should alert endocrinologists and surgeons that lower levels of elevated serum PTH do not primarily exclude the possibility of carcinoma.

Comparative analysis of clinicopathologic features between adenoma and hyperplasia in surgically treated patients for hyperparathyroidism: A retrospective study

BackgroundHyperparathyroidism (HPT) is a common endocrine disorder resulting from overproduction of parathyroid hormone (PTH). Usually HPT is caused by parathyroid adenoma (PA) or parathyroid hyperplasia (PH). Our aim is to assess clinicopathologic features associated with PA and PH in patients with HPT. MethodsWe retrospectively collected 29 cases of HPT recorded at the Department of Pathology of Hassan II University Hospital of Fes, Morocco, from 2013 to 2016. ResultsThe mean age was 52.14 ± 15.7 years (range of 22–76 years), 13 patients (44.8%) had primary HPT, 16 (55.2%) had secondary HPT. The largest size of the resected parathyroid specimens ranged from 1 to 3.6 cm (mean of 2.26 ± 0.66 cm). Seventeen patients (58.6%) had PA, the remaining cases were diagnosed as PH. There were no significant statistical differences between PA and PH in age, sex, clinical presentation, preoperative serum PTH, or in parathyroid gland size (P > 0.05). However compared to PH, PA is more often a single-gland disease, found in primary HPT with higher preoperative calcium level (P ˂ 0.05). ConclusionsIn patients surgically treated for HPT, PA is associated with some distinctive clinicopathologic features. These findings could be helpful to pathologists and clinicians for appropriate clinicopathologic management.

Tired of Being Ignored: Fatigue as a Presenting Symptom in Primary Hyperparathyroidism

BackgroundFatigue is a common presenting symptom in primary hyperparathyroidism (PHPT). Although fatigue alone is not currently an indication for parathyroidectomy, it can have a significant detrimental effect on quality of life. The purpose of this study was to determine if there are underlying differences in demographic or disease characteristics in patients with PHPT who present with fatigue compared with those who do not. MethodsWe reviewed a prospective database of 2197 patients undergoing parathyroidectomy for PHPT by three endocrine surgeons from 2001 to 2019. Patients were divided into two groups based on the presence or absence of fatigue as a presenting symptom. Objective measures of disease severity were then compared between groups. ResultsA total of 1379 (63%) patients presented with fatigue. Patients presenting with fatigue were more likely to be female and to have a prior fracture, lower preoperative serum calcium (Ca), and normocalcemic PHPT. There were no statistically significant differences between groups in age, body mass index, history of nephrolithiasis, or preoperative serum parathyroid hormone levels. Patients presenting with fatigue were also more likely to have smaller parathyroid glands and multiglandular disease. No statistically significant differences were detected in postoperative serum Ca and parathyroid hormone levels, or cure or recurrence rates. ConclusionsPatients with PHPT who report fatigue as a presenting symptom present with more complex disease as manifested by a higher incidence of multiglandular disease and normocalcemic PHPT. Despite this, surgical cure is equivalent to other patients. Therefore, fatigue should be a discrete indication for parathyroidectomy in PHPT.

Analyses of risk factors for temporarily inhibited parathyroid hormone secretion of postoperative primary hyperparathyroidism

Objective: To study relative risk factors for temporarily inhibited parathyroid hormone (PTH) secretion after surgery of primary hyperparathyroidism (PHPT). Methods: Seventy-two cases with PHPT from October 2017 to March 2019 in Beijing Chaoyang Hospital were analyzed retrospectively, including 22 males and 50 females aged from 13 to 83 years old. They were reviewed and divided into a complete inhibition group (24 cases, PTH=0 pg/ml), an incomplete inhibition group (23 cases, 0<PTH<12.4 pg/ml), and a non-inhibition group (25 cases, PTH≥12.4 pg/ml) according to the PTH level on the first day after surgery of PHPT. With the Kruskal-Wallis multi-group rank sum test and the Nemenyi test, preoperative and postoperative biochemical parameters and endocrine indexes, including the preoperative serum levels of calcium, phosphorus, PTH, 25-hydroxyvitamin D, and alkaline phosphatase, as well as the levels of PTH 10 min after focal resection, calcium on the first day after surgery, and PTH on the third day after surgery, were compared among three groups to evaluate potential risk factor for postoperative temporary inhabitation of PTH secretion. The predictive values of various risk factors for postoperative temporary inhibition of PTH secretion were evaluated with ROC curve analysis. Results: Preoperative serum PTH, calcium levels, and serum calcium level on the first day after surgery in the complete inhibition group were higher than those in the non-inhibition group,respectively, with statically significant differences [256.5(141.6,585.3) pg/ml vs. 130.2(92.1,256.6) pg/ml, 2.90(2.69,3.22) mmol/L vs. 2.61(2.50,2.75) mmol/L, 2.23(2.08,2.41) mmol/L vs. 2.12(2.05,2.14) mmol/L, χ(2) were 7.17, 11.90, 8.32, respectively, all P<0.05]. When the preoperative serum calcium level was higher than 2.62 mmol/L (AUC=0.698, 95%CI: 0.57-0.83, P=0.006) or the preoperative PTH level was higher than 115.9 pg/ml (AUC=0.697, 95%CI: 0.58-0.82, P=0.007), patients tended to inhibit completely PTH secretion after operation. Conclusions: Preoperative serum calcium and PTH levels are risk factors for postoperative temporary PTH inhibition in PHPT.

Efficacy of Scintigraphy, Ultrasound and Both Scintigraphy and Ultrasonography in Preoperative Detection and Localization of Primary Hyperparathyroidism.

Objective: The aim of our study was to evaluate the efficacy of preoperative dual-phase 99mTc-methoxyisobutylnitrile (MIBI) parathyroid scintigraphy (PS), and ultrasound (US) in primary hyperparathyroidism (pHPT) diagnosis and compare the results with the surgical findings.Methods: Forty-five patients were enrolled in this study. Preoperative serum parathyroid hormone (PTH) levels, calcium (Ca), phosphate (P), and alkaline phosphatase (AP) levels were measured. All parathyroid patients were evaluated by ultrasonography, dual phase 99mTc-MIBI. Surgical findings were used as a reference standard.Results: Of the 45 patients included in this study, 30 were females (66.7%) with an age range between 30 years and 70 years (mean age 41± 13). The sensitivity and specificity of 99mTc-MIBI scintigraphy was 97.4% and 71.4%, respectively, while the sensitivity of ultrasound was 94.4% and specificity 44.4%. The sensitivity, specificity, and accuracy of combined scintigraphy and ultrasound was higher-97.4%, 83.3%, and 95.6%, respectively.Conclusions: The combination of MIBI and US appears promising for localizing parathyroid pathology in patients with primary hyperparathyroidism. The concordance rate is high together with a lower chance of missing concomitant thyroid pathology, which might alter the surgical approach.

Influence of concurrent chronic kidney disease on intraoperative parathyroid hormone monitoring during parathyroidectomy for primary hyperparathyroidism

BackgroundThe influence of chronic kidney disease on intraoperative parathyroid hormone monitoring during parathyroidectomy for primary hyperparathyroidism has not been well-established. We hypothesize that chronic kidney disease influences intraoperative parathyroid hormone degradation kinetics during parathyroidectomy. MethodsThis is a single institution retrospective cohort study of consecutive patients with primary hyperparathyroidism underdoing parathyroidectomy. Patients were stratified according to normal kidney function (glomerular filtration rates ≥60 mL/min/1.73 m2 or presence of chronic kidney disease (glomerular filtration rates 15 − 60 mL/min/1.73 m2). Demographics, laboratory data, operative findings, and intraoperative parathyroid hormone data were compared between groups. ResultsOf the 964 study patients, 235 had chronic kidney disease (24.4%), while 729 (75.6%) had normal kidney function. The chronic kidney disease population had a greater median preoperative serum parathyroid hormone (PTH) (125 vs 114 pg/mL; P < .001), but similar median intraoperative parathyroid hormone levels (chronic kidney disease versus normal): baseline (190 vs 189; P = .232), 5 minutes (51 vs 47; P = .667), 10 minutes (37 vs 35; P = .626), and at 15 minutes postexcision (28 vs 27; P = .539). There was no significant difference in the kinetics of the intraoperative parathyroid hormone degradation slope from the baseline to the 15-minute postexcision levels comparing chronic kidney disease with normal kidney function (−21.02 vs −20.83; P = .957). Patients with chronic kidney disease had 15-minute postexcision intraoperative parathyroid hormone levels within the normal range (12 − 65 pg/mL) as frequently as patients with normal kidney function (81% vs 82%; P = .906) and had similar rates of persistent disease (3.4% vs 3.4%; P = .985). ConclusionPatients with chronic kidney disease undergoing parathyroidectomy for primary hyperparathyroidism have similar intraoperative parathyroid hormone degradation kinetics, and the intraoperative parathyroid hormone criteria used to predict cure should be similar to those with normal kidney function.

Impact of the Introduction of Calcimimetics on Timing of Parathyroidectomy in Secondary and Tertiary Hyperparathyroidism

BackgroundHyperparathyroidism (HPT), both secondary and tertiary, is common in patients with end-stage renal disease, and is associated with severe bone disorders, cardiovascular complications, and increased mortality. Since the introduction of calcimimetics in 2004, treatment of HPT has shifted from surgery to predominantly medical therapy.ObjectiveThe aim of this study was to evaluate the impact of this change of management on the HPT patient population before undergoing (sub-)total parathyroidectomy (PTx).MethodsOverall, 119 patients with secondary or tertiary HPT undergoing PTx were included in a retrospective, single-center cohort. Group A, who underwent PTx before January 2005, was compared with group B, who underwent PTx after January 2005. Patient characteristics, time interval between HPT diagnosis and PTx, and postoperative complications were compared.ResultsGroup A comprised 70 (58.8 %) patients and group B comprised 49 (41.2 %) patients. The median interval between HPT diagnosis and PTx was 27 (interquartile range [IQR] 12.5–48.0) and 49 (IQR 21.0–75.0) months for group A and B, respectively (p = 0.007). Baseline characteristics were similar among both groups. The median preoperative serum parathyroid hormone (PTH) level was 936 pg/mL (IQR 600–1273) for group A versus 1091 pg/mL (IQR 482–1373) for group B (p = 0.38). PTx resulted in a dramatic PTH reduction (less than twofold the upper limit: A, 80.0 %; B, 85.4 %), and postoperative complication rates were low in both groups (A: 7.8 %; B: 10.2 %) [p = 0.66].ConclusionsThe introduction of calcimimetics in 2004 is associated with a significant 2-year delay of surgery with continuously elevated preoperative PTH levels, while parathyroid surgery, even in a fragile population, is considered a safe and effective procedure.

Parathyroid Hormone as a Marker for Predicting the Severity of Hypocalcaemia Following Parathyroidectomy.

The purpose of this study is to determine preoperative predictors of the severity of the hypocalcaemia following parathyroidectomy. The case records of 70 patients who underwent parathyroidectomy for primary hyperparathyroidism from 2000 to 2013 was retrospectively studied. Their symptoms at presentation, biochemical parameters serum calcium, parathyroid hormone, alkaline phosphatase and parathyroid size on ultrasound were compared with their serial post-operative serum calcium levels at 24, 48, 72 and 96h. For the purpose of analysis, patients were divided into three groups. Group 1-asymptomatic, biochemically normal (serum calcium always ≥8.5mgs%); Group 2-asymptomatic, biochemically below normal (at least one reading <8.5, but none <8.0); Group 3-symptomatic (any one reading <8.0). No correlation was found between the severity of the presenting symptoms, pre-operative serum calcium levels or the parathyroid size with the post-operative calcium levels in the three groups. Though preoperative serum alkaline phosphatase levels were higher in Group 3, it was not statistically significant (p=0.069). However, preoperative serum parathyroid hormone levels significantly correlated with postoperative serum calcium levels in all three groups (p=0.006). Pre-operative serum parathyroid hormone levels may serve as a marker for severe post-operative hypocalcaemia and thus identify patients requiring closer monitoring and longer hospitalization following parathyroidectomy.

ARE BIOCHEMICAL VALUES PREDICTIVE OF ADENOMA’S WEIGHT IN PRIMARY HYPERPARATHYROIDISM?

Preoperative laboratory findings may carry some predictive value about the size of the abnormal parathyroid tissue that needs to be removed in primary hyperparathyroidism. In a retrospective study from 1988 to 2003, records of 71 patients with parathyroid adenoma were reviewed. The correlation between preoperative serum calcium, phosphate and parathyroid hormone (PTH) with adenoma's weight was analysed separately. There was a significant correlation between preoperative serum PTH and calcium with adenoma's weight (P < 0.001 and P = 0.03, respectively). The correlation between preoperative serum phosphate and adenoma's weight was not significant (P = 0.1). Preoperative PTH level cannot be used as a definite guide to the parathyroid adenoma's weight. Large parathyroid adenomas seem to secrete less PTH per unit weight than small adenomas. Calcium and phosphate do not seem to be of much value in predicting adenoma's weight in primary hyperparathyroidism.

Impact of Surgical Treatment on Respiratory Muscle Dysfunction in Symptomatic Hyperparathyroidism

We hypothesized that surgical treatment would improve respiratory muscle strength in symptomatic hyperparathyroidism (HPT). Prospective clinical trial. A tertiary referral center. Fifteen consecutive patients with symptomatic HPT and 10 with euthyroid multinodular goiter (control group) without a history of obstructive or restrictive lung disease. Forced vital capacity and forced expiratory volume in 1 second were measured before and 6 months after surgery to estimate respiratory muscle involvement. These measurements were compared with the reference values estimated individually in each patient. Mann-Whitney and Wilcoxon signed rank tests were used for statistical analysis, and P<.05 was considered statistically significant. Respiratory dysfunction in patients with symptomatic HPT, pulmonary function after parathyroidectomy, and the correlation between the preoperative serum parathyroid hormone and total serum calcium values and the impairment in pulmonary function. Preoperative forced vital capacity and forced expiratory volume in 1 second measurements were below the reference values in 11 (73%) and 9 (60%) patients, respectively. All the patients were normocalcemic, and forced vital capacity and forced expiratory volume in 1 second measurements significantly improved at postoperative month 6 (P = .001). No significant difference was detected in the control group. Improvement in pulmonary function correlated with preoperative serum calcium and parathyroid hormone values in patients with HPT (P<.05 and P<.001, respectively). Symptomatic HPT impairs inspiratory and expiratory components of respiratory function, and normalization of serum calcium levels after surgical treatment is associated with a significant improvement in lung function.

Does propofol anesthesia affect intraoperative parathyroid hormone levels? A randomized, prospective trial

Intravenous propofol (2,6-diisopropylphenol) infusion is used commonly for sedation/anesthesia during operations. Several authors have reported that propofol can interfere with intact parathyroid hormone (PTH) testing in vitro. Therefore, many surgeons avoid propofol during parathyroidectomy. To determine whether propofol affects intraoperative PTH levels in vivo, we randomly assigned 34 patients (80% power; alpha < .05) with secondary hyperparathyroidism to undergo surgery for dialysis access. Patients were assigned randomly to local anesthesia with either propofol (n = 17 patients) or midazolam (n = 17 patients) sedation. PTH values were obtained before the procedure and at 10 minutes and 30 minutes after the start of the propofol or midazolam. Median preoperative serum PTH and calcium levels were 175 pg/mL (range, 27-2646 pg/mL) and 9.2 mg/dL (range, 8.1-10.8 mg/dL), respectively. There was no statistically significant difference between the PTH levels in the 2 groups at each of our time points. There was also no difference in the percentage of change from baseline in the PTH values between our 2 groups. No patient in either group had a sustained drop in their PTH level of greater than 50%. Intravenous propofol infusion does not alter PTH levels significantly during the operation. Therefore, we believe the intraoperative PTH assay can be used safely during propofol sedation when parathyroid surgical procedures are being performed.

Parathyroid Hormone Content Distinguishes True Normal Parathyroids from Parathyroids of Patients with Primary Hyperparathyroidism

The purpose of this study was to clarify the pathophysiology of primary hyperparathyroidism by looking for differences between parathyroids from eucalcemic patients and patients with primary hyperparathyroidism (HPT) with respect to the following parameters: intracellular parathyroid content of parathyroid hormone (PTH) and parathyroid hormone messenger RNA (PTH mRNA); and serum PTH and calcium levels of patients and patient age. Coded samples of human parathyroid biopsies were assayed for PTH content with a C-terminal-specific radioimmunoassay. Total cellular RNA was extracted, and PTH mRNA was quantified by dot-blot analysis. These results were tabulated along with associated data on patient age, preoperative serum PTH, and preoperative calcium levels. The content of PTH was significantly higher in true normal (TN) parathyroids than in parathyroids from patients with hyperparathyroidism. PTH content of adenomas and hyperplasias were similar. PTH content of normal parathyroids biopsied from patients with parathyroid adenomas (NA) was statistically higher than that of adenomas but statistically lower than that of TN parathyroids. PTH mRNA and PTH content were correlated (p < 0.001) for TN parathyroid glands; however, it was not true for glands (grossly normal or otherwise) in patients with HPT. Patient groups were similar with regard to mean patient age and intracellular PTH mRNA levels. Hypercalcemic patients were similar with regard to preoperative serum calcium and PTH levels. NA parathyroids, adenomas, and hyperplasias are different from TN parathyroids with regard to their PTH content. PTH mRNA was similar across all groups. The relation between intracellular PTH mRNA and PTH was significantly absent in patients with HPT compared with TN glands. Furthermore, we have found that PTH content of normal parathyroid in patients with adenoma is similar to that of hyperplastic and adenoma tissues. These data suggest that the PTH content of parathyroid tissues may be of use in differentiating normal from abnormal parathyroids.

Factors related to the recurrent hyperfunction of autografts after total parathyroidectomy in patients with severe secondary hyperparathyroidism.

Total parathyroidectomy with autotransplantation has been widely accepted as the appropriate treatment for patients with hyperparathyroidism due to chronic renal failure on long term hemodialysis. However, recurrence has been an enigma and therefore, the factors involved in the recurrence of hyperparathyroidism were studied in 128 patients followed for more than 2 years after surgical treatment. The preoperative serum parathyroid hormone (PTH) concentrations correlated with the total weights of the parathyroid glands. When the original autotransplanted glands were divided into two groups, being diffuse and nodular, the rate of recurrent hyperparathyroidism due to graft hyperfunction was significantly higher in the patients who received nodular glands (24%) than in those who received diffuse glands (8.4%) (P < 0.05). To investigate whether PTH synthetic activity is different in diffuse and nodular glands, the amount of PTH mRNA was studied by in situ hybridization. There was no significant difference in the amount of PTH mRNA in the cells from either diffuse or nodular glands. These data suggest that the recurrence of hyperparathyroidism is not due to enhanced PTH synthetic activity of autotransplant grafts but to the abnormal growth rate of the transplanted gland.

Adenoma weight: A predictor of transient hypocalcemia after parathyroidectomy

To evaluate the relationship of parathyroid adenoma weight to perioperative serum calcium levels, 51 selected patients with pathologically confirmed single adenomas and minimal biopsy at operation were reviewed. Three age- and sex-matched groups were established according to adenoma weight. Compared with Group 1 patients who had adenomas of less than 1 g, Group 3 patients with adenomas of more than 2 g demonstrated significantly higher preoperative serum parathyroid hormone and calcium levels, and significantly lower preoperative serum phosphate levels. Multiple regression analysis revealed a strong correlation between adenoma weight to preoperative parathyroid hormone and calcium levels (r = 0.63, p < 0.001). These results suggest that larger adenomas may be associated with a more severe form of primary hyperparathyroidism. The incidence of transient postoperative hypocalcemia in the 51 patients who underwent adenoma excision was 37 percent. Permanent hypoparathyroidism did not develop in any of them. Compared with Group 1 patients, Group 3 patients demonstrated a higher incidence of postoperative transient hypocalcemia (69 percent versus 14 percent in Group 1, p < 0.001) and significantly lower mean serum calcium levels on the third and fourth postoperative days. Increased adenoma weight may be a valuable aid in identifying those patients at risk for transient hypocalcemia after neck exploration.

Parathyroid Hormone Assay in Primary Hyperparathyroidism: Experiences with a Radioimmunoassay Based on Commercially Available Reagents

Abstract A radioimmunoassay is described for parathyroid hormone in human serum, in which commercially available reagents are used almost exclusively. This assay can be done by any laboratory with experience in radloimmunoassay. Thirty-two of thirty-three patients with surgically proven primary hyperparathyroidism had detectable concentrations of parathyroid hormone in their serum, and concentrations of the hormone exceeded the normal range in 24 of them. Significant positive correlations were found between pre-operative serum calcium, pre-operative serum parathyroid hormone, and the weight of parathyroid tissue removed at operation. These three parameters were also significantly correlated with severity of the skeletal changes as assessed by semiquantitative histological methods.