The impact of vitamin D status and tumor size on the intraoperative parathyroid hormone dynamics in patients with symptomatic primary hyperparathyroidism

Primary hyperparathyroidism-related giant parathyroid adenoma (Review)

Primary hyperparathyroidism (PHPT), an endocrine condition caused by a parathyroid adenoma (PTA) in 80-85% of the cases, has shifted in the modern era to a mildly symptomatic phenotype due to the prompt recognition of hypercalcemia and to a minimally invasive surgical approach which has a curative potential. Clinical complications of PHTH are either related to high calcium or parathyroid hormone [also parathormone (PTH)] or both, while the originating tumor typically is small, without local mass effects. A distinct entity is represented by giant PTA (GPTA) which is considered at a weight of more than 3 (3.5) grams. The present article is a review of the literature involving practical points of non-syndromic PHPT-related GPTA. Most authors agree that pre-operatory calcium and PTH are higher in GPTA vs. non-GPTA. However, the clinical presentation of PHPT may be less severe, probably due to local mass effects that bring the patient to an early medical evaluation. Age distribution, sex ratio, rate of successful pre-operatory location do not differ from non-giant PTA. Hypovitaminosis D is more frequent in PTA of higher dimensions. Post-operative hypocalcemia, but not recurrent/persistent PHPT, is expected, even hungry bone disease. A higher rate of atypia is described although the tumor is mostly benign. Unusual presentations such as cystic transformation, initial diagnosis during pregnancy or auto-infarction have been reported. The ectopic localization of PTA presented in almost 15% of all cases may also be found in GPTA. What are the exact cutoffs for defining GPTA is still an open issue.

Influence of common clinical variables on intraoperative parathyroid hormone monitoring during surgery for primary hyperparathyroidism

BACKGROUND

Intraoperative monitoring of parathyroid hormone (IOPTH) is a reliable method of predicting the cure of primary hyperparathyroidism (PHPT). The aim of this study is to assess whether common clinical variables (CCV) frequently encountered in patients with PHPT may affect the magnitude of PTH drop or the likelihood of patients meeting the intraoperative cure criterion.

DESIGN

Patients who were surgically cured from PHPT caused by single gland disease (SGD) and had full IOPTH protocol (4 measurements) were stratified according to age, gland weight, renal function, vitamin D status and severity of hypercalcemia. The percentage of IOPTH drop and the frequency of patients who had true positive IOPTH test results were compared among groups.

RESULTS

762 patients had surgery for PHPT, of whom 746 were (98%) cured. Of these 746 patients, 511 who had SGD and a full IOPTH protocol were included in this study. The median IOPTH drop was significantly higher among younger patients, those with severe hypercalcaemia at 5, 10, 15 min after gland excision, giant glands (at 5-min only), patients with vitamin D deficiency (at 10, 15 min), and those with normal renal function (at 15 min only). The likelihood of the patients meeting the intraoperative cure criterion was not significantly affected among the groups except in patients with mild hypercalcaemia, who were significantly less likely to have 50% IOPTH drop than those with severe hypercalcaemia at all time points. The frequency of mildly hypercalcaemic patients who met cure criterion was significantly improved by extending measurement to 15 min.

CONCLUSIONS

IOPTH monitoring has the ability to mitigate the variability of IOPTH kinetics associated with most clinical variables. Mildly hypercalcemic patients in particular may benefit from waiting for 15-min measurement before any surgical decision is made.

Comparison between Second- and Third-Generation PTH Assays during Minimally Invasive Parathyroidectomy (MIP)

METHODS

112 patients (of which 72.3% females) underwent MIP by the same surgeon. Age, sex, body mass index (BMI), pre- and postoperative serum calcium, creatinine, 25(OH)D levels, PTH at baseline (PTH T0), and PTH at 10 minutes after adenoma resection (PTH T10) were recorded. Both PTH 2G and PTH 3G assays were assessed using the Diasorin assays.

RESULTS

The mean age was 56.1 ± 14.7 years. Mean value of BMI, preoperative calcium, 25(OH)D, and CKD-EPI-eGFR were, respectively, 26.8 ± 4.8 kg/m², 110.9 ± 7.9 mg/L, 19.3 ± 9.2 ng/mL, and 88.6 ± 25.6 mL/min/1.73 m². PTH 2G and PTH 3G assays were well correlated at PTH T0 and PTH T10 (respectively, correlation coefficient 0.74 and 0.72 for intraclass correlation type 3). The median PTH fall was, respectively, of 79.9% and 82.5% for PTH 2G and PTH 3G. Multivariate analysis using the combined PTH 2G and PTH 3G as a dependent variable with 2 repeated measurements (at PTH 0 and PTH 10) showed a significant effect of preoperative calcium on IOPTH fall (p=0.001, effect size 0.13), while no significant effects were observed for sex, age, BMI, and 25(OH)D.

CONCLUSION

PTH 2G and PTH 3G assays resulted in a similar drop in IOPTH values. Elevated preoperative calcium levels are the only independent predictor of IOPTH decline. Further studies are needed to determine other factors that can influence PTH kinetics.

THE VOLUME OF SOLITARY PARATHYROID ADENOMA IS RELATED TO PREOPERATIVE PTH AND 25OH-D3, BUT NOT TO CALCIUM LEVELS

Purpose

To correlate the volume of parathyroid adenomas with the hormonal and metabolic profile at patients diagnosed with primary hyperparathyroidism (pHPTH).

Patients and Methods

Cross-sectional multicentric study, enrolling 52 patients with pHPTH from two medical institutions. Serum calcium and PTH were evaluated in all patients before surgery, whereas 25OHD3 was measured only in the 33 patients recruited form one medical unit. The volume of parathyroid adenoma was measured by using the formula of a rotating ellipsoid.

Results

We observed a significant correlation of the volume of parathyroid adenomas with PTH at patients from the two units and in the whole group (p < 0.0001), but not with serum calcium (p = 0.494). Twenty-five out of the 33 patients at whom 25OHD3 was measured had levels in the range of deficiency. 25OHD3 was not correlated with PTH or calcium levels, but was negatively correlated to the adenoma volume and positively to the PTH/volume ratio (p = 0.041 and p = 0.048, respectively).

Conclusions

The volume of parathyroid adenoma seems to be related to preoperative PTH and 25OHD3, but not to calcium level. Vitamin D deficiency is frequently found at patients with pHPTH and may contribute to particular disease profiles, including larger parathyroid adenomas.

Correlating pre-operative vitamin D status with post-thyroidectomy hypocalcemia

OBJECTIVE

To examine the relationship between pre-operative vitamin D status and post-thyroidectomy hypocalcemia.

METHODS

Retrospective study examining 264 total and completion thyroidectomies conducted between 2007 and 2011. Subjects included had a recorded 25-hydroxyvitamin D (25[OH]D) level within 21 days prior to or 1 day following surgery, did not have a primary parathyroid gland disorder, and were not taking 1,25-dihydroxyvitamin D3 (calcitriol) prior to surgery. Some subjects were repleted with vitamin D pre-operatively if a low 25(OH)D level (typically below 20 ng/mL) was identified. Pre-operative 25(OH)D, concurrent neck dissection, integrity of parathyroid glands, final pathology, postoperative parathyroid hormone (PTH), calcium nadir and repletion, and length of stay were examined.

RESULTS

The mean pre-operative 25(OH)D for all subjects was 25 ng/mL, and the overall rate of post-operative hypocalcemia was 37.5%. Lower pre-operative 25(OH)D did not predict postoperative hypocalcemia (P = .96); however, it did predict the need for postoperative 1,25-dihydroxyvitamin D3 administration (P = .01). Lower postoperative PTH levels (P = .001) were associated with postoperative hypocalcemia.

CONCLUSION

Pre-operative 25(OH)D did not predict a postoperative decrease in serum calcium, although it did predict the need for 1,25-dihydroxyvitamin D3 therapy in hypocalcemic subjects. We recommend that 25(OH)D be assessed and, if indicated, repleted pre-operatively in patients undergoing total thyroidectomy.