VITAMIN D DEFICIENCY DOES NOT AFFECT THE LIKELIHOOD OF PRESURGICAL LOCALIZATION IN ASYMPTOMATIC PRIMARY HYPERPARATHYROIDISM.

OBJECTIVE: Vitamin D deficiency (VDD) was previously associated with larger adenoma size in primary hyperparathyroidism (PHPT), but this topic was not addressed in patients with the mild/asymptomatic form of the disease (aPHPT). METHODS: We retrospectively retrieved from our series of patients affected by PHPT, 96 consecutive subjects with aPHPT in whom 25-hydroxyvitamin D (25OHD) levels had been assayed and compared those results with localizing imaging studies. RESULTS: Twenty-five of 96 patients had VDD (25OHD <20 ng/mL), but positive ultrasound and scintigraphic studies were not different between patients with and without VDD (52.3% versus 55.7% and 42.9% versus 52.4%, respectively). Upon logistic regression analysis, after adjusting for different variables, including the presence of goiter, VDD was not an independent predictor of localization by imaging studies. CONCLUSION: VDD does not affect the likelihood of positive pre-operative imaging in aPHPT and the consequent surgical decisions.

Unexpected results using rapid intraoperative parathyroid hormone monitoring during parathyroidectomy for primary hyperparathyroidism.

Rapid intraoperative parathyroid hormone (RIOPTH) monitoring predicts complete removal of all hypersecreting tissue by means of a significant parathyroid hormone (PTH) decrease. In this study we have tried to provide an explanation for some unexpected results of RIOPTH monitoring observed during a series of 125 conventional parathyroidectomies for primary hyperthyroidism, discussing the possible consequences on the surgical strategy. Three main groups can be recognized: (1) spikes: a PTH increase 10 minutes after removal of the diseased gland was observed in three patients; (2) false-negative results: six patients showed an inadequate PTH decreases at 10 minutes, three of them resulting in cure at 20 minutes (all six patients were cured at follow-up); (3) false-positive results: five patients with multiglandular disease showed a PTH decrease to a cure level despite excision of one adenoma only (in two of these patients a 20-minute sample showed a PTH increase soon after manipulation of the second adenoma). We concluded that the spike, almost certainly a consequence of manipulating the adenoma, when detected should be considered the "true" baseline value. False-negative results are to some extent related to undetected spikes. The assay used for RIOPTH determination and PTH half-life variability may also play a role. A false-negative result usually prolongs the surgical time. False-positive results are usually related to a double adenoma, one functionally prevailing over the other. Because in our experience manipulation of the second adenoma brought a PTH increase detected with RIOPTH monitoring, we believe that the second adenoma should be excised.