Effects of Parathyroidectomy on Normocalcemic Primary Hyperparathyroidism and the Role of Intraoperative PTH Measurement

Abstract

Background Normocalcemic primary hyperparathyroidism (NCpHPT) and normohormonal primary hyperparathyroidism (NHpHPT) are recently recognized variants of primary hyperparathyroidism. Current guidelines for the management hyperparathyroidism recognize NCpHPT as one of the areas that are recommended for more research due to limited available data. Methods A retrospective review of patients who had parathyroidectomy between 2014 and 2019. We excluded patients with multiple endocrine neoplasia syndromes and secondary and tertiary hyperparathyroidism. Included patients were classified based on the biochemical profile into classic or normocalcemic hyperparathyroidism group. Collected data included demographics, preoperative localizing imaging, intraoperative parathyroid hormone levels, and postoperative cure rates. Results 261 patients were included: 160 patients in the classic and 101 patients in the normocalcemic group. Patients in the normocalcemic group had significantly more negative sestamibi scans (n = 58 [8.2%] vs 78 [51.3%], P = <.01), smaller parathyroid glands (mean weight 436.0 ± 593.0 vs 742.4 ± 1109.0 mg, P = .02), higher parathyroid hyperplasia rates (n = 51 [50.5%] vs 69 [43.1%]), and significantly higher intraoperative parathyroid hormone at 10 minutes (78.1 ± 194.6 vs 43.9 ± 62.4 1, P = .04). Positive predictive value of both intraoperative parathyroid hormone and cure rate was lower in the normocalcemic group (84.2% vs 95.7%) and (80.5% vs 95%), respectively. Conclusion Normocalcemic hyperparathyroidism is a challenging disease. Surgeons should be aware of the lower cure rate in this group, interpret intraoperative parathyroid hormone with caution, and have a lower threshold for bilateral neck exploration and 4 glands visualization.

Comparison of 4D computed tomography and F‐18 fluorocholine PET for localisation of parathyroid lesions in primary hyperparathyroidism: A systematic review and meta‐analysis

“…Hence conventional imaging modalities could have a suboptimal detection rate in this subset of cases. Ehab Alameer et al reported more negative sestamibi scans significantly in nPHPT (8.2% vs. 51.3%, p < .01) than hypercalcemic PHPT 23 . Cunha‐Bezerra et al showed better performance of 4DCT (44.4%) compared to USG (22.2%) and scintigraphy (11.1%) in nPHPT patients for accurate localisation of abnormal glands 24 .…”

Parathyroidectomy for Normocalcemic Primary Hyperparathyroidism is Associated with Improved Bone Mineral Density Regardless of Postoperative Parathyroid Hormone Levels

“…Earlier studies suggest that parathyroidectomy for nPHPT results in comparable biochemical cure rates as hypercalcemic PHPT (hPHPT) [6]. However, as recent publications have become more rigorous in the diagnosis of nPHPT, some have highlighted that large proportions of nPHPT patients actually do not achieve biochemical cure after surgery, as defined as normalization of PTH levels by 6 months postoperatively [7,8]. Furthermore, while it has been shown that parathyroidectomy has long-term benefits in bone mineral density (BMD) in hPHPT patients, and it remains unclear whether these benefits are seen in nPHPT patients [7,[9][10][11].…”

Letter to the Editor: Parathyroidectomy for Normocalcemic Primary Hyperparathyroidism (nPHPT) is Associated with Improved Bone Mineral Density Regardless of Postoperative Parathyroid Hormone Levels

“…Did they use Intra Operative PTH monitoring in their cohort of nPHPT? [4]. If so what was the result and what criteria did they use?…”