Parathyroid Hormone Fluctuations During Thyroid and Parathyroid Surgery

Objective: Stress hormone levels such as cortisol and epinephrine increase with general anesthesia (GA) and surgery. Parathyroid hormone (PTH) has been shown to increase with GA in those undergoing parathyroidectomy (PT) with abnormal parathyroid function, but there are conflicting reports of it in those with normal parathyroid function. In this study, we aim to determine the effects of anesthetic and surgical stress on those with abnormal parathyroid function undergoing PTs as well as those with normal parathyroid function undergoing unilateral/total thyroidectomies (UTs/TTs). Study Design: Prospective study. Setting: Single tertiary academic center. Methods: Patients undergoing TT, UT, and PT were studied. PTH was measured consecutively during the preoperative, postanesthetic induction before incision, intraoperative, and postoperative periods. Results: One hundred sixty patients were included, with 77 and 31 undergoing TT and UT, respectively, and 52 undergoing PT. Mean PTH levels were significantly higher following induction and intubation across all groups (TT: 139.2 vs 65.1 pg/mL, 113.8% increase; UT: 130.4 vs 57.1 pg/mL, 128.4% increase; PT: 219.6 vs 163.7 pg/mL, 34.1% increase) and remained elevated until excision (TT: 131.8 pg/mL; UT: 124.9 pg/mL; PT: 228.7 pg/mL). Following UT, mean PTH declined to preoperative levels by 1 hour postexcision. Compared to thyroidectomy groups, PTH in the PT group showed more variable responses to anesthesia induction. Conclusion: PTH consistently increases in response to anesthetic and surgical stress in adults undergoing UT and TT with normal preoperative parathyroid function. In contrast, those with hyperparathyroidism demonstrated variable changes.