Endocrine Abstracts

JOINT261

Introduction: Patients with large adenoma and hyperparathyroidism induced hypercalcemic crisis are managed with bisphosphonates and mostly operated in the same sitting. The use of bisphosphonates provides the knife happy endocrine surgeon valuable time for imaging and protects the patient from cardiac effects of hypercalcemia. The effect of bisphosphonates on parathyroid gland is not clearly understood. In this study, we describe the texture of parathyroid gland after giving zoledronic acid.

Methodology: Prospectively maintained surgical data (October 2022 – October 2023). All patients who underwent focused parathyroidectomy for PHPT in hypercalcemic crisis who received bisphosphonates preoperatively were included in the study and compared with no Zoledronic acid group. Patient demographics, Serum Calcium, PTH, Vitamin D, size and weight of the gland ex vivo and percentage fall in IOPTH value were noted. All patients received Zoledronic acid 4mg and the duration between administration of bisphosphonate and surgery recorded. Histopathology of all adenoma was reviewed by a single pathologist trained in Endocrine pathology. Data was statistically analysed using SPSS 15.

Results: Among 10 studied patients (mean age: 45.0 ± 15.02 years, M:F ratio 2:3), mean S.PTH was 75.60 ± 50.09 pmol/l, S.Calcium 14.28 ± 0.74 mg/dL, and ex vivo weight 5.14 ± 6.92 g. One patient had parathyroid carcinoma; most had parathyroid adenomas. Intraoperatively, adenomas showed reduced vascularity and increased peri-gland adhesions. HPE showed more fibrosis when compared to no zoledronic acid group

Conclusions: While the effect of bisphosphonates on spinal metastasis is documented, their mechanism in lowering hypercalcemia remains unproven. The observed reduced vascularity and increased adhesions suggest a potential direct impact on enlarged parathyroid glands. Notably, zoledronic acid rapidly lowered calcium levels within 48 hours, persisting over 2 weeks in some patients, with added cardioprotective benefits during anesthesia