Serum Parathyroid Hormone and Vitamin D Levels as Predictors of Hypocalcemia after Total/ Near Total Thyroidectomy

Abstract

Background: Post-operative Hypocalcaemia is the most-common complication of total and near-total thyroidectomy which is a selective treatment for benign and malignant thyroid diseases. Incidence ranges from 0.5-50%. Objectives: The role of vitamin-D and Parathyroid hormone(PTH) in incidence of Hypocalcemia after thyroidectomy has been taken into consideration. Methods: This is a prospective interventional study is conducted in Kasturba Medical College and hospital, Manipal after taking written informed consent from the participants. It aimed at surveying the serum level of preoperative Vitamin D, PTH and calcium before total-thyroidectomy surgery and its relationship with the incidence of postoperative hypocalcemia after the surgery. The study was done on 70 patients who were-planned for total/near total thyroidectomy. Preoperative Vitamin D, PTH, calcium and Postoperative 4 hours-PTH, Calcium were measured on POD-1, POD-2-4, the results obtained were then analysed. Results: Considering the cut-off of calcium as 8.6mg/dl, 42 patients developed hypocalcemia on POD-1, 28 patients on POD-2. Preoperative calcium and postoperative PTH levels in people having hypocalcaemia where significantly less compared to the patients having normal calcium. 4-hours post-operative PTH measurements showed 51% sensitivity, 100% specificity and strong co-relation between postoperative hypocalcemia and drop in PTH levels- (p=<0.001). Out of 42 patients who developed hypocalcemia 28- (65%) patients had vitamin-D deficiency(p=0.5) on POD-1 and out of 51 patients with hypocalcemia on POD 2-4, 33(78%) had-vitamin-D-deficiency(p=0.3852). Which was not statically significant. Conclusion:4 hours post-operative PTH level is a predictor of early postoperative hypocalcemia, by detecting this we can effectively manage postoperative hypocalcemia