Hypoparathyroidism following total thyroidectomy

Abstract

Objective To predict the occurrence of hypoparathyroidism following total thyroidectomy. Methods In this study, 124 patients underwent total thyroidectomy, 46 for thyroid cancer and 78 for multinodular goiter, additional neck dissection was performed on cancer patients. Serum calcium and parathyroid hormone (PTH) levels were examined preoperatively and at 1 h, 1 d and 2 d postoperatively. The occurrence of postoperative hypoparathyroidism was observed. Receiver operating characteristic curve analysis was employed to identify the best indicator to early predict the occurrence of clinical hypocalcemic symptoms. Results Fifty-eight (46.8%) patients suffered from postoperative transient hypoparathyroidism, with 22 ( 47. 8% ) cases in thyroid cancer group and 36 ( 46. 2% ) in multinodular goiter group ( λ2 = 0. 033, P = 0. 857). One (0.8%) patient in cancer group had permanent hypoparathyroidism. 90 patients (72.6%) had postoperative hypocalcaemia, 58 (46. 8% ) had subnormal serum PTH levels, 40 (32. 3% ) had hypocalcaemia symptoms. Postoperative serum calcium (F=21. 358,P =0. 000) and PTH ( F = 18.253, P =0.000) levels decreased more in cancer group than in goiter group.Receiver operating characteristic curve analysis demonstrated that the percentage of serum PTH level decline at 1 h postoperatively was most predictive and 76. 6% decline was the best cut-off value for the occurrence of clinical hypocalcaemia symptoms ( area under the curve being 0.933 ) with a sensitivity of 89. 7% and a specificity of 87.9%. Conclusions Neck dissection added to total thyroidectomy can decrease the postoperative serum calcium and PTH levels more seriously, but may not increase the incidence of postoperative transient hyperparathyroidism. The percentage of serum PTH level decline at 1 h postoperatively predicts the occurrence of clinical hypocalcaemia symptoms. Key words: Thyroidectomy;  Postoperative complications;  Hypoparathyroidism;  Hypocalcemia