HYPOCALCEMIA FOLLOWING THYROIDECTOMY FOR THYROTOXICOSIS

Background Temporary postoperative hypocalcaemia is a relatively commo n complication following thyroidectomy for thyrotoxicosis. Damage, dev ascularization or inadvertent removal of the parathyroid glands is the most widely accepted reason, but other causes have been postulated in cluding release of calcitonin during operative manipulation and 'hungr y bone syndrome' due to postoperative reversal of thyrotoxic osteodyst rophy. Methods The study included 63 patients who had subtotal thyroid ectomy, 51 for thyrotoxicosis and 12 for non-toxic goitre. Ninety-two per cent had at least three parathyroid glands preserved. All had post operative levels of parathyroid hormone measured. Results The incidenc e of biochemical hypocalcaemia was 46 per cent and that of symptomatic hypocalcaemia was 21 per cent. No patient was hypoparathyroid. The in cidence of hypocalcaemia was 27 of 51 in thyrotoxic patients compared with two of 12 in the non-toxic goitre group (P < 0.05). Conclusion Hy poparathyroidism does not appear to be the main reason for hypocalcaem ia after thyroidectomy, and other causes such as 'hungry bone syndrome ' may be important contributory factors.