Background: Calcium supplementation has been proposed after bilateral thyroid surgery, either to all patients or to those with biochemical hypocalcaemia. It has also been suggested that supplementation aids parathyroid recovery and prevents permanent hypoparathyroidism. This single-centre study investigated the feasibility of a restrictive management of post-thyroidectomy hypocalcaemia.

Methods: Serum calcium was checked before surgery, on postoperative day 1 (POD) 1, at a follow-up visit 6-8 weeks after surgery and after a minimum of 12 months in all patients. Regardless of serum calcium levels, patients with symptoms of hypocalcaemia were prescribed oral calcium supplementation (0·5-1·0 g twice daily) and asymptomatic patients were not. Asymptomatic patients were informed about hypocalcaemic symptoms and instructed to contact the surgical ward should symptoms appear.

Results: Some 640 patients underwent bilateral thyroid surgery without previous or intentional simultaneous parathyroidectomy. A subnormal serum calcium level (below 2·15 mmol/l) was observed in 412 patients (64·4 per cent) on POD 1. By comparison, only 63 patients (9·8 per cent) experienced symptoms of hypocalcaemia in the postoperative period, all but one with a corresponding biochemical hypocalcaemia on POD 1. Calcium levels in all patients with asymptomatic postoperative hypocalcaemia recovered to normal without supplementation. Serum calcium was also normalized during follow-up in all symptomatic patients, except 22 (3·4 per cent) who became permanently hypoparathyroid. No patient without early hypocalcaemic symptoms developed permanent hypoparathyroidism.

Conclusion: The proposed restrictive management of postoperative hypocalcaemia after bilateral thyroid surgery avoids unnecessary supplementation for most patients.