Calcium maelstrom: recalcitrant hypocalcaemia following rapid correction of thyrotoxicosis, exacerbated by pregnancy

A 29-year-old pregnant woman with Graves’ disease presented with severe persistent hypocalcaemia after thyroidectomy. Six months prior to presentation she was diagnosed with Graves’ disease and remained uncontrolled with methimazole. She was confirmed pregnant prior to radioactive iodine ablation (RAI), and underwent total thyroidectomy during her second trimester. After surgery, continuous intravenous calcium infusion was required until delivery of the fetus allowed discontinuation at postoperative day 18, despite oral calcium and calcitriol administration. A total of 38 g of oral and 7.5 g of intravenous elemental calcium was administered. We report an unusual case of recalcitrant hypocalcaemia thought to be due to a combination of postoperative hypoparathyroidism, combined with thyrotoxic osteodystrophy and pregnancy, after surgical correction of Graves’ disease. Increased vigilance and early calcium supplementation should be a priority in the management of these patients.