Recalcitrant hypocalcaemia in a patient with post-thyroidectomy hypoparathyroidism and Roux-en-Y gastric bypass

Roux-en-Y gastric bypass (RYGB) places patients at an increased risk of hypocalcaemia due to the reduction in calcium absorption (because the procedure bypasses the duodenum and jejunum) and vitamin D deficiency. Subsequent thyroid surgery increases the risk of severe hypocalcaemia due to potential post-operative hypoparathyroidism. Only a few cases have been published before of this type of treatment-challenging hypocalcaemia.

We report the case of a 31-year-old woman with a previous RYGB, who suffered severe and symptomatic chronic hypocalcaemia after total thyroidectomy. She required aggressive therapy with oral calcium and calcitriol and frequent calcium infusions, but there was no improvement in serum calcium level. Due to the lack of response to standard therapy, teriparatide treatment was started (first with subcutaneous injections and thereafter with a multipulse subcutaneous infusor) but the results were disappointing. As there was no response to different medical treatments, reversal of RYGB was performed with no complications and a subsequent sustained increase in serum calcium level.

This case shows that patients with postoperative hypoparathyroidism and RYGB have increased risk of severe recalcitrant symptomatic hypocalcaemia. In our case teriparatide was ineffective but, as this is the first patient reported, more results are needed to evaluate properly the effect of teriparatide in this multifactorial hypocalcaemia. Reversal of RYGB should be considered when medical therapy has failed, because surgery restores an adequate absorption of calcium and vitamin D from previously bypassed duodenum and proximal jejunum.