Endocrine Abstracts

Background: Hypocalcaemia is a common electrolyte disorder and it can occur following parathyroidectomy or thyroidectomy. It has been suggested that some post-operative hypocalcaemic crises may reflect severe vitamin D deficiency and vitamin D supplementation may have a protective effect.

Objectives: To establish the prevalence of severe post-operative hypocalcaemia (as defined by the requirement for i.v. calcium gluconate) following parathyroid surgery and total thyroidectomy, and to explore its relationship with vitamin D status.

Methods: The sample (n=466) comprised of patients admitted to ward 44 at the RVI, Newcastle for parathyroid surgery (selective adenomectomy or full neck exploration) or a total thyroidectomy 7/12/2010–7/01/2014. The list of patients who required i.v. calcium was obtained from e-prescribing records. The data was collected from paper notes and electronic records using a proforma.

Results: The prevalence of severe post-operative hypocalcaemia was 3%. It was the highest in the total thyroidectomy group (6.71%) and the lowest in the minimally invasive parathyroidectomy group (0%). 50% of patients who required i.v. calcium were found to have vitamin D levels <50 in the perioperative period, whereas 36% had vitamin D levels >50.

Conclusions: Severe post-operative hypocalcaemia is a rare event that is almost never encountered these days in the context of selective parathyroid adenomectomy and only infrequently in the context of full neck exploration and/or excision of more than one parathyroid gland. The relative risk seems to be higher in the total thyroidectomy group, which suggests that these patients should be monitored more closely. Hungry bone disease (defined as prolonged, resistant hypocalcaemia following surgery for primary hyperparathyroidism) no longer appears to exist as a clinical entity at the RVI. Vitamin D insufficiency was common. Correcting vitamin D levels did not provide 100% protection against severe post-operative hypocalcaemia. Further work in that area is needed.