Endocrine Abstracts

Serum parathyroid hormone (PTH) and other parameters are measured post-parathyroidectomy to assess cure. A persistently raised serum PTH may indicate an unsuccessful procedure. However, vitamin D deficiency is increasingly recognised in the general population, and may be a cause of raised PTH post-surgery (secondary hyperparathyroidism). Persistently elevated post-operative PTH may continue to stimulate bone turn over and bone loss post-surgery. Our aim was to determine whether an elevated PTH is associated with hypovitaminosis D following parathyroidectomy.

The hospital database (ECAMIS) was accessed and cross-referenced with our parathyroid database for the last 12 months. The following data was recorded: pre- and post-operative PTH, pre- and post-operative serum calcium, and 25-hydroxy vitamin D for all patients undergoing parathyroid surgery.

Of the 35 patients having parathyroidectomy within the last 12 months (with post-operative normocalcaemia), 20 (57%) of patients had an elevated PTH despite surgery. 17 (85%) of these patients had vitamin D levels assessed. All had vitamin D levels of <30 μg/l (possible vitamin D deficiency) with 11 (65%) of patients had levels <20 μg/l (overt vitamin D deficiency). This compared to only 1 patient (14% of cohort) with a normal PTH and a vitamin D measured at <20 μg/l post-parathyroidectomy.

In assessing cure post parathyroidectomy, in patients without hypercalcaemia, vitamin D deficiency is a common acompliment of elevated PTH levels and is not an indicator of a failed intervention. Assessment of vitamin D is not undertaken routinely in patients with primary hyperparathyroidism either pre or post surgical intervention. Measurement of vitamin D status may be helpful in patients undergoing parathyroid surgery in order to not only reduce the risks of post-operative hypocalcaemia and ‘hungry bone syndrome’, but also to aid with the definition of ‘cure’ post surgery.