Endocrine Abstracts

Introduction: A persistently elevated parathyroid hormone (PTH) following parathyroidectomy is usually associated with vitamin D deficiency. We have previously demonstrated this to occur in ~60% of post-operative patients. We have examined the effect of routine vitamin D replacement pre-operatively on the proportion of patients with persistently elevated PTH post-operatively.

Methods: Data was collated retrospectively from our parathyroid database, including: patient demographics; pre- and post-operative biochemical results; operative data; and vitamin D treatment.

Results: 126 consecutive patients undergoing parathyroidectomy for sporadic primary hyperparathyroidism were examined retrospectively (88 (70%) female). Pre-operative ultrasound resulted accurately localised 72% patients and nuclear medicine localised 64% allowing 82 patients (65%) to undergo targeted (minimally invasive) parathyroidectomy.

Median pre-operative serum calcium was 2.9 mmol/l (range 2.6–4.0), and median pre-operative PTH was 13.1 (range 4.5–849 pmol/l). 116 patients (92%) had a single gland excised. 70 of 88 (79.5%) patients who had vitamin D levels measured were found to be vitamin D deficient pre-operatively (<50 nmol/l) – median pre-operative serum vitamin D 35.1 nmol/l (range 7–127).

All patients received vitamin D (cholecalciferol 1000–2000 IU daily) at least 3 months prior to parathyroidectomy. There were no episodes of severe hypercalcaemia requiring more urgent surgical intervention. 97.6% patients were rendered normocalcaemic following parathyroidectomy (failure rate 2.4%). Of these, 45 post-operative patients (36%) were found to be vitamin D deficient. There were no episodes of prolonged hypocalcaemia post-operatively (Hungry Bone Syndrome).

Conclusions: A series previously presented by this unit reported 57% patients with persistently elevated PTH following parathyroidectomy. We now routinely replace vitamin D three months prior to parathyroidectomy, resulting in a reduction in this proportion. There were no adverse consequences of vitamin D replacement and replacement was successful in reducing post-op vitamin D deficiency. This reduction in secondary hyperparathyroidism is likely to relate to better bone health, which we are exploring.