PTH spikes during parathyroid exploration—a possible pitfall during PTH monitoring?

Background and aims Parathyroid hormone (PTH) spikes caused by unintentional manipulation of the hypersecreting glands may lead to interpretation problems in intraoperative PTH monitoring. Their frequency and surgical consequences were evaluated. Materials and methods Intraoperative PTH values of 401 patients with primary hyperparathyroidism and single gland disease were analysed. Patients were divided into four groups: extensive increase (>150 pg/ml), moderate PTH increase (<150 pg/ml), no increase (±50 pg/ml) and decrease before excision as referred to the baseline level before skin incision. PTH was measured before and up to 25 min after removal of the enlarged gland. Results Twenty-two (5.5%) patients had an extensive and 36 (9%) a moderate intraoperative PTH increase. The PTH decline was prolonged to 15 min in 7 (31.8%) and to 25 min in 12 (54.5%) patients after extensive manipulation and in 9 patients (25%) each after moderate manipulation, respectively. No increase occurred in 162 (40.4%) and a decrease in 181 (45.1%) patients. The surgical approach (bilateral exploration vs open, minimally invasive parathyroidectomy) did not show a difference in the rate of PTH spikes. Conclusion PTH spikes often cause a prolonged PTH decline but, when recognized, do not lead to a change in the surgical strategy. Presented at the 2nd Biennial Congress of the ESES, May 2006, Krakow, Poland.