Focused parathyroidectomy with intraoperative parathyroid hormone monitoring in patients with lithium-associated primary hyperparathyroidism

Background Lithium-associated hyperparathyroidism has been attributed to multigland hyperplasia requiring bilateral exploration and subtotal parathyroidectomy. Recent studies suggest that some patients may have single gland disease and be eligible for minimally invasive parathyroidectomy. Methods We performed a retrospective review of a prospective, single institution parathyroid database of 1,010 patients who underwent parathyroidectomy between December 1999 and October 2010. Results Nineteen patients with a history of lithium therapy and sporadic hyperparathyroidism were identified. Median age was 50 years (16–68); median duration of therapy was 19 years (1–37); 11 (58%) were on active therapy with lithium for multiple reasons. Preoperative median serum calcium was 10.9 mg/dL (10.0–12.3), median parathyroid hormone was 111 pg/mL (60–186). A total of 18 patients underwent preoperative imaging. Of 12 patients with single-site localization, 6 (50%) underwent a minimally invasive parathyroidectomy, 2 (17%) underwent unilateral explorations, 1 (8%) underwent bilateral exploration, and 3 (25%) had concomitant thyroidectomies. Six patients did not localize and underwent bilateral exploration for multigland disease. One patient without preoperative imaging had single-gland disease. In all operations surgeons used intraoperative parathyroid hormone (IOPTH) monitoring and met intraoperative criteria. Median IOPTH decrease was 74% (54–86) in single-gland disease and 85% (76–95) in multigland disease. Median abnormal gland weight was 590 mg (134–6,750) in single-gland disease and 296 mg (145–2,170) in multigland disease. All patients were normocalcemic at a median follow-up of 19 months (2–118). Conclusion Of 19 patients with lithium exposure, 6 (32%) had multigland disease. However, of the 13 (68%) patients with single gland disease, all 12 who had preoperative imaging had single-site localization. If localization suggests single gland disease, minimally invasive parathyroidectomy with IOPTH monitoring can be successfully performed.