Background: Patients with mildly elevated parathormone (PTH) and calcium levels consistent for primary hyperparathyroidism (pHPT) may present with more underlying multiglandular disease (MGD) and higher operative failure and recurrence rates than those with conventional, or "classic" pHPT. This study compared the clinical characteristics and surgical outcomes of patients with biochemically mild versus conventional pHPT.
Methods: A series of 707 consecutive patients underwent initial targeted parathyroidectomy with intraoperative parathormone monitoring (IPM) at a single institution. Biochemically mild (BM) pHPT was defined as PTH > 65 and <100 pg/ml with serum calcium >10.4 and <11 mg/dl. Conventional pHPT was defined as calcium ≥11 mg/dl and PTH ≥ 100 pg/ml. Prospectively collected data for all patients, including operative indication, preoperative laboratory values, imaging, IPM dynamics, and postoperative laboratory values were retrospectively reviewed. Additional assessments included presence of MGD, bilateral neck exploration (BNE), single-gland volume, and operative failure or success, and recurrence.
Results: Of 60 patients with BM-pHPT, 46 reported preoperative bone pain, kidney stones, fatigue, and/or mental disturbances. The remaining 14 BM-pHPT patients underwent parathyroidectomy based on published asymptomatic guidelines. Patients with BM-pHPT had significantly more kidney stones, MGD, and BNE. Average single-gland volume and postoperative PTH levels were significantly lower in BM-pHPT patients. There were no significant differences between groups regarding preoperative localization accuracy, IPM dynamics, or operative success/failure, recurrence rates.
Conclusions: BM-pHPT patients had more MGD requiring BNE but achieved operative success rates similar to those of patients with conventional disease. IPM successfully identifies MGD in BM-pHPT patients, who should be counseled regarding more extensive operations than limited parathyroidectomy.