SIGNIFICANCE OF ELEVATED PARATHYROID HORMONE AFTER PARATHYROIDECTOMY FOR PRIMARY HYPERPARATHYROIDISM

Objective: To provide a clinical update on persistent parathyroid hormone (PTH) elevation after surgical resection for primary hyperparathyroidism (PHPT) and to suggest a schedule for follow-up monitoring and strategies for future study. Methods: We reviewed the literature targeting studies with detailed analysis of biochemical parameters before and after parathyroidectomy for PHPT. We focused on potential etiologies and currently available outcome data. Results: PTH elevation with eucalcemia after parathyroidectomy for PHPT occurs in 12% to 43% of patients. Underlying etiology is probably multifactorial, and possible causes include bone hunger, vitamin D deficiency, inadequate calcium intake or absorption, reduced peripheral sensitivity to PTH, underlying chronic kidney disease, and/or a renal leak of calcium. No consensus exists on how to follow-up and treat these patients. Conclusions: Although most patients with PTH elevation after parathyroidectomy will have normalization of PTH levels with time and/or calcium and vitamin D supplementation, this finding may be an early indicator of autonomous parathyroid secretion in a small number of patients. Patients with persistent PTH elevation should be monitored over time for recurrence of PHPT and other possible complications. A standardized follow-up protocol is needed to better study and elucidate the clinical significance of elevated PTH after parathyroidectomy.