The use of pre-operative imaging and intraoperative parathyroid hormone level to guide surgical management of tertiary hyperparathyroidism from X-linked hypophosphatemic rickets: a case report.

INTRODUCTION: To describe the use of combined preoperative imaging and intraoperative parathyroid hormone as a novel approach in the surgical management of a patient with tertiary hyperparathyroidism associated with X-linked hypophosphatemic rickets.

CASE PRESENTATION: We present the first documented description of combined preoperative imaging and intraoperative parathyroid hormone as well as a review of the literature surrounding the surgical management of tertiary hyperparathyroidism in the setting of X-linked hypophosphatemic rickets. A 23 year-old female with X-linked hypophosphatemic rickets and renal impairment presented with symptomatic hypercalcemia and tertiary hyperparathyroidism. She had failed medical management and presented for surgical evaluation. Technitium-99 m Sestamibi SPECT imaging and parathyroid ultrasound were used to localize the enlarged parathyroid glands preoperatively. Intraoperative findings correlated well with pre-operative imaging. She underwent successful subtotal parathyroidectomy for four-gland hyperplasia, using intraoperative parathyroid hormone guidance. Despite severe post-operative bone hunger, her serum calcium normalized and she experienced resolution of her preoperative symptoms.

CONCLUSION: X-linked hypophosphatemic rickets is an uncommon disorder of phosphate metabolism resulting in bone deformity. Patients are predisposed to the development of secondary hyperparathyroidism due to chronic vitamin D supplementation which may progress to tertiary hyperparathyroidism with autonomous parathyroid function. Preoperative evaluation with Technitium-99 m Sestamibi SPECT and ultrasound imaging, as well as the use of intraoperative parathyroid hormone are effective in guiding surgical resection. Subtotal parathyroidectomy with cryopreservation is indicated to produce operative cure and limit the risk of recurrence. Although these patients are susceptible to severe postoperative bone hunger, appropriate supplementation with intravenous and oral calcium can minimize hypocalcemic symptoms.