Transient Primary Hyperparathyroidism: A Case Report

ABSTRACT Objective: To describe a case of transient primary hyperparathyroidism. Methods: We present the clinical, laboratory, and radiologic findings in a patient with an unusual clinical course of primary hyperparathyroidism as well as a review of relevant literature. Results: A 48-year-old man with no family history or past medical history of hypercalcemia and kidney stones was referred by his primary care physician for evaluation of new onset hypercalcemia. Blood work showed a serum calcium level of 11.6 mg/dL, intact parathyroid hormone (iPTH) level of 124 pg/mL, and 25-hydroxyvitamin D (25OHD) level of 15.2 ng/mL, whereas his calcium level 3 months prior was 10.1 mg/dL. On repeat lab work, his serum calcium level was 11.8 mg/dL, iPTH was 161 pg/mL, 25OHD was 23 ng/mL, and a 24-hour urine calcium was 604 mg. Thyroid sonogram and sestamibi scan were consistent with left parathyroid adenoma. The patient was then referred for minimal invasive parathyroidectomy. A repeat blood test just before surgery showed a calcium level of 9.6 mg/dL, iPTH of 64 pg/mL, and 25OHD of 25 ng/mL. Surgery was cancelled, and his serum calcium level remained normal for 2 years. A repeat thyroid sonogram conducted 1 year later showed a smaller adenoma. Conclusion: This case illustrates that hypercalcemia and elevated iPTH levels in primary hyperparathyroidism can be transient. Repeat calcium and iPTH levels before parathyroidectomy might be required to avoid unnecessary surgery. Abbreviations: 25OHD = 25-hydroxyvitamin D BMD = bone mineral density iPTH = intact parathyroid hormone PHPT = primary hyperparathyroidism T4 = thyroxine TSH = thyroid-stimulating hormone