Transient hyperthyroidism after total parathyroidectomy for tertiary hyperparathyroidism: a report of two cases

Surgical removal of enlarged parathyroid glands is the treatment of choice in most cases of tertiary renal hyperparathyroidism. Complications of this surgical procedure are rare. We report two cases of patients who developed acute hyperthyroidism after total parathyroidectomy with parathyroid autotransplantation for refractory tertiary hyperparathyroidism. The patients had no history or biochemical or radiologic evidence of thyroid disease. They were not taking drugs affecting thyroid function. Thyroid function (thyroid stimulating hormone, free T(3) and free T(4)) was measured preoperatively, immediately after surgery and again three months later. Total parathyroidectomy was successful in both patients. Circulating levels of parathyroid hormone were at the lower limit of normal values. Postoperative thyroid function tests demonstrated acute hyperthyroidism with a rapid increase in free T(3) and T(4) levels above normal and a drop in thyroid stimulating hormone below normal in both patients. The course of hyperthyroidism was short (normalization of fT(3) and fT(4) values within 14-21 days). Neither patient had symptoms of thyrotoxicosis. Transient hyperthyroidism may be an under-recognized complication of total parathyroidectomy for tertiary hyperparathyroidism. These patients should be monitored with thyroid function tests and assessed for clinical signs attributable to thyrotoxicosis.