Daily follow-up of serum parathyroid hormone and calcium after surgery forprimary hyperparathyroidism

Objective: To describe the course of parathyroid hormone (PTH) and serum ca lcium after surgery for primary hyperparathyroidism and to evaluate the use fulness of daily measurement of these parameters. Design: Prospective clinical study. Setting: University hospital K. U. Leuven. Method: Daily monitoring of PTH and serum calcium (preoperatively, the firs t to the 5th postoperative day, and around the 10th day) in 30 patients whe re a parathyroid adenoma was removed and in 1 patient with a negative neck exploration. Results: In the adenoma cases, PTH and serum calcium showed a sharp drop of PTH to a very low level already on the first postoperative day, whereafter a rapid recovery of the PTH was seen. Serum calcium decreased more slowly: on average, the lowest calcium level was measured on the third day, when a majority of the patients were temporarily hypocalcemic; after 2 weeks, onl y four patients remained slightly hypocalcemic and no one showed recurrence of the hypercalcemia. In contrast, after unsuccessful surgery (biopsy of f our normal glands), the PTH decrease on the first day was far less pronounc ed and the hypercalcemia disappeared only for a short time. Conclusions: After removal of a parathyroid adenoma, an abrupt fall of PTH precedes the decrease of serum calcium. The first day's PTH level is a reli able indicator of the success of the intervention, and it should be a major point in the postoperative biochemical follow-up. Repeated measurements of serum calcium are useful, but the daily dosage of PTH might be omitted for economic reasons.