What is the most common cause of an elevated serum PTH with normal serum calcium after parathyroidectomy?
Persistent PTH elevation with normal serum calcium can be observed in up to 30% of patients after parathyroidectomy. This can be disconcerting to the patient and the surgeon, but in the vast majority of cases, it is not caused by persistent or recurrent HPT. The cause of this phenomenon is likely multifactorial, but vitamin D deficiency, rapid bone turnover (“hungry bone syndrome”), and inadequate calcium intake are thought to be the main causes. Postoperative supplementation with calcium and vitamin D decreases this phenomenon. Long-term studies have shown that the PTH level eventually returns to normal in most patients and that the long-term recurrence rate is not increased in this subset of patients.