Hyperparathyroidism and gastroenteropancreatic hormone levels.

The diagnosis of multiple endocrine neoplasia (MEN) in patients with presumed hyperparathyroidism has important ramifications for patient management especially since as many as 20% of patients with hyperparathyroidism may have associated MEN. Gut hormone levels were measured before and after surgery in 28 patients who underwent resection of a single parathyroid adenoma for biochemical or clinical evidence of hyperparathyroidism. The mean serum calcium level was 11.9 +/- 0.2 mg/dl before surgery and 9.3 +/- 0.3 mg/dl after surgery (p less than 0.001). Two or more hormone levels were elevated in 32% of patients before surgery and 21% after surgery. The same hormone abnormalities (pancreatic polypeptide [PP] and gastrin) occurred 56% of the time. Of elevated preoperative levels of PP, 91% were in the normal range after surgery. In patients with elevated preoperative PP levels, the postoperative level of PP decreased by an average of 64% of the preoperative level. In 27% of patients the level increased more than double the preoperative value. In two of four patients with high levels of PP after surgery the serum calcium level failed to fall. Of 18 patients whose PP levels fell, 17 had a fall in serum calcium levels. Of six patients whose PP levels rose, four had a significant fall in calcium levels. There was no correlation between the absolute levels or the decremental change of calcium and the change in PP. Several abnormalities in gut hormone secretion occur in patients with primary hyperparathyroidism and a parathyroid adenoma. An elevated serum level of PP does not signify MEN syndrome and must be reevaluated after resection of the parathyroid adenoma. Failure of adequate tumor resection is attended by persistent elevation of serum calcium and PP levels.