A lack of unique pathophysiologic background for nephrolithiasis of primary hyperparathyroidism

The metabolic picture of 32 patients with surgically proven primary hyperparathyroidism presenting with renal stones was compared with that of 37 patients without stones. Between stone-forming and nonstone-forming groups, there was no significant difference in serum 1,25-dihydroxyvitamin D [6.82 +/- 2.62 vs. 6.22 +/- 2.33 ng/dl (mean +/- SD); P greater than 0.05], fractional (intestinal) calcium absorption (0.726 +/- 0.141 vs. 0.690 +/- 0.120), urinary calcium (299 +/- 139 vs. 284 +/- 144 mg/day), serum calcium, phosphorus, and parathyroid hormone, or bone density. Similarly, no differences were found between 29 patients presenting with stones alone and 9 presenting with bone disease alone with respect to the above measures. Moreover, urinary environment was typically supersaturated with respect to stone-forming salts regardless of the presence of stones. The results indicate that there is no unique pathophysiological background for the nephrolithiasis of primary hyperparathyroidism.