Outpatient evaluation of patients with calcium urolithiasis.

Eighty patients with proved calcium urolithiasis participated in an outpatient study designed to define the most likely metabolic problem related to the cause of the stone disease. Diagnostic categories included absorptive hypercalciuria (33 patients), renal leak hypercalciuria (20 patients), hypomagnesiumuria (27 patients), hyperuricemia and hyperuricuria (16 patients), hyperoxaluria (15 patients), normal stone-former (4 patients), renal tubular acidosis (2 patients) and suspicion of hyperparathyroidism (7 patients). Of the 80 patients 40 had more than 1 defect. Patients with a high suspicion of hyperparathyroidism were excluded from the study. Based on these criteria treatment plans incorporating medications, diet or both were instituted. Of 21 patients observed for greater than 2 years 90 per cent have shown no new stone disease.