Pattern of calcium metabolism in normo- and hypercalciuric patients with calcium urolithiasis in Saudi Arabia

Urinary calcium excretion was measured in 100 consecutive normocalcemic patients with calcium urolithiasis and 12 Saudi Arabian controls while the patients and the controls were eating their usual diet of unknown calcium content. Only 16 patients were hypercalciuric using the definition of twenty-four-hour urinary calcium of more than 300 mg for males and more than 250 mg for females, and one of these patients was subsequently found to have hyperparathyroidism. The twenty-four-hour urine calcium was less than 200 mg in 60 per cent of male patients and in all the male controls. Since the dietary intake of calcium during the twenty-four-hour urinary collection was unknown, a 1,000-mg calcium loading test was performed in an attempt to differentiate various patterns of abnormal calcium excretion. Of the twenty-four-hour normocalciuric patients 10 (18%) had "absorptive hypercalciuria" and 16 patients (29%) demonstrated a "renal hypercalciuria" pattern. Thirty-nine patients (57%) and all 12 controls had normocalciuria before and after calcium loading.