Incidence of normocalcemic hyperparathyroidism in idiopathic hypercalciuria: evaluation by dietary calcium deprivation test.
Calcium metabolism was studied in 37 patients with "idiopathic hypercalciuria" on a home diet and after 10 days of low calcium dietary intake (less than 400 mg/24h). After low calcium intake, urinary calcium excretion returned to within normal limits in 70% of the cases. In the group of patients which failed to respond to calcium restriction, TmPO4/GFR values were reduced and, furthermore, in 20% of them plasma iPTH and urinary cAMP levels were increased. These data seem to indicate that: the incidence of absorptive hypercalciuria is higher than hypercalciuria of renal origin; normocalcemic hyperparathyroidism due to primary calcium leak is present only in a limited number of cases, consequently, hypercalciuria secondary to renal phosphate leak is a rather frequent occurrence.
D002118:Calcium / Q000097:blood / Q000378:metabolism / Q000652:urine*; D002136:Calcium, Dietary; D000242:Cyclic AMP / Q000652:urine; D003937:Diagnosis, Differential; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications*; D007668:Kidney / Q000378:metabolism; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D012737:Sex Factors; D014545:Urinary Calculi / Q000209:etiology*
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D010710:Phosphates; D000242:Cyclic AMP; D002118:Calcium