SERUM IONIZED CALCIUM AND PARATHYROID-HORMONE IN RENAL STONE DISEASE

Abstract

Serum Ca2+ was significantly elevated in a group of 28 subjects with idiopathic hypercalciuria in whom the mean total serum Ca concentration was within normal limits. Measurement of parathyroid hormone levels confirmed that elevated values are suppressible by infusion of Ca. Ten subjects with simultaneous elevation of serum Ca2+ and parathormone levels above 3 SD of normal were referred for neck exploration; a parathyroid adenoma was found and removed in 9. Significant decreases to normal values of serum Ca2+ and parathormone levels of urine and Ca excretion were documented some weeks following operation. The results conflict with both the alimentary Ca hyperabsorption theory and the renal Ca leak theory of the etiology of idiopathic hypercalciuria, and support the possibility that idiopathic hypercalciuria in many cases represents an early or mild form of normocalcemic primary hyperparathyroidism.