Hematuria preceding renal calculus formation in children with hypercalciuria.

Five children were evaluated for painless hematuria; currently recommended diagnostic studies were unsuccessful in determining a diagnosis. A renal calculus subsequently was passed or detected radiographically in each child from 14 to 20 months after the initial evaluation. Hypercalciuria was then demonstrated by quantitation of 24-hour urinary calcium excretion or by measurement of urinary calcium/creatinine ratio. Calculi and hematuria have not recurred following thiazide therapy. We infer that idiopathic hypercalciuria was a probable cause of the unexplained painless hematuria.