Natural history of hematuria associated with hypercalciuria in children
C. D. Garcia, L. A. Miller and F. B. Stapleton
Department of Nephrology, Children's Hospital of Buffalo, State University of New York 14222.
Hypercalciuria (HCU) is frequently found during the evaluation of children
with hematuria; the long-term implications of untreated HCU in children are
uncertain. Since 1981, we have identified HCU (urinary calcium, greater
than 0.1 mmol.kg-1.d-1) in 58 patients (41 male) with hematuria; 64% had
gross hematuria and 74% had a relative with urolithiasis. Renal HCU was
diagnosed in 19 patients and absorptive HCU in 24 patients. In 15 children,
the calcium loading test was nondiagnostic. In nine patients (16%),
urolithiasis developed, and in one patient, a renal calcification
developed. These 10 patients (seven male) were older (10.1 vs 7.5 years)
than the other 48 patients and initially presented with gross hematuria
(nine of 10). All 10 patients had a family history of urolithiasis. The
initial urinary calcium value was similar between the 10 patients with
stones (0.15 mmol.kg-1.d-1) and the patients without stones (0.14
mmol.kg-1.d-1); five had absorptive HCU and four had renal HCU. At least
one follow-up urinary calcium measurement was available for 23 patients who
were not receiving thiazide therapy during 1 to 6 years after diagnosis
(mean, 3.1 years). At 1-year follow-up, 12 of 17 patients had HCU and five
had hematuria. Twenty-one patients were studied 2 to 3 years from
diagnosis; 11 had HCU and eight had hematuria. After 4 years, six of seven
patients had HCU and three had hematuria. We concluded that children with
HCU and hematuria are at significant risk for urolithiasis, especially if
they have gross hematuria and a family history of urolithiasis.
Hypercalciuria may be episodic in children with hematuria, and factors
other than urinary calcium concentration may be responsible for urinary
bleeding.
