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Natural history of hematuria associated with hypercalciuria in children
C D Garcia1, L A Miller, F B Stapleton
1Department of Nephrology, Children's Hospital of Buffalo, State University of New York 14222.
Insights
Children with hypercalciuria (HCU) and hematuria face a significant risk of developing kidney stones. Early identification and monitoring are crucial, especially for those with gross hematuria and a family history of urolithiasis.
Area of Science:
- Pediatric Nephrology
- Urology
- Metabolic Disorders
Background:
- Hypercalciuria (HCU) is common in children with hematuria, but its long-term effects are not fully understood.
- Untreated HCU in children may have uncertain long-term implications, particularly regarding urolithiasis.
- The study evaluates the long-term outcomes of HCU in pediatric patients presenting with hematuria.
Purpose of the Study:
- To assess the long-term risk of urolithiasis and renal calcification in children diagnosed with hypercalciuria and hematuria.
- To investigate the characteristics of children who develop stones or calcifications.
- To understand the persistence of HCU and hematuria over time.
Main Methods:
- Retrospective analysis of 58 children with HCU and hematuria identified since 1981.
- Diagnosis of renal or absorptive HCU using calcium loading tests.
- Follow-up monitoring of urinary calcium levels and hematuria for up to 6 years.
Main Results:
- 16% of patients developed urolithiasis (9/58) or renal calcification (1/58).
- Patients who developed stones were older, more likely to have gross hematuria, and had a family history of urolithiasis.
- HCU and hematuria were often persistent during follow-up, suggesting episodic nature or other contributing factors.
Conclusions:
- Children with HCU and hematuria are at significant risk for urolithiasis, particularly those with gross hematuria and a family history.
- Hypercalciuria in children with hematuria may be episodic, and other factors might contribute to urinary bleeding.
- Long-term monitoring is essential for pediatric patients with HCU and hematuria to prevent stone formation.
Abstract:
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.