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Isolated proteinuria: analysis of a school-age population
Insights
Isolated proteinuria in schoolchildren is usually transient and benign. Renal disease is unlikely if hematuria and other signs are absent, making renal biopsy unnecessary for intermittent proteinuria.
Area of Science:
- Pediatric Nephrology
- Clinical Screening Programs
Background:
- Proteinuria screening in schoolchildren identified a prevalence of 10.7% in at least one sample and 2.5% in at least two samples.
- The clinical significance of isolated proteinuria in children requires further investigation to assess renal disease risk.
Purpose of the Study:
- To evaluate the risk of renal disease in schoolchildren with isolated proteinuria detected during a screening program.
- To determine if renal biopsy is indicated for children with intermittent proteinuria.
Main Methods:
- Systematic clinical evaluation of proteinuric schoolchildren after excluding those with hematuria.
- Renal function studies, intravenous pyelography, and renal biopsies were performed on children with high protein excretion rates or persistent proteinuria.
Main Results:
- No overt renal disease was found in children with isolated proteinuria after excluding hematuria.
- Proteinuria was transient or intermittent in all evaluated children.
- Renal biopsies showed mild, nonspecific changes in some cases, with no significant abnormalities indicating serious renal disease.
Conclusions:
- Isolated intermittent proteinuria in children, without hematuria or other signs, is typically benign.
- Routine renal biopsy is not indicated for children with isolated intermittent proteinuria due to the low risk of significant renal pathology.
Abstract:
Proteinuria was found in at least one of four specimens in 10.7% and in at least two of four specimens in 2.5% of 8,594 schoolchildren, ages 8 to 15 years. To determine the risk of renal disease in isolated proteinuria, the screening program was followed by a systematic clinical evaluation of the proteinuric children. After those with both proteinuria and hematuria were excluded, none of the remaining children was found to have an overt renal disease. Despite urinary protein concentrations in excess of 1,000 mg/dl and protein excretion rates of up to 1 gm in 24 hours, proteinuria proved to be transient or intermittent in every child when a large enough number of urine samples was tested. Children with the highest protein excretion rates (more than 6 mg/hour/m2 at night or more than 20 mg/hour/m2 during the day) and those with the most persistent patterns of proteinuria underwent renal function studies, intravenous pyelography, and renal biopsy. No significant abnormalities was found. Mild nonspecific changes were seen in 12 of 28 biopsies, with mesangial deposits in four. The results show that if hematuria and other signs have been excluded, a benign renal morphologic picture is almost invariably to be expected in intermittent proteinuria; renal biopsy, therefore, is not indicated.