Increased urinary nitrite excretion in children with minimal change nephrotic syndrome

Objective: We tested the hypothesis that nitric oxide synthesis by the kidney is increased in children with primary nephrotic syndrome. Methods: We examined the urinary excretion of nitrite, a stable metabolite of nitric oxide, using the Griess reaction, in children with nephrotic syndrome. Results: In comparison with healthy children, patients with minimal change nephrotic syndrome had increased urinary nitrite excretion regardless of whether the disease was in relapse or remission (p < 0.025). In contrast, urinary nitrite excretion was similar in control subjects and patients with focal segmental glomerulosclerosis or IgA nephropathy. Conclusion: These findings indicate that measurement of urinary nitrite excretion may be a useful test to help discriminate between minimal change nephrotic syndrome and focal segmental glomerulosclerosis in children with idiopathic nephrotic syndrome.