High plasma aldosterone is associated with a risk of reversible decreased eGFR in childhood idiopathic nephrotic syndrome.

BACKGROUND Oedema formation in nephrotic syndrome (NS) may be associated with volume overload or volume contraction. The present study investigates if plasma aldosterone was related to a clinical course symptomatic of either volume expansion or hypovolaemia. METHODS Twenty patients with NS were included. Blood and urine samples were collected before treatment of NS and at stable remission. Aldosterone and other vasoactive hormones were measured in plasma and the patients were classified based on the aldosterone concentrations. RESULTS Five patients were classified with stimulated aldosterone, mean 611 pg/mL [95% confidence interval (CI): 365-993], 12 with suppressed aldosterone, mean 13 pg/mL (95% CI: 6-26), and 3 with unchanged aldosterone, mean 117 pg/mL (95% CI: 101-135). Patients with high aldosterone were characterized by lower estimated glomerular filtration rate (eGFR) (87 ± 30 versus 142 ± 30, P < 0.01), and increased albuminuria (14 ± 11 versus 6 ± 4 g/L, P = 0.03) compared with the remaining patients. eGFR was normalized rapidly by volume expansion in four of these five patients. CONCLUSIONS Elevated plasma aldosterone during NS may be associated with a risk of temporary reduced eGFR. The normalization of eGFR by volume expansion supports the hypothesis of functional hypovolaemia in some patients. Our data suggest that acute measurement of aldosterone may have implications for the management of oedema.