SODIUM-BALANCE IN RENAL-FAILURE

Sodium balance in patients with renal failure varies with the severity and clinical manifestations of renal disease. Progressive chronic ren al insufficiency is typified by an adaptive increase in the sodium exc retion rate per nephron as the total glomerular filtration rate declin es. This increase is caused, at least in part, by the effect of atrial natriuretic peptide and other natriuretic peptides, whose release is augmented in the setting of volume expansion and renal failure, Howeve r, exogenous administration of natriuretic peptides in clinical chroni c and acute renal disease does not consistently increase renal sodium excretion. As the glomerular filtration rate progressively declines to wards end-stage renal disease, total renal sodium excretion eventually decreases, and extracellular volume expansion, hypertension, and edem a develop. Sodium removal, induced by high dose diuretics or via conve ctive ultrafiltration during dialysis, is necessary to decrease the ex tracellular volume to normal.