Sodium Retention



Renal salt retention, expressed clinically either as. edema formation or as volume overload and hy­pertension, is another common feature of glo­merular disease. A reduction in GFR may account for some of the decreased ability to excrete salt, but other factors are usually present. Alterations in glomerular hemodynamics may independently compromise the ability of the kidney to excrete sodium. In this case, a change in glomerulotubular balance leads to increased salt and volume ab­sorption in the proximal nephron. A decrease in the effective circulating blood volume due to a reduction in oncotic pressure may stimulate the renin-aldosterone axis and lead to hormone-de­pendent renal sodium retention in nephrotic pa­tients. Renin and aldosterone secretion may also be increased in cases of nephritis in which renal blood flow is significantly reduced.