[Role of aldosterone in the development of edema]

Patients with edema not caused by a primary renal inability to excrete sodium show elevated aldosterone levels but to a very variable degree. The low levels can be explained by the absence of hypovolemia resulting from compensatory volume restoration, as in some patients with heart failure, or a concomitant renal excretory impairment as in many patients with nephrotic syndrome and possibly some early phases of liver cirrhosis. When aldosterone is high it is never the sole factor involved. Ironically, some patients with idiopathic edema seem to be the best examples of volume induced sodium retention in which (inappropriate) aldosterone stimulation is a crucial factor.