IDIOPATHIC EDEMA AND HYPERALDOSTERONURIA: POSTURAL VENOUS PLASMA POOLING

Abstract

A female adolescent with onset of the syndrome of "idiopathic edema and secondary hyperaldosteronuria" is reported. Investigations conducted over a 28-month period documented hyperaldosteronuria and an increased aldosterone response to salt restriction. The usual diurnal variation of salt and water excretion was observed. Recumbent posture, spirolactone or sympathomimetric drugs were observed to produce salt and water diuresis. Recumbent renal function tests were normal; erect posture, however, produced a marked decrease in sodium excretion and in PAH and creatinine clearance. Immediately exchangeable plasma volume (30 min I131 albumin space) increased 38% between 8:00 A.M. and 6:00 P.M. during erect posture. An "arterial anemia" pattern of vascular response to erect posture was observed in tilt table studies; diastolic pressure increased normally but pulse rate increase was excessive. Blood pressure response to infusion of exogenous angiotensin II was normal; that to norepinephrine infusion seemed abnormal and was associated with a rather marked decrease in pulse rate and increase in pulse pressure suggesting mobilization of "sequestered" blood volume. Four-hour recumbent excretion of catecholamines and the 4-hour excretion response of norepinephrine to erect posture seemed normal. Partial elimination of the edema occurred with chronic sympathomimetic drug therapy. It is concluded that this unusual syndrome probably occurs secondary to a defect in peripheral venous structure or autonomic vasomotor innervation leading to excessive blood volume pooling in the lower body, excessive reduction in renal blood flow and glomerular filtration rate, and hyperaldosteronuria. Consequent retention of salt and water with increase in plasma volume and dependent edema ensues. Sympathomimetic drug therapy may enhance peripheral venous tone and produce clinical improvement.