Inappropriate Response to Upright Posture: A Precipitating Factor in the Pathogenesis of Idiopathic Edema

The patterns of postural adaptation in 21 women suffering from idiopathic edema with elevated aldosterone excretion are compared with those in 21 healthy women. In the period free of edema induced by bed rest the patients with idiopathic edema presented a higher morning-evening weight difference; in the upright posture they presented a deeper fall in systolic blood pressure, a higher increase in leg volume, a significantly increased urinary sodium retention, and a higher plasma renin activity and urinary aldosterone increase than the healthy women. However, there was no significant difference in the urinary excretion of epinephrine and norepinephrine between the two groups. Many of the patients had anovulatory cycles with progesterone deficiency and relative estrogen excess. The hemodynamic and hormonal response to upright posture is exaggerated in this disease and results in an excessive sodium retention. This response may precipitate the manifestation of a preexisting latent disposition to this disease.