The role of posture in idiopathic oedema.

Idiopathic oedema is a common disorder in women, and is diagnosed by exclusion of known causes of oedema. In 26 of 31 patients studied, the oedema was shown to be orthostatic, i.e. induced by the upright posture and relieved by recumbency. Approximately half of the patients with orthostatic oedema are orthostatic sodium retainers owing to excessive transudation from presumably defecive capillaries with a consequent fall in plasma volume, reduction in glomerular filtration rate and, frequently, excessive renal tubular reabsorption of filtered sodium because of orthostatic hyperaldosteronism. The other patients are orthostatic water retainers, perhaps because of abnormal ADH secretion in the upright posture. Measurement of changes in sodium and water excretion in the recumbent and upright postures are described for the differentiation of these conditions. When conventional diuretic therapy and sodium restriction lose their effectiveness - as often happens after several months - orthostatic sodium retainers may be treated with a combination of the following sympathomimetic amines (dextroamphetamine or ephedrine) to reduce fluid transudation, spironolactone (Aldactone) to promote excretion during recumbency of sodium retained in the upright posture, the use of elastic stockings during the day, and a conventional diuretic together with recumbency from 20h00 most evenings. The last three measures are also useful in orthostatic water retention. Considerable symptomatic improvement can usually be accomplished by these means.