The Pathophysiologic Difference Between Idiopathic and Self-induced Edema on Chronic Furosemide Abuse

Han, Sang Woong; Min, Kyoung Hwan; Kang, Seok Woo; Ryu, Jun Ho; Mun, Jung Don; Kim, Ho Jung

Abstract

Patients suffering from idiopathic or self-induced edema are uniformly characterized by chronic use of furosemide, which leads to vicious cycle of edema. Among chronic furosemide users who don't have any other specific edema forming diseases, 9 patients from the outpatient clinic(OC) and 6 patients examined at the emergency room(ER) used it mainly for weight reduction and for cyclical edema, respectively. All of the ER group patients were presented with severe hypokalemia(2.04+/-0.2mEq/L; range 1.3 to 2.7 mEq/L) and alkalosis(748+/-0.01; range 7.44 to 7.51) but none from the OC group showed such results. Other baseline parameters including Plasma renin activity(PRA) and aldosterone level on recumbency, and FEn(2)were similar in both groups. In contrast, daily working hours(6.1+/-0.5 vs 10+/-0.6hr, p<0.01), average body weight gain between AM and PM(0.4+/-0.1 vs 0.9+/-0.lkg, p<0.01), peak weight gain interval(9+/-0.8 vs 5+/-0.1day, p<0.05), PRA(7.6+/-1.5 vs 23.5+/-7.2ng/ml/h, p<0.05) and aldosterone level(22.1+/-4.2 vs 64.8+/-10.4 ng/dl, p<0.01) on ambulation, and FEk. on normokalemia(ll+/-2A vs 36+/-7.7%, p<0.01) were statistically different between the two groups. In comparison to the OC group, both the amout of urine(617+/-39 vs 358+/-26ml, p<0.01) and the percent change of PRA(-14+/-4 vs -3+/-2%, p<0.05) and al-dosterone level(-17+/-5 vs -4+/-3%, p<0.05) after saline loading(lL over 1hr, IV) following ambulation were smaller in the Elt group. Moat of the ER group patients(5/6) required aldosterone antagonist (spironolactone) added to K+ supplement, but all of the OC group patients were managed to maintain an edema-free status with conservative treatment. In conclusion, patients with idiopathic edema seem to have more fluid transudation out of intravascular space during orthostasis with a prominent degree of deranged renin-aldosterone axis and K+ metabolism than those with self-induced edema.