The exception of secondary hyperaldosteronism without edema or hyper- tension is Bartter syndrome. Bartter syndrome is caused by a defect in the loop of Henle in which it loses NaCl. This is due to a defect in the Na-K-2Cl cotransporter. This is like having a furosemide-secreting tumor.
In Bartter syndrome there is juxtaglomerular hyperplasia, normal to low blood pressure, no edema, severe hypokalemic alkalosis, defect in renal conservation of sodium or chloride, and renal loss of sodium, which stimulates renin secretion and aldosterone production.