Health Human Disease Blog

This rare disorder affects mostly women, who present with stunted growth plus symptoms of polyuria and recurrent muscular weakness. The biochemical profile is that of hypochloremic met­abolic alkalosis, profound hypokalemia (1.5 to 2.5 mEq/L), hyper-feninemia, and hyperaldosteron-ism. Despite high renin values the patients are normotensive and are insensitive to the pressor effect of angiotensin II (All). Urinary excretion of potassium and chloride remains high despite the hypochloremic, hypokalemic state. Juxtaglomer­ular apparatus hyperplasia is the distinguishing renal lesion.

The renal manifestations of Bartter’s syndrome are associated with excessive renal prostaglandin E2 (PGE2) activity and excretion. PGE2 has been shown to stimulate renin secretion, to block va­soconstriction produced by All, and to inhibit salt absorption in the thick ascending limb of Henle. Suppression of PGE2 production with cyclo-ox-ygenase inhibitors (aspirin, indomethacin) re­duces urinary PGE2 excretion, restores vascular sensitivity to exogenous All, and reduces urinary chloride losses. The lack of total correction of hy­pokalemia by these drugs has led to the notion that Bartter’s syndrome is due to a primary defect in the tubular handling of chloride or of potas­sium, and that the increased PGE2 production is secondary to hypokalemia.