[Bartter's syndrome. A condition with chronic hypokalemia].

Bartter's syndrome (BS) is a disease with severe hypokalaemia due to renal potassium wasting. The potassium loss is due to lesions at different sites within the renale tubule. Additional features include metabolic alkalosis, excess renal production of prostaglandins, hyperreninaemia, hyperaldosteronism and impaired pressor responses to exogenous angiotensin II. These secondary features are the result of renal potassium wasting. Symptoms are due to potassium deficiency, but many adult patients feel well despite marked hypokalaemia. The hypocalciuric variant of BS is called Gitelman's syndrome. These patients have a more benign course. The diagnosis of BS is one of exclusion, mainly of surreptitious vomiting, diuretic or laxative abuse. The primary treatment is potassium supplementation often in combination with potassium-sparing diuretics, prostaglandin inhibitors or ACE-inhibitors. With coexisting magnesium deficiency, magnesium supplementation might be effective.