In this prospective controlled cross over clinical trial, the investigators aim to evaluate the efficacy and safety of acetazolamide for the management of metabolic alkalosis in children with Bartter syndrome. Urine and blood electrolytes will be measured before and after acetazolamide treatment. The primary end point is a change in polyuria, hypokalemia, and metabolic alkalosis.

Bartter syndrome is a hereditary salt-loosing tubulopathy caused by several gene mutations encoding the sodium reabsorption in the thick ascending limb of loop of Henle, with poor response to treatment. The effects of inhibition of proximal tubular reabsorption of bicarbonate by acetazolamide have not been previously studied in Batter patients.

The present study is designed to assess he efficacy and safety of acetazolamide for the management of children with Bartter syndrome. The primary end point is change in polyuria, hypokalemia, and metabolic alkalosis.

In this prospective observational crossover clinical trial, patients between ages 1 and 10 years with clinical diagnosis of Bartter syndrome (hypokalemia, metabolic alkalosis, normal blood pressure, elevated urine chloride >20 milliequivalent per liter, high serum aldosterone and plasma renin levels) will be enrolled in a 4- week clinical trial. After initial clinical and laboratory evaluations, patients will receive acetazolamide 5.0 mg/kg orally as a single daily dose and each patient will act as his/her own control. Renal electrolyte and 24-hour urine output will be measured at baseline and after the 4 weeks acetazolamide treatment.

Inclusion Criteria:

• Hypokalemia
• metabolic alkalosis
• normal blood pressure
• random urine chloride >20 milliequivalent per liter (mEq/L)
• Elevated serum aldosterone and renin levels

Exclusion Criteria:

• Hypertension
• History of emesis
• Prior use of laxatives
• Cystic fibrosis ofpancrease

Children between 1 and 10 years of age with failure to thrive, polyuria and unexplained hypokalemic metabolic alkalosis will be recruited for this trial.