Paediatrics: Bartter’s syndrome

Bartter’s syndrome

This is a relatively rare form of renal tubular dysfunction. The condition is best described as a defect in chloride reabsorption in the ascending loop of Henlé, resulting in:

·  excessive potassium excretion;

·  increased prostaglandin synthesis;

·  stimulation of the renin–angiotensin–aldosterone system.

Clinical features

Young children present with:

·  failure to thrive;

·  poor growth;

·  muscle weakness;

·  constipation.

Polyuria and polydipsia due to excessive salt and water loss may be evident.

Diagnosis

Characteristic findings include:

·  hypokalaemia;

·  hypochloraemia;

·  raised plasma renin and aldosterone levels;

·  normal BP.

Urine potassium and chloride levels are high.

Treatment

Goals are to maintain serum potassium levels >3.5mmol/L and to ensure adequate nutrition. Therapy includes a combination of oral potassium sup-plement together with a potassium-sparing diuretic (e.g. spironolactone) and indomethacin (prostaglandin inhibitor).