Cystic fibrosis presenting with chronic electrolyte depletion, metabolic alkalosis and hyperaldosteronism.

A five month old infant who presented with failure to thrive and was found to have severe electrolyte depletion, metabolic alkalosis and hyperaldosteronism is described. The diagnosis of cystic fibrosis was made by demonstrating abnormal sweat electrolytes and pancreatic insufficiency. It is important to exclude cystic fibrosis in any infant presenting with this biochemical abnormality.