A very unusual case of hypokalaemia.

Cystic fibrosis (CF) is diagnosed in the first years of life. There are only two reports in the literature of adult patients with unusual presentation of newly diagnosed CF. We report here an adult patient apparently in a good health, who presented with serious hypokalaemia and metabolic alkalosis as the only abnormalities, who, through a fortuitous event, was tested by additional means for seemingly unrelated conditions that led to evidence of signs typical of CF, which was then confirmed by genetic analyses. This is the first adult patient in Italy with newly diagnosed CF. As unexplained hypokalaemia in an apparently healthy adult is very rare and has now been shown to represent an uncommon presentation of CF, physicians must take these facts into account when determining an appropriate imaging, biochemical work-up and genetic analyses to arrive at a diagnosis.