Meet Archie.
Archie is an 7-year-old boy brought to the GP by his mother because he has been wetting the bed over the last few nights.
Archie has previously had normal urinary continence and was dry by day from 2-3 years of age. Over the last fortnight his mother has heard him getting up to pass urine in the night and he has actually wet the bed 5 times in the last week.
On direct questioning his mother reports that he seems to be drinking more and he has been complaining of nausea and stomach aches.
He is otherwise fit and well and does not take any regular medication.