ABSTRACT
For each of the following scenarios, select the most likely underlying condition. Each option may be used once, more than once or not at all.
1. A 2-week-old boy is failing to thrive and is producing vast quantities of urine. Investigation shows that he is dehydrated and has a low urinary sodium concentration. He is referred for a water deprivation test, during which desmopressin fails to concentrate his urine.
