A 16-year-old morbidly obese male is brought to the ER in an ambulance. He is comatose, with a weak, rapid heart rate, low blood pressure, dry mucous membranes, and pale cool skin. His mother reports...

A 16-year-old morbidly obese male is brought to the ER in an ambulance. He is comatose, with a weak, rapid heart rate, low blood pressure, dry mucous membranes, and pale cool skin. His mother reports that he has recently begun to complain of excessive thirst and increased urination. What is your diagnosis and how can you confirm it?