A 16-year-old girl comes to the physician because of increased thirst and urination over the past 2 weeks. She has lost 5-kg during this period despite an increased appetite. She had an upper respiratory infection a few weeks ago that self-resolved. Serum studies show:
Sodium 130 mEq/L
Potassium 3.7 mEq/L
Bicarbonate 26 mEq/L
Which of the following is the most likely explanation for these findings?
Decreased secretion of vasopressin from hypothalamus
Decreased sensitivity of medullary collecting duct to vasopressin
DNA virus
Increased consumption of water
RNA virus
