A 60-year old woman is always thirsty and is unable to sleep…
A 60-year old woman is always thirsty and is unable to sleep for 8 hours at a time because she must get up to urinate. Her plasma osmolarity is 303 mOsm/L ((higher than normal) and her urine osmolarity is 70 mOsm/L (range is 70-1200 mOsm). Her plasma levels of ADH are higher than normal and her urine glucose is essentially zero. What is the BEST explanation for the CAUSE of her condition?