A 27-year-old female presents with a
history of passing large volumes of urine, excessive thirst and drinking
copious amounts of water.
On examination she does not look
dehydrated her blood pressure was 120/80 with no postural drop.
Urea 2.3 mmol/L
Sodium 128 mmol/L
Potassium 3.4 mmol/L
Glucose 5.1 mmol/L
Albumin 35 g/L
Plasma osmolality 265 mOsmol/kg
Urine osmolality 50 mOsmol/kg
In this patient which one of the
following would you arrange next?
Glucose tolerance test
Water deprivation test
Short synacthen test
Overnight dexamethasone suppression test