acute exacerbation of CHF leads to reduced CO --> hypervolemic hyponatremia, body perceives it as hypovolemic (so you expect high ADH) ["non-osmotic release of ADH"]

• this pt is clinically hypervolemic (edema, rales, distended neck veins)

• urine should be concentrated (UOsm >100 mOsm/kg) because kidneys should be fine and ADH is doing its job, just with bad information

• if urine is dilute, it's not CHF, it's psychogenic (can be caused by schizophrenia or factitious disorder)

let's say she wasn't crazy and really was having CHF exacerbation - tx with diuretic and fluid restriction as they did--> note that you can also use vaptan drugs for CHF-related hyponatremic hypervolemia (block ADH) --> should cause the urine to be dilute which will reduce the hypervolemia and reduce salt resorption to correct the hyponatremia

random diabetes inspidius side note for psychogenic polydipsia (DI dx is hypernatremia/normal, hypovolemia, dilute urine <100mOsm/kg)

• can also use the water deprivation test for a pt with polyuria and polydipsia

--> if urine concentrates, it's psychogenic

--> if it does not concentrate, give desmopressin and if it concentrates = central DI, does not concentrae = nephrogenic DI

This is a BS question - I still picked the “right” answer because nothing else made sense, but this is not how this happens in real life. Having taken care of a million of these patients, they’re not trying to fake a disease or symptoms -> they’re thirsty and selfish with no ability to regulate their own behavior, and they throw temper tantrums and ring the call bell all day long asking for water - they’re definitely not hiding their water consumption. I’ve even seen people get desperate enough to drink out of the toilet because they’re “dying of thirst.”