NBME Answers ↦
This one is tricky and come downs to choosing the “best” option. I can see why you were confused. However do note that in an autonomic dysfunction you will never present tachycardia as this patient does. I guess the key here is seeing how her BP normalizes once she is laying down? Sorry, this one is a kinda unusual presentation of Orthostatic hypo.
Not sure if this is correct thinking but how I got this right was:
1. She is hypovolemic
2. Likely retaining salt so water follows (ADH or just renal dynamics in general). This is how I ruled our hypokalemia and hyponatremia
3. If she is hyponatremic b/c sweating then why wouldn't she also be hypokalemic? so both have to wrong because both can't be right
4. Volume depletion ==> orthostatic hypotension