My husband is the same and I know from experience how frustrating it is when your spouse gets worked up - I've even experienced the same diabetes panic for the exact same reason. There's a delicate balance between trying to calm them down and having them lash out that you aren't taking it seriously and want them to die. I don't think there is much you can do other than talk your spouse calmly through her panic and anxiety. There's a common medical phrase doctors use "when you hear hooves, think horse not zebra" that might help with the dr google and webmd searches. Basically, the most common and simple scenario is much more likely than the rare one, ie if you're really thirsty, you're probably not drinking or eating too much salty food.