Interesting. I've never heard in my life (the blood dehydration). My first textbook classic migraine hit me when i was in 7th grade. Of course, i had no idea what was going on and it scared me 'cause it was pretty brutal.
What's odd -and i've never come across this either- is that (unless it's part of the blocked out memories) i never had another until i was around 18 or 19. And now i get one every frelling day.
You know, yours may be somewhat atypical, if the catalyst was a type of brain surgery.
I was in the E.R., and nothing was helping, and this was 10.0 on the migraine richter scale, shot of demerol did nothing; and then i was put on an I.V. of compazine, ten minutes later it was gone. And i was watching the clock, it was 10 minutes. I felt like someone who had made a pilgrimage to that fountain (i forget it's name) and been healed.
Compazine was part of my regular meds, to control the naeusea, and i looked at this doctor in astonishment.
He told me that compazine reacts differently in the body according to how it's introduced. So you can see, it makes me curious what was in your I.V. I mean, they can't just give you water, a neutral I.V. is usualy Ringers (my dad's a paramedic) and at the moment -'cause yes i have a migraine right now and it blows my apart my thought process- i can't remember what's in a Ringers solution.
Anyway, i'm exceedingly glad it worked out so well for you, and it's truly an interesting story.