Waz, thanks for the kind words. Migraines and AMS may have similarities in that cerebral blood vessel dilatation or the opposite constriction may be a result of the high altitude trigger on one hand, and the migraine unknown trigger on the other.But AMS has the additional causation in that simple AMS headache taken to its farthest extreme is brain swelling (High Altitude Cerebral Edema or HACE) . So there really is a difference in pathophysiology.
I do not know if a migraine sufferer at altitude can always tell if their headache is one or the other.The worst headache I personally ever had at high altitude was a day flat on my back at 19, 000ft. It was as bad as the time I had viral meningitis. So I have empathy for anyone with a bad headache.
Harvey
PS So water is the newest Rx du jour for migraines? Wish it was that simple!
