This happens to me every time I look up in my spice cabinet when I'm cooking. I had assumed it was the meds.

HI,I have had these dizzy spells ever since AS, been to a cardiologist, neurologist but no one every figured out the blood pressure issue.  My mother also has this issue and she has AS, but her doctors did a tilt table test on her to see what her blood pressure does in different positions.  My mother's BP drops dramatically when standing.   THis is called Hypotension.

I did my own test with my blood pressure machine.   My BP shoots sky high when I stand, I don't feel dizzy right then, but about a minute or two after standing up, my BP them plummets to below normal, that is when I feel dizzy.  When I say they BP changes is goes from 110/70 when laying down to 200/100 when standing up to one minute later to 80/90.  That is dramatic.  BP changes from minute to minute normally but a change this much is an issue. Thus why I feel dizzy.

I also can have this happen when I sit in a chair for too long where my feet are on the floor, if I am reclining, it does not happen.  The dizzy spells are only during AS flares, and usually are part of a entire systemic experience. I have the BP issue, gut involvement and the BP changes all at the same time.

And when some of the diving bombing and rising BP is really bad, my eyes cross, I can't speak or think.  I have told this to numerous doctors and they look at me like I making this up. But people have seen me do this and have told me that my eyes cross, like I am having a stroke or something.

I've been diagnosed with that as well.  Did they do a tilt study on you?  I fell down the stairs a lot because when I'd start down them I'd get dizzy and end up tumbling.  Did they give you anything for the dizzy spells?

I have them at times, but I don't guess I've ever related them to my AS -- or at least I've never paid attention to whether it only happens during a flare.  I also get dizzy, almost to the point of nausea, if I lay completely flat on the ground, as you would to do a situp.  This didn't start until I was 20, which is soon after my doctor believes my AS set in, so perhaps they're related?  I should be clear that I don't have spikes so much when I stand, just the dips.

I don't think I do, but when my neck gets really stiff I tend to get dizzy if I turn my head.  Even if I only move my eyes to see something.  Sorry I could not help.