OSH and migraine aura

I have idiopathic episodes of orthostatic hypotension (tilt-table negative, etc.) that only occurs when I arise from sitting for 20 or more minutes (never from laying down) or when I arise and tilt my head back.  Oddly, in 80% of the instances of the OSH episode (lasting less than 1 minute) I develop a bilateral migraine aura (visual only, no bodily sensation or parathesisia) that lasts about 20 minutes.  I may or may not be left with a slight headache (unilateral, no preference to side).
A literature search (JAMA and NEJM) has not revealed anything profound, so I'm wondering if anyone in the neurological community has heard of such symptoms.

[Caryopteris]

I know nothing about what you describe specifically; only that I have observed a lot of people with food allergies have migraines as reactions.  You might want to see if you have food allergies.  I have migraines from gluten and nuts.  My boyfriend has migraines from citrus fruit.