THEORY ONE
The Monro-Kellie hypothesis is fascinating (
http://en.wikipedia.org/wiki/Intracranial_pressure) Dr Driscoll's (prettyill.com) theories may seem new, but it's been known for a long time that the relationship of all the fluid and tissue in the cranium (skull) works in a delicate balance automatically controlled by the body. Or put simply - imagine you're baking a recipe using flour, milk and water. If you use more milk, you must reduce the water or you'll end up with a slush. Well, the body is pretty clever and does this automatically. What's more, they've known this since the 19th century!
So the volume of blood, tissue, fluid inside the cranuim is a fixed volume and operates at a fixed pressure. The cranium and all the bits inside - blood, cerebral spinal fluid (CSF), and brain tissue - work in such a way, that an increase in one of those things means one of the others MUST be compensated for by a decrease in volume of another.
So, if you have an EDS cranium with too much CSF and too much pressure, what happens? The blood volume reduces to protect the brain ... and so you develop POTS.
As Dr Driscoll rightly identified, Diamox is targets CSF and reduces its volume. It's used by mountaineers for exactly that, when they climb to a different pressure, the body cannot adjust instantly, so Diamox is taken to reduce cranial pressure that would otherwise cause altitude sickness. Interestingly, it takes the body 5 days to soak up or manufacture the 'right' fluids to rebalance the volume and pressure in your brain ... so when you start taking Diamox to mend your POTs and migraines, in 5 days your body will cleverly have manufactured more blood to rebalance the lost CSF. Absolutely amazing!
They already use this theory in other places. For example, in head trauma patients where the brain is swollen, the medics actually artificially reduce blood and CSF volume to immediately reduce pressure, rather than wait the 5 days for the body to 'rebalance' itself. This leads me to...
THEORY TWO
I also found this brilliant research by NASA,which talks a lot about intercranial pressure and the Monro-Kelly principle and ocular /eye pressure issues among astronauts as they return from zero gravity:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110014672_2011015438 .pdf
NASA also understand that 5 days is the 'sweet spot' because the body is clever enough to automatically increase blood volume in response to decreased intercranial pressure, reaching the 'optimum balance' on day 5. So lots of research out there that supports Dr Driscoll's theory and I have found when talking to crusty old doctors, they seem to buy into their "head-trauma peers" (as an etiology for brain hypertension) and NASA more than they do the Driscoll theory which is not peer reviewed and doesn't come via their official medical channels. A pity, because this drug has huge potential for the EDS community if managed correctly.
