I would for sure check up on all possible causes, like those from meds and such, but I did want to throw out there also that I have a relatively benign condition (had it long before the CRPS) called neurocardiogenic syncope Of course, they did a total workup (brain, heart, etc.) before coming to that conclusion. There is a relatively simple test called a tilt test that can confirm the diagnosis, although not reacting on the test doesn't mean that you don't have it.

For me, it's a reaction to pain. I have a pretty decent pain tolerance luckily, but when something hurts too badly, I have a tendency to pass out. The neuro said that the only danger really is that I'd hurt myself (like you did) during one of the faints.

I've gotten pretty good at reading the signs. If I feel it coming down, I can't always communicate it to others, but I can sit quickly. While I can't always ward it off entirely, I can at least prevent myself from injuring myself.

Again, no clue if this is what you have, but I thought I'd throw it out there just in case.