Your profile says you're a fellow Ohioan? If so, if I were you I would do everything necessary to travel to Cleveland Clinic and be seen at the syncope/autonomic clinic there. I'm a patient there myself, and that's definitely THE place to go in Ohio to get the diagnosis you're seeking (and have confidence in it). I'm also a patient at Ohio State University Medical Center, and though they have some doctors that are understanding of these disorders, they do not have any of the cutting edge testing equipment that Cleveland Clinic has. Case has *most* of what Cleveland Clinic has, but when it comes to the question of MSA ... well, you're a nurse, so I'm sure you understand the gravity of the question you're asking. Just go straight to the top and get the answer that will put your mind at ease.
Here's the page where we have the contact info for CC:
That being said, I think that considering your age and the symptoms you are describing, MSA is very unlikely. I'm not a doctor; I'm not a nurse; I'm just a patient who reads medical journal articles and medical textbooks. Even a doctor can't diagnose a person over the internet, and my novice hunch based on a few paragraphs likely isn't worth even two cents. But my flimsy hunch is that it's extremely unlikely that this will end up being diagnosed as MSA, for whatever minute comfort that is to you.
In my experience, if your doc calls and makes the referral to Cleveland Clinic and faxes your records over, they should be able to get you seen in a matter of 2-3 weeks. If you have far to drive and/or have difficulty with transportation issues, make sure to let them know that when you schedule; normally, they only give special transportation consideration to people from out of state. But if you tell them, they will try to accommodate and squeeze things into one trip as much as possible so you don't have to keep making trips back and forth. Make sure that your sleep apnea is discussed by your doc when the referral is made; they may want you to be seen by a sleep specialist while you are there or even have another sleep study done there. (They sometimes like to repeat tests if they don't "like" the protocol for the test that your local hospital used and want it done using a different protocol, or the only way to properly get their own interpretation of the original test is to repeat it.)
Oh, as for more information on MSA, have you been solely looking at journal articles? Do you want recommendations of medical texts that include info on MSA and PAF? Let me know if so. If you don't have medical library access, you can get the books through interlibrary loan through the public library system, though it may be a bit slow. I've been able to get several loaned out of medical libraries in different areas of Ohio, and even from as far away as NY.