As a quick recap for those new to these terms:
Orthostatic Intolerance (OI) is a group of conditions where the patient has trouble maintaining a steady blood pressure (BP) and/or heart rate (HR) while upright.
OI is an integral part of our disease, occurring in over 97% of ME/CFS patients and about 75% of those with fibromyalgia (and many of those with Lyme Disease).
The two most common forms of OI in ME/CFS are Neurally Mediated Hypotension (NMH), where the BP drops while the patient is upright, and Postural Orthostatic Tachycardia Syndrome (POTS), where the patient's HR gets higher when he or she is upright. Most ME/CFS patients have NMH, many have POTS, and quite a few of us have both conditions.
OI underlies much of what we think of as ME/CFS and fibro symptoms - brain fog, low energy, lightheadedness, post-exertional crashes, and more. The good news is that treating OI often brings dramatic improvement to ALL symptoms. You can read more about OI and how to treat it in this excellent article by an expert on OI in ME/CFS, Dr. Peter Rowe from Johns Hopkins. This article is also perfect for printing and sharing with your doctor. Here are links to a webinar Dr. Rowe did on OI, along with some Q&A.
So, what does this new study mean? It clearly shows that a single OI test (typically a tilt table test or an in-office standing test) is NOT always sufficient to show POTS (this study focused only on POTS but the same applies to NMH). The study showed differences depending on the time of day the test was administered and concluded that the diagnosis can be missed with only a single test. For this reason, they conclude that multiple tests at different times of day (or in the morning when their study showed POTS showed up more clearly) are best. While tilt table testing is expensive (and really unnecessary), any doctor can do a simple standing test in his or her office in under 30 minutes. Dr. Rowe can provide instructions and a form for this (or you can e-mail me).
Bottom line? If you have ME/CFS, you have some form of OI, so don't draw conclusions based on a single OI test. Further, if you have the symptoms of OI but your test says you don't have it, then additional testing or just treating would be advisable.
If you are in that situation, where a single OI test did not show either POTS or NMH, then show this study to your doctor and request another test...or list your symptoms related to OI and ask to try treatments. That's what Dr. Rowe suggested when we were having trouble testing our 8-year old son many years ago - he said that kids that young just can't stand still enough for a valid OI test (especially true for our son!), so he advised our pediatrician to try treating his OI based on his symptoms. After a month on Florinef, he was mostly symptom-free (his ME/CFS was milder), much as treatment with Florinef allowed our older son to go back to school full-time. Florinef works less often for adults, but my older son and I have had excellent results with beta blockers, which have greatly reduced our post-exertional crashes and allowed us both to be much more active.
One more note from personal experience: I have had clear NMH and POTS ever since I got ME/CFS, and my doctor has seen my BP drop many times, even with just a few minutes of standing up. However, when her office did an "official" OI standing test for me for my Social Security Disability appeal, the POTS showed clearly (I was actually scaring the tester because I looked so bad within 10 minutes of standing!), but my results did not meet the official criteria for NMH. Fortunately, my doctor recognized the limits of a single test and explained in the letter she wrote for me that she had witnessed the BP drop on many other occasions. So, I was glad to see this study and that someone finally confirmed what experience has shown!
Have you been tested or treated for OI yet?