Diagnosis of diffferent types of Orthostatic Intolerance
You can do your own poor man's tilt table test with a bp cuff. Have something to write with handy.
Just lay down flat for an hour and remain calm. Then take your bp and heart rate. I do this with my arm extended outright and my hand resting on something so that my arm is relaxed. I try to simulate how they do it at the doctors office.
Next stand up straight and don't move except to take your bp. Take it at 1 min, 2 min, 3 min and then 10 minutes. A word of caution on the 10 minute test .. I was close to passing out and it took me an hour at least to recover fully. Of course if you feel faint stop and ask someone to help you.
A 20 pt drop in your bp 3 minutes means you have orthostatic intolerance. And a 30 pt increase in heart rate after 10 minutes indicates tachycardia / pots.
This type of home testing will find some types of Orthostatic Intolerance but it will also miss some types. Plus, as xchocoholic says, be very careful that you don't pass out! You could hurt yourself if you fainted and fell over. I wouldn't recommend doing this test at home without someone with you. (maybe I'm way too cautious but thought I'd mention it)
My own type of Orthostatic Intolerance (OI) is Neurally Mediated Hypotension (NMH) and it would not have shown up on a home test like this. I took the tilt table test twice (why twice? the second one was medically unnecessary--exact wording from my doctor--but it was required as evidence for my ERISA long term disability claim. I think they were expecting it to be normal the second time and they were quite surprised that it was so obviously abnormal again. In other words, their strategy of forcing me to take the test completely backfired).
Anyway, on both tests my blood pressure dropped quite suddenly (to some value that could not be measured by the BP cuff) and I passed out, just from the standing (no isoproteronol required). It was a clearly abnormal result that was obvious even to my cardiologist who is not a specialist in autonomic dysfunction.
The point is that it took between 20-30 minutes before my BP dropped so suddenly. 10 minutes of standing would not have been long enough for me. Also, as the test went on I was quite uncomfortable, getting a lot of symptoms (esp. nausea) and I was fidgeting and moving my feet without being aware of it. Obviously, my subconscious was aware that moving around would help to keep my BP from dropping. The technicians running the test had to come over and tell me to stop moving. As soon as I made myself stop moving around then very quickly after that my BP dropped. Someone trying to do this test at home might think they were being still enough but might be moving around or fidgeting more than they realize.
For an expert's description (as opposed to my rambling anecdote!
) here's an extract from the Johns Hopkins document on Orthostatic Intolerance (
Full document here - PDF file):
How are NMH and POTS diagnosed?
NMH and POTS cannot be detected with routine, resting blood pressure or heart rate
screening. The diagnoses can be made with a prolonged standing test or a tilt table test. Although
a 10-minute test is all that is needed to diagnose POTS, this is too brief for diagnosing NMH,
which usually requires at least a 45-minute period of upright posture. Many hospitals and
academic centers throughout the world perform tilt table testing. It allows careful measurement
of the heart rate and blood pressure responses to the head-up position, usually at a 70-degree
angle, in an almost standing position. The usual reason for performing a tilt table test in the past
had been for the evaluation of recurrent fainting. Many people with NMH develop adaptations to
keep from fainting, such as crossing their legs, fidgeting, or sitting or lying down when they get
lightheaded or tired. However, during the tilt table test they must remain still, and they cannot
call upon these natural defenses. As a result, fainting can occur for the first time during the tilt
table test. Increased fatigue and malaise often occur for a few days after the test is performed,
although our experience has suggested that these symptoms can be minimized if the individual is
treated with intravenous saline solutions immediately after completion of the tilt test.
I'm not at all trying to say that everyone out there needs to get a tilt table test. I'm just saying that this home testing may not reveal anything for a certain subset of OI patients.
I hope this was not too much of a tangent from the original post!
