I'm 32 and, after previously being quite healthy, developed POTS after having gone through four years of chronic pain from a freak muscle spasm in my pec, chest and neck resembling TOS and continues to this day.

I've been seen at Stanford by Dr. Jaradeh in autonomic neurology, who found delayed orthostatic hypotension with sparing of the parasympathetics, caused by mild to moderate dysautonomia (the drop in blood pressure gives me orthostatic tachycardia; strictly speaking, this isn't POTS, which has no drop in blood pressure). I've got GI symptoms as well, plus widespread muscle tenderness, pain (and lately, burning sensation) to go with it (mostly in my calves and hips, but even in weird places like my jaw muscles). There seems to be no inflammatory cause, though, since rheumatological and inflammatory neuropathy workup has been strictly negative.

Now, I've never been diagnosed with EDS, although I am tall and thin enough to classify as borderline marfanoid habitus (I'm a couple inches longer in my arm span than my height.)

I'm pretty much at my wits end with what could be causing the POTS, though. As of now I am presuming it to be instigated by chronic pain radiating from the chest to the spine.

The really troublesome thing is my "TOS" doesn't really seem to be TOS at all, because although it continues to cause me great pain in the thoracic outlet area and pec, none of the diagnostic criteria for TOS show up when I do provocative tests like raising my arm. Instead I've been diagnosed by pain management as having intercostal neuralgia of the first rib and possible costochondritis. I can push my finger below my clavicle where it meets my sternum and elicit a lot of pain, which radiates to my pec. Earlier this summer I had a diagnostic nerve block in the intercostal area of the first rib, and it killed the pain locally (my neck and shoulder are still in a lot of pain).

As of now I am hoping a procedure I have scheduled to zap the first rib area will numb the pain long enough to do some kind of physical therapy consistent with what TOS patients do. The procedure is shy of RF ablation of the intercostal nerve, and is instead what's called pulsed RF neuromodulation, which doesn't quite melt the nerve, but is meant to interfere with the pain signals (much like TENS).

I've read in the literature that POTS has been seen in TOS patients. What's frustrating to me is that I am in about as much pain, but because as far as I can tell it's not actually TOS, I either don't need or don't want something like surgery. And yet here I am years later, having reassured myself that surgery wouldn't be indicated, but wound up with autonomic dysfunction / POTS anyway. In a way I regret simply not pursuing pain management earlier, and yet costocondritis isn't supposed to last this long from what I've read.

(I have never been referred to a TOS surgeon for evaluation, but I think about four doctors by now have had me do the provocative TOS measures, with negative results of course. A part of me thinks I should just self-refer anyway and have them at least do a TOS ultrasound to see what's going on.)