I know of a few men with this disorder, so you are not alone in it. You’re symptoms ring so familiar. Yes, so many people just don’t ‘get it’. The basic P.O.T.S. orthostatic intolerance is bad enough on it’s own, when we can’t get about our daily affairs without having to seek out somewhere to sit all the time. When that’s further compounded by a myriad of seemingly disconnected symptoms each disrupting different systems, it’s starts to drag you down. As you say, when each symptom is considered in isolation it doesn’t seem too bad really, however when they are all suffered in unison, the body becomes in distress, as it battles daily (and fails) to maintain equilibrium.
I’m not surprised you’ve had all of those tests (as I have my friend) indeed many of us have undergone them. They may come back negative but all that has done, in my book, is rule out the obvious – and that’s where they seem to stop, which is a big FAIL. That should be the start of their testing, not the end. I believe (as an ex systems analyst/tester) that they are giving us the WRONG tests. The majority of the medical fraternity don’t seem to know what they are looking for basically, in this complex condition, so very few know what tests will trap it.
I too have flown many times without trouble, then twice suffered with excruciating head/temple pain, then a long haul flight from New York (to UK) was spent with my head in a sick-bag! – all related to pressure I’d say, the later probably affecting my brainstem. Can you remember what position your head was in on the plane. Was it in flexion for a prolonged time, as this aggravates things ?
I’m wondering if it was an increase in brainstem pressure that subdued your ‘breathing’. The brainstem helps control your autonomic nervous system, which includes controlling your breathing. If your breathing was low, your blood would probably have been low in oxygen, your heart would have to beat much faster to supply the required amount (hence the tachycardia). If insufficient oxygen was getting to the brain, that would shoot up your BP too. Nausea can result from brainstem compression too.
As many of us have a ‘heart filling’ problem too (LVDD – cardiologist needs to be looking for Left Ventricular Diastolic Dysfunction) and low blood volume, this wouldn’t have helped. Your body certainly sounded like it was in an awful lot of distress at the time. I have had one or two ‘do’s’ like that, going to hospital in an ambulance but tests came back clear and they’d look at me barmy. I think it’s some sort of P.O.T.S. autonomic crisis.
I don’t wish to alarm you, as it doesn’t seem that that was the case but a chest x-ray doesn’t always pick up a pulmonary embolism – I know because it totally missed mine!
The problem with urinary frequency is that it can be a sign of pituitary problems, which again many of us have (undiagnosed!) due to the raised intracranial pressure. When your pituitary is not producing enough antidiuretic hormone, you will pass more urine than you’re supposed to. This depletes your blood volume (as well as fluid from tissue) and causes dehydration (and possibly ‘thick’ blood). When I had obvious dehydration the worst, my POTS and chest tightness episodes was the at it’s worst too. I think it’s a contributing factor to POTS. Look for signs of dehydration when it happens again – pinch your skin and if it’s slow to return it’s possibly a sign. I’d just press my finger in my cheek and it would stay indented! Remember you need salt also, to retain fluids when you are re-hydrating.
I also noticed that my ‘diastolic’ (lower number) blood pressure was always above 90 when I had a chest tightening. Be governed by the way you feel my friend, don’t try to stand up if it causes chest tightness or pain, this just adds to the burden, you’re heart is obviously struggling under it’s current conditions (your internal state) it needs your help to do so. Carry out tasks in a seated position as much as possible for now, until you can get to the bottom of it.
Your raised heart-rate from sitting to standing is typical of POTS autonomic dysfunction. From your additional symptoms, dizzyness it does sound like possible raised intracranial pressure. I’d be asking my GP for a head and neck MRI. I’d be asking the radiographer to look for an ‘Empty Sella’ or ‘Partially Empty Sella’ (Squashed pituitary); any degree of ‘cerebellar ectopia’ this is where you hindbrain descends into (or beyond) the opening of your skull (foramen magnum) and can press on your brainstem; any amount of excess CerebroSpinal Fluid (CSF) in and around the brain area; any stenosis of the Transverse Sinus; any enlargement of the Internal Jugular Vein (which can put pressure on the Vagus Nerve).