Orthostatic intolerance

why do children have OI ?

.. instantaneous orthostatic hypotension (INOH). The symptoms include chronic fatigue, orthostatic dizziness, weakness, sleep disturbance, syncope or near syncope, headache, and loss of appetite.

These results suggest that mechanisms responsible for INOH may depend on insufficient sympathetic activation during standing, possibly due to centrally mediated sympathetic inhibition, thus causing impairment of quality of life including school absenteeism. INOH is an important pathologic condition in children with complaints of orthostatic intolerance and can be an unrecognized cause of chronic fatigue. This condition can be identified by using a noninvasive beat-to-beat continuous blood pressure monitoring system.

1999
https://www.ncbi.nlm.nih.gov/pubmed/10590025
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I know it sounds weird, and I'm not sure that I can explain it properly, but it is possible to attribute symptoms caused by being upright to something else. It took me several years before I started to figure out that being upright (also heat) led to a certain set of symptoms like nausea, dizziness, cold sweat, feeling shaky, etc.

When symptoms like nausea or dizziness hit first me 29 years ago, even though they often came on while I was upright, I did not associate these symptoms with being upright.

I know that sounds hard to believe. How could someone be so unobservant? But it never occurred to me that standing still, or even sitting upright for long periods, could cause anyone problems! (maybe standing still for hours, but not minutes) So I thought the cause was something else.

For example, sudden nausea? Must have been something I ate earlier. Dizziness? Maybe I didn't sleep well last night. Feeling a bit weak in the knees? Maybe I did too much yesterday.

I had so many symptoms. Many of them seemed random. I could not figure out any pattern. The only thing I knew was resting made things better and exertion made things worse. And even that was a bit shaky because of the delayed post-exertional symptoms. I felt like Alice in Wonderland. This was 1990-1994 so it was hard to find other patients (I did find a listserv).

Also, not a single doctor ever asked me whether standing still or sitting upright made me feel worse. So I never thought about being upright as a trigger.

If I had ever fainted back then either my doctors or myself might have suspected that some symptoms were due to being upright. But I've never fainted other than on the tilt table test (first test was 1995). In real life (other than once last year) I've always been able to sit down in time.

Another reason I did not make the connection between being upright and having symptoms is because, for me, there is a variable delay between being upright and onset of symptoms. It is not a set time limit. It could be a few minutes or it could be 15 minutes (it's shorter now than it was back then). And sometimes, on good days (especially cold days, or in a place with good A/C), I had hardly any problems with being upright (again, that was in the early days, before I had pushed myself so much).

Also, my symptoms come on faster if I stand still right after some exertion (walk for 5-6 minutes and then stop to talk with someone) vs. getting up and standing still after I've been sitting down resting for a while. Another variable is trying to stand still right after a full meal vs on an empty stomach. [ Actually, that one I figured out early but had no idea why. I told the doctors that I had more energy (in the short term) on an empty stomach. If I skipped lunch I could do more during the afternoon. Doctors could not give me any answers on that one. ]

And last of all, I was doing subconscious things to compensate, such as leaning on things (grocery cart, walls) without realizing it, or pacing when I had to stand in line, or fidgeting in some other way.

This fidgeting was pointed out to me when my first tilt table test was done. I had started to move my feet and legs a lot. The technician told me that I needed to stop moving. If he had not mentioned it I would not have even realized I was doing it. As soon as I stopped moving my legs, I fainted. (roughly 20 minutes into the test).

I don't have the mental ability or educational background to debate theories about why being upright causes my symptoms. I'm happy to accept that we need more research to figure out what's going on.

But I can definitely tell you that I did NOT realize that being upright was causing some of my symptoms. I didn't figure it out during the first 3-4 years of my illness. Call me clueless, but it's true.

Edited to add: For me, it's not just being upright, it's being upright and being still. Walking for 5 minutes is much easier than standing still for 5 minutes. That's one of the things that made it hard to find a pattern.
 
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That makes a lot of sense @ahimsa .

But I guess for you it is not OI but intolerance of standing still. That is probably a more helpful term, maybe televant to others. It would be quite different from the common orthostatic hypotension of tall young people that comes on immediately and only with change in posture.
 
Sasha said:
I don't know enough to debate the value of tilt test but there is a certain amount of autonomic testing that can be done for OI apart from that, in order to try to find out what flavour of OI you have and to point to possible suitable treatments. So I think it's worth knowing that this is a specific symptom in its own right, and getting on the investigation/treatment track.

Some PWME seem to have done very well on their OI treatments and have regained a lot of functionality.
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I understand impedance cardiograph testing may indicate orthostatic intolerance,(https://www.ncbi.nlm.nih.gov/pubmed/12920435) if used while supine and then standing. I am not sure if this is the usual way to use this machine (the standing bit), or not. And, Holter monitor testing may indicate autonomic dysfunction, which is as I understand more of an umbrella term, and not just about problems with standing.

Doesn't Dr. Bateman's Nasa lean test sometimes show people's feet may darken or get splotchy after a few minutes of standing? I couldn't find any reference to this colour change in feet or legs, although Dr. Bateman does say in this link to watch for skin colour changes. I don't know if that means one's face getting pale, or other changes as well: https://batemanhornecenter.org/wp-content/uploads/2016/09/NASA-Lean-Test-Instructions.pdf

ETA: I am aware of impedance cardiograph testing done while supine, and then compared to standing. This may not be the usual way to do this testing. I haven't been able to find this method noted on the Net, however, I do this method has been used.
 
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alex3619 said:
I have hypertension and severe OI. The first partially protects me from the second. However doctors do not know what to make of this nor how to treat it.
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Sorry, that sounds rough. :(

I remember reading about that years ago. If I remember correctly the resting blood pressure starts out high but then has sudden drops. It sounds very difficult to treat.
 
ahimsa said:
I remember reading about that years ago. If I remember correctly the resting blood pressure starts out high but then has sudden drops. It sounds very difficult to treat.
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If I get tired enough, due to lack of sleep or over-activity, then my blood pressure can drop alarmingly and suddenly. I pass out. During my tilt table test I flat-lined. That is what severe OI can do, but nobody understands how that works with high blood pressure, and some of us also get malignant hypertension. I do wonder if some of our high blood pressure is an adaptive response.
 
Sasha said:
just googled and couldn't find a trial (which isn't to say that there isn't one). Waist-high compression stockings (of the type used for OI) are so incredibly difficult to get on that I'd be amazed if anyone kept wearing them without being convinced that they were helping them keep upright.
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I know of one trial looking exactly at that, by a POTS specialist. It may take a couple of years before that gets published, but he is a prolific researcher. I was invited but i did not feel that this particular study was worth a plane ticket, hotel and other expenses for wearing compression stockings. It is a mere mechanical device that may help in the short term but doesn’t fix anything. And indeed, the compression stockings may be useful at times, but can be hard to put on, uncomfortable in hot days and not practical on a daily basis. They are also expensive and you have to wash them. So lots of effort, little reward or benefit and then, can you actually compress our torso to squeeze extra blood to the brain? i didn’t think so. :rolleyes:
 
rvallee said:
Not that it would have changed much, there is still no expertise in either OI or dysautonomia in Canada and when I asked my GP she had never heard of it
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There are. For instance the doctors who work with spinal cord injuries are well aware of POTS and autonomic disruptions as it applies to paraplegic population. They get POTS. There is a cardiologist in Calgary who sees and researches POTS patients and other dysautonomias. There is a cardiologist in Vancouver who is knowledgeable.
 
Milo said:
There are. For instance the doctors who work with spinal cord injuries are well aware of POTS and autonomic disruptions as it applies to paraplegic population. They get POTS. There is a cardiologist in Calgary who sees and researches POTS patients and other dysautonomias. There is a cardiologist in Vancouver who is knowledgeable.
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Which cardiologist? I know someone who has an appointment in Vancouver coming up about this.
 
alex3619 said:
If I get tired enough, due to lack of sleep or over-activity, then my blood pressure can drop alarmingly and suddenly. I pass out. During my tilt table test I flat-lined. That is what severe OI can do, but nobody understands how that works with high blood pressure, and some of us also get malignant hypertension. I do wonder if some of our high blood pressure is an adaptive response.
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I’ve only ever passed out once and it wasn’t through standing I had a bad cough and was watching a very funny film which set me laughing so hard I was crying coughing and laughing all at the same time. Which made me pass out. I definitely don’t have severe OI. In fact until we started this discussion i didn’t know that OI was simply having problems standing - and doesn’t need to be immediately on standing - but covers having difficulty when required to stand still for a few minutes such as at a shop till or Drs Reception desk. And as I have problems standing for a few minutes I therefore have the symptom OI. (A term which I promise never to mention when talking with my GP and will only ever describe in plain English)

Maybe I only have trouble standing it on these occasions because my hypertension balances it out the rest of the time. BP is reasonably well controlled by meds my systolic is more normal than my diastolic. I don’t know if that’s relevant. GPs seem less bothered about diastolic than systolic.
 
Years ago preparing for my first visit at Dr Klimas, i was asked to take my BP and HR first thing in the morning, first laying down, then 1 minute after standing, then 5 minutes, then 10 minutes. 7 days in a row. The first time i did it, i actually passed out. Thankfully i was standing by my bed.

i really dislike the term orthostatic intolerance. Intolerance suggests mental weakness when it is a physiological issue.
 
This is a pretty interesting topic. I get the feeling OI is sort of peripheral and I think it's fair to say we don't quite know what's causing the OI. Is there any evidence it simply isn't low blood volume? What worried me from Systrom's talk is he said boluses of saline alleviated the preload failure and normalized results. If that's the case, what is the significance of the preload failure finding.

I've had a liter of saline infused, I'll admit, I felt a little more limber, but still quite I'll.

I wonder if it's neuromuscular things could cause OI just as much as autonomic problems. Or simple it taking more energy to stand.
 
Here's a link to Miriam Tucker's article on orthostatic intolerance and exercise intolerance findings presented at the NIH conference. It has been linked elsewhere on the forum, but I think it's relevant here. To me, it looks like there is progress on finding explanations for the orthostatic intolerance symptoms.

(Medscape requires registration, but it's easy.)

https://www.medscape.com/viewarticle/911666#vp_1
 
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dreampop said:
Is there any evidence it simply isn't low blood volume?
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There seems to be evidence from Systrom for an apparent low blood volume when cycling. There have also been reports of real low blood volume using tracers The question for me is whether these are the same thing and what, if any, this has to do with the autonomic nervous system.

If the problem is an autonomic one then the suggestion is that failure of constriction of lower veins leads to a low central venous pressure (low preload). But that does not mean threw blood volume, just that it is all in the feet when upright. This situation would be expected to be associated with an actual increase in blood volume because the blood vessel capacity would be increased by being 'flabby'.

This is where accounts be people like Peter Rowe leave me confused. Taking in more salt or water might be relevant to a real low blood volume but would not be relevant to an apparent low volume of autonomic origin, at least not on a steady state basis. Yet he seems to link the problem to the autonomic nervous system.
 
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