Disequilibrium, Rather than [POTS], Is the Primary Determinant of Orthostatic Intolerance in Patients with [LC], 2026, Miwa

[forestglip]

Disequilibrium, Rather than Postural Orthostatic Tachycardia Syndrome, Is the Primary Determinant of Orthostatic Intolerance in Patients with Long COVID

Miwa, Kunihisa

Background
Orthostatic intolerance (OI) is an important factor affecting daily functional capacity in patients with long COVID. Traditionally, most OI symptoms have been attributed to exaggerated sympathetic nervous system activation associated with postural orthostatic tachycardia syndrome (POTS). Disequilibrium, also referred to as postural instability, may contribute to the development of OI in patients with long COVID.

Methods
This study evaluated 32 patients with long COVID using neurological examinations and the active 10-min standing test. Disequilibrium was assessed using the Romberg and tandem gait tests. OI was defined as the inability to complete the active 10-min standing test.

Results
Seven patients (22%) were diagnosed with OI. None of them had POTS, whereas six (86%) demonstrated disequilibrium, as detected by the Romberg and/or tandem gait test. POTS was observed in eight patients (25%), none of whom had OI. Disequilibrium was observed in nine patients (28%), six of whom (67%) had OI.

Multiple regression analysis revealed that disequilibrium was positively associated with OI (r = 0.64, p < 0.001), whereas POTS was inversely associated (r = −0.38, p < 0.05).

After 6 weeks of oral minocycline treatment in six patients and 2 weeks of repetitive transcranial magnetic stimulation therapy following minocycline in the other one patient, symptom amelioration was reported in six patients with OI. OI concomitant with disequilibrium recovered in five of the six patients treated and tested, although one patient who experienced symptom recovery failed to undergo the repeated standing test.

Conclusions
Disequilibrium, rather than POTS, was the primary determinant of OI in patients with long COVID.

Web | DOI | PDF | Journal of Clinical Medicine | Open Access

 

[Hutan]

It's all quite a mess, isn't it? We can't define the problem very well and we are throwing all sorts of treatments at it, but the treatment is outside proper trials that might actually tell us something useful.

 

[Utsikt]

There are several threads on papers by Miwa. They have been talking about disequilibrium for a while, and have a track record of doing pilots with no control group.

Search results for query: Miwa

s4me.info

 

[rvallee]

Weird stuff. Disequilibrium seems to be mostly analogous to lightheadedness here, but also mostly analogous to what orthostatic intolerance describes, so mostly circular. I have no idea how they make out that this is a primary determinant simply because it's rather common. Thirst is a common symptom of diabetes, this hardly makes it a determinant, primary or even secondary.

I've long had roughly what they describe. My balance is generally fine, I have excellent proprioception, but indeed when I close my eyes my balance becomes much less steady. It's a mostly minor issue, though, so not something I would ever think of mentioning. It seems more of a common symptom, a minor one that rarely gets asked about and seldom mentioned because it's so minor. I don't think it makes sense to think of POTS as a primary determinant of OI, so the premise is, uh, odd.

POTS was observed in eight patients (25%), none of whom had OI

This seems obviously wrong to me. I can't make sense of POTS that isn't also OI.

Damn is this all a giant mess.

 

[Jonathan Edwards]

This seems obviously wrong to me. I can't make sense of POTS that isn't also OI.

If it is just POT it makes perfect sense. Postural tachycardia is not necessarily associated with any orthostatic intolerance.

My balance is generally fine, I have excellent proprioception, but indeed when I close my eyes my balance becomes much less steady. It's a mostly minor issue,

The emergence of unsteadiness when closing eyes is an important and pretty reliable neurological sign indicating that the person is relying more on vision and proprioception for stability than is normal. It usually indicates a failure of vestibular function or something more central in midbrain. But in someone with severe 'flu' it may just indicate the severe 'flu'. It would make sense to me that it might show up in ME/CFS without a specific vestibular problem.

 

[ahimsa]

I have orthostatic intolerance (OI). I thought my symptoms were mostly due to dropping blood pressure. Could disequilibrium be a factor?

I often get an increase in heart rate when standing. I'm not sure if I qualify for POTS now but at one point I did according to my cardiologist. My other diagnosis was NMH (Neurally Mediated Hypotension) but I'm not sure how doctors/researchers view that diagnosis now (too old? outdated?).

Heart rate increases are not much of a problem for me compared to the (delayed) drop in blood pressure. I fainted on the tilt table test after 20 minutes. I get lots of presyncope symptoms if I have to stand still (at worst case I've had to sit down on the ground to avoid fainting). Moving around makes it better but eventually that's not enough and I must sit down. Lying down is even better.

I have no idea how disequilibrium relates to blood pressure drops (if at all) but I thought I'd ask about it.

Sometimes it seems like folks focus more on the heart rate increase part of OI and don't talk about blood pressure drops. But maybe I'm an unusual case? Maybe most patients don't get blood pressure drops? Or is it that blood pressure does not get measured as often?

 

[Felis Catus]

Sometimes it seems like folks focus more on the heart rate increase part of OI and don't talk about blood pressure drops. But maybe I'm an unusual case? Maybe most patients don't get blood pressure drops? Or is it that blood pressure does not get measured as often?

I've come across orthostatic hypotension* a lot but first time hearing about NMH. My ME/CFS was triggered by COVID, so my reading and interactions have been skewed towards LC and only limited to the last few years.

* drop of >20 mm Hg systolic or >10 mm Hg diastolic within 3 minutes of standing

 

[InitialConditions]

Sometimes it seems like folks focus more on the heart rate increase part of OI and don't talk about blood pressure drops. But maybe I'm an unusual case? Maybe most patients don't get blood pressure drops? Or is it that blood pressure does not get measured as often?

You might know this already, but PoTS diagnosic criteria exclude othostatic hypotension and therefore blood pressure should always be measured when testing for PoTS.

I don't know why people focus on PoTS more than OH. It would be interesting to know how prevalent each is in people with ME/CFS and OI.

 

[Kitty]

The emergence of unsteadiness when closing eyes is an important and pretty reliable neurological sign indicating that the person is relying more on vision and proprioception for stability than is normal.

I've been unable to balance with my eyes shut for as long as I remember, which I thought was just dyspraxia—am one of those people who've never caught a thrown ball or been able to walk down stairs without carefully watching every step.

But I also get so dizzy I can't sit in a rocking chair and have only ever been on one fairground ride (I blacked out), so I suppose it might be vestibular.

Or my mam was right, and I'm just clumsy and hopeless.

 

[Felis Catus]

I don't know why people focus on PoTS more than OH.

Some people always refer to their problem as POTS but if you get into conversation, it turns out they were never diagnosed with POTS but with OI and/or OH. I don't know if they prefer to call it POTS because of disinformation from their doctors or because they think POTS is a more recognised and supported condition.

 

[Jonathan Edwards]

I've been unable to balance with my eyes shut for as long as I remember, which I thought was just dyspraxia—am one of those people who've never caught a thrown ball or been able to walk down stairs without carefully watching every step.

It does not have to be vestibular. You work that out by going through all the other neurological signs. But a positive Romberg test (which is this) is abnormal and usually has an identifiable explanation.

Of course, someone with ME/CFS with OI will have OI with their eyes open so the test is not actually showing the mechanism of OI. But the test indicates that your normal set of balance mechanisms is not fully operating and I don't think it would be surprising if it showed up if the mechanism was similar to that in acute infection.

 

[Yann04]

I don't know if they prefer to call it POTS because of disinformation from their doctors or because they think POTS is a more recognised and supported condition

I think in many Post-COVID / ME/CFS communities POTS is used interchangeably with OI.

 

[rvallee]

The emergence of unsteadiness when closing eyes is an important and pretty reliable neurological sign indicating that the person is relying more on vision and proprioception for stability than is normal. It usually indicates a failure of vestibular function or something more central in midbrain. But in someone with severe 'flu' it may just indicate the severe 'flu'. It would make sense to me that it might show up in ME/CFS without a specific vestibular problem.

In my case it might be a case of labyrinthitis that happened not long after I started having health issues and recurred more or less annually for several years. It still sometimes causes the odd spinning if I move my slightly in the wrong (usually to the right) direction, so might be independent of ME/CFS, but I doubt I'll ever know, the only attempt I had at making something of it ended in the one and only "must be anxiety" I received from an ENT specialist.

I do notice however that I can walk steadily with my eyes close, but doing that while standing still feels woozy but it does fix itself as soon as I open my eyes and 'reset' my, uh, equilibrium, I guess.

 

[Utsikt]

I just tried the Romberg test now, and I notice I have to make more corrections with my eyes closed, but I’m not swaying a lot and able to stand in one spot.

I tried the gait test and really struggled with just one step.

 

[ahimsa]

You might know this already, but PoTS diagnosic criteria exclude othostatic hypotension and therefore blood pressure should always be measured when testing for PoTS.

I hope this is not too rambling (this topic is so complicated, hard to describe) but I'll try to answer.

People have different definitions of orthostatic hypotension (OH). Most of the definitions I've seen say the blood pressure drop has to happen within the first three minutes. That's the typical type of OH - when you stand up quickly you see stars, or your vision greys out, or you faint.

That type of OH does not happen to me at all. All blood pressure tests I've done in doctors' offices over the years - BP taken while lying, then sitting, then standing - were normal.

My understanding is that these typical office screenings for BP in different positions can detect OH (because it happens within a few minutes) but will not detect Neurally Mediated Hypotension (NMH), the diagnosis I got after my tilt table test - https://www.cardiovasculardiseasehub.com/archives/17731

On the tilt table test both blood pressure and heart rate are measured. I started getting symptoms after about 4-5 minutes (pre-syncope symptoms) but my blood pressure readings were normal. No blood pressure drop. After about 20 minutes of the test my BP dropped suddenly and I fainted.

Years later I had another tilt table test years for my disability insurance claim and had about the same response. This time the sudden blood pressure drop / faint happened closer to 30 minutes.

In addition to NMH (or neurocardiogenic syncope ?) I have also seen the term "delayed orthostatic hypotension." Here's one link I've saved - https://www.sciencedirect.com/science/article/abs/pii/S1566070220301582.

I have no idea what the right terms are! Especially these days because I don't read as much about it any more. ( I've been sick since 1990 )

If OH is an umbrella term for any type of drop in blood pressure while upright then yes, it applies to me. I have NMH, or delayed OH, or ??? (choose the right diagnostic term)

But my symptoms/signs do not match the typical OH definitions that I've heard a lot of doctors use. Otherwise my OH would have been detected a lot earlier earlier.

Also, it used to be (years ago) that it was possible to have a diagnosis of both NMH and POTS. But perhaps that information is outdated. Here's a link to an old handout on Orthostatic Intolerance:

https://www.dysautonomiainternational.org/pdf/RoweOIsummary.pdf

For all I know the technical part of this handout (description of why things happen) is completely wrong. But the section on how/when symptoms are triggered (bottom of page 3) matches me very well. Things that I thought were completely unrelated back in my first few years of illness (e.g., heat, standing, full stomach after eating) are all listed here.

Anyway, I hope this helps a bit and has not confused things further. I have no strong feelings about diagnostic labels, LOL!

EDIT: I forgot to add that on my first tilt table test my heart rate did not rise enough to qualify for a POTS diagnosis. I'm not sure about the heart rate on my second tilt test.

Some years later my cardiologist took my heart rate sitting/standing (not a tilt test, during an office visit) and said he thought I had POTS as well as NMH. But the POTS diagnosis really wasn't that important to me after all those years because it did not change my treatment.

EDIT 2: I also forgot to mention that during my tilt table test I was moving my feet, without even realizing it, to try to stop the blood pressure from dropping. The technician running the test came over and told me to stop moving my feet. I passed out within a minute or so after that. So that seems to be pretty good evidence that movement can lessen or delay the blood pressure drop.

 

[duncan]

I'm not sure what the authors mean by primary determinant, but I was diagnosed with OI years before I was diagnosed with POTS. Each diagnosis was made by separate well-known ME/CFS specialists. POTS was made after four days in hospital, with staff checking HR and BP after standing like once every other hour.

More to the point, besides cognitive decline, easily my most prominent symptom is lack of balance. I am constantly at risk for falling. Fortunately, I am very careful and deliberate, but my gait is more like a tilting shuffle because of the equilibrium issues. If I try to stand on one leg, like when putting on trousers, falls are frequent.

A decade or so ago, the NIH did say I had severe bilateral vestibular damage, and they speculated it could be viral in origin- but it was only speculation.

Whatever it is, it is gradually progressive, and it affects not just me standing and walking, but it has long since perished any ability of mine to drive.

 

[Felis Catus]

On the tilt table test both blood pressure and heart rate are measured. I started getting symptoms after about 4-5 minutes (pre-syncope symptoms) but my blood pressure readings were normal. No blood pressure drop. After about 20 minutes of the test my BP dropped suddenly and I fainted.

Years later I had another tilt table test years for my disability insurance claim and had about the same response. This time the sudden blood pressure drop / faint happened closer to 30 minutes.

It's possible that NMH is less common among pwME/CFS but I wonder if more clinicians have been doing the 10-minute NASA lean test, especially in the LC space, instead of the table tilt test, so they miss cases like yours.