Understanding Muscle Fatigue in Chronic Fatigue Syndrome

[msf]

It´s a pity that Wessely and his ilk seem to have co-opted a perfectly good word. It´s made the discussion a PC one rather than a scientific one. If you are a scientist (or even just a rational thinker), and someone is perceiving (or feeling if you don´t like that word) pain because of lactic acid etc, what is more likely to stop them perceiving pain, CBT or getting rid of the lactic acid?

 

[jimells]

There is plenty here to criticize, even in such a short document.

a debilitating disorder of unknown aetiology, characterised by severe disabling fatigue in the absence of alternative diagnosis.

We have seen this misleading description so many times that we don't even notice it anymore. My illness is *not* characterized by fatigue; it is characterized by an inability to create energy. Not even a psychobabbler would describe a broken bone as "characterized by disabling pain". "Absence of alternative diagnosis" is equally problematic. I would have the "alternative diagnosis" of M.E. if I could find a competent physician that dared to use it.

patient descriptions of their fatigue regularly cite difficulty in maintaining muscle activity due to perceived lack of energy.

"Perception" is irrelevant. Muscles fail to contract when they run out of ATP and/or other important molecules. Once again, "perceived" is used as a weasel word. I reject this attempt to sit on the fence between the psychobabblers and competent biomedical research. It may well be an attempt at diplomacy, but it is not helpful for patients, and does nothing to eradicate the stigma against us. These researchers should know better by now.

I sure hope the full text is written better than the abstract.

 

[Chrisb]

If fatigue is not perceived you will not know that you suffer from it.

 

[duncan]

The concept of "perceived" is redundant when a word like pain or fatigued is used in the context of the sufferer.

It potentially has embedded in it the same derogatory element as "self-reported" symptoms.

It is yet another possible psychological end-around.

 

[Marco]

But the results of the review didn't seem to indicate a signalling issue:

To be fair to me (which I'm all in favour of) I haven't read the paper yet but as @msf said I fear we're tying ourselves in knots because of how others have misappropriated certain words.

At the moment all we have is perception. If the paper is saying that there is proven pathophysiology that can explain the perception of fatigue (or to use another word, our experience of fatigue) then surely that's a good thing?

 

[Marco]

If it were just "perceived", because signalling is broken, then how do you explain PEM? Our "fatigue" and other symptoms are signalling us we're doing too much, if we don't listen we'll get PEM. If it were just a signaling problem, we'd just ignore fatigue and lead a normal life. We'd be fatigued but functioning.

Who is the 'we' in this scenario? After receiving certain signals indicating say pain, fatigue or infection, pre-conscious parts of the brain will initiate various immune and autonomic reactions which have nothing to do with whether or not we choose to ignore them. For example 'viral onset' causes a persistent immune signalling dysfunction long after the infection has cleared. The brain can't distinguish between a real infection and dysfunctional syndrome. That's one possibility - I'm sure there are many others.

 

[msf]

It seems like most of you are seeing this as a sop to Wessely and co., which it might be, but it´s sad when scientific debates are affected by concerns about political correctness. The only way I think Prof Newton could have avoided this is if she went step-by-step through how lactic acid in the muscles ends up as a sensation in the brain, but I´m not sure that the entire mechanism is actually understood.

Anyway, the fact that I saw this as a step forward shows just how mired in psychobabble the whole UK ME effort is (with the possible exception of those B cells guys, although I haven´t really looked into that).

 

[Sasha]

To be fair to me (which I'm all in favour of)

I haven't read it either - just the abstract.

I fear we're tying ourselves in knots because of how others have misappropriated certain words.

Those people are still very active and dominate the field in the UK so I think they'll take every opportunity to keep right on misappropriating.

At the moment all we have is perception. If the paper is saying that there is proven pathophysiology that can explain the perception of fatigue (or to use another word, our experience of fatigue) then surely that's a good thing?

The abstract doesn't even seem to be saying that - it's saying that there's pathophysiology and "Potentially, these abnormalities may lead to the perception of severe fatigue in CFS/ME". So it's plastering a lot of doubt over even the idea that what's been seen to lead to a perception of fatigue. And it seems very odd not to say, "could lead to either severe fatigue or the perception of severe fatigue".

I don't understand the mechanism of fatigue (and I don't know any biology so I don't know if anybody does) but if their tests showed that our muscles have completely run out of oxygen (for example), surely that would be just plain fatigue and not "the perception of fatigue", because the lack of oxygen would cause the inability to do more work?

 

[msf]

I don´t think that is the case though, at least not in all but the bedbound (who they never study anyway). I mean, if I saw a tiger in the street I am sure I would still run away from it, even on my worst day, and even if I felt really tired at the time.

 

[Sasha]

I don´t think that is the case though, at least not in all but the bedbound (who they never study anyway). I mean, if I saw a tiger in the street I am sure I would still run away from it, even on my worst day, and even if I felt really tired at the time.

I meant that as an analogy rather than literally (sorry - I should have made that clear!). I don't know what the body consumes for energy at a cellular level and what the biochemistry is that limits work. Plus a jolt of adrenaline is going to do something).

 

[Cheshire]

Who is the 'we' in this scenario? After receiving certain signals indicating say pain, fatigue or infection, pre-conscious parts of the brain will initiate various immune and autonomic reactions which have nothing to do with whether or not we choose to ignore them. For example 'viral onset' causes a persistent immune signalling dysfunction long after the infection has cleared. The brain can't distinguish between a real infection and dysfunctional syndrome. That's one possibility - I'm sure there are many others.

So in that case scenario, it's not just sensation involved. It triggers other "automatic" reactions.
A simple signalling impairment can't explain anything. Or it supposes we are neurotics excessively afraid of ("real") fatigue feelings.

 

[Marco]

The abstract doesn't even seem to be saying that - it's saying that there's pathophysiology and "Potentially, these abnormalities may lead to the perception of severe fatigue in CFS/ME". So it's plastering a lot of doubt over even the idea that what's been seen to lead to a perception of fatigue. And it seems very odd not to say, "could lead to either severe fatigue or the perception of severe fatigue".

That sort of equivocal language seems pretty typical in many papers - perhaps necessarily where findings need to be replicated and causal links have yet to be established. But fair point.

 

[Marco]

So in that case scenario, it's not just sensation involved. It triggers other "automatic" reaction.
A simple signalling impairment can't explain anything. Or it supposes we are neurotics excessively afraid of ("real") fatigue feelings.

I tend to disagree. A signalling abnormality that triggers physiological response could explain a lot.

 

[msf]

I meant that as an analogy rather than literally (sorry - I should have made that clear!). I don't know what the body consumes for energy at a cellular level and what the biochemistry is that limits work. Plus a jolt of adrenaline is going to do something).

But if there is always an ability to do more work then the inactivity can´t be explained without reference to the amount or quality of fatigue that the brain perceives, which after all makes the decision about how whether to do an activity or not.

Haha, now I´m starting to sound like a psychobabbler. It should be simple: pain, heat and sound are all perceived; all these perceptions ultimately have physical causes, even if they originate in the brain. The physical cause in this case most likely does not originate in the brain, but rather in the muscles as a result of over production of lactic acid.

 

[Sasha]

But if there is always an ability to do more work then the inactivity can´t be explained without reference to the amount or quality of fatigue that the brain perceives, which after all makes the decision about how whether to do an activity or not.

When I was talking about adrenalin I was assuming that adrenalin gives you a short-term alternative chemical pathway that produces energy but that once you've burned through that, you're stuffed, and even if a tiger is chasing you, you've got nothing more in the tank. I really was indeed talking about biochemical limits of energy production. There must be some.

 

[msf]

Yes, but I don´t think those apply in the case of ME, apart from perhaps in the bedbound, who like I said are not included in UK ME studies anyway.

 

[jimells]

I really was indeed talking about biochemical limits of energy production. There must be some.

When I am halfway up the basement stairs and my legs start quivering because the muscles are unable to sustain contraction, that is clearly a biochemical limit of energy production. I first experienced this sort of complete muscle failure while playing saxophone. Any wind instrument requires continuous contraction of facial muscles. When those muscles stop working, it is quite dramatic and noticeable because what comes out of the horn in no way resembles "music".

 

[msf]

So does someone help you up the rest of the stairs? What happens if they don´t?

I´m not doubting that people ME do not produce enough energy in their muscles, but I think the brain is aware of this (it perceives it through some neurochemical process) and unsurprisingly adjusts the amount of activity accordingly.

 

[Seven7]

@msf I think is more a blood vessel issue, Because I have the same issue, If I am stuck middle of the stairs and cannot keep going I do turn off like a tv slowly, I stop talking, being unable to hear then all goes black (apparently as my husband moves me I shake) then a few hours later I come to consciousness.

Funny enough, If I take the vasoconstriction drug none of this happens (midodrine). So when I am in midodrine I can go up the stairs, when the drug runs off I can then not go up the stairs. Is very interesting to feel the difference and understanding the energy production issues when you use the drugs. Because you can compare your reaction to the different activities when on it vs not. You learn to differentiate the ME vs OI issues. About pain, I have a few types. The immune activation one (joints pain) then that one there is no amount of OI meds that will take it of it. Flue like symptoms (is ME not OI) and so on.

 

[BurnA]

The concept of "perceived" is redundant when a word like pain or fatigued is used in the context of the sufferer.

Just noticed this paper co authored by J Newton
Perceived fatigue is highly prevalent and debilitating in patients with mitochondrial disease.

I don't know why perceived is used here either but thought i'd mention it. Its seems completely unnecessary.