Post-Exertional Malaise - a discussion including defining and measuring PEM

[Andy]

I would actually challenge the idea that anyone actually experiences 'energy depletion'.

I consider myself challenged then.

I suspect that they have an overwhelming sense of inability to initiate a task.

If that were true then why would pacing be so important? I have nothing like what you suggest - if I let myself then I would have numerous initiated tasks that I would then not complete, due to what I can only describe as a lack of energy, however technically accurate that might or might not be.

 

[richie]

That doesn't seem to me to describe my experience at all.

It's not about autopilot. I know very well the routine of, for example, having a shower, and do it on 'autopilot' but am completely exhausted by it. If I have a shower on the same day as one or two other activities of equal amount of physical activity, or try to shower every day for several consecutive days while doing my normal very limited routine of other lighter activities and rests, I'm likely to crash.

The idea of autopilot, if I understand it correctly, doesn't seem to take into account the cumulative effect of lots of individually manageable activities, especially if done without sufficient rest between them, that can lead to crashing.

I can walk about my house, that's on autopilot, I start walking without any feeling of effort requiring extra concentration, yet after about 10 steps it becomes less secure, and if I try to keep walking for more than about 20 metres, I feel my legs are going to collapse. Standing still is even worse than walking. Apart from feeling generally unwell at the start of my ME, that feeling of legs about to collapse and an urgent need to sit down was startling and seemed really odd.

Yes, I agree.
I was paraphrasing past posts from other people but I also recognise your account from past posts. It isn't a simple autopilot thing. And I recognise your account from my own recent post-Covid phases. But it seems quite complex.

When we first discussed these things five years ago I remember emphasis on it being post-exertion rather than post-activity/exercise - I think largely driven by the fact that mental exertion could cause PEM. Now I hear you saying, in effect, that showering, at least to start with, does not require exertion, just letting the body do its routine. So the problem is post-activity.

To me that leads back to the idea that there is some accounting system going on in the central nervous system that is likely sensitive to immune cytokines at nerve endings and maybe shifts in sugar hormones that is at a subliminal level and that operates over quite long time frames (more than minutes at least) which, like a trip switch on a fancy modern appliance, turns off the operating system despite all measurable molecules being normal. And when it trips it can take a long time to free up.

Maybe we are searching around for a simple account of what seem to be cause and effect relations when the process is going on at a control level that at present we cannot think of a good model for.

Maybe a division can be made between PEM with explanations along your lines and other exertion intolerance where such things as muscle probs from aberrant protein, low o2 uptake may be part of the mechanistic picture. As stressors they may contribute

Yes, I agree.
I was paraphrasing past posts from other people but I also recognise your account from past posts. It isn't a simple autopilot thing. And I recognise your account from my own recent post-Covid phases. But it seems quite complex.

When we first discussed these things five years ago I remember emphasis on it being post-exertion rather than post-activity/exercise - I think largely driven by the fact that mental exertion could cause PEM. Now I hear you saying, in effect, that showering, at least to start with, does not require exertion, just letting the body do its routine. So the problem is post-activity.

To me that leads back to the idea that there is some accounting system going on in the central nervous system that is likely sensitive to immune cytokines at nerve endings and maybe shifts in sugar hormones that is at a subliminal level and that operates over quite long time frames (more than minutes at least) which, like a trip switch on a fancy modern appliance, turns off the operating system despite all measurable molecules being normal. And when it trips it can take a long time to free up.

Maybe we are searching around for a simple account of what seem to be cause and effect relations when the process is going on at a control level that at present we cannot think of a good model for.

What about the question of what is benign controlled ?. I'm thinking of e.g the aberrant muscle protein or C Thomas low oxygen uptake . It may be the accounting system is wrong but that there are perhaps abnormalities that need accounting for which strain and corrupt the system.

 

[Jonathan Edwards]

If that were true then why would pacing be so important?

Andy, you seem to be conflating the situation where you feel reasonably 'energy replete' when you might have taken on a task but know not to because of learning to pace and the situation of having done the task, feeling 'energy depleted' and at that stage having an overwhelming sense of not being able to initiate anything further.

Surely the symptom of energy depletion is the second situation. Pacing is designed to steer away from it.

 

[Trish]

Now I hear you saying, in effect, that showering, at least to start with, does not require exertion, just letting the body do its routine. So the problem is post-activity.

No, that's not quite right either. If I could stop after a minute or so and go and rest for half an hour before doing the next minute, that would be true, but the exhaustion, increasing weakness, pain, OI etc kicks in fast, it doesn't wait for me to complete the activity.

 

[Jonathan Edwards]

What about the question of what is benign controlled ?. I'm thinking of e.g the aberrant muscle protein or C Thomas low oxygen uptake . It may be the accounting system is wrong but that there are perhaps abnormalities that need accounting for which strain and corrupt the system.

When I say a control system I am talking about control of the capacity to execute tasks. Lots of control systems may affect that - cardiovascular regulation, which fails in heat failure, sugar regulation which fails in some (rare) endocrine conditions, central nervous regulation as in Parkinson's, acid base regulation in kidney disease etc. For most of these except CNS we ought to have been able to measure some abnormalities, at least in severe cases, and so far we haven't.

I am not sure what C Thomas low oxygen uptake is.

I think that you are suggesting that there might be some failure of muscle cell metabolism such that however much the control system works there is a limit on capacity for activity. From everything I have seen so far this seems to me unlikely. People with ME who are doing quite well suddenly relapse badly and I don't see how that is easily explained with some continuing defect of muscle metabolism. Most muscle pathologies are to some degree regional - distal or proximal or something like that. As a result people develop trick movements to take advantage of the less affected muscles - and may get patterns of atrophy and hypertrophy. I don't see any evidence for that in ME.

What would make sense would be some genetic variation that made muscle more susceptible to a control system failure through cytokine signalling in response to activity or something like that.

 

[Trish]

Andy, you seem to be conflating the situation where you feel reasonably 'energy replete' when you might have taken on a task but know not to because of learning to pace and the situation of having done the task, feeling 'energy depleted' and at that stage having an overwhelming sense of not being able to initiate anything further.

Surely the symptom of energy depletion is the second situation. Pacing is designed to steer away from it.

What about the experience of running out of energy during a task and having to stop?

I don't know what is going on physiologically, but I know it feels like running out of energy, but it could, biologically, be something different I guess, perhaps something switching off like not enough nerve impulses reaching the right muscle cells, or something.

The question of whether we can initiate a task, or resist doing so because we know we need to pace seems confusing to me.

I think it's more about whether we can do (ie start or continue) an activity at any particular moment physically, even if we're choosing to ignore pacing and any concerns about consequences.

 

[Andy]

Andy, you seem to be conflating the situation where you feel reasonably 'energy replete' when you might have taken on a task but know not to because of learning to pace and the situation of having done the task, feeling 'energy depleted' and at that stage having an overwhelming sense of not being able to initiate anything further.

No, I'm not conflating anything. I feel a sense of energy depletion all the time - and this gets worse the more I do, up to a point where I don't feel the ability to initiate anything else. Sorry if that doesn't make scientific sense but that is how it is for me, and I believe many other people as well.

 

[Trish]

No, I'm not conflating anything. I feel a sense of energy depletion all the time - and this gets worse the more I do, up to a point where I don't feel the ability to initiate anything else. Sorry if that doesn't make scientific sense but that is how it is for me, and I believe many other people as well.

Me too, Andy, except I would add - it gets worse the more I do, up to a point where I have to stop what I'm doing and don't feel the ability to initiate anything else.

The effect is cumulatlve.

 

[Jonathan Edwards]

No, that's not quite right either. If I could stop after a minute or so and go and rest for half an hour before doing the next minute, that would be true, but the exhaustion, increasing weakness, pain, OI etc kicks in fast, it doesn't wait for me to complete the activity.

OK then I would say you aren't on autopilot anymore because the need to exert to keep showering has kicked in right away! Although I actually think the previous version was better.

 

[Trish]

OK then I would say you aren't on autopilot anymore because the need to exert to keep showering has kicked in right away! Although I actually think the previous version was better.

You may be right. I think it could be an imagery problem where I'm interpreting the use of the autopilot image differently from you. I think of the pilot as the brains and the plane as the muscle, and I'm saying I shower on autopilot in the sense that I'm not needing to use my brain more to shower. The problem is engine failure, not pilot error, to mess up the analogy further.

 

[Jonathan Edwards]

No, I'm not conflating anything. I feel a sense of energy depletion all the time - and this gets worse the more I do, up to a point where I don't feel the ability to initiate anything else.

I understand that Andy, but you did say that if it wasn't for self-discipline through pacing that you would go off and do things and then regret it later.

As for what Trish says, it all makes sense as a starting point for scientific modelling but I am just wary of using the term energy depletion when even in colloquial terms it looks as if it has more than one meaning.

 

[duncan]

it all makes sense as a starting point for scientific modelling but I am just wary of using the term energy depletion when even in colloquial terms it looks as if it has more than one meaning

Would malaise work better for you? As a scientific term?

 

[Jonathan Edwards]

The problem is engine failure, not pilot error, to mess up the analogy further.

And maybe I am saying that we should not think it is likely to be either. It is the circuitry in the cockpit electronics that makes the pilot rightly sense the plane is un-flyable even though the fuel tanks are full and the engines ticking over.

It is like my new gas boiler. It stopped working. It was under guarantee. We wanted it sorted and rang the people who fitted it. They suggested getting on to the boiler company to check if the problem was under the guarantee. But the guarantee was only valid if we had had the boiler serviced. So we went back to the fitters to ask for a service. The boiler was fine that day. So we got our service box ticked and had a working boiler. But the next day the boiler didn't work. The coming Monday it did work and the fitting people said there was no point in looking at it again if it was working. Especially as I had tried every possible combination of turning things on and off to see what tripped the problem and got no sensible answer whatsoever. So we had a boiler that was totally unreliable for reasons that made no sense and probably were not under the guarantee that now was valid because ewe had had a service.

Fortunately after a fortnight the boiler stopped not working and has been fine since.

Having had two recent bouts of post-viral (Covid) fatigue I am pretty certain that this sort of model applies there. The body has all the right equipment to run for a bus but trying to change a lightbulb leaves me lying on the sofa feeling sick and exhausted. At the moment our understanding of neuroimmune connections does not provide any obvious explanation for the longer term ME situation and nobody can find anything wrong, but I am sure there is.

 

[Andy]

As for what Trish says, it all makes sense as a starting point for scientific modelling but I am just wary of using the term energy depletion when even in colloquial terms it looks as if it has more than one meaning.

So what should we use then? What terminology would be 'acceptable' to researchers? It seems to me that, as per usual, pwME, who after all also have to deal with cognitive issues, are in a bind where we use the words available to us to describe our experience but because the words we use don't fit current scientific understanding we get, at best, criticised for using the 'wrong' words, or at worse dismissed as unreliable witnesses. Frankly I'm fed up with it.

 

[richie]

When I say a control system I am talking about control of the capacity to execute tasks. Lots of control systems may affect that - cardiovascular regulation, which fails in heat failure, sugar regulation which fails in some (rare) endocrine conditions, central nervous regulation as in Parkinson's, acid base regulation in kidney disease etc. For most of these except CNS we ought to have been able to measure some abnormalities, at least in severe cases, and so far we haven't.

I am not sure what C Thomas low oxygen uptake is.

I think that you are suggesting that there might be some failure of muscle cell metabolism such that however much the control system works there is a limit on capacity for activity. From everything I have seen so far this seems to me unlikely. People with ME who are doing quite well suddenly relapse badly and I don't see how that is easily explained with some continuing defect of muscle metabolism. Most muscle pathologies are to some degree regional - distal or proximal or something like that. As a result people develop trick movements to take advantage of the less affected muscles - and may get patterns of atrophy and hypertrophy. I don't see any evidence for that in ME.

What would make sense would be some genetic variation that made muscle more susceptible to a control system failure through cytokine signalling in response to activity or something like that.

Thanks for the clarification though I am not sure I have understood and I am surprised that nothing has been found over such a range of systems. Thomas found low o2 uptake in PMNBC's at Newcastle in an ME cohort. I have read one article from Bath (I think) where a disorder of proprioception was treated and relieved ME symptomology (or what was labelled as ME).
There are imo a variety of scenarios.

 

[Jonathan Edwards]

Would malaise work better for you? As a scientific term?

Malaise works for me on a very simple basis - that PWME do not feel tired, they feel ill. And that situation is familiar to me and most people having had flu (the malaise paradigm) and trying to do things resulting in feeling terrible. That does not make me equate the two but just the basic idea that PEM is not tiredness was crucial to my getting some idea of what it might men.

And it seems that even the colloquial use of 'energy' is confusing. 'I don't have the energy' is used for something that we recognise can be reversed in an instant. It can also be used for something that you can do nothing about if bombs are dropping. So it is very open to a BPS reading.

 

[richie]

You may be right. I think it could be an imagery problem where I'm interpreting the use of the autopilot image differently from you. I think of the pilot as the brains and the plane as the muscle, and I'm saying I shower on autopilot in the sense that I'm not needing to use my brain more to shower. The problem is engine failure, not pilot error, to mess up the analogy further.

Could be both. Engine problems, pilot keeps flying, enginen gets worse (potentially), pilot gets tired/overwrought. Two systems one flight experience.

 

[duncan]

Malaise works for me on a very simple basis - that PWME do not feel tired, they feel ill. And that situation is familiar to me and most people having had flu (the malaise paradigm) and trying to do things resulting in feeling terrible. That does not make me equate the two but just the basic idea that PEM is not tiredness was crucial to my getting some idea of what it might men.

Do you think, even for a moment, that malaise is any less onerous and injurious to the patient community than fatigue? Any less colloquial and laden with cultural baggage?

And it seems that even the colloquial use of 'energy' is confusing. 'I don't have the energy' is used for something that we recognise can be reversed in an instant. It can also be used for something that you can do nothing about if bombs are dropping. So it is very open to a BPS reading.

And malaise is not?

If you are searching for science speak, you'll not find it there. Science may be able to rise above culture, but it has been my experience of well over 25 years that most physicians cannot.

 

[Jonathan Edwards]

because the words we use don't fit current scientific understanding

It is nothing to do with not fitting scientific understanding or being the 'wrong' words, Andy. It is simply a matter of being unambiguous in conveying subjective symptoms to someone trying to work out what to look for to explain them. As I said before, very often when trying to make a diagnosis it helps to ask patients to forget any words they think people would often use in a context and use 'their own words' in the sense of anything you like that might help someone who cannot actually experience it. But preferably words that do not involve a hidden metaphor like energy depletion does. It assumes some sort of explanation - that there is some stuff that is at a low level.

For rheumatoid disease there is a symptom called early morning stiffness that is a bit like PEM for ME. But I would never want patients to learn to say 'I had a lot of EMS this week.' Unfortunately there are people called 'patient partners' who get taught to teach doctors how they have 'EMS'. In reality every person is different and at every clinic session I would be interested in something different about the symptom pattern, in the context of what we were trying to achieve with treatment. Nobody ever needed to define EMS in detail - the term just flags up a range of problems that are important for management.

 

[Jonathan Edwards]

Do you think, even for a moment, that malaise is any less onerous and injurious to the patient community than fatigue?

I have absolutely no interest in whether or not it is seen as onerous. I am purely interested in trying to help people research the cause so that PWME can get some treatment.

I see no evidence that the BPS people have taken malaise to be psychologisable in this context. Most of them try to deny it even exists. I am pretty sure that the term PEM was invented by people who understood malaise the way I do and that medical professions as a whole do the same.