Deconstructing post-exertional malaise in myalgic encephalomyelitis/ CFS: A patient-centered, cross-sectional survey, Chu et al, 2018

[Tom Kindlon]

 

[Tom Kindlon]

 

[Tom Kindlon]

 

[Tom Kindlon]

 

[Tom Kindlon]

 

[Tom Kindlon]

 

[Mithriel]

Their results chimed very well with my experience and spelt out the differences between the reaction to exertion in ME and other illnesses. i have tried to explain this so many times over the years and now I have a good way of doing it.

If I have really overdone things, I start by having a sore throat, swollen glands, fever and fluey feeling but after a few days I start to feel depressed and hopeless. I never mad the connection myself but when it was pointed out to me I could see it was happening. It passes in a few days.

When my kids were small and I was drop down exhausted I would get a sudden intense depression. If I had a quick nap, even a few minutes, it passed.

 

[Mithriel]

Thinking how to describe sensory overload. I experience actual pain and distress in the presence of loud noise. Bright lights make me disorientated and even milder noise and light wear me out.

I think it might be that the brain can't filter out input.

Reading the paper again, it seems like it gives us a good starting point for finding if someone has PEM. If no other illnesses have immune symptoms after exertion that gives a specific category of disease not matter which definition they fulfil otherwise. I would like research on ME and for the pseudodisease CFS to be dropped (not the patients, the disease category) but if we all have this sort of PEM we could all be moved to whatever we call that category and then subdivided afterwards.

 

[Hoopoe]

It is not surprising that PEM time course fluctuates within individuals. The post-Fukuda case definitions [19–22] as well as patient accounts [22, 38, 46] note that there are variations not only between but within individuals. The threshold needed to trigger, moment of initiation of, severity of, and time span of PEM depends on both the baseline state of individuals (e.g. Did they sleep well the night before? Do they have a concurrent cold? How much total activity did they engage in this week so far?) and the type, intensity, duration, and frequency of the trigger applied. As one patient who is also a physician described it, the “safety zone” for avoiding PEM “moves around” [46] and this unpredictability contributes to patients’ problems scheduling and participating in occupational, educational, recreational, social, and personal care activities.

I was revisiting this today and found this paragraph. This seems to confirm that I'm not the only one who thinks that activity during the previous days matters.

This has implications for research, treatment and guidelines: that a patient was able to do something without symptom worsening does not mean that they can do it again or do it frequently or that they are no longer susceptible to PEM. For example the approach developed by heart rate assisted pacing proponents can sometimes sound as if the only major factor is avoiding exertion of a certain intensity (heart rate).

An accurate understanding of PEM triggers could make it possible to develop a predictive model. It probably tells us something about the illness, although I don't know what.

 

[Mithriel]

I don't think it will be possible to predict PEM, it is just too variable. I have type 2 diabetes which most people can control with diet or medication. However my blood sugars vary dramatically and unpredictably because of my ME. The liver releases sugar if someone feels ill and there is a lot of advice for both types of diabetes on how to deal with it in acute illness but nothing about chronic illness.

The ME makes my blood sugar go up, the high blood sugar makes my ME worse. This is in a system I can measure with a machine but the same thing must be happening in many if not most bodily systems.

Also, a system becomes chaotic when it changes state even though there is a steady force acting on it. Think of a pile of sand. If more sand is being dropped on it at a steady rate it will suddenly change shape. These systems are impossible to map.

In our bodies we can have something going wrong because of ME, say a lack of available ATP is preventing the signal going to your nervous system to increase your blood pressure as you stand. The drop in blood pressure triggers other consequences like making you feel faint so you have to lie down. The ME is only affecting the brain every place else is working perfectly but the consequence of that is to make our PEM feel worse.

I am probably not explaining myself very well. What I do hope is that the underlying mechanism of ME can be elucidated so we can treat PEM at source before it begins. That will give us an understand which might make it more manageable.

 

[Sly Saint]

This might have been posted elsewhere and is not direct response to this paper but to another attempting to validate SEID.
I picked up on it because of this, written by Lily Chu:

Second, although the authors acknowledge lack of a PEM-specific item in their study, I wish to re-emphasize that post-exertional fatigue is not equivalent to post-exertional malaise. As described in the NAM report, PEM is not only increased fatigue following activity but also involves exacerbation of other symptoms, like muscle/joint pain, problems sleeping, headaches, cognitive dysfunction, sore throats, tender lymph nodes, and flu-like feelings (1). Furthermore, PEM can be delayed by hours to days relative to the triggering event and last hours, days, and even longer. In a recent survey (4) of almost 800 patients, over 90% endorsed the NAM’s description of PEM. In contrast, almost 70% felt that Dr. Jason’s conception of PEM, with its focus on fatigue (5) and lack of time-related characteristics, did not match their experiences. If PEM is conceived of as only post-exertional fatigue and chronological traits are not accounted for, study participants who do not actually experience PEM may be mis-classified as fitting the SEID criteria. The NAM report recognized that, currently, no short, accurate questionnaire exists for identifying PEM and strongly urged development of one.

https://bmjpaedsopen.bmj.com/content/post-exertional-fatigue-not-equivalent-post-exertional-malaise