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

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197811

 

I admit to on!y reading the abstract but:

Is it normal to experience emotional distress as part of PEM?

In the early days I got upset because I just couldn't figure out what the hell was happening, but this was a consequence of PEM not part of it.

Nowadays, it naffs me off, but I don't find it distressing so much as frustrating. Sometimes, not even that as I know it it's just part and parcel of having ME.

 

I read that as, both physical and cognitive exertion and emotional distress caused PEM for 90% of people in the study. It then goes on to say, "Almost all were affected by exertion but 14 (10%) reported no effect with emotion", and "Exertion precipitated significantly more symptoms than emotional distress..."

 

Ah, OK. I read this as PEM including physical, cognitive issues and emotional distress, rather than caused by.

I was a bit surprised.

 

Properly defining PEM is extremely important – all too often it seems to get confused with plain exercise intolerance - so I appreciate the efforts by the authors.

Unfortunately the article is too long for me to read in full so can't comment on how well they have achieved this but I was puzzled by this apparent contradiction:

First the authors capably discuss the various diagnostic criteria including the problem with Fukuda – i.e. that PEM is optional.

But then they use Fukuda (PEM optional) to select patients for their own study that has as its express purpose to explore PEM???!!!

Have I missed something that explains this?

 

My assumption would be that they didn't want to presuppose anything about PEM, or at least no more than was unavoidable. This seems to be borne out by a section discussing limitations of the study:

 

I’ve read this and I like, it mainly because it goes way beyond fatigue and properly defines PEM with key symptoms. It is an informed definition of PEM with defined triggers, symptoms and timeframes using a reasonably sized cohort. Worth a read.

“The overwhelming majority (90%) of subjects experienced PEM with physical/ cognitive exertion and emotional upheaval. Aggravation of multiple symptoms, a median of 7 and 5, respectively, was the rule rather than the exception. For 8 out of 11 symptoms, at least a third of subjects encountered them under either situation (Table 1). Some symptoms are commonly observed with physical exertion even in healthy people (e.g. muscle pain) while others are atypical (e.g. flu-like feelings, gut-related symptoms, sensory overload), neither reported by healthy people nor people affected by other medical conditions. Because our questionnaire listed specific symptoms rather than combinations (e.g. “sore throat/ tender lymph nodes” [35]) or categories of symptoms (e.g. “autonomic” [36]), a direct comparison to Workwell’s findings is not possible. Nevertheless, the multitude of symptoms recollected by our subjects reflect those of Workwell’s subjects. For example, fatigue-, pain-, and sleep-related symptoms were the top 3 categories noted by Davenport [36], analogous to the first, fourth, and fifth most common symptoms observed by us post-exertion (fatigue, muscle pain, sleep disturbances). Other symptom combinations they used such as “light-headedness/ vertigo” were not a part of the 11 symptoms we listed but emerged in the open-ended portion of our questionnaire.”

 

There's a lot of good stuff in here, especially how they describe PEM in the discussion section.

But I do think they could have done more and better with their own study and method.

They could have enrolled patients diagnosed via International consensus or Canadian criteria, not Fukuda, thus making sure patients were actually likely to have true PEM (though that probably still isn't 100% certain unless the diagnosing clinician is experienced enough to not confuse PEM and exercise intolerance – part of the point of the paper). As a bonus, this would also send a signal to other, maybe less well-informed researchers to stop using Fukuda almost as a reflex. While they're at it, they could stop using those pointless Fatigue score questionnaires with questions so vague they cannot possibly be answered in any meaningful way. (This is discussed in @Trish's members only thread on FSS – also used in the present study - “How would you fill in the Fatigue Severity Scale?”)

Alternatively they could have stratified their enrolled patients into those who meet International/Canadian and those who only meet Fukuda and reanalyse their data separately. This could potentially have shown differences in how PEM is reported, qualitatively or quantitatively. It might also have explained the discrepancy between their own findings and Workwell's.

This raises – but doesn't answer - the question whether it actually was only 42% of their subjects who experienced “true” PEM and the others experienced various versions of exercise intolerance symptoms? A bit like the difference between strictly defined ME and more broadly defined CFS maybe? Or whether their idea that a different set of symptoms may detect more cases of PEM is correct. I was for example surprised their chosen 11 symptoms didn't include orthostatic intolerance or tachycardia.

In summary, the discussion of PEM in this paper is excellent. The actual study is a little disappointing because it doesn't add a great deal new, though it's always good to confirm findings from prior research, especially when that research is still a bit sparse.

 

Lily Chu has been quietly and humbly being our champion and ally for so many years, and I am continually blown away by her contributions. Of course it goes without saying that so have Montoya et al, but I wanted to take a moment to offer a much-deserved shout-out to Ms. Chu who has stayed the course and keeps showing up for us in so many different powerful ways. Thank you Lily Chu!

 

Out of curiosity, is there a clear definition of flu-like feelings and sensory overload?

Does flu-like feeling refer to a specific kind of sensation that appears in the flu (together with less specific sensations such as malaise, fatigue, fever) or is it a term used to describe how you feel during an infectious illness?

What is sensory overload exactly?

 

I think it is and flu is generally known.

 

I agree. She was a great help to me in 2010-2011 with my paper:
"Reporting of Harms Associated with Graded Exercise Therapy and Cognitive Behavioural Therapy in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome"
http://iacfsme.org/PDFS/Reporting-of-Harms-Associated-with-GET-and-CBT-in.aspx

A small correction: she is a qualified medical doctor so best to call her Dr Chu

 

https://twitter.com/user/status/1003770439074832385

 

Tuesday, 3 July 2018
More welcome research on post-exertional malaise (PEM) in ME/CFS
by
Paul Whiteley PhD
<https://questioning-answers.blogspo...search-on-post-exertional-malaise-cfs-me.html>

 

useful for reference for NICE?

 

New phrase to me

 

I imagine a big contributing factor to the discrepancy is that the Workwell Foundation studies involved repeat exercise testing. That is an extreme exertion that many people would avoid.

 

People could add other symptoms. Here are the others mentioned:

 

https://twitter.com/user/status/1015679690550468608