Myalgic Encephalomyelitis or What? The International Consensus Criteria (Frank Twisk, 2019)

Bit confused now. Maybe if I rephrase my argument our differences will become clear. As I see it, the authors used different phrases to describe PEM from different case definition or questionnaires.

One phrase that came from the Ramsay’s definition was “Prolonged worsening of symptoms after physical activity”. That one got the highest approval (89%) of ME/CFS patients. But this has little to do with muscle fatigability.

I suppose there were other phrases that came from Ramsay’s definition such as the phrases that refer to muscle fatigability. These however got much lower approval (around 70%).
That is lower than many phrases that came from the ICC such as ‘Symptoms worsen with exertion’ (87%) or ‘Post-exertional exhaustion that is immediate or delayed’ (85%).

So I don’t think it’s correct to say that muscle fatiguability is “more highly endorsed as a description of PEM than the actual descriptions given in ME-ICC.”

Hope this makes sense and that I’m not missing something.

 

That's where I think PEM and muscle fatiguability may differ. We think of PEM as being delayed, but that's not necessarily the case with his muscle fatiguability.

Ramsay talks about rapid weakness of muscles after exertion. So exactly what's in that study: a higher (relatively) result, then a lower one that suggests a drop in power. Ramsay describes patients walking around the building and repeating tests so the weakness can set in. So I think it's relatively fast as opposed to the 24-72-hour delay of PEM.

Yes, I understand. You're right.

I misread that section and assumed it was about muscle fatiguability rather than prolonged worsening of symptoms. That's my bad.

 

I hope I'm not too lost in all the various replies re what PEM/PENE is, or what it should be.

I would go with Ramsay's "prolonged worsening of symptoms", but say it's after physical or mental activity. It's not just muscle tiredness/weakness.

For me, and I would suspect many, if not all, outside of PEM, there is also increased pain, fatigue, weakness, OI etc., while doing an activity for a short while, such that the activity cannot be completed, or is done less ably or well. For example, something one feels just must get done, which is physically quite taxing for pwME, and half way through, the muscle pain, weakness etc., necessitate stopping. Then, next day, or the day after there is PEM. But, we also have this early fatigability, that is important. I don't know if this phenomenon is recognized enough. It's not deconditioning - when one's muscles burn so much from such short term activity. My arm muscles burn with writing or typing, not a very phsyical activity.

Hope this makes sense - just two days out of surgery, so a bit more cognitively challenged than normal!

 

I suffer from PERI - Post Exertional Rheumatic Injury instead of PEM. Exertions can cause permanent worsening. I don't meet the CCC, ICC, or SEID, yet I'm considered very severe (100% bed bound).

Edit: I would say I have atypical ME although it could be an undiscovered form of EDS.

 

I usually experience muscle ‘burning’ almost immediately during/after minor exertion. It is unusual for me not to have burning in my arms, for example, it is almost constant. I imagine this is what Ramsay meant by fatigability? I guess I think of PEM more as the day after - or hours after - when you feel generalised awfulness, slammed by exhaustion, and all or many other ME symptoms worsen, such as head feeling punched/inflamed. And cognitive function declines too. FWIW I also had muscle abnormalities documented in late 1983 by EMG and muscle biopsy, under Behan who worked with Ramsay.

Edit: just to add PEM was not used in 1983, I am not sure when I first became aware of its being used...And I definitely experience both PEM and muscle fatigability, but I can almost separate them out in my own illness, though they do tend to bleed into one another. Muscle weakness I also experience but I see that as different from fatigability though of course one can experience both at once.

 

Same here.

 

In a paper about inherited peripheral neuropathies, burning muscles (and fast muscle fatiguability) went under muscle weakness.

 

And how many subtypes are being umbrellad (if that is a word) under one definition?

I have been thinking it would be worthwhile approaching it from the clinical / patient lived experience end and gather an exhaustive list of all symptoms from all PWME and then ask many individuals to say which symptoms apply to them now, also which they have previously had and see if there are different groups of symptoms which occur together indicating subtypes.

IMHO it may be there are several similar in effect but different in nature syndromes all being treated as one condition. If a single set of criteria is trying to serve different subtypes, its not going to satisfy anyone completely and will keep being pulled this way and that.

Does that make sense? My brain is absolutely frazzled lately, can hardly string two sentences together!