My underlining:
- From the ICC:
"A. Post-Exertional Neuroimmune Exhaustion (PENE pen׳-e) Compulsory
This cardinal feature is a pathological inability to produce sufficient energy on demand with prominent symptoms primarily in the neuroimmune regions. Characteristics are: ..."
This is already an interpretation. And as there isn´t so far any mechansism to focus on. So it´s premature and very unwise, it may be misleading. For example, it could also be that a mechanism of "feeling ill" or "feeling weak" is affected -
my underlining and >><<
"...1. Marked, rapid physical and/or cognitive fatigability in response to exertion, which may be minimal such as activities of daily living or simple mental tasks, can be debilitating and cause a relapse.
[...]
5. Low threshold of physical and mental fatigability (lack of stamina) results in a substantial reduction in pre-illness activity level."
And from p. 18: "
a. PENE is the pronounced summation effects and after–effects of >>numerous interactive dysfunctions.<< Effects: physical and mental exhaustion, weakness, symptom flare and a prolonged recovery."
I think
this is right. But >>this<< then is once more a premature interpretation. It may hinder to grasp the difficult thing better.
I don´t want to say that there aren´t numerous interactive dysfunctions, but there are so far only tendencies known. Though there might be one core that gathers them.
It would be better to say "numerous possible interactive dysfunctions" anyway, and to let open which ones, and if they are up -or downstream of such a core, which might be the physiological correlative for the stiff exhaustion we suffer with.
I.e. fast fatiguability includes fast fatiguability of the muscles (which elsewhere was called "muscle weakness") and excludes endurance activities.
When I quickly detoriated I had for one week a "muscle weakness", I could not lift things of a certain wight. After a weak it was gone, though I still went detoriating, sadly. Also when I had EBV my movements tended to reach too far, and I was weak too - to me this looks neurological.
All the pwME I know have muscle issues, but of course that needn't be representative because I know only a very small portion out of millions pwME. If I remember correctly, Ramsay defined ME primarily via muscle weakness.
Some ppl can play guitar for six h´s but cannot walk. I can walk but can´t play guitar for longer than 2 min (then I get exhausted). Several times I have read that patients from the EBV subset would suffer from leg pain, and this is true for myself,
but I had muscle pain only under very special circumstances. And then EBV is a prominent trigger for mecfs.
My impression is that the symptoms do vary a lot. So, what is the common thing that could define one illness? I like to put:
- Why do patients feel exhausted but basically never nicely tired? Which mechanisms could be an explanation? Of note is, I think, that our disease is not degenerative, so again, why?
- Why can the exhaustion appear delayed? And even regularily delayed, as 24 or 48h seems to be often the case?
- Why is pacing a common possibilty? (I don´t see at all that pacing is restricted to movements, whilst I see that some movements are sadly part of everydays necessity.)
- Which structure could bundle all the (very) different and often strange experiences together?
- Which structure could be vulnerable (through many possible triggers) to become badly - or (better) wrongly - functioning?
- (And why would the recovery rate in outbreaks differ from that in sporadic or endemic cases, if so?)
If scientists don´t ask the right questions, they will not find out. If the data - here so far only the patient´s reports and behaviour - are not structured adroitly and possibly open (if needed), the sight will be obstructed.
I don´t thing that muscles are of any major interest, the pain is just one concrete symptom that happens to appear very often.