I added the "not explained by anything else", but otherwise that basically seems like the NICE definition. They don't specify any specific symptoms in this definition.PEM is not defined as «delayed worsening of any symptoms not explained by anything else», though?
Why not? I think the most potentially useful way to separate PEM from pretty much anything else is that following a delay after exertion, symptoms get worse. The delay and the exertion components are the interesting parts, not the specific symptoms, in my opinion.What if you only get a delayed headache? Or only delayed light sensitivity? Is that PEM? What about other symptoms like vomiting? Seizure?
I meant for studying. If you want to test your hypothesis about PEM, only include those with often-delayed worsening as subjects. That may entail the risk of incomplete picture, but that's better than ending up with a wrong picture. At least till we have some idea what its mechanism is.And I’m not sure what you mean by «for research purposes», can you clarify?
That seems reasonable to me.I think something that might make sense would be to exclude people that do not have «often delayed» PEM from research, i.e. that appears to have «mostly instant PEM» or «mostly instant symptom worsening». At least until we figure out the ones with delay.
I’ve taken that to mean «symptoms within the context of what we have described ME/CFS as».I added the "not explained by anything else", but otherwise that basically seems like the NICE definition. They don't specify any specific symptoms in this definition.
I agree that the delay after exertion is the interesting part - but if you don’t use an inclusion criteria of symptoms you definitely have to experience worsening of, you’ll end up including lots of things that probably are not related at all.Why not? I think the most potentially useful way to separate PEM from pretty much anything else is that following a delay after exertion, symptoms get worse. The delay and the exertion components are the interesting parts, not the specific symptoms, in my opinion.
Maybe. So in that case, delayed fatigue, brain fog, and unrefreshing sleep are the three things required for it to be PEM?I’ve taken that to mean «symptoms within the context of what we have described ME/CFS as».
If someone had worsening fatigue, brainfog, and vomiting after 24 hours consistently, and the vomiting was considered related to PEM and not some total coincidence, then I don't see why it can't be related to PEM if it's on its own.If you have fatigue, OI, brainfog, and/or all of the «usual» ME/CFS symptoms, but the only thing that happens 24 hrs after exertion is that you start vomiting, do you have PEM?
We don't even know if ME/CFS is one thing. Maybe if it's just the symptoms listed on NICE, it's one process, and if it includes gut symptoms and feeling cold, it's something entirely different. If we don't know whether these different presentations are the same or different, how can we know whether any specific symptoms are "probably" something different?you’ll end up including lots of things that probably are not related at all.
I wouldn’t like that definition. Definitely had “refreshing sleep” until I became very severe.Maybe. So in that case, delayed fatigue, brain fog, and unrefreshing sleep are the three things required for it to be PEM?
I would think so? You have to have those symptoms, and they have to generally worsen when you get symptoms worsening following exertion.Maybe. So in that case, delayed fatigue, brain fog, and unrefreshing sleep are the three things required for it to be PEM?
I was thinking about if only vomiting occurred, and the other symptoms stayed the same. Sorry, should have been clear about that.If someone had worsening fatigue, brainfog, and vomiting after 24 hours consistently, and the vomiting was considered related to PEM and not some total coincidence, then I don't see why it can't be related to PEM if it's on its own.
Because it doesn’t make any sense that the same process can lead to completely different symptoms worsening following exertion. Some variation around common themes - sure. Completely different in unrelated systems - I don’t understand how.We don't even know if ME/CFS is one thing. Maybe if it's just the symptoms listed on NICE, it's one process, and if it includes gut symptoms and feeling cold, it's something entirely different. If we don't know whether these different presentations are the same or different, how can we know whether any specific symptoms are "probably" something different?
My main concern would be avoiding misdiagnosis of potentially treatable/manageable conditions. I think of it a bit like hEDS vs EDS. The latter have a genetic signature, the former is just lumped together because some of the symptoms are the same as EDS and is probably not a very helpful concept.My main concern is patients having a diagnosis and a community, and I don't think it's helpful to exclude people based on picking out specific symptoms when we already have the decent cutoff description using delay and exertion.
Yeah, good point. The CCC have some symptoms you have to have, and some from a list where you need X of Y.I wouldn’t like that definition. Definitely had “refreshing sleep” until I became very severe.
My sleep helped so much. I was just sleeping like 14 hours.
What about a definition that needs at-least 3 from a list of things like:
- fatigue
- brain fog
- unrefreshing sleep
- headaches and migraines
- stomach/bowel/ibs type symptoms
I think it is absolutely possible to have one common underlying process with different sets of "modulating" factors on top of it that change disease presentation. I would have said that my own early illness and later illness + stimulant PEM patterns were completely different except for the fact that I was fatigued in both. there is probably different biology happening due to disease duration and the various effects of a stimulant, but there has to be some driving force that's the same in both cases.Because it doesn’t make any sense that the same process can lead to completely different symptoms worsening following exertion. Some variation around common themes - sure. Completely different in unrelated systems - I don’t understand how.
No, I understood. I'm saying if we accept that vomiting is part of the pathophysiological PEM process if it occurs alongside fatigue, it seems logical to assume it could be related on its own as well.I was thinking about if only vomiting occurred, and the other symptoms stayed the same. Sorry, should have been clear about that.
I'm mainly considering a delay of a single symptom if it's already associated with PEM if combined with other symptoms, as above for vomiting or fatigue. For other symptoms, the question I have is if a delay of some completely unrelated symptom after exertion even happens in anyone consistently, and doesn't already have a name?Because it doesn’t make any sense that the same process can lead to completely different symptoms worsening following exertion. Some variation around common themes - sure. Completely different in unrelated systems - I don’t understand how.
Who is missing out on treatment in this situation? I'm saying specifically if an explanation comes along for a delay of a specific symptom after exertion, like vomiting, it gets to graduate to a new label. If not, the people with only the vomiting symptom aren't missing out.My main concern would be avoiding misdiagnosis of potentially treatable/manageable conditions. I think of it a bit like hEDS vs EDS. The latter have a genetic signature, the former is just lumped together because some of the symptoms are the same as EDS and is probably not a very helpful concept.
Well research already often uses stricter criteria. Even if the NICE definition was amended to not require unrefreshing sleep, researchers could continue on using CCC.And too much noise for research.
I just think its arbitrary to use 3 symptoms instead of 1. I think we should err on the side of being potentially over-inclusive, not over-exclusive, for the sake of patients who, without the established ME/CFS communities [edit: like this forum] and support systems, [edit: and without any other diagnosis], might be left to fend for themselves.What about a definition that needs at-least 3 from a list of things like:
But literally 50+ % of the population is likely to have delayed fatigue or muscle soreness after exertion.I just think its arbitrary to use 3 symptoms instead of 1. I think we should err on the side of being potentially over-inclusive, not over-exclusive, for the sake of patients who, without the established ME/CFS communities [edit: like this forum] and support systems, [edit: and without any other diagnosis], might be left to fend for themselves.
I agree on prolonged recovery but delay is also noted in sarcoid post exertional worsening (but not always), so even delay is not a fool-proof identifier. I have heard "the next day....." from Pompe's disease sufferers and that is a definite metabolic disorder.Mea Culpa. I left out "typically" or "often".
Actually, no. I'm talking more about PEM definition applied to other condition rather than ME/CFS. Not requiring the delay will end up including energy deficit and others. And I'm not sure if requiring prolonged recovery time can differentiate ME/CFS PEM from PEM look-alikes of other conditions, including aging.
Stricter definition is necessary IMO if you are trying to investigate "PEMs" of other conditions are indeed worthy of looking into for ME/CFS PEM investigation.
Is that the case? With muscle soreness, there's the DOMS diagnosis, right? But, people often suddenly get a lot more fatigued a day later? Maybe I'm working with an incorrect assumption that that is pretty rare.But literally 50+ % of the population is likely to have delayed fatigue or muscle soreness after exertion.
I’m just working from how I experience things when I was healthy and my friends and family talk.Is that the case? With muscle soreness, there's the DOMS diagnosis, right? But, people often suddenly get a lot more fatigued a day later? Maybe I'm working with an incorrect assumption that that is pretty rare.
Even it vomiting is the only symptom that happens? So you go from baseline fatigue, OI, etc., do an exertion, and then start throwing up a day later, but with no changes to your other symptoms? Is the vomiting then PEM?No, I understood. I'm saying if we accept that vomiting is part of the pathophysiological PEM process if it occurs alongside fatigue, it seems logical to assume it could be related on its own as well.
I don’t understand what you mean here, I might be too foggy atm.I'm mainly considering a delay of a single symptom if it's already associated with PEM if combined with other symptoms, as above for vomiting or fatigue.
I don’t know if it happens to others or if it has a name. But it isn’t automatically PEM just because it hasn’t been defined as something else.For other symptoms, the question I have is if a delay of some completely unrelated symptom after exertion even happens in anyone consistently, and doesn't already have a name?
I don’t know if they are missing out on treatments. But what are they missing out on if not included in PEM? And why is even «not wanting people to miss out» an argument for expanding a diagnosis?Who is missing out on treatment in this situation? I'm saying specifically if an explanation comes along for a delay of a specific symptom after exertion, like vomiting, it gets to graduate to a new label. If not, the people with only the vomiting symptom aren't missing out.
If we treat PEM as we would with a diagnosis, then it makes no sense to include things in PEM that we don’t have a reason to believe will behave like «regular» ME/CFS PEM.The bottom line is that medical diagnoses are really much more about predicting the future than describing the situation now. They are there to tell people what will happen, including how likely treatments are to change what happens.
Hmm, yeah I suppose. I think my mental model of PEM is a delay plus it lasting strangely long (greater than 2 or 3 days) plus it being quite out of proportion to the exertion.I’m just working from how I experience things when I was healthy and my friends and family talk.
But it seems pretty common to have a big day where you’re pumped up with energy, do a lot of things, feel pretty good. And then the next day you try to do something and realise “oh damn I’m tired”, and have to take a chill day. So usually not delayed 24+ hours but like 1-12 hours.
Yeah the out of proportion thing is crucial.Hmm, yeah I suppose. I think my mental model of PEM is a delay plus it lasting strangely long (greater than 2 or 3 days) plus it being quite out of proportion to the exertion.