The Concept of ME/CFS, 2024, Edwards

Sorry @Simon, I miss things.
Are you saying that you think there are two groups of PVF (inc post-Covid):
1. Similar to more typical fatigue, delayed or non-resolution of the initial fatigue?
2. And ME/CFS or similar?

I am suggesting that most post-viral fatigue may not be ME/CFS - in that it is a prolongation of maybe a 'sickness behaviour' infection response and lacks certain crucial elements of ME/CFS symptomatology that may indicate it is not the same process. (There may of course be further subdivisions.) I am not sure that it would necessarily be that similar to the fatigue of heart failure or MS.

In rheumatology we have arthritis (comparable to fatigue maybe). A major proportion of cases have mechanical causes (osteoarthritis) and behave differently in things like not having prolonged inflammatory stiffness in the morning. Then we have inflammatory arthritis which we divide up into what we can now see are different processes but which in some cases are very hard to tell apart. There are differences in sex ratios, number of joints affected, cyclicity of signs and then things like rashes.

I wonder if usual PVS after EBV has a more or less 1:1 sex ratio for instance? And does it have 'crashes'?

Some of the first category might wind up with an ME/CFS diagnosis but my guess is that most will be recognised as just failure to improve after EBV - i.e. PVFS.

I have no doubt that some people develop ME/CFS in the aftermath of EBV. Whether they are distinguishable in the first year from those who will resolve I don't know. I am not sure that I have seen things analysed to tease that out. The Dubbo study I think assumed that ME/CFS was just the long tail of an exponential decay of fatigue that went on after 2 years.

I really don't know but my main point is that although ME/CFS and PVFS may look indistinguishable in many cases they may be distinct and maybe we could do more to separate them out. It is of course possible that the trigger to ME/CFS is early PVFS - that ME/CFS engages a loop, onearm of which is provided by the PVFS.

 

There's unlikely to be a better time to study that as right now. There seem to be a lot of people whose experience of long Covid looks broadly comparable to post-EBV fatigue. Perhaps it tends to persist for longer, but they do recover.

I wonder if they experience that urgent need to lie down (if sitting up), or sit down (if standing)?

 

Actually, the more one thinks of this the more complicated it may get.
I remember in post EBV fatigue that I thought I could try stuff and then felt feeble and wretched if I did. With post Covid fatigue I just feel there is no way that I can try stuff. Moreover, if I do, I just feel more of the same 'empty battery' but do not feel wretched as I did post EBV. I am not saying that I think that will be consistent for others but it seems to mean that there are several components to this that can combine in different ways.

 

Different cohorts in this imaginary study, then? It'd be interesting to know if there are symptoms or experiences reported in ME/CFS that a significant proportion of those who recover don't get.

The sex ratio idea is an interesting one. Still room for bias in the results, but maybe less subjective than looking at symptoms alone.

 

I'm interested to find out more of her thinking on this. If she hasn't already she will have to take into account that there will be moderate and mild patients whose horizontal hours will be pacing hours, not due to severity but to keep from deteriorating to a severer level.

I will check to see if we have a thread on this already.

 

Thanks for expanding on PVFS vs ME/CFS.

Dubbo looked at changes in symptom pattern using the SPHERE questionnaire that captures psychological and physical symptom: they used factor analysis to reduce these to 6 domains 2 they felt captured acute illness:

• “acute sickness” (including items such as “headaches” and “fevers”)
  
• “irritability” (including “feeling irritable or cranky” and “rapidly changing moods”).

Four others were "reminiscent of classic descriptions of post-infective or chronic fatigue states".

• Fatigue
• “musculoskeletal pain”
• “mood disturbance” (with items such as “feeling nervous or tense” and “feeling unhappy or depressed”),
• neurocognitive disturbance”. (featuring “poor memory” and “poor concentration”).

I don't know if the neurocognitive factor and maybe muscle pain are features of PVFS. There was a substantial change over time, shown in fig 3 (more detail in fig 2):

After 6 months, they said the pattern was similar across all 3 precipitating infections.

Does the above shed any light on this?
The changes over time might reflect changes for everyone, or it could be that the 28 cases with CFS (Fukuda) looked different early on.

Only 5 cases in Dubbo; I'm not sure about other studies, but I don't think there is a pronounced sex ratio difference, though all the studies are small.

Seem to - but neurocognitive symptoms were prominent as well as fatigue, and appeared later.

 

Maybe we need a Dubbo brainstorming session. I should look t it again. I am a bit occupied with other things for a bit but then that is always the case!

 

Great idea. I think it's a fascinating study, but too small, and I'm not sure the stats are totally sound due to multiple comparisons.

Curiously, a much bigger, EBV-only Sydney version of Dubbo was planned but never happened. Even though Dubbo is probably the most highly cited biomedical-pointing study (888 citations, Pace has >1,100, but many of those will be critical). But then psychiatrists and psychologists were prominent Dubbo authors - Andrew Lloyd is an infectious diseases specialist, but (now at least) strongly BPS in outlook. A much later reanalysis of Dubbo data featuring key original authors played up psychological and psychosocial factors.

There was the later and larger Lenny Jason study at Northwestern university EBV/GF study that looked for biomedical factors. But the timing of blood sampling was erratic. That may or may not be why they found little without creating an apparently post hoc oddly defined "severe-ME/CFS" category (based on criteria not severity data)- though they found no evidence of psych causation either.

 

That is an interesting feature.

My starting point is that not only are cognitive problems my most disabling symptom (in terms of what I want to do, though my physical symptoms are in some ways more severe), but that over 90% of PwME report having them. And I had assumed that it was a major problem for many people - maybe that's not the case.

Agreed!

I agree it is important and was not questioning it, only whether it should be at the top of the symptom list.

Can you point me to data on the proportion of people experiencing it? I had thought it was a symptom that is often neglected in surveys. Particularly when framed as 'the need to lie (sit) down'.

I think it would be very helpful to get better data on the recumbency issue vs cognitive problems.

I don't know the best way to measure severity. Certainly hours affected by OI-type issues is one, but it might depend on activity. I spend around 3 hours lying down on a well-paced good day, it could be most of the day when I need to take part in travel and cognitive activity - such as a trip to hospital. Bu I don't want to drag the thread off topic.

 

Important to think of OI as not just recumbency but feet-upsy. I lie down several hours a day but for the rest have to have my feet up, apart from about an hour of feet on the floor.

 

I didn't take it as having been used in a hierarchical sense in the paper. I took it as a useful symptom (from a long list, some of them common in other conditions) to highlight because it's both characteristic and odd.

Doctors who read the paper will be familiar with patients who find it difficult to stand upright for long periods, but there's usually some explanation for it. And they don't tend to have the same difficulty sitting upright.

Some people with ME/CFS have significant difficulty with both, and it makes no sense at all. That makes it distinctive and interesting.

 

This is helpful, and I like the "hours with feet on the floor" question.

But without knowing severity, it's hard to judge the relative important of a symptom to someone.. I wonder if we need a measure of how much a symptom impact on someone (which is severity independent to a degree). I suspect no single Q won't do it, but perhaps it would help if people listed/ranked the three symptoms that impact them most.

 

Would it be easier when answering a symptom questionnaire to also have a point system for impact of said symptom on daily functioning and how badly one would rate this symptom on a scale of 1 to 5? Might be a bit harder to directly deduce which symptom is "worse" from such a questionnaire, but that might anyways be a bit tricky since symptoms seem to overlap somethimes (for example cognitive dysfunction seems to be related to PEM or someone might report worsened cognitive fnction when upright etc). To get what you want the scale would then probably also somehow have to be shifted towards one side to get meaningful answers (or you could introduce a further question for all the things that were rated as maximally impacting), otherwise you'd get the same maximal scores for something like OI and cognitive dysfunction simply because they severely affect someones life, even if that person thinks the one symptom is actually much worse than the other.

If you were to only ask people which symptom is worse than the other you might learn more about what they value or what their previous profession was rather than how "bad the symtoms are" (one person might value being able to spend more time upright and doesn't care much about their cognition, because being upright alone let's them enjoy one of their hobbies or perform a job, whilst someone else might say they don't care if they are upright or not as long as their brain functions normally as this might give them back the ability to work if they can do so purely using their thoughts whilst lying flat).

 

Yes, that's an interesting one.

I've so rarely had difficulty spending my waking hours with my feet on the floor that the issue wouldn't even feature on my symptom list, yet I'm severely affected by standing for very short periods. I have to use a powerchair even when I can manage the walk from my car to a shop counter, because if there's someone ahead of me in the queue, I can't stand for long enough.

I don't know whether my feet on the floor time has an impact on my moderately severe cognitive dysfunction. It might do, it's just difficult to test properly because I can't sit with my feet up on a stool or a recliner (an unrelated condition makes it really painful), and lying down is also more uncomfortable pain-wise than sitting up.


Other people will probably have different examples of ways their ME/CFS presentation varies from the typical, but it's still important to be able to capture it. It might eventually say something about subgroups or alternative diagnoses.

 

A brief peer review on Qeios by Nigel Speight:

Link | PDF

 

Thanks for the heads up. They used to notify me but don't seem to now.
I thought I was pretty rude about the BPS people!

 

Sky's the limit, though!