Onset patterns and course of myalgic encephalomyelitis/ chronic fatigue syndrome, 2019, Chu et al

Open access at https://www.frontiersin.org/articles/10.3389/fped.2019.00012/abstract

ETA: Change "Paywall" to "Open access"

 

Since this adds up to 123%, it's pretty clear that some patients, perhaps many, had multiple "peri-onset events."

I'm not really concerned that 39% reported peri-onset "stressful incidents." Chronic stress might well alter the way the body responds to an infection and/or exposure to an environmental toxin.

Personally, I had all three of these "most common" peri-onset events, assuming that long hours working in a stressful job and chronic sleep deprivation counts as a "stressful incident." All three (chronic stress, infection, toxic exposure) came together about two weeks prior to onset. Oddly, on the day of onset, I actually felt that I was finally clear of all these issues.

 

Interesting. I had similar. Prolonged stress in my life including a lot of very traumatic stuff, then finally took a holiday and came down with a viral infection, and that was that.

 

I wonder if the respondents are patients who got ill when they were children/adolescents and are now adults or if they're still children/adolescents, as the journal is frontiers in Pediatrics.

And I wonder why they are using Fukuda criteria..

 

Same. Given the group, that seems odd.

If I had to guess, I'd say they had referrals from a doctor who still used Fukuda.

 

I'm pleased somebody is trying to look at different onset patterns and course of the illness.

However I'm dubious about the quality of the data obtained because:

One, they use Fukuda.

Two, 97% of the patients have co-morbidities, many with significant symptom overlap with ME/CFS.

Three, how did they overcome memory recall bias? In this information age most patients will know what a typical onset is supposed to look like. As a result a patient could easily remember a nasty viral illness around the time of the first major signs of ME and conclude that those were the trigger and onset respectively. Yet the patient may have forgotten less noticeable earlier symptoms; the patients may have had very mild ME or some form of pre-ME for quite some time and the virus just caused a crash.

Pity we don't have access to the whole paper to see how they dealt with that.

ETA: Not saying that sudden viral onset doesn't happen, just that we look back into our memory with today's knowledge and to some degree at least we find what we think we should find based on today's knowledge.

 

I am more interested in the " evolution of symptoms" part of this paper. I can recognise 5 distinct stages in my illness. Same symptoms but just different intensities leading to different levels of functioning. Each stage lasts for years so recall is fairly easy. I don't think it has anything to do with how I manage the illness.

 

Frustrating that this article is behind a paywall, as I believe what they are attempting to do is very important. Reading the abstract raises various thoughts which may or may not be relevant to this survey.

Sample size

However 150 participants is potentially very small unless we can be certain there are no inherent biases in their selection processes. Presumably any ME/CFS study in the current situation of inadequate and inconsistent medical provision will have problems ensuring a truly random sample.

That is not to say that it should not be attempted, but we must be cautious of any generalisation to all people with ME/CFS.

What is interesting is are there overall patterns, but is this sample big enough to adequately draw out any patterns of symptoms?

Stress and onset

I am sceptical of how accurate or meaningful it is to talk about stressful events being associated with onset, as most people regularly experience events that could be retrospectively designated as stressful and how do you attempt to distinguish any event(s) selected as relevant to the onset from all the other stressors in your life that were not associated with the onset of you ME/CFS.

Also given we are desperately trying to understand what is happening to us, is there not a danger we arbitrarily pick on a significant life event, that was arround the time of onset?

At the initial onset of my ME I was doing an impossible job (at the time I estimated to do it properly required at least three full time people) but that situation had been continuing for a number of years and I was also renovating a house and training as a yoga teacher and enjoying my life, until the glandular fever struck. So one could claim stress was associated with the onset, but I feel that is an arbitrary post hock association.

After a few years I seemed to experience a complete remission, I was then working part time and would say it was one of the least stressful times of my life, enjoying the opportunities of lots of free time, planting a garden, travelling, etc. I then got a bad dose of flue that triggered a major reoccurrence/relapse in my ME. How do you after the fact measure stress levels? if you believe stress is a causal or contributory factor can you predict who will or who will not get ME/CFS in the future on the basis of current stress levels/factors.

Did this study attempt to evaluate how unique the linked stressful event or stress levels were in the individuals life? If they were in a car crash, was it a unique event in their life or had they previously experience comparably significant events that were not associated with the onset of ME/CFS.

Further retrospectively we may over estimate stress because things we could do fairly easily pre onset, at onset instantaneously become very difficult and stressful because of our condition. My job was very hard work before my initial onset, but it became impossiblely stressful instantaneously with the deterioration in health. Do people project the stressfulness of a situation or activity backwards to before onset? Managing an understaffed city wide service was challenging, but once I was unwell it became impossibly stressful; can I objectively distinguish between how it impacted on me pre and post the onset of my ME now some twenty five years later?

I am not saying stress can not be a causal factor in the onset of ME/CFS but that it may be almost impossible to demonstrate it is, unless you measure stress in whole populations before the onset of any ME/CFS.

Distinguishing co occurring conditions from symptoms of ME/CFS

How do we distinguish between what is a symptom of ME/CFS and what is a co occurring condition? For example I get migraines both as result of food intolerances and as part of PEM, both of which only occurred after the onset of my ME. So I would personally describe my migraines as a symptom of my ME rather than a separate condition, though presumably in this study my migraines would be classified as a co occurring condition.

Similarly my IBS occurs as either a consequence of my food intolerances or as part of a crash. However I had had a previous episode of IBS some ten years before the onset of my ME following salmonella poisoning, though that totally resolved after a couple of months. So I still am uncertain if it is now a consequence of my ME or a cooccurring additional condition.

Ultimately such studies as this might be helpful in understanding what is a symptom of ME/CFS and what a co occurring condition.

How to establish what symptoms to look at?

We do not fully know how exhaustive or accurate current symptom lists are.

I now have orthostatic intolerance, but have no idea how long I have had this symptom befor I became aware this was a possible symptom. For some years, after several periods of detailed activity monitoring, I became aware that resting in a chair was less restful than lying fully prone, however I had attributed it to sitting even with my head supported requiring more exertion than lying. As my ME deteriorated over the last five or six years I became increasingly aware both of the concept of orthostatic intolerance and of the syndrome of POTS and that the amount of time I spend vertical is as much a restriction on activity as levels of exertion.

However there was a period of time, when I retrospectively believe orthostatic intolerance was emerging, but when I would not have been aware enough to include it under an 'other symptoms' ootion on a questionnaire.

How much does our current understanding of potential symptoms impact on what we are able to report? How much does the researchers' symptom list impact on their results?

How long post onset?

I was surprised that the twelve common symptoms declined in severity over time, but wonder what this relates to. My personal experience is that my responses to such questions would relate to when I was surveyed, given I have a relapsing and remitting form of the disease, but overall my lows get lower and the number of symptoms I experience increases over time.

Given cognitive factors are reported as getting worse over time, does this imply there is ongoing neurological damage that has cumulative effects?

Also with symptoms like fatigue, they could decline in severity over time not because the condition is remitting but because the individual gets better at managing the condition, better at avoiding triggers of PEM.

The longer post onset the harder the concept of 'normal' becomes. Should I be comparing what I can do now as an unfit sixty year old with what I did as a fit and active thirty something year old? Can I clearly remember what it feels like not to be unwell? I do remember in periods of remission how amazing it was to have a fully functioning brain, and being surprised at how I had come to accept impaired cognition as normal. Can we distinguish in questionnaire data, between actual functional improvement and acceptance or normalisation of impairment.

Also over time the demands we make on ourselves changes dramatically. Pre onset, I might work a ten hour day, do an hours' house work, have a shower, cook a couple of meals from scratch, socialise, take the dog for several walks, have a yoga practice and do some study in a day, and immediately post onset I strove to get back to doing that. Whereas now a very good day might involve heating two microwave meal, stepping out of the front door once, having a shower and watching a couple of hours of TV lying on the sofa; how do you compare subjective things like fatigue between a situation where I was attempting sixteen hours plus of full on activity and wher I am attempting gentle activity for four or five hours spread across a whole day!

I guess these questions could only be addressed by prospective studies, following people newly diagnosed over years and decades.

(Sorry this got such a long comment. Tried to use formatting to make it easier to read.)

 

One possible answer is that, as time goes by, patients learn how to manage their ME as best they can and consequently reduce the number of crashes/amount of time spent in PEM.

 

Like many people, I had an infection from which I never recovered so there is no recall bias involved. Remembering whether you had a childhood trauma, say, is one thing but knowing when you went from an active functioning person to a sick mess is another; you experienced it and are not trying to recall something.

Before CFS, extreme widespread pain was seen as part of ME, afterwards I was surprised when that pain began to be called a distinct illness. Fukuda CFS includes pain but is a bit wishy washy about it so I believe fibromyalgia is overdiagnosed in people with ME as not enough doctors try hard enough to distinguish between them. Likewise anxiety is not exactly a separate disease the way having psoriasis or asthma would be.

Many people with MS believe that stressful situations caused the first major episodes of MS they experienced (looking back they can often remember dropping things or tripping over their feet but not unusual enough to see a doctor) My own psoriasis flared up during a stressful time. If ME involves autoimmune disease or immune dysfunction it may well be the same.

I think Andy is right that we learn to cope with things. I do not experience many of the symptoms I used to get even though I am generally worse because I am never so exhausted nowadays. Now I can stop as I no longer have children depending on me.

 

Also changes in our circumstance, as you highlight, can make a big difference. Not working now places far fewer demands on me, therefore my symptoms, on average, aren't as bad as they used to be.

 

There are UK CFS clinics where patients are told that they "must" have had a stressful event before onset and encouraged to remember what it was... By stressful they mean emotionally stressful.

It's still happening here even now.

 

Strange isn't it? The post-viral hypothesis was discounted because, it was said, everyone is exposed to several viruses each year (though not the sort that cause a once or twice in a lifetime illness). On the other hand, if you look hard enough, you will find a stress factor-notwithstanding that everyone has several stress factors. It's all quite clear and rational...just not to me.

 

When will researchers stop using Fukuda?

Emphasizing stress as a precursor is very popular in less understood illnesses. It blames the patient. People who break a leg aren't asked if they were stressed beforehand.

 

Well, maybe they should? If they were stressed, maybe they didn't pay enough attention to where they were going and so put themselves at risk for breaking a leg. See? That way we could blame even more people for their health issues

 

Yes! The Ministry of Blame and Illness Prevention.

 

I don't feel there is "neurological damage" in my case, it feels more like an energy deficit.

 

I think it says "provisionally accepted" and "will be published soon".

 

The white matter hyperintensities seen on my MRI imply damage, albeit of a very mild stripe.

 

@JaimeS I'm sorry to hear this. Based on your symptoms, do you feel that your cognitive function is declining over time? Do you have periods where you feel 'normal' again?

There are times when my cog function is poor, but I go through periods where I'm functioning higher than healthy people! This is why I feel that in my case it isn't permanent.