Importance of Post-Exertional Malaise Ignored/CDC/ CFS Case Definition

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From na <[log in to unmask]>:

Importance of Post-Exertional Malaise Ignored and other Problems in

CDC's CFS Case Definition

na AgardyAccording to an article in CFIDS Chronicle 2005-06 the CDC

will revise its case definition of CFS. Let us hope that such a

redefinition will clarify the ambiguities, distortions and

incompleteness in the current Criteria. I raise three issues in relation

to the definition. Confusion in the Use of 'Fatigue' Terminology

Much of the literature and also the abstracts of the recent

Computational Challenge arising from the 'Genetic and Environmental

Factors Impact Chronic Fatigue Syndrome' study

(http://co-cure.org/pharmacogenomics.htm)

illustrate the ambiguities in the terminology which give rise to unease

and irritation in sufferers and confusion to all who try to make sense

of it. The terms 'Chronic Fatigue Syndrome', 'chronic fatigue', 'chronic

medically unexplained fatigue', 'fatiguing syndromes', 'fatiguing

illness' appear to be used interchangeably. The terms are not

interchangeable. Calling the condition 'fatigue' in the first place has

been a source of abuse to sufferers as it continues to be misconstrued

as tiredness or psychiatrically induced lassitude. Is this deliberate or

is it careless reporting? Consistency in the use of terminology is

essential and it is time the CDC put an end to the confusion instead of

perpetuating it. Not only is CFS a heterogenous condition, the CDC

reports fudge it with other heterogeneous 'fatigue' conditions.

Notwithstanding the potential of discoveries for the diagnosis of CFS

the basic definition will remain important so that sufferers can be

selected for advanced diagnostic tests.

Central Importance of Post-Exertional Malaise is Ignored

The CDC's emphasis on ubiquitous 'fatigue' confuses CFS with the

symptoms of any number of fatiguing conditions. Yet, even severe fatigue

does not differentiate CFS from other conditions. Surely, it would be

more productive to focus on the symptom which does differentiate CFS

from other conditions; post-exertional malaise. How many other diseases

are accompanied by a condition where periods of activity might be

possible, only to be followed by debility which is delayed so that it

may not even begin for 24-48 hours after exertion and lasts for days or

weeks, even months if the exertion was severe? The quaint word

'malaise', reminiscent of 'the vapours', barely begins to describe the

crushing experience which may consist of all of the symptoms in the

definition and many more. The centrality of this symptom is widely

recognised by researchers and clinicians including the authors of the

Canadian case definition who have been consulted by many thousands of

CFS patients.

Apart from distorting the symptomatology of CFS, ignoring the

significance of post-exertional malaise has allowed CFS sufferers to be

subjected to exercise programs which have severely damaged some of them.

How does the CDC manage to side-step such an extraordinary symptom which

is surely unique? One would think that any scientist whose job is the

disinterested investigation of phenomena would be agog with curiosity at

such a symptom. Instead, the phenomenon is shunted aside in favour of

amorphous 'fatigue', the extraordinary is treated as ordinary and the

phenomenon is listed as just one among a rag-bag and incomplete

collection of symptoms. Its significance is further minimised or even

omitted by some writers about CFS. Dr Vernon et al in their preliminary

study of gene expression recognise the significance of exercise for

sufferers but in their study we are still not told whether the subjects

had post-exertional malaise as a symptom before the study. Its recent

study again illustrates how the CDC virtually ignores this symptom.

None of the abstracts of the CFS Computational Challenge following the

Genetic and Environmental Factors study mention post-exertional malaise

and its relationship to the findings. Perhaps this is because it was

never specified as a variable in its own right among the various

measures, but rather appears to have been bundled into a total score of

items in the CDC CFS Symptom Inventory.

(www.pophealthmetrics.com/content/3/1/8)

It appears that in the self-rating scale subjects were asked to state

the frequency of post-exertional malaise (most of the time, some of the

time, etc) and the score was combined with severity ratings. However,

post-exertional malaise is triggered by activity and so anyone

successfully avoiding activity triggers would be likely to underrate its

occurrence although it is part of their symptom list. As far as we can

tell this was the only measure which included post-exertional malaise,

giving it a minuscule role in the total scores. The other scales used in

the study appear to be concerned with general measures of fatigue and

disability applicable to a variety of conditions.

With the use of the current case definition what does it mean when a

researcher states that the subjects in their study 'met the CDC criteria

for CFS'? How can this extraordinary symptom be treated as optional in

four out of eight symptoms when researchers are trying to discover the

defining characteristics of this complex illness? How can it be

considered as an alternative to, for example, impaired memory and

concentration, headache, muscle pain and joint pain? How can the CDC

carry out scientific investigations with such ambiguous criteria? Is

such ambiguity and looseness tolerated in any other area of medical or

other science? The physiological correlates of this symptom should be

urgently investigated.

The study by Peckerman et al (

www.cfids-cab.org/cfs-inform/Coifs/peckerman.etal.03.pdf ) illustrates

that clear results can be achieved by sub-grouping subjects according to

this symptom. It found that people with post-exertional malaise had

lower cardiac output compared to those without the symptom. This should

be treated as a finding of great significance!

In the interest of precision in science and in the interest of patients

one would hope that the CDC will make this symptom an essential part of

the case definition, specify its presence or absence in its own research

and require other researchers to specify the same.

'Medically Unexplained Fatigue'

It must also be time to remove from the CFS definition that 'fatigue'

should be 'medically unexplained'. The corollary of this statement is

that if there is an explanation the condition is not CFS. There is by

now enough evidence from numerous studies (ignored by the CDC), of

severe underlying factors in CFS. The practical consequence of this part

of the definition has been that as soon as a diagnosis of CFS is

suspected and basic tests are normal, doctors are discouraged from

carrying out more advanced tests, thus confirming the preconception that

there are no abnormal findings and no medical condition underlying CFS.

This again has caused CFS sufferers no end of harm, resulting in them

being labelled lazy, malingering, having erroneous beliefs, etc.

Hopefully, there will soon be an end to this circular, unscientific

thinking.

There are also many omissions in the CDC definition, for example,

cardiac symptoms, low blood volume, orthostatic intolerance,

neurological problems, infections and sensitivities, just to name a few.

It is hoped that the CDC will include the full reality of CFS in its new

definition and provide for use of a consistent name which refers

consistently to the same condition, acknowledge the centrality of

post-exertional malaise and stop stating that CFS symptoms are medically

unexplained. All of these issues matter very much to patients and

doctors in the everyday search for a diagnosis of CFS where genetic and

other complex tests are not yet within reach.

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