Norwegian researchers asked ‘What exactly is myalgic encephalomyelitis?’ and found it is not the same as chronic fatigue syndrome. Broad criteria results in misdiagnosis and incorrect treatment. Researchers need narrower criteria to develop effective treatments.
Myalgic encephalomyelitis is a “reasonably well-defined disorder with distinct clinical characteristics”, according to research published in October 2015, which reviewed the major clinical definitions.
“Patients with myalgic encephalomyelitis have more severe symptomatology than those with chronic fatigue syndrome, but better mental health…we believe that it is important to distinguish between myalgic encephalomyelitis and chronic fatigue syndrome. Many studies have included very heterogeneous patient populations, where perhaps only a minority of individuals had what we would define as myalgic encephalomyelitis.”
The authors recommend a “more deliberate use of the diagnostic criteria” to improve understanding of the disease, treatment and patients’ lives. They also believe it will lay foundations for ramping up biomedical research.
They warn that “use of broad inclusion criteria has created a heterogeneous patient population… This has increased the risk of erroneous conclusions, misdiagnosis and incorrect treatment”. Stating the lack of success of the PACE trial, “it is unfortunate that psychosomatic therapy continues to be recommended by the health authorities”.
Better defining patient cohorts will lead to more useful research they say, but point out Norway’s Directorate of Health confusingly recommend either the Fukuda or Canadian criteria, which have many differences between them.
Agreeing with other recent research, they state ME “may consist of several subtypes, which cannot at present be distinguished using existing diagnostic criteria. Such subtypes may have distinct aetiologies and pathogenic mechanisms, which could require different therapeutic approaches.” The paper mentioned Rituximab, “the antibody treatment against B lymphocytes had beneficial effects in a majority of patients”.
They point out a recent USA NIH report “concludes that continued use of the Oxford criteria (the broadest) may impair progress and cause harm, and recommends that these criteria should no longer be used.”
Not in this paper, but it is interesting to note agreement with other scientists: At the 2015 Sweden Seminar on Essential Features of ME and CFS, Dr Leonard Jason of DePaul University (Chicago, USA) was asked about the SEID criteria (40 minutes into the video). Dr Jason said only 20 per cent of those meeting SEID criteria would meet Fukuda, due to medical and psychiatric exclusions, and that there are many different types on illness within that criteria. Comparing patients who meet the SEID criteria to those who meet the Canadian Consensus Criteria, the Canadian is the more impaired group. For researchers, the aim is to have patients as comparable as possible, however for clinical purposes, the IOM are easier to use but Dr Jason expresses concern it should not be used as research criteria.
The Norwegian paper (in English) is well worth reading for the summary of criteria alone:
Oxford criteria for chronic fatigue syndrome (1991)
Drafted by an English group consisting largely of psychiatrists (27). The main criterion is severe fatigue for at least six months. Other diseases must be excluded. The Oxford criteria are very broad, but are still used to some degree in research. Neither the Norwegian Directorate of Health nor the US health authorities recommend use of these criteria today.
Fukuda criteria for chronic fatigue syndrome (1994)
Drafted by the Centers for Disease Control and Prevention (CDC) on the basis of Fukuda et al. (28). In addition to severe fatigue for at least six months, and the exclusion of other diseases, at least four of eight defined symptoms must be present: impaired short-term memory and/or concentration, sore throat, tender lymph nodes, muscle pain, joint pain, new-onset headache, unrefreshing sleep, and post-exertional malaise. These criteria have been central to research.
Canadian criteria for myalgic encephalomyelitis/chronic fatigue syndrome (2003)
Drafted by doctors and researchers and represent a refinement and narrowing of the Fukuda criteria (6). The Canadian criteria require the patient to have six different symptoms: severe physical and mental fatigue, post-exertional malaise or fatigue, sleep dysfunction, pain in muscles, joints and the head, neurological/cognitive features (minimum of two symptoms, e.g. confusion, impaired concentration, ataxia), and autonomic, e.g. nausea and irritable bowel, neuroendocrine, e.g. loss of thermostatic stability, or immune disorders.
International consensus criteria for myalgic encephalomyelitis (2011)
Drafted by an international panel of experts from 13 countries (4) and a refinement of the Canadian criteria. A diagnosis of myalgic encephalomyelitis requires the patient to fulfil criteria within four categories: (a) post-exertional neuroimmune exhaustion, often with significantly prolonged recovery period, (b) neurological impairments, i.e. symptoms from three of four categories: cognitive abilities, pain, sleep disturbances and/or neurosensory, perceptual or motor disturbances, (c) immune, gastrointestinal and genitourinary impairments from three of five categories, including flu-like symptoms, nausea and hypersensitivity, and (d) impairments of energy production and energy transport within one of four categories: cardiovascular, respiratory, thermoregulatory and/or intolerance of extreme temperatures. The criteria have also been adapted for paediatric populations.
Paediatric criteria for myalgic encephalomyelitis and chronic fatigue syndrome (2006)
Various paediatric diagnostic criteria have been used. The Norwegian Directorate of Health recommends the criteria presented by Jason et al. (29), which require chronic fatigue for at least three months and exclusion of other diseases. Additional requirements include post-exertional malaise/fatigue, unrefreshing sleep or other sleep disturbances, pain in muscles, joints, stomach or head, neurocognitive features, at least 2 of 12, and at least one symptom within the three groups autonomic, neuroendocrine and immune. Severe psychiatric disorders that could explain the chronic fatigue, such as anorexia and bulimia, are exclusionary.
Systemic Exertion Intolerance Disease (SEID) criteria (2015)
Proposed by the Institute of Medicine in the United States (5). The diagnosis requires a significant loss of functional capacity, post-exertional malaise (PEM) and sleep disturbances (unrefreshing sleep). Additional criteria are also proposed, including cognitive impairment and/or orthostatic intolerance. The proposers suggest that the term myalgic encephalomyelitis should be replaced with «Systemic Exertion Intolerance Disease» (SEID).
11 thoughts on “Norwegian researchers ask 'What exactly is M.E.?'”
◾“In my experience, CFS is one of the most disabling diseases that I care for, far exceeding HIV disease except for the terminal stages.”—Dr. Daniel Peterson (Introduction to Research and Clinical Conference, Fort Lauderdale, Florida, October 1994; published in JCFS 1995:1:3-4:123-125)
◾“My H.I.V. patients for the most part are hale and hearty thanks to three decades of intense and excellent research and billions of dollars invested. Many of my C.F.S. patients, on the other hand, are terribly ill and unable to work or participate in the care of their families.
I split my clinical time between the two illnesses, and I can tell you if I had to choose between the two illnesses (in 2009) I would rather have H.I.V. But C.F.S., which impacts a million people in the United States alone, has had a small fraction of the research dollars directed towards it.”—Dr. Nancy Klimas, AIDS and CFS researcher and clinician, University of Miami (“Readers Ask: A Virus Linked to Chronic Fatigue Syndrome,” New York Times, October 15, 2009)
◾“Fatigue is what we experience, but it is what a match is to an atomic bomb.”—Laura Hillenbrand, author of Seabiscuit and Unbroken (NYT, “An Author Escapes From Chronic Fatigue Syndrome”, February 4, 2011)
◾“The whole idea that you can take a disease like this and exercise your way to health is foolishness. It is insane.”—Dr. Paul Cheney, CFS researcher and clinician (comment made at the Invest in ME conference in May 2010)
Hello Erik,
Thank you for commenting.
Regarding your first quote, 1994 was well was before the Canadian or International Consensus Criteria was published.
Regarding Dr Klimas’ quote, you may be aware she is an author of the International Consensus Criteria
“Name: Myalgic encephalomyelitis, a name that originated in the 1950s, is the most accurate and appropriate name because it reflects the underlying multi-system pathophysiology of the disease. Our panel strongly recommends that only the name ‘myalgic encephalomyelitis’ be used to identify patients meeting the ICC because a distinctive disease entity should have one name. Patients diagnosed using broader or other criteria for CFS or its hybrids (Oxford, Reeves, London, Fukuda, CCC, etc.) should be reassessed with the ICC. Those who fulfill the criteria have ME; those who do not would remain in the more encompassing CFS classification.” (http://emerge.org.au/wp-content/uploads/2014/06/Myalgic-Encephalomyelitis-International-Consensus-Primer-2012-11-26.pdf)
Your third quote references New York Times. Lauren Hillenbrand herself describes her illness as M.E. in this more recent New York Times article: “Many doctors and patients, including Hillenbrand, believe the words “chronic fatigue” sound trivial. They prefer the term “myalgic encephalomyelitis,” or M.E.” (http://www.nytimes.com/2014/12/21/magazine/the-unbreakable-laura-hillenbrand.html)
The final quote is from Dr Cheney who appears to agree with Dr Klimas and others that “the term ‘ME/CFS’ (or ‘CFS/ME’) is diagnostically accurate and, unlike CFS, is not pejorative to patients” according this website http://www.cfs-healing.info/name-change.htm.
As research progresses, things can change.
This makes sense.
“They warn that “use of broad inclusion criteria has created a heterogeneous patient population… This has increased the risk of erroneous conclusions, misdiagnosis and incorrect treatment”.’
I’ll say!
“They point out a recent USA NIH report “concludes that continued use of the Oxford criteria (the broadest) may impair progress and cause harm, and recommends that these criteria should no longer be used.”’
INDEED!
Good article.
Thank you Janet.
I have to say that I disagree with this.
Firstly, the Norwegians have misrepresented the Jason et al study. It didn’t find that “patients with myalgic encephalomyelitis have more severe symptomatology than chronic fatigue syndrome, but better mental health”. It found that the ICC diagnostic tool identified a cohort with worse symptomatology than the Fukuda definition. The assumption being that the two instruments were measuring different conditions, but this is an assumption. Also, the Jason et al study found no differences found between the cohorts in mental health scores.
The ICC definition refers to ME and CFS as synonymous, and adopts the term ME because “it is more appropriate and correct… because it indicates an underlying pathophysiology”. There is no indication in the ICC that it assumes that these are separate and distinct conditions.
We must be careful not to confuse the map with the territory. We have too many maps in this field. That they use different words and terms (eg: CFS (Fukuda) ME (ICC) ME/CFS (ME/CFS)) doesn’t necessarily mean that they’re describing different entities. Much like a group of blindfolded people, trying to describe something. We can’t yet tell whether they’re all describing the same elephant.
There are many problems with our current set of diagnostic criteria. Not least of which is that there are so many, and that there is little agreement on the name of the illness or even on the core symptoms. Each of these maps has received justified criticism for flaws. None are perfect descriptions, though some are arguably much better than others (eg: the Oxford definition should clearly be retired).
Until we get biomarkers, we only have the descriptions of blindfolded people. We need to remember that that is all they are.
Hello Simone,
Thank you for commenting.
“Patients with” is a fair way of describing a cohort defined using a diagnostic tool, that isn’t a misrepresentation by the Norwegian researchers. The assumption is made that they are different because they have different criteria but they didn’t say they were exclusionary.
It is incorrect to say Jason et al study found no differences found between the cohorts in mental health scores, Table 3 in the Functional Status shows the difference on both the DePaul and Newcastle samples.
It is incorrect to say the ICC definition refers to ME and CFS as synonymous. It says the opposite, that “ME should be removed from the broad category of CFS”.
Here is the full quote from the ICC Primer:
“Name: Myalgic encephalomyelitis, a name that originated in the 1950s, is the most accurate and appropriate name because it reflects the underlying multi-system pathophysiology of the disease. Our panel strongly recommends that only the name ‘myalgic encephalomyelitis’ be used to identify patients meeting the ICC because a distinctive disease entity should have one name. Patients diagnosed using broader or other criteria for CFS or its hybrids (Oxford, Reeves, London, Fukuda, CCC, etc.) should be reassessed with the ICC. Those who fulfill the criteria have ME; those who do not would remain in the more encompassing CFS classification.
2. Remove patients who satisfy the ICC from the broader category of CFS. The purpose of diagnosis is to provide clarity. The criterial symptoms, such as the distinctive abnormal responses to exertion can differentiate ME patients from those who are depressed or have other fatiguing conditions. Not only is it common sense to extricate ME patients from the assortment of conditions assembled under the CFS umbrella, it is compliant with the WHO classification rule that a disease cannot be classified under more than one rubric. The panel is not dismissing the broad components of fatiguing illnesses, but rather the ICC are a refinement of patient stratification. As other identifiable patient sets are identified and supported by research, they would then be removed from the broad CFS/CF category.”
From: http://emerge.org.au/wp-content/uploads/2014/06/Myalgic-Encephalomyelitis-International-Consensus-Primer-2012-11-26.pdf
This paper acknowledges the latest criteria aren’t perfect when they state “We believe that myalgic encephalomyelitis may consist of several subtypes, which cannot at present be distinguished using existing diagnostic criteria.”
To borrow your elephant analogy, the earlier and broader CFS definition is blind people feeling a whole herd of elephants! At least with the more modern Consensus Criteria, it is narrowing the search for researchers, and the blind people are feeling a couple of elephants, instead of dozens.
To add to the confusion, where does fibromyalgia fit into this? I have been diagnosed with either one or the other.
Fibromyalgia I think is linked to this because of inflammation i blood wessels… the norwegian scientist said so. Many are misdiagnosed wrong with FM, and it is ME.
I take issue with some of the information in this article. I may have missed it, but who are the Norwegian researchers? It would help if the article from which this information derived was listed as a reference.
If the Norwegian researchers have questions regarding the validitiy of MECFS diagnoses due to the use of different criteria, how did they come up with the answer that the ICC criteria was the most accurate? And how did they determine ME is more severe that CFS? Many doctors, researchers and scientists are working on this very issue and would be quite surprised to find out it has already been determined by this group. To date, there has been no scientific proof that “ME” is a different disease from CFS, let alone more severe. Unfortunately, I think we have a ways to go before we get that answer.
Hello Heidi,
The link to the full paper is at the bottom of the article and here is the full URL again: http://tidsskriftet.no/article/3404849/en_GB
The authors’ describe themselves as “six professors who, in different ways, are all involved in issues related to myalgic encephalomyelitis. Some of us are medics and scientists who participate actively in research into the condition, while others are social scientists or ethicists who have taken a critical look at the literature in the field from a social and socio-medical perspective.”
The researchers arrived at their conclusion after examining research including Prof Leonard A Jason’s (DePaul University) published papers. The evidence they used is in the data sets. Jason et al “analyzed two discrete data sets and found that the Myalgic Encephalomyelitis International Consensus Criteria identified more impaired individuals with more severe symptomatology [than those meeting the Fukuda criteria]”.
Others are referenced in the Norwegian article so I won’t delve too far!
Agree that we have a way to go, hopefully using narrower research criteria will get us there more quickly! These researchers are positing that using the ICC criteria for research will bring us closer to finding answers, rather than using the older, broader CFS criteria.
I would also urge you to look at the twelve or so distinguished clinicians and researchers on the International Consensus Criteria panel: http://emerge.org.au/wp-content/uploads/2014/06/Myalgic-Encephalomyelitis-International-Consensus-Primer-2012-11-26.pdf
I hope that gives you some interesting reading! If you have any links to share on the topic, please post them as I’d be interested.
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