Myalgic Encephalomyelitis: Symptoms and Biomarkers

Abstract:

Myalgic Encephalomyelitis (ME) continues to cause significant morbidity worldwide with an estimated one million cases in the United States. Hurdles to establishing consensus to achieve accurate evaluation of patients with ME continue, fueled by poor agreement about case definitions, slow progress in development of standardized diagnostic approaches, and issues surrounding research priorities. Because there are other medical problems, such as early MS and Parkinson’s Disease, which have some similar clinical presentations, it is critical to accurately diagnose ME to make a differential diagnosis.

In this article, we explore and summarize advances in the physiological and neurological approaches to understanding, diagnosing, and treating ME. We identify key areas and approaches to elucidate the core and secondary symptom clusters in ME so as to provide some practical suggestions in evaluation of ME for clinicians and researchers.

This review, therefore, represents a synthesis of key discussions in the literature, and has important implications for a better understanding of ME, its biological markers, and diagnostic criteria. There is a clear need for more longitudinal studies in this area with larger data sets, which correct for multiple testing.

 

Source: Jason LA, Zinn ML, Zinn MA. Myalgic Encephalomyelitis: Symptoms and Biomarkers. Curr Neuropharmacol. 2015;13(5):701-34. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4761639/ (Full article)

 

Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms

Abstract:

Although myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are considered to be synonymous, the definitional criteria for ME and CFS define two distinct, partially overlapping, clinical entities. ME, whether defined by the original criteria or by the recently proposed criteria, is not equivalent to CFS, let alone a severe variant of incapacitating chronic fatigue.

Distinctive features of ME are: muscle weakness and easy muscle fatigability, cognitive impairment, circulatory deficits, a marked variability of the symptoms in presence and severity, but above all, post-exertional “malaise”: a (delayed) prolonged aggravation of symptoms after a minor exertion. In contrast, CFS is primarily defined by (unexplained) chronic fatigue, which should be accompanied by four out of a list of 8 symptoms, e.g., headaches.

Due to the subjective nature of several symptoms of ME and CFS, researchers and clinicians have questioned the physiological origin of these symptoms and qualified ME and CFS as functional somatic syndromes. However, various characteristic symptoms, e.g., post-exertional “malaise” and muscle weakness, can be assessed objectively using well-accepted methods, e.g., cardiopulmonary exercise tests and cognitive tests. The objective measures acquired by these methods should be used to accurately diagnose patients, to evaluate the severity and impact of the illness objectively and to assess the positive and negative effects of proposed therapies impartially.

 

Source: Twisk FN. Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms. World J Methodol. 2015 Jun 26;5(2):68-87. doi: 10.5662/wjm.v5.i2.68. ECollection 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4482824/ (Full article)

 

Diagnostic Methods for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review for a National Institutes of Health Pathways to Prevention Workshop

Abstract:

BACKGROUND: The diagnosis of myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is based on clinical criteria, yet there has been no consensus regarding which set of criteria best identifies patients with the condition. The Institute of Medicine has recently proposed a new case definition and diagnostic algorithm.

PURPOSE: To review methods to diagnose ME/CFS in adults and identify research gaps and needs for future research.

DATA SOURCES: MEDLINE, PsycINFO, and Cochrane databases (January 1988 to September 2014); clinical trial registries; and reference lists.

STUDY SELECTION: English-language studies describing methods of diagnosis of ME/CFS and their accuracy.

DATA EXTRACTION: Data on participants, study design, analysis, follow-up, and results were extracted and confirmed. Study quality was dual-rated by using prespecified criteria, and discrepancies were resolved through consensus.

DATA SYNTHESIS: Forty-four studies met inclusion criteria. Eight case definitions have been used to define ME/CFS; a ninth, recently proposed by the Institute of Medicine, includes principal elements of previous definitions. Patients meeting criteria for ME represent a more symptomatic subset of the broader ME/CFS population. Scales rating self-reported symptoms differentiate patients with ME/CFS from healthy controls under study conditions but have not been evaluated in clinically undiagnosed patients to determine validity and generalizability.

LIMITATIONS: Studies were heterogeneous and were limited by size, number, applicability, and methodological quality. Most methods were tested in highly selected patient populations.

CONCLUSION: Nine sets of clinical criteria are available to define ME/CFS, yet none of the current diagnostic methods have been adequately tested to identify patients with ME/CFS when diagnostic uncertainty exists. More definitive studies in broader populations are needed to address these research gaps.

 

Source: Haney E, Smith ME, McDonagh M, Pappas M, Daeges M, Wasson N, Nelson HD. Diagnostic Methods for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review for a National Institutes of Health Pathways to Prevention Workshop. Ann Intern Med. 2015 Jun 16;162(12):834-40. doi: 10.7326/M15-0443. http://annals.org/aim/article/2322800/diagnostic-methods-myalgic-encephalomyelitis-chronic-fatigue-syndrome-systematic-review-national (Full article)

Comments

  • Ellen M Goudsmit 2015 Dec 02

    Sad to note today that the journal chose to publish letters, favouring opinion above the correction of factual errors. How can science progress if editors collude in the perpetuation of inaccuracies and myths? Who will know that there ARE research criteria for ME as described by Ramsay? That there are helpful alternatives to CBT and GET?

    Postscript 2016. The editors decided not to publish the comment as a letter in the journal as they rejected the view that there were factual errors. Thus while I was not a co-author of the criteria cited in the article, and I’m not named in the reference given, listing me as a co-author is not a ‘factual error’ in their eyes. Nor is the claim that a trial I discussed selected patients using two sets of criteria, not just the one referred to in the article. In my view, this failure to correct errors and misleading information is inconsistent with good science.

  • Ellen M Goudsmit 2015 Jul 17

    As someone who has studied myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) since the 1980s, I appreciate the work completed by The National Institutes of Health Pathways to Prevention Workshops on what is now known as ME/CFS. Unfortunately, some of the information in the two reviews is inaccurate, incomplete and misleading (1,2). For example, in the report on diagnostic methods, the reviewers included the London criteria for ME but gave details in the table based on a version written by a layperson, rather than the four individuals cited in their reference (3). Moreover, they did not consider the updated criteria for ME (4), although one of the authors had emailed the panel on two separate occasions during the consultation phase to alert them to their existence.

    The second review (2) encourages further research on subgroups and outcomes other than fatigue and function but did not identify one of the few controlled studies which had employed such a design (5). For instance, in the Appendix, Table 1 lists the programme evaluated by Goudsmit and colleagues under ‘counseling and behavioural therapies’, and describes the treatment as ‘counseling’. It also states that patients were selected using the Oxford criteria, that the duration of follow-up was six months and that the outcomes were function and fatigue.

    In fact, the trial evaluated a physician-led multi-component programme comprising medical care, information on the illness, diet and relaxation, as well as advice on activity management and some counselling (5). It was conducted in the naturalistic setting of an NHS hospital clinic, patients were diagnosed using criteria for post-viral fatigue syndrome as well as the Oxford criteria, and data were available for a number of symptoms including cognitive impairment, as well as other variables. Fatigue improved as noted in the review but the latter did not convey that 82% of the patients rated themselves as ‘better’, that 23% were well enough to be discharged at six months and that the improvements were maintained at 1 year. Given the missing details, the study’s rating as ‘poor’ is understandable.

    The reviewers concluded that “more definitive studies comparing participants meeting different case definitions, including ME… are needed to fill research gaps”. It was therefore disappointing that they did not recognise the positive aspects of a study that used a different case definition and assessed a range of symptoms, not just fatigue.

    1. Haney E, Smith MEB, McDonagh M, Pappas M, Daeges M, Wasson N, et al. Diagnostic methods for myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review for a National Institutes of Health Pathways to Prevention Workshop. Ann Intern Med. 2015;162: 834-40. [PMID: 26075754] doi:10.7326/M15-0443
    2. Smith MEB, Haney E, McDonagh M, Pappas M, Daeges M, Wasson N, et al. Treatment of myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review for a National Institutes of Health Pathways to Prevention Workshop. Ann Intern Med. 2015;162:841-
    3. [PMID: 26075755] doi:10.7326/M15-0114
    4. Dowsett E, Goudsmit E, Macintyre A, Shepherd C. London Criteria for myalgic encephalomyelitis. In: Report from The National Task Force on Chronic Fatigue Syndrome (CFS), Post Viral Fatigue Syndrome (PVFS), Myalgic Encephalomyelitis (ME). Westcare. 1994. 96-98. Available from: http://www.actionforme.org.uk/Resources/Action for ME/Documents/get-informed/national task force.pdf
    5. Goudsmit E, Shepherd C, Dancy CP, Howes S. ME: Chronic fatigue syndrome or a distinct clinical entity? Health Psychol Update. 2009;18(1):26-33. Available from: http://shop.bps.org.uk/publications/publications-by-subject/health/health-psychology-update-vol-18-no-1-2009.html
    6. Goudsmit EM, Ho-Yen DO, Dancey CP. Learning to cope with chronic illness. Efficacy of a multi-component treatment for people with chronic fatigue syndrome. Patient Educ Couns. 2009;77:231–6. [PMID: 19576714 ] doi:10.1016/j.pec.2009.05.015

    Ellen M Goudsmit PhD FBPsS

    Comment also on Annals of Internal Medicine website under Haney et al.

 

A critical analysis of the proposal of the Institute of Medicine to replace myalgic encephalomyelitis and chronic fatigue syndrome by a new diagnostic entity called systemic exertion intolerance disease

Abstract:

The Institute of Medicine (IOM) recently published their report in response to an assignment “to define diagnostic criteria for Myalgic Encephalomyelitis (ME)/chronic fatigue syndrome (CFS), to propose a process for reevaluation of these criteria in the future, and to consider whether a new name for this disease is warranted”.

The basic pre-assumption of the IOM committee for the development of evidence-based diagnostic criteria for ME/CFS was that ME and CFS denote conditions with similar symptoms, hence ME/CFS. The IOM committee recommends: (1) that ME/CFS will be renamed ‘systemic exertion intolerance disease’ (SEID); and that a new code should be assigned to SEID in the International Classification of Diseases (ICD), replacing the existing codes for ME (a neurological disease: G93.3) and CFS (‘signs, symptoms, and abnormal clinical and laboratory findings, not elsewhere classified’: R53.82); (2) that a diagnosis of SEID should be made if the new diagnostic criteria are met; (3) that the Department of Health and Human Services develops a toolkit appropriate for screening and diagnosing patients; and (4) that a multidisciplinary group re-examines the new diagnostic criteria when necessary.

This editorial reviews the working procedure of the IOM and two of the outcomes: the recommendation to introduce a new clinical entity (SEID) and new diagnostic criteria. Based upon the contents of the report, and the arguments of the IOM, a search of PubMed and the archive of the Journal of Chronic Fatigue Syndrome using the search terms ME (and old synonyms) and CFS, and a search of PubMed related to the five core symptoms of SEID was conducted.

Reviewing the working method and the recommendations, it is concluded that the new diagnostic criteria for SEID are based upon important methodological shortcomings and that the introduction of SEID to replace both ME and CFS has several profound negative consequences outweighing the advantages.

 

Source: Twisk FN. A critical analysis of the proposal of the Institute of Medicine to replace myalgic encephalomyelitis and chronic fatigue syndrome by a new diagnostic entity called systemic exertion intolerance disease. Curr Med Res Opin. 2015;31(7):1333-47. doi: 10.1185/03007995.2015.1045472. Epub 2015 May 29. https://www.ncbi.nlm.nih.gov/pubmed/25912615 (Full article)

 

Defining Essential Features of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome

Abstract:

Considerable debate surrounds the search for the defining features of patients with Myalgic Encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Current case definitions were created through clinical consensus. Failure to operationalize these case definitions has led to considerable variability in the identification of patients. In addition, some case definitions (e.g., Fukuda et al., 1994) do not require cardinal symptoms of this illness, where as other case definitions do require core symptoms of this illness (Carruthers et al., 2003, 2011), and these latter case criteria appear to identify a more impaired group of patients.

 

Criterion variance is most likely to occur when operationally explicit criteria do not exist for diagnostic categories (Spitzer, Endicott, & Robins, 1978), or when there are varying criteria for contrasting case definitions, which is an impediment to the research in this field. To deal with this problem, it is possible to differentiate those that meet more loosely defined criteria from those that are more narrowly and defined, thus differentiating CFS from ME.

In order to progress the search for biological markers and effective treatments, essential features need to be operationalized and broadly used in order to increase the probability that individuals included in samples have the same underlying illness.

 

Source: Jason LA, Sunnquist M, Brown A, Reed J. Defining Essential Features of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome. J Hum Behav Soc Environ. 2015;25(6):657-674. Epub 2015 May 6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817848/ (Full article)

 

Improving the diagnostic criteria and procedures for chronic fatigue syndrome

Abstract:

Since the publication of the case definition for chronic fatigue syndrome (CFS) in 1988 the diagnostic criteria have been revised twice in the U.S. None of the case definitions were derived empirically. As a result, there is concern regarding the sensitivity, specificity, and reliability of the criteria.

The goal of the present study was to identify methods for improving the diagnostic criteria for CFS. Three groups of 15 participants each were recruited: participants with (1) CFS, (2) major depressive disorder (MDD), and (3) healthy controls.

Using statistical procedures, three methods for improving the diagnostic criteria were explored: identification of new diagnostic symptoms, the use of severity ratings for symptomatology, and the identification of standardized measures that differentiate cases of CFS from other conditions. Results of the present study suggest that these three methods hold promise for improving the sensitivity, specificity, and reliability of the diagnostic criteria for CFS.

 

Source: King C, Jason LA. Improving the diagnostic criteria and procedures for chronic fatigue syndrome. Biol Psychol. 2005 Feb;68(2):87-106. http://www.ncbi.nlm.nih.gov/pubmed/15450690

 

Developing case definitions for symptom-based conditions: the problem of specificity

Symptom-based conditions are postulated organic diseases that are characterized primarily by chronic physical (somatic) symptoms (1, 2). Contemporary conditions associated with multisystem complaints are generally referred to as chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivities, silicone associated atypical rheumatic disease, sick building syndrome, and most recently, Gulf War syndrome (table 1). Possibly related disorders that will not be considered in the following analysis include epidemic neuromyasthenia, hyperventilation syndrome, reactive hypoglycemia, post-lyme disease syndrome, and irritable bowel syndrome (3).

Although the need to consistently define symptombased conditions has been repeatedly emphasized, there has been limited progress in establishing widely accepted diagnostic criteria (1,4). Based on reports in English-language publications, symptom-based conditions were analyzed to determine why it has been difficult to develop case definitions of unique diseases.

You can read the rest of this article here: http://epirev.oxfordjournals.org/content/20/2/148.long

 

Source: Hyams KC. Developing case definitions for symptom-based conditions: the problem of specificity. Epidemiol Rev. 1998;20(2):148-56. http://epirev.oxfordjournals.org/content/20/2/148.long (Full article)

Primary juvenile fibromyalgia syndrome and chronic fatigue syndrome in adolescents

Abstract:

Chronic fatigue syndrome (CFS) and primary juvenile fibromyalgia syndrome (PJFS) are illnesses with a similar pattern of symptoms of unknown etiology. Twenty-seven children for whom CFS was diagnosed were evaluated for fibromyalgia by the presence of widespread pain and multiple tender points.

Eight children (29.6%) fulfilled criteria for fibromyalgia. Those children who met fibromyalgia criteria had a statistically greater degree of subjective muscle pain, sleep disturbance, and neurological symptoms than did those who did not meet the fibromyalgia criteria. There was no statistical difference between groups in degree of fatigue, headache, sore throat, abdominal pain, depression, lymph node pain, concentration difficulty, eye pain, and joint pain.

CFS in children and PJFS appear to be overlapping clinical entities and may be indistinguishable by current diagnostic criteria.

 

Source: Bell DS, Bell KM, Cheney PR. Primary juvenile fibromyalgia syndrome and chronic fatigue syndrome in adolescents. Clin Infect Dis. 1994 Jan;18 Suppl 1:S21-3. http://www.ncbi.nlm.nih.gov/pubmed/8148447

 

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome

Abstract:

Operational diagnostic criteria for fibromyalgia were applied to most clinical studies during the past year. Similar diagnostic criteria for chronic fatigue syndrome are being revised, but criteria for myofascial pain have not been agreed on or tested. Intense research efforts focused on the role of neurohormones and the hypothalamic-pituitary-adrenal axis in fibromyalgia and chronic fatigue syndrome over the past year.

 

Source: Goldenberg DL. Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome. Curr Opin Rheumatol. 1993 Mar;5(2):199-208. http://www.ncbi.nlm.nih.gov/pubmed/8452771

 

Diagnostic criteria for chronic fatigue syndrome by the CFS Study Group in Japan

Abstract:

Much interest recently has been given to chronic fatigue syndrome (CFS) in Japan as other countries. The CFS Study Group sponsored by the Ministry of Health and Welfare has been developed since April 1991, A diagnostic criteria for CFS was newly proposed by this group. The criteria is substantially based upon the working case definition, which was made by Holmes and colleagues in 1988. There are some modification from CDC working case definition; the criteria of probable cases of CFS was defined, and postinfectious CFS was also given.

 

Source: Kitani T, Kuratsune H, Yamaguchi K. Diagnostic criteria for chronic fatigue syndrome by the CFS Study Group in Japan. Nihon Rinsho. 1992 Nov;50(11):2600-5. [Article in Japanese] http://www.ncbi.nlm.nih.gov/pubmed/1287236