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Review
. 2020 Jul 29;18(1):289.
doi: 10.1186/s12967-020-02455-0.

Review of case definitions for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Eun-Jin Lim  1 , Chang-Gue Son  2
Affiliations
Review

Review of case definitions for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Eun-Jin Lim et al. J Transl Med. .

Abstract

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with unknown causes. From the perspectives on the etiology and pathophysiology, ME/CFS has been labeled differently, which influenced changes in case definitions and terminologies. This review sought to feature aspects of the history, developments, and differential symptoms in the case definitions.

Methods: A search was conducted through PubMed published to February 2020 using the following search keywords: case definition AND chronic fatigue syndrome [MeSH Terms]. All reference lists of the included studies were checked. Of the included studies, the number of citations and the visibility in the literatures of the definitions were considered for comparisons of the criteria.

Results: Since the first 'ME' case definition was developed in 1986, 25 case definitions/diagnostic criteria were created based on three conceptual factors (etiology, pathophysiology, and exclusionary disorders). These factors can be categorized into four categories (ME, ME/CFS, CFS, and SEID) and broadly characterized according to primary disorder (ME-viral, CFS-unknown, ME/CFS-inflammatory, SEID-multisystemic), compulsory symptoms (ME and ME/CFS-neuroinflammatory, CFS and SEID-fatigue and/or malaise), and required conditions (ME-infective agent, ME/CFS, CFS, SEID-symptoms associated with fatigue, e.g., duration of illness). ME and ME/CFS widely cover all symptom categories, while CFS mainly covers neurologic and neurocognitive symptoms. Fatigue, cognitive impairment, PEM, sleep disorder, and orthostatic intolerance were the overlapping symptoms of the 4 categories, which were included as SEID criteria.

Conclusions: This study comprehensively described the journey of the development of case definitions and compared the symptom criteria. This review provides broader insights and explanations to understand the complexity of ME/CFS for clinicians and researchers.

Keywords: Case definition; Chronic fatigue syndrome; Diagnostic criteria; Myalgic encephalomyelitis; Systemic exertion intolerance disease.

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Conflict of interest statement

There are no potential conflicts of interest to disclose.

Figures

Fig. 1
Fig. 1
Developmental timeline of ME/CFS case definitions and terminologies. ME/CFS myalgic encephalomyelitis and chronic fatigue syndrome, CDC Centers for Disease Control and Prevention, NICE National Institute for Health and Clinical Excellence, IOM Institute of Medicine, SEID systemic exertion intolerance disease. Case definition, a specific set of criteria used to define a disease for surveillance. Diagnostic criteria, guidance to indicate the presence of an illness (signs and symptoms, test results)
Fig. 2
Fig. 2
Scope of ME/CFS symptoms by case definitions. CFS, chronic fatigue syndrome, IOM, Institute of Medicine. SEID, systemic exertion intolerance disorder. ME myalgic encephalitis, CCC Canadian Consensus Criteria, ICC International Consensus Criteria, GI gastro-intestinal, GU genito-urinary symptoms
See this image and copyright information in PMC

References

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    1. Osoba T, Pheby D, Gray S, Nacul L. The Development of an epidemiological definition for myalgic encephalomyelitis/chronic fatigue syndrome. J Chronic Fatigue Syndr. 2007;14:61–84.
    1. American ME and CFS Society. How many people have ME/CFS? U.S. 2019. https://ammes.org/how-many-people-have-mecfs/. Accessed 31 Jan 2019.
    1. Bethesda M. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) research: workshop report. State of the knowledge workshop. National Institutes of Health. 2011. https://www.meassociation.org.uk/wp-content/uploads/2011/08/SoK-Workshop.... Accessed 25 Mar 2019.
    1. Institute of Medicine. Beyond myalgic encephalomyelitis/chronic fatigue syndrome; Redefining an illness. Institute of medicine of the national academies. 2015. www.nap.edu. Accessed 12 Feb 2019.

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