The Concept of 'ME/CFS' - Jonathan Edwards https://www.qeios.com/read/NXCXM1 ME/CFS appears to stand for myalgic encephalomyelitis and chronic fatigue syndrome but in an important sense it stands for neither. It is a newer concept, differing from both. The problem with ‘CFS’ is that it is 'vague symptom-based syndrome' defined by 'chronic or profound fatigue 'and is a 'diagnosis of exclusion' and is confused with 'Myalgic Encephalomyelitis (aka Enteroviral Encephalomyelitis)' which is an "acute onset" neurological disease, diagnosable upon onset with specific testing. The term was originally devised to describe a supposed acute, polio-like, neurological illness due to an unknown virus, typified by an outbreak at the Royal Free Hospital in 1955 and also one in Iceland. ‘Encephalomyelitis’ was used because patients appeared to have localising neurological signs consistent with central nervous system lesions. The basis for these signs was never confirmed but that is not relevant to the quite different illness now called 'CFS' (aka ME/CFS) Syndromes allow heterogeneity of contributing causes and need not be mutually exclusive with other clinical categories; grey areas may be extensive. What may have been a persistent mistake in trying to define 'CFS' (aka ME/CFS) is reliance on physical signs or tests suggestive of a favoured aetiology when what we are primarily trying to define is a symptom-based syndrome. Diagnostic and management strategies have drawn on all sorts of theoretical models, including neuroinflammatory, psychosocial, metabolic, immunological or haematological but until there is reliable evidence for any of these, 'CFS' (aka ME/CFS) remains a symptom complex. The re-introduction of assumptions about mechanism by the later International Consensus Criteria (for ‘M.E.’) looks to have been a step backwards which, fortunately, has not been followed by many. [The ICC was a poor attempt at defining Enteroviral Encephalomyelitis & Enteroviral Meningoencephalomyelitis aka Myalgic Encephalomyelitis] It has nothing to do with 'CFS' or 'ME/CFS' which are umbrella terms, defined by 'chronic or profound fatigue' and 'a plethora of common symptoms' to a whole bunch of illnesses. They account for a heterogeneous group of 'misdiagnosed' individuals, with 'unexplained fatigue'. "The science community must swallow the unpalatable truth that it is the patient community that has brought methodological rigour to the subject, not the academics. For more than one reason, physicians should listen to patients."