A perspective on causation of the chronic fatigue syndrome by considering its nosology

Abstract

The causes of chronic fatigue syndrome (CFS) remain unknown, with many failures to replicate new findings. This may be because the condition is hard to diagnose, difficult to classify, or because of its heterogeneous nature. Authors have problems in differentiating CFS from myalgic encephalomyelitis (ME), which leads many to label it as a hybrid CFS/ME or ME/CFS. Attempts to validate the many published criterion‐based definitions have ended in failure. The International Classification of Diseases provide several different descriptions to choose from, although the latest 11th edition has narrowed this down. This paper describes conventional attempts to define and classify the illness, suggesting that this may be what leads to a failure to replicate putative causes. The approach to CFS/ME may require a shift in the assumption that the illness is homogeneous. An alternative approach is provided by studies suggesting that the condition is heterogeneous. Conclusion The way forward may be to be over‐inclusive regarding the diagnosis as a first step, while subdividing the condition into likely subgroups as a means of finding valid and reliable associations with potential causes. Studies of aetiology must involve prospective designs since cross‐sectional studies cannot inform either aetiology or pathophysiology.

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

“…Meanwhile, these various and undefined pathophysiology strongly suggest the possibility of heterogeneous or subsets of ME/CFS [29]. From the empirical analyses of patient symptoms, the neurologic and neurocognitive symptoms were identified as the core symptoms across the major eight definitions [41,42].…”

“…In line with this, to objectively assess PEM, a key symptom of ME/CFS, a standardized technique to measure the level of oxygen uptake using cardiopulmonary exercise testing (CPET) has recently been developed [59]. In addition to the development of advanced diagnostic tools, fine study design or strategies such as the well-constructed patient database, prospective cohort studies and clinical trials for the objective measurement of the core symptoms in particular are needed to comprehensively understand the illness [1,29,49].…”

“…Subsequently, the ICD-10 (2016) classified it as PVFS (code G93.3) indexing only 'benign ME' [27]-'benign' was dropped in the 2019 version [28]. Herein, 'CFS' was not coded; therefore, clinicians instead often used the code of malaise and fatigue (R53), fatigue syndrome (F48) or even neurasthenia (F48) [28,29]. Meanwhile, the latest version ICD-11 (2019) includes both '(benign) ME' and 'CFS' under PVFS (code 8E49), which noticeably specified exclusion of fatigue (MG22) from the category [30].…”

Interactions between persons—Knowledge, decision making, and the co‐production of practice

“…It includes papers on the nature of reasoning and evidence, the on-going problems of how to "integrate" different forms of scientific knowledge with each other, and with broader, humanistic understandings of reasoning and judgement, patient and community perspectives. [37][38][39][40][41][42][43][44][45][46][47][48] Discussions of the epistemological contribution of patient perspectives to the nature of care, and the crucial and still underdeveloped role of phenomenology in medical epistemology, [49][50][51] are followed by a broad range of papers focussing on SDM, analysing its proper meaning, its role in policy, methods for realizing it and its limitations in real-world contexts.…”

“…This, the 10th philosophy thematic edition of the journal, presents papers conducting urgent research into the social context of scientific knowledge and the significance of viewing clinical knowledge not as something that “sits within the minds and bodies” of researchers and practitioners but as a relational concept, the product of social interactions. It includes papers on the nature of reasoning and evidence, the on‐going problems of how to “integrate” different forms of scientific knowledge with each other, and with broader, humanistic understandings of reasoning and judgement, patient and community perspectives . Discussions of the epistemological contribution of patient perspectives to the nature of care, and the crucial and still under‐developed role of phenomenology in medical epistemology, are followed by a broad range of papers focussing on SDM, analysing its proper meaning, its role in policy, methods for realizing it and its limitations in real‐world contexts …”