Deconstructing post-exertional malaise in myalgic encephalomyelitis/ chronic fatigue syndrome: A patient-centered, cross-sectional survey

Abstract

BackgroundPost-exertional malaise (PEM) is considered to be the hallmark characteristic of myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS). Yet, patients have rarely been asked in formal studies to describe their experience of PEM.ObjectivesTo describe symptoms associated with and the time course of PEMMethodsOne hundred and fifty subjects, diagnosed via the 1994 Fukuda CFS criteria, completed a survey concerning 11 symptoms they could experience after exposure to two different types of triggers. We also inquired about onset and duration of PEM and included space for subjects to write in any additional symptoms. Results were summarized with descriptive statistics; McNemar’s, paired t-, Fisher’s exact and chi-square goodness-of-fit tests were used to assess for statistical significance.ResultsOne hundred and twenty-nine subjects (90%) experienced PEM with both physical and cognitive exertion and emotional distress. Almost all were affected by exertion but 14 (10%) reported no effect with emotion. Fatigue was the most commonly exacerbated symptom but cognitive difficulties, sleep disturbances, headaches, muscle pain, and flu-like feelings were cited by over 30% of subjects. Sixty percent of subjects experienced at least one inflammatory/ immune-related symptom. Subjects also cited gastrointestinal, orthostatic, mood-related, neurologic and other symptoms. Exertion precipitated significantly more symptoms than emotional distress (7±2.8 vs. 5±3.3 symptoms (median, standard deviation), p<0.001). Onset and duration of PEM varied for most subjects. However, 11% reported a consistent post-trigger delay of at least 24 hours before onset and 84% endure PEM for 24 hours or more.ConclusionsThis study provides exact symptom and time patterns for PEM that is generated in the course of patients’ lives. PEM involves exacerbation of multiple, atypical symptoms, is occasionally delayed, and persists for extended periods. Highlighting these characteristics may improve diagnosis of ME/CFS. Incorporating them into the design of future research will accelerate our understanding of ME/CFS.

A Brief Questionnaire to Assess Post-Exertional Malaise

“…Several studies have indicated that the duration of symptoms is possibly a unique aspect of PEM among patients with ME and CFS. For example, Jason et al [12] found that 75% of participants experienced PEM exacerbation more than 24 h after engaging in light activity, a finding comparable to that found by others [13]. …”

“…PEM duration had an area under the curve (AUC) of 0.88 ( SE = 0.1, CI = 0.85–0.90, p < 0.001). A previous study [13] indicated that most patients with ME and CFS experience PEM lasting longer than 12 h, whereas some case definitions require lasting more than 24 h [11]. Therefore, the authors examined PEM duration from 14 to 23 h and 24 h or more.…”

The Impact of a Structured Exercise Programme upon Cognitive Function in Chronic Fatigue Syndrome Patients

“…Overall, it could be concluded that both acute physical exercise bout and effects of physical exercise programme can lead to cognitive function improvement in many patient populations. However, in the case of ME/CFS patient's further research on this topic is needed because participation in a physical exercise programme has the potential to induce post-exertional malaise at least in some participants [40]. The high drop-out rate amongst ME/CFS patients in this study with a number of individuals not showing improved cognitive function highlights the need for care in advocating SEP therapy and the potential heterogeneity of this patient group.…”

Post-Exertional Malaise in People with Chronic Cancer-Related Fatigue

“…peak oxygen uptake, heart rate, rating of perceived exertion (RPE) and blood lactate) is reported for the purpose of characterizing the test and describing the sub-study participants. Borg's RPE scale (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) [29] was administered according to published instructions [30]. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint…”

“…PEM in ME/CFS has also been described as a constellation of extensively disabling signs and symptoms in response to exertion [14]. Historically, there has been difficulty in defining and measuring PEM (see [15,16] for more information), but for the purposes of this study, PEM will be used to denote concepts related to post-exertional symptom exacerbation [15].…”