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.
Highlights
Myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) is a common, chronic, complex, medical condition that affects at least one million people in the United States, equal to or more than multiple sclerosis, rheumatoid arthritis, or systemic lupus erythematosus [1]
We inquired about onset and duration of post-exertional malaise (PEM) and included space for subjects to write in any additional symptoms
This study provides exact symptom and time patterns for PEM that is generated in the course of patients’ lives
Summary
Myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) is a common, chronic, complex, medical condition that affects at least one million people in the United States, equal to or more than multiple sclerosis, rheumatoid arthritis, or systemic lupus erythematosus [1]. Patients must suffer from unrelenting or recurrent, function-limiting fatigue unresponsive to rest for 6 months, they must have experienced at least four out of the following eight symptoms concurrently: unrefreshing sleep, tender cervical/ axillary lymph nodes, muscle pain, multi-joint pain without signs of inflammation, sore throat, impaired memory or concentration, new or changed headaches, and post-exertional malaise (PEM). Many of these same symptoms occur in healthy people transiently and in multiple medical conditions (e.g. major depression, fibromyalgia, sleep apnea, various viral infections). Patients have rarely been asked in formal studies to describe their experience of PEM
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