Background Dysautonomia describes a group of conditions associated with a malfunction of the autonomic nervous system. Symptoms of dysautonomia and inflammation have been described in Fibromyalgia (FM) and Myalgic encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) [1–4]. Symptoms include increased disabling fatigue, pain, dizziness and digestive problems.
Objectives This ongoing study investigates, for the first time, how a sympathetically mediated challenge and induced systemic inflammatory state impact on mood, pain, fatigue, and autonomic function.
Methods In a randomized, double-blind, placebo-controlled study, 25 participants with FM and/or ME/CFS underwent an autonomic- and inflammatory challenge during three visits. Outcome measures included a range of questionnaires including the Profile of Mood States (POMS), Pain visual analogue scales (VAS), measures of heart rate (HR), Pressure Pain Threshold (PPT), alongside subjective pain and fatigue measures. Autonomic function was assessed using a passive non-invasive tilt-test (upright tilt of 60°) and active-stand (AS) with beat-to-beat HR and blood pressure monitoring. Remaining visits involved an inflammatory challenge using intramuscular typhoid- and saline (placebo) injection.
Results Tilt-table test was positive in 20% participants and AS in 92% participants indicated by HR rise >30 bpm or a sustained HR of 120 bpm. Overall fatigue correlated with peak HR during tilt (r=.465, p=.025, n=23). There was a positive correlation between the average HR during AS under typhoid after controlling for placebo and average HR during tilt (r=.517, p=.049, n=15). Scores on the Wide Spread Pain Index (WPI) at screening correlated with the change in POMS pre-and post-typhoid after controlling for placebo (r=.479, p=.045, n=18). Scores on the Fibromyalgia Severity Scale correlated with the change in physical fatigue pre-and post-typhoid after controlling for placebo (r=.633, p=.015, n=14). Pain at screening correlated with change in physical fatigue pre-and post-tilt (r=.405, p=.044, n=25). Scores on the pain severity scale at baseline correlated with change in pain measured on a visual analogue scale pre and post tilt (r=.517, p=.049, n=15). Mean change in heart rate pre-post active stand correlated with a change in pain VAS pre-and post-typhoid after controlling for placebo (r=.582, p=.047, n=12).
Conclusion Preliminary findings suggest that dysautonomia and induced inflammation significantly impacts on pain, fatigue, and autonomic function in FM and ME/CFS. On-going data collection of 100 participants (25 controls) will allow extended analyses to test how autonomic function and inflammation affect symptom domains that impact on quality of life.
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Disclosure of Interests None declared
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