Experiences of pain in paediatric chronic fatigue syndrome/myalgic encephalomyelitis: a single-centre qualitative study

Abstract:

Background Moderate to severe pain affects up to two-thirds of children with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and is associated with worse fatigue and physical functioning. This research aims to gain a greater insight into pain experienced by these children.

Methods Thematic analysis of qualitative data from semistructured interviews with 13 children with CFS/ME (mean age=15.3 years, 67% female) was completed.

Results Thematic analysis enabled construction of three themes: children’s wide-ranging experiences of pain, negative impact of pain and lack of effective treatment for pain and nine subthemes. The first theme demonstrated highly varied pain experiences, ranging from ‘like [being]… on fire’, like ‘being stabbed’ to ‘like…lead’. Children experienced pain in multiple sites and with wide-ranging frequency and severity. The second theme highlighted the profound negative impact of pain on multiple aspects of children’s lives. Physical activity was severely impaired; some children ‘couldn’t leave bed’ or ‘couldn’t…brush [their] own hair’. Abdominal pain meant some would ‘go…days without eating’. Pain substantially impacted on mental health, leaving children feeling ‘agitated’, experiencing ‘really bad panic attacks’ or making them ‘[want to] breakdown’. Children felt they ‘can’t do the things that everyone else can do’, had ‘missed out’ and are ‘behind everyone’. Some avoided socialising as they ‘don’t want to stop everyone else’. The final theme demonstrates the absence of adequate treatment for pain, with participants reporting ‘nothing has ever really got rid of it’ and only ‘slightly [takes] the edge off’ and other experiencing side effects.

Conclusions Pain in paediatric CFS/ME is highly variable, common and often results in severe physical limitation and poor mental health. Effective treatments for pain represent an unmet need.

Source: Serafimova TAscough CParslow RM, et al. Experiences of pain in paediatric chronic fatigue syndrome/myalgic encephalomyelitis: a single-centre qualitative study.

The Role of Autonomic Function in Exercise-induced Endogenous Analgesia: A Case-control Study in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Healthy People

Abstract:

Background: Patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) are unable to activate brain-orchestrated endogenous analgesia (or descending inhibition) in response to exercise. This physiological impairment is currently regarded as one factor explaining post-exertional malaise in these patients. Autonomic dysfunction is also a feature of ME/CFS.

Objectives: This study aims to examine the role of the autonomic nervous system in exercise-induced analgesia in healthy people and those with ME/CFS, by studying the recovery of autonomic parameters following aerobic exercise and the relation to changes in self-reported pain intensity.

Study design: A controlled experimental study.

Setting: The study was conducted at the Human Physiology lab of a University.

Methods: Twenty women with ME/CFS- and 20 healthy, sedentary controls performed a submaximal bicycle exercise test known as the Aerobic Power Index with continuous cardiorespiratory monitoring. Before and after the exercise, measures of autonomic function (i.e., heart rate variability, blood pressure, and respiration rate) were performed continuously for 10 minutes and self-reported pain levels were registered. The relation between autonomous parameters and self-reported pain parameters was examined using correlation analysis.

Results: Some relationships of moderate strength between autonomic and pain measures were found. The change (post-exercise minus pre-exercise score) in pain severity was correlated (r = .580, P = .007) with the change in diastolic blood pressure in the healthy group. In the ME/CFS group, positive correlations between the changes in pain severity and low frequency (r = .552, P = .014), and between the changes in bodily pain and diastolic blood pressure (r = .472, P = .036), were seen. In addition, in ME/CHFS the change in headache severity was inversely correlated (r = -.480, P = .038) with the change in high frequency heart rate variability.

Limitations: Based on the cross-sectional design of the study, no firm conclusions can be drawn on the causality of the relations.

Conclusions: Reduced parasympathetic reactivation during recovery from exercise is associated with the dysfunctional exercise-induced analgesia in ME/CFS. Poor recovery of diastolic blood pressure in response to exercise, with blood pressure remaining elevated, is associated with reductions of pain following exercise in ME/CFS, suggesting a role for the arterial baroreceptors in explaining dysfunctional exercise-induced analgesia in ME/CFS patients.

Source: Oosterwijck JV, Marusic U, De Wandele I, Paul L, Meeus M, Moorkens G, Lambrecht L, Danneels L, Nijs J. The Role of Autonomic Function in Exercise-induced Endogenous Analgesia: A Case-control Study in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Healthy People. Pain Physician. 2017 Mar;20(3):E389-E399. PMID: 28339438. https://www.painphysicianjournal.com/linkout?issn=&vol=20&page=E389 (Full text)

Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study in Patients and Healthy Subjects

Abstract:

Purpose: Oxidative stress has been proposed as a contributor to pain in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). During incremental exercise in patients with ME/CFS, oxidative stress enhances sooner and antioxidant response is delayed. We explored whether oxidative stress is associated with pain symptoms or pain changes following exercise, and the possible relationships between oxidative stress and parasympathetic vagal nerve activity in patients with ME/CFS versus healthy, inactive controls.

Methods: The present study reports secondary outcomes from a previous work. Data from 36 participants were studied (women with ME/CFS and healthy controls). Subjects performed a submaximal exercise test with continuous cardiorespiratory monitoring. Levels of thiobarbituric acid–reactive substances (TBARSs) were used as a measure of oxidative stress, and heart rate variability was used to assess vagal activity. Before and after the exercise, subjects were asked to rate their pain using a visual analogic scale.

Findings: Significant between-group differences in pain at both baseline and following exercise were found (both, P < 0.007). In healthy controls, pain was significantly improved following exercise (P = 0.002). No change in oxidative stress level after exercise was found. Significant correlation between TBARS levels and pain was found at baseline (r = 0.540; P = 0.021) and after exercise (r = 0.524; P = 0.024) in patients only. No significant correlation between TBARS and heart rate variability at baseline or following exercise was found in either group. However, a significant correlation was found between exercise-induced changes in HRV and TBARS in healthy controls (r = −0.720; P = 0.001).

Implications: Oxidative stress showed an association with pain symptoms in people with ME/CFS, but no exercise-induced changes in oxidative stress were found. In addition, the change in parasympathetic activity following exercise partially accounted for the change in oxidative stress in healthy controls. More research is required to further explore this link.

Source: Andrea Polli, MSc, Jessica Van Oosterwijck, PhD, Jo Nijs, PhD, Greta Moorkens, PhD, Luc Lambrecht, MD, Kelly Ickmans, PhD. Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study in Patients and Healthy Subjects. Clinical Therapeutics. ORIGINAL RESEARCH| VOLUME 41, ISSUE 4, P641-655, APRIL 01, 2019. Published online: January 18, 2019. Accepted: December 14, 2018. DOI: https://doi.org/10.1016/j.clinthera.2018.12.012 https://www.clinicaltherapeutics.com/article/S0149-2918(18)30611-8/fulltext#secsectitle0010 (Full article)

Pain-related post-exertional malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia: A systematic review and three-level meta-analysis

Abstract:

Objective: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia (FM) are two debilitating, moderately comorbid illnesses in which chronic musculoskeletal pain symptoms are prevalent. These individuals can experience post-exertional malaise (PEM), a phenomenon where symptom severity is worsened 24hr or longer following physical stress, but the pain-related component of PEM is not well characterized.

Design: Systematic review and meta-analysis.

Methods: Case-control studies involving adults with ME/CFS or FM and measuring pain symptoms before and after exposure to a standardized aerobic exercise test were included. Hedges’ d effect sizes were aggregated using random effects models and potential moderators were explored with meta-regression analysis. Results were adjusted for nesting effects using three-level modeling.

Results: Forty-five effects were extracted from 15 studies involving 306 patients and 292 healthy controls. After adjusting for nesting effects, we observed a small-to-moderate effect indicating higher post-exercise pain in patients than controls (Hedges’ d=0.42; 95% CI: 0.16, 0.67). The mean effect was significantly moderated by pain measurement timepoint (b = -0.19, z = -2.57, P = 0.01) such that studies measuring pain 8-72hr post-exercise showed larger effects (d = 0.71, 95% CI = 0.28-1.14) than those measuring pain 0-2hr post-exercise (d = 0.32, 95% CI = 0.10-0.53).

Conclusions: People with ME/CFS and FM experience small-to-moderate increases in pain severity following exercise which confirms pain as a component of PEM and emphasizes its debilitating impact in ME/CFS and FM. Future directions include determining mechanisms of pain-related PEM and developing exercise prescriptions that minimize symptom exacerbation in these illnesses.

Source: Barhorst EE, Boruch AE, Cook DB, Lindheimer JB. Pain-related post-exertional malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia: A systematic review and three-level meta-analysis. Pain Med. 2021 Oct 20:pnab308. doi: 10.1093/pm/pnab308. Epub ahead of print. PMID: 34668532. https://pubmed.ncbi.nlm.nih.gov/34668532/

Central sensitisation in chronic fatigue syndrome and fibromyalgia; a case control study

Abstract:

Introduction: Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are both complex conditions that are challenging to treat. This may be related to an incomplete understanding of their pathophysiology, itself obfuscated by their heterogeneity. The symptomatic overlap between them and their common comorbidity suggests a shared vulnerability, which might be explained by central sensitisation.

Methods: 19 CFS cases, 19 FM cases and 20 age and sex matched healthy controls (HC) were recruited primarily from secondary care clinics in London. Those with other pain disorders, psychiatric diagnoses and those taking centrally acting or opiate medications were excluded. Participants were asked to abstain from alcohol and over the counter analgaesia 48 h prior to assessment by static and dynamic quantitative sensory tests, including measures of temporal summation (TS) and conditioned pain modulation (CPM).

Results: CS, as defined by the presence of both enhanced TS and inefficient CPM, was present in 16 (84%) CFS cases, 18 (95%) FM cases, and none of the HC (p < 0.001). Pressure pain thresholds were lower in CFS (Median222kPaIQR 146-311; p = 0.04) and FM cases (Median 189 kPa; IQR 129-272; p = 0.003) compared to HC (Median 311 kPa; IQR 245-377). FM cases differed from HC in cold-induced (FM = 22.6 °C (15.3-27.7) vs HC = 14.2 °C (9.0-20.5); p = 0.01) and heat-induced (FM = 38.0 °C (35.2-44.0) vs HC = 45.3 °C (40.1-46.8); p = 0.03) pain thresholds, where CFS cases did not.

Conclusion: Central sensitisation may be a common endophenotype in chronic fatigue syndrome and fibromyalgia. Further research should address whether central sensitisation is a cause or effect of these disorders.

Source: Bourke JH, Wodehouse T, Clark LV, Constantinou E, Kidd BL, Langford R, Mehta V, White PD. Central sensitisation in chronic fatigue syndrome and fibromyalgia; a case control study. J Psychosom Res. 2021 Sep 21;150:110624. doi: 10.1016/j.jpsychores.2021.110624. Epub ahead of print. PMID: 34600309. https://pubmed.ncbi.nlm.nih.gov/34600309/

Complement Component C1q as a Potential Diagnostic Tool for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Subtyping

Abstract:

Background: Routine blood analytics are systematically used in the clinic to diagnose disease or confirm individuals’ healthy status. For myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a disease relying exclusively on clinical symptoms for its diagnosis, blood analytics only serve to rule out underlying conditions leading to exerting fatigue. However, studies evaluating complete and large blood datasets by combinatorial approaches to evidence ME/CFS condition or detect/identify case subgroups are still scarce.

Methods: This study used unbiased hierarchical cluster analysis of a large cohort of 250 carefully phenotyped female ME/CFS cases toward exploring this possibility.

Results: The results show three symptom-based clusters, classified as severe, moderate, and mild, presenting significant differences (p < 0.05) in five blood parameters. Unexpectedly the study also revealed high levels of circulating complement factor C1q in 107/250 (43%) of the participants, placing C1q as a key molecule to identify an ME/CFS subtype/subgroup with more apparent pain symptoms.

Conclusions: The results obtained have important implications for the research of ME/CFS etiology and, most likely, for the implementation of future diagnosis methods and treatments of ME/CFS in the clinic.

Source: Castro-Marrero J, Zacares M, Almenar-Pérez E, Alegre-Martín J, Oltra E. Complement Component C1q as a Potential Diagnostic Tool for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Subtyping. J Clin Med. 2021 Sep 15;10(18):4171. doi: 10.3390/jcm10184171. PMID: 34575280. https://pubmed.ncbi.nlm.nih.gov/34575280/

High Prevalence of Perineural Cysts in Patients with Fibromyalgia and Chronic Fatigue Syndrome

Abstract:

Objective: Pain in fibromyalgia (FM) and chronic fatigue syndrome (CFS) is assumed to originate from central sensitization. Perineural cysts or Tarlov cysts (TCs) are nerve root dilations resulting from pathologically increased cerebrospinal fluid pressure. These cysts initially affect sensory neurons and axons in dorsal root ganglia and produce sensory symptoms (pain and paresthesia). Symptomatic TC (STC) patients often complain about widespread pain and fatigue. Consequently, STC patients may initially be diagnosed with FM, CFS, or both. The objective of this study was to document the prevalence of TCs in patients diagnosed with FM or CFS.

Design: A retrospective study.

Setting: An outpatient clinic for musculoskeletal disorders.

Subjects: Patients diagnosed with FM according to the 1990 American College of Rheumatology criteria or with CFS according to the 1994 Centers for Disease Control criteria were selected.

Methods: Review of lumbar and sacral magnetic resonance imaging scans including TCs ≥5 mm in size.

Results: In total, 197 patients with FM, CFS, or both underwent magnetic resonance imaging. Ninety-one percent were women. The mean age was 48.1 (±11.9) years. TCs were observed in 39% of patients, with a mean size of 11.8 (±5.2) mm. In males, the prevalence was 12%, vs. 42% in females.

Conclusions: In patients diagnosed with FM or CFS, the prevalence of TCs was three times higher than that in the general population. This observation supports the hypothesis that STCs, FM, and CFS may share the same pathophysiological mechanism, i.e., moderately increased cerebrospinal fluid pressure, causing irritation of neurons and axons in dorsal root ganglia.

Source: Hulens M, Bruyninckx F, Dankaerts W, Rasschaert R, De Mulder P, Stalmans I, Vansant G, Bervoets C. High Prevalence of Perineural Cysts in Patients with Fibromyalgia and Chronic Fatigue Syndrome. Pain Med. 2020 Dec 1:pnaa410. doi: 10.1093/pm/pnaa410. Epub ahead of print. PMID: 33260218. https://pubmed.ncbi.nlm.nih.gov/33260218/

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

Abstract:

Oxidative stress can be induced by various stimuli and altered in certain conditions, including exercise and pain. Although many studies have investigated oxidative stress in relation to either exercise or pain, the literature presents conflicting results. Therefore, this review critically discusses existing literature about this topic, aiming to provide a clear overview of known interactions between oxidative stress, exercise, and pain in healthy people as well as in people with chronic pain, and to highlight possible confounding factors to keep in mind when reflecting on these interactions. In addition, autonomic regulation and epigenetic mechanisms are proposed as potential mechanisms of action underlying the interplay between oxidative stress, exercise, and pain.

This review highlights that the relation between oxidative stress, exercise, and pain is poorly understood and not straightforward, as it is dependent on the characteristics of exercise, but also on which population is investigated. To be able to compare studies on this topic, strict guidelines should be developed to limit the effect of several confounding factors. This way, the true interplay between oxidative stress, exercise, and pain, and the underlying mechanisms of action can be revealed and validated via independent studies.

Source: Hendrix J, Nijs J, Ickmans K, Godderis L, Ghosh M, Polli A. The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms. Antioxidants (Basel). 2020 Nov 23;9(11):1166. doi: 10.3390/antiox9111166. PMID: 33238564; PMCID: PMC7700330. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7700330/  (Full text)

Pain in adolescent chronic fatigue following Epstein-Barr virus infection

Abstract:

Objectives: Acute Epstein-Barr virus (EBV) infection is a trigger of Chronic Fatigue (CF) and Chronic Fatigue Syndrome (CFS). The aim of this cross-sectional study was to investigate pain symptoms and pressure pain thresholds in fatigued and non-fatigued adolescents six months after acute EBV-infection, and in healthy controls. This study is part of the CEBA-project (CF following acute EBV infection in adolescents).

Methods: A total of 195 adolescents (12-20 years old) that had undergone an acute EBV infection six months prior to assessment were divided into fatigued (EBV CF+) and non-fatigued (EBV CF-) cases based on questionnaire score. The EBV CF+ cases were further sub-divided according to case definitions of CFS. In addition, a group of seventy healthy controls was included. Symptoms were mapped with questionnaires. Pressure pain thresholds were measured through pressure algometry. One way ANOVA were used for between-group analyses. Linear regression analyses were used to explore associations between Pediatric Quality of Life (dependent variable), pain symptoms and other variables within the EBV (CF+) group.

Results: The EBV CF+ group had significantly higher scores for pain symptoms as compared with the EBV CF- group and healthy controls, but pressure pain threshold did not differ significantly. The number of pain symptoms as well as pain severity were strongly and independently associated with quality of life.

Conclusions: CF and CFS following acute EBV-infection in adolescents is characterized by high pain symptom burden, which in turn is associated with a decline in quality of life. Pain in CF and CFS is of considerable clinical importance, and should be a focal point for further investigation and intervention in these patient groups.

Source: Brodwall EM, Pedersen M, Asprusten TT, Wyller VBB. Pain in adolescent chronic fatigue following Epstein-Barr virus infection [published online ahead of print, 2020 Sep 7]. Scand J Pain. 2020;/j/sjpain.ahead-of-print/sjpain-2020-0031/sjpain-2020-0031.xml. doi:10.1515/sjpain-2020-0031  https://pubmed.ncbi.nlm.nih.gov/32892183/

Chronic Pain Syndromes and Their Laryngeal Manifestations

Abstract:

IMPORTANCE: Fibromyalgia syndrome (FMS), irritable bowel syndrome (IBS), and chronic fatigue syndrome (CFS) are traditionally considered as distinct entities grouped under chronic pain syndrome (CPS) of an unknown origin. However, these 3 disorders may exist on a spectrum with a shared pathophysiology.

OBJECTIVE: To investigate whether the clinical presentation of FMS, IBS, and CFS is similar in a population presenting with voice and laryngeal disorders.

DESIGN, SETTING, AND PARTICIPANTS: This case series was a retrospective review of the medical records and clinical notes of patients treated between January 1, 2016, and December 31, 2017, at the Johns Hopkins Voice Center in Baltimore, Maryland. Patients with at least 1 CPS of interest (FMS, IBS, or CFS) were included (n = 215), along with patients without such diagnoses (n = 4034). Diagnoses, demographic, and comorbidity data were reviewed. Diagnoses related to voice and laryngeal disorders were subdivided into 5 main categories (laryngeal pathology, functional voice disorders, airway problems, swallowing problems, and other diagnoses).

MAIN OUTCOMES AND MEASURES: Prevalence and odds ratios of 45 voice and laryngeal disorders were reviewed. Odds ratios (ORs) were calculated by comparing patients with CPS with control patients.

RESULTS: In total, 4249 individuals were identified; 215 (5.1%) had at least 1 CPS and 4034 (94.9%) were control participants. Patients with CPS were 3 times more likely to be women compared with the control group (173 of 215 [80.5%] vs 2318 of 4034 [57.5%]; OR, 3.156; 95% CI, 2.392-4.296), and the CPS group had a mean (SD) age of 57.80 (15.30) years compared with the mean (SD) age of 55.77 (16.97) years for the control group. Patients with CPS were more likely to present with functional voice disorders (OR, 1.812; 95% CI, 1.396-2.353) and less likely to present with laryngeal pathology (OR, 0.774; 95% CI, 0.610-0.982) or airway problems (OR, 0.474; 95% CI, 0.285-0.789).

CONCLUSIONS AND RELEVANCE: The voice and airway presentation of patients with FMS, IBS, and/or CFS appears to be indistinguishable from each other. This finding suggests that these 3 diseases share upper airway symptoms.

Source: Piersiala K, Akst LM, Hillel AT, Best SR. Chronic Pain Syndromes and Their Laryngeal Manifestations. JAMA Otolaryngol Head Neck Surg. 2020 Apr 30. doi: 10.1001/jamaoto.2020.0530. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/32352483