Endogenous Pain Facilitation Rather Than Inhibition Differs Between People with Chronic Fatigue Syndrome, Multiple Sclerosis, and Controls: An Observational Study

Abstract:

BACKGROUND: Commonalities in the core symptoms of fatigue and cognitive dysfunction experienced by chronic fatigue syndrome (CFS, also known as ME) and multiple sclerosis (MS) patients have been described. Many CFS and MS patients also experience chronic pain, which has been attributed to central sensitization in both groups of patients. However, the characteristics of pain in CFS and MS patients have not been compared.

OBJECTIVES: To compare experimental pain measurements in patients with CFS or MS and healthy controls.

STUDY DESIGN: Observational study.

SETTING: This study took place in Belgium at Vrije Universiteit Brussel and the University of Antwerp.

METHODS: Pressure pain thresholds, temporal summation, conditioned pain modulation, and occlusion cuff pressure thresholds rated as painful (1st cuff pressure threshold) and as 3/10 on a verbal numerical scale (2nd cuff pressure threshold) were measured in patients with CFS (n = 48), MS (n = 19) and healthy pain-free controls (n = 30). Adjusted between-group differences were estimated using linear regression models.

RESULTS: Finger pain pressure thresholds of patients with CFS, compared with patients with MS, were 25% lower (difference ratio 0.75 [95% CI 0.59, 0.95], P = 0.02) and shoulder pain pressure thresholds were 26% lower (difference ratio 0.74 [0.52, 1.04], P = 0.08). Compared with patients with MS, patients with CFS had 29% lower first cuff pressure threshold (difference ratio 0.71 [0.53, 0.94], P = 0.02) and 41% lower 2nd cuff pressure threshold (0.59 [0.41, 0.86], P = 0.006). Finger temporal summation was higher in patients with CFS than in patients with MS (mean difference 1.15 [0.33, 1.97], P = 0.006), but there were no differences in shoulder temporal summation or conditioned pain modulation at either site. Differences between patients with CFS and MS tended to be greater than between either patient group and healthy controls. Pain pressure thresholds and cuff pressure thresholds tended to be positively correlated, and temporal summation negatively correlated, with higher physical function and lower fatigue in both groups of patients. Subjective pain in patients with CFS but not in patients with MS was strongly negatively correlated with pain pressure thresholds and cuff pressure thresholds, and positively correlated with temporal summation.

LIMITATIONS: The main limitations of our study are the relatively small sample sizes, its cross-sectional design, and its exploratory nature.

CONCLUSIONS: We found differences in the characteristics of pain symptoms reported by patients with CFS and patients with MS, which suggest different underlying mechanisms. Specifically, overactive endogenous pain facilitation was characteristic of pain in patients with CFS but not in patients with MS, suggesting a greater role for central sensitization in CFS.

Source: Collin SM, Nijs J, Meeus M, Polli A, Willekens B, Ickmans K. Endogenous Pain Facilitation Rather Than Inhibition Differs Between People with Chronic Fatigue Syndrome, Multiple Sclerosis, and Controls: An Observational Study. Pain Physician. 2017 May;20(4):E489-E497. http://www.painphysicianjournal.com/linkout?issn=1533-3159&vol=20&page=E489 (Full article available as PDF.)

A Comparison of Neuroimaging Abnormalities in Multiple Sclerosis, Major Depression and Chronic Fatigue Syndrome (Myalgic Encephalomyelitis): is There a Common Cause?

Abstract:

There is copious evidence of abnormalities in resting-state functional network connectivity states, grey and white matter pathology and impaired cerebral perfusion in patients afforded a diagnosis of multiple sclerosis, major depression or chronic fatigue syndrome (CFS) (myalgic encephalomyelitis). Systemic inflammation may well be a major element explaining such findings. Inter-patient and inter-illness variations in neuroimaging findings may arise at least in part from regional genetic, epigenetic and environmental variations in the functions of microglia and astrocytes.

Regional differences in neuronal resistance to oxidative and inflammatory insults and in the performance of antioxidant defences in the central nervous system may also play a role. Importantly, replicated experimental findings suggest that the use of high-resolution SPECT imaging may have the capacity to differentiate patients afforded a diagnosis of CFS from those with a diagnosis of depression. Further research involving this form of neuroimaging appears warranted in an attempt to overcome the problem of aetiologically heterogeneous cohorts which probably explain conflicting findings produced by investigative teams active in this field. However, the ionising radiation and relative lack of sensitivity involved probably preclude its use as a routine diagnostic tool.

Source: Morris G, Berk M, Puri BK. A Comparison of Neuroimaging Abnormalities in Multiple Sclerosis, Major Depression and Chronic Fatigue Syndrome (Myalgic Encephalomyelitis): is There a Common Cause? Mol Neurobiol. 2017 May 17. doi: 10.1007/s12035-017-0598-z. https://www.ncbi.nlm.nih.gov/pubmed/28516431 

Incidence of myalgic encephalomyelitis/chronic fatigue syndrome in a large prospective cohort of U.S. nurses

Abstract:

Background: The incidence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), the rates of both under-diagnosis and over-diagnosis, and the nature of the onset of the condition have not been assessed in large studies of health professionals.

Purpose: To determine the cumulative incidence of ME/CFS in a large population of health professionals, to examine the nature of the onset of the illness, and to estimate the frequency of both over-diagnosis and under-diagnosis of ME/CFS.

Methods: We sent an email questionnaire to participants in the Nurses’ Health Study II (NHS II), a large prospective cohort of female nurses. Forty-two thousand three hundred and ninety-four women completed the questionnaire, which included the 1994 Centers for Disease Control and Prevention (CDC) criteria for ME/CFS.

Results: One-hundred and two women (240 per 100,000 surveyed) developed an illness that met criteria for ME/CFS between 1989 and 2009. The onset of ME/CFS was gradual in 40.6%, sudden (following flu-like illness or other precipitating events) in 18.8%, followed emotional or physical trauma in 32.3%, and was uncertain in the rest. Under-diagnosis was common: only 15 (15%) of the women who met criteria for ME/CFS reported having been diagnosed. Over-diagnosis also was common: four times as many subjects had been diagnosed with ME/CFS by community doctors as actually met criteria. The distribution of symptoms was not different in comparing cases with a sudden onset to those with a gradual onset.

Conclusions: In this large cohort of female nurses, we found a low cumulative incidence of ME/CFS. Over-diagnosis and under-diagnosis were high, even in this medically sophisticated population.

Source: Natalia Palacios, Kathryn C. Fitzgerald, Anthony L. Komaroff & Alberto Ascherio. Incidence of myalgic encephalomyelitis/chronic fatigue syndrome in a large prospective cohort of U.S. nurses .Fatigue: Biomedicine, Health & Behavior. Pages 1-8 Received 08 Mar 2017, Accepted 24 Apr 2017, Published online: 18 May 2017. http://www.tandfonline.com/doi/full/10.1080/21641846.2017.1323576

Once again, the PACE authors respond to concerns with empty answers

Abstract:

In their response to Geraghty, the PACE investigators state that they have “repeatedly addressed” the various methodological concerns raised about the trial. While this is true, these responses have repeatedly failed to provide satisfactory explanations for the trial’s very serious flaws. This commentary examines how the current response once again demonstrates the ways in which the investigators avoid acknowledging the obvious problems with PACE and offer non-answers instead—arguments that fall apart quickly under scrutiny.

Source: David Tuller. Once again, the PACE authors respond to concerns with empty answers. Journal of Health Psychology. First Published April 27, 2017. http://journals.sagepub.com/doi/full/10.1177/1359105317703788 (Full article)

PACE investigators’ response is misleading regarding patient survey results

Abstract:

The PACE investigators’ citation of a patient survey might mislead readers into thinking that the experience of people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) supports PACE findings. In fact, patient survey evidence directly contradicts the results of the PACE trial. A review of survey data published between 2001 and 2015 reveals that for most patients, graded exercise therapy leads to worsening of symptoms, cognitive behavioural therapy leads to no change in symptoms, and pacing leads to improvement. The experience of people with ME/CFS as reflected in surveys is a rich source of information, made more compelling by the consistency of results. Consequently, patient survey evidence can be used to inform practice, research and guidelines. Misrepresentation of patient experience must be vigorously challenged, to ensure that patients and health professionals make decisions about therapies based on accurate information.

Source: Karen D. Kirke. PACE investigators’ response is misleading regarding patient survey results. Journal of Health Psychology. First Published May 11, 2017. http://journals.sagepub.com/doi/full/10.1177/1359105317703787 (Full article)

Distress signals: Does cognitive behavioural therapy reduce or increase distress in chronic fatigue syndrome/myalgic encephalomyelitis?

Abstract:

Reducing the psychological distress associated with chronic fatigue syndrome/myalgic encephalomyelitis is seen as a key aim of cognitive behavioural therapy. Although cognitive behavioural therapy is promoted precisely in this manner by the National Institute of Clinical Excellence, the evidence base on distress reduction from randomised controlled trials is limited, equivocal and poor quality. Crucially, data derived from multiple patient surveys point to worsening and increase distress; however, despite being invited, such data have been dismissed as second class by National Institute of Clinical Excellence. Crucially, the claim by National Institute of Clinical Excellence that cognitive behavioural therapy reduces distress in chronic fatigue syndrome/myalgic encephalomyelitis is not only at odds with what patients repeatedly report in surveys, but with their own gold-standard randomised controlled trial and meta-analytic data.

Source: Keth R. Laws. Distress signals: Does cognitive behavioural therapy reduce or increase distress in chronic fatigue syndrome/myalgic encephalomyelitis? Journal of Health Psychology.  First Published May 17, 2017. http://journals.sagepub.com/doi/full/10.1177/1359105317710246 (Full article)

The variation of the 5-hydroxytryptamine system between chronic unpredictable mild stress rats and chronic fatigue syndrome rats induced by forced treadmill running

Abstract:

The aim of this study was to observe the variation in the 5-hydroxytryptamine (5-HT) system between a chronic unpredictable mild stress (CUMS) model and a chronic fatigue syndrome (CFS) model. The total distance, the crossing pieces, and rearing times in the open-field test of the CUMS group and the CFS group were all less than those of the control group to different degrees.

The concentrations of tryptophan, 5-HT, and 5-HIAA of the CUMS group were obviously lower than those of the control group. In the CFS model, the concentrations of tryptophan, 5-HT, and 5-HIAA were obviously higher than those of the control group. The expressions of tryptophan hydroxylase-2 (TPH-2) and 5-HT1A receptor in protein level and mRNA level were also different among the three groups. The expressions of TPH-2 and 5-HT1A were higher in the CFS group than in the CUMS group. The expressions of TPH-2 and 5-HT1A receptor were lower in the CUMS group than in the control group. We can find that in different situations of mood disorders, the variation of 5-HT system may also be opposite.

Source: Cao Y, Li Q. The variation of the 5-hydroxytryptamine system between chronic unpredictable mild stress rats and chronic fatigue syndrome rats induced by forced treadmill running. Neuroreport. 2017 May 12. doi: 10.1097/WNR.0000000000000797. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28505018

Randomised controlled trial of online continuing education for health professionals to improve the management of chronic fatigue syndrome: a study protocol

Abstract:

INTRODUCTION: Chronic fatigue syndrome (CFS) is a serious and debilitating illness that affects between 0.2%-2.6% of the world's population. Although there is level 1 evidence of the benefit of cognitive behaviour therapy (CBT) and graded exercise therapy (GET) for some people with CFS, uptake of these interventions is low or at best untimely. This can be partly attributed to poor clinician awareness and knowledge of CFS and related CBT and GET interventions. This trial aims to evaluate the effect of participation in an online education programme, compared with a wait-list control group, on allied health professionals' knowledge about evidence-based CFS interventions and their levels of confidence to engage in the dissemination of these interventions.

METHODS AND ANALYSIS: A randomised controlled trial consisting of 180 consenting allied health professionals will be conducted. Participants will be randomised into an intervention group (n=90) that will receive access to the online education programme, or a wait-list control group (n=90). The primary outcomes will be: 1) knowledge and clinical reasoning skills regarding CFS and its management, measured at baseline, postintervention and follow-up, and 2) self-reported confidence in knowledge and clinical reasoning skills related to CFS. Secondary outcomes include retention of knowledge and satisfaction with the online education programme. The influence of the education programme on clinical practice behaviour, and self-reported success in the management of people with CFS, will also be assessed in a cohort study design with participants from the intervention and control groups combined.

ETHICS AND DISSEMINATION: The study protocol has been approved by the Human Research Ethics Committee at The University of New South Wales (approval number HC16419). Results will be disseminated via peer-reviewed journal articles and presentations at scientific conferences and meetings.

TRIAL REGISTRATION: ACTRN12616000296437.

© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Source: Li SH, Sandler CX1, Casson SM, Cassar J, Bogg T, Lloyd AR, Barry BK. Randomised controlled trial of online continuing education for health professionals to improve the management of chronic fatigue syndrome: a study protocol. BMJ Open. 2017 May 10;7(5):e014133. doi: 10.1136/bmjopen-2016-014133. https://www.ncbi.nlm.nih.gov/pubmed/28495811

Whole blood gene expression in adolescent chronic fatigue syndrome: an exploratory cross-sectional study suggesting altered B cell differentiation and survival

Abstract:

Background: Chronic fatigue syndrome (CFS) is a prevalent and disabling condition affecting adolescents. The pathophysiology is poorly understood, but immune alterations might be an important component. This study compared whole blood gene expression in adolescent CFS patients and healthy controls, and explored associations between gene expression and neuroendocrine markers, immune markers and clinical markers within the CFS group.

Methods: CFS patients (12–18 years old) were recruited nation-wide to a single referral center as part of the NorCAPITAL project. A broad case definition of CFS was applied, requiring 3 months of unexplained, disabling chronic/relapsing fatigue of new onset, whereas no accompanying symptoms were necessary. Healthy controls having comparable distribution of gender and age were recruited from local schools. Whole blood samples were subjected to RNA sequencing. Immune markers were blood leukocyte counts, plasma cytokines, serum C-reactive protein and immunoglobulins. Neuroendocrine markers encompassed plasma and urine levels of catecholamines and cortisol, as well as heart rate variability indices. Clinical markers consisted of questionnaire scores for symptoms of post-exertional malaise, inflammation, fatigue, depression and trait anxiety, as well as activity recordings.

Results: A total of 29 CFS patients and 18 healthy controls were included. We identified 176 genes as differentially expressed in patients compared to controls, adjusting for age and gender factors. Gene set enrichment analyses suggested impairment of B cell differentiation and survival, as well as enhancement of innate antiviral responses and inflammation in the CFS group. A pattern of co-expression could be identified, and this pattern, as well as single gene transcripts, was significantly associated with indices of autonomic nervous activity, plasma cortisol, and blood monocyte and eosinophil counts. Also, an association with symptoms of post-exertional malaise was demonstrated.

Conclusion: Adolescent CFS is characterized by differential gene expression pattern in whole blood suggestive of impaired B cell differentiation and survival, and enhanced innate antiviral responses and inflammation. This expression pattern is associated with neuroendocrine markers of altered HPA axis and autonomic nervous activity, and with symptoms of post-exertional malaise.

Trial registration Clinical Trials NCT01040429

Source: Chinh Bkrong Nguyen, Lene Alsøe, Jessica M. Lindvall, Dag Sulheim, Even Fagermoen, Anette Winger, Mari Kaarbø, Hilde Nilsen and Vegard Bruun Wyller. Whole blood gene expression in adolescent chronic fatigue syndrome: an exploratory cross-sectional study suggesting altered B cell differentiation and survival. Journal of Translational Medicine 2017 15:102. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-017-1201-0 (Full article)

The spread of EBV to ectopic lymphoid aggregates may be the final common pathway in the pathogenesis of ME/CFS

Abstract:

According to the hypothesis presented here, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develops over 3 steps:

Step 1 is characterized by the aggregation of lymphoid cells in dorsal root ganglia or other nervous structures. The cause of this formation of ectopic lymphoid aggregates may be an acute infection, asymptomatic reactivations of a common neurotropic virus, exposure to a neurotoxin, or physical injury to peripheral nerves.

In step 2, Epstein-Barr virus (EBV)-infected lymphocytes or monocytes bring EBV from the circulation to one or several of these lymphoid aggregates, whereupon cell-to-cell transmission of EBV and proliferation of latently EBV-infected lymphocytes lead to the presence of many EBV-infected cells in the lymphoid aggregates. The EBV-infected cells in the aggregates ignite an inflammation in the surrounding nervous tissue. This local inflammation elicits, in turn, a wave of glial cell activation that spreads from the EBV-infected area to parts of the nervous system that are not EBV-infected, disturbing the neuron-glial interaction in both the peripheral – and central nervous system.

In step 3, immune cell exhaustion contributes to a consolidation of the pathological processes. There might be a cure: Infusions of autologous EBV-specific T-lymphocytes can perhaps remove the EBV-infected cells from the nervous system.

Copyright © 2017 Elsevier Ltd. All rights reserved.

Source: Eriksen W. The spread of EBV to ectopic lymphoid aggregates may be the final common pathway in the pathogenesis of ME/CFS. Med Hypotheses. 2017 May;102:8-15. doi: 10.1016/j.mehy.2017.02.011. Epub 2017 Feb 28. https://www.ncbi.nlm.nih.gov/pubmed/28478837