From neurasthenia to post-exertion disease: Evolution of the diagnostic criteria of chronic fatigue syndrome/myalgic encephalomyelitis

Abstract:

Changes in the terminology and diagnostic criteria for chronic fatigue syndrome/myalgic encephalomyelitis are explained in this paper. This syndrome is a complex and controversial entity of unknown origins. It appears in the medical literature in 1988, although clinical pictures of chronic idiopathic fatigue have been identified since the nineteenth century with different names, from neurasthenia, epidemic neuromyasthenia, and benign myalgic encephalomyelitis up to the current proposal of disease of intolerance to effort (post-effort). All of them allude to a chronic state of generalised fatigue of unknown origin, with limitations to physical and mental effort, accompanied by a set of symptoms that compromise diverse organic systems.

The International Classification of Diseases (ICD-10) places this syndrome in the section on neurological disorders (G93.3), although histopathological findings have not yet been found to clarify it. Multiple organic alterations have been documented, but a common biology that clarifies the mechanisms underlying this disease has not been established. It is defined as a neuro-immune-endocrine dysfunction, with an exclusively clinical diagnosis and by exclusion.

Several authors have proposed to include CFS/ME within central sensitivity syndromes, alluding to central sensitisation as the common pathophysiological substrate for this, and other syndromes. The role of the family doctor is a key figure in the disease, from the detection of those patients who present a fatigue of unknown nature that is continuous or intermittent for more than 6 months, in order to make an early diagnosis and establish a plan of action against a chronic disease with high levels of morbidity in the physical and mental sphere.

OBJECTIVE: To carry out a bibliographic review of the terminology and diagnostic criteria of the chronic fatigue syndrome/myalgic encephalomyelitis, in order to clarify the pathology conceptually, as a usefulness in the diagnosis of Primary Care physicians.

Copyright © 2019. Publicado por Elsevier España, S.L.U.

Source: Murga Í, Lafuente JV. From neurasthenia to post-exertion disease: Evolution of the diagnostic criteria of chronic fatigue syndrome/myalgic encephalomyelitis. Aten Primaria. 2019 Jun 7. pii: S0212-6567(19)30191-X. doi: 10.1016/j.aprim.2019.04.004. [Epub ahead of print][Article in Spanish] https://www.ncbi.nlm.nih.gov/pubmed/31182238

Genetic Predisposition for Immune System, Hormone, and Metabolic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Study

Abstract:

Introduction: Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a multifactorial illness of unknown etiology with considerable social and economic impact. To investigate a putative genetic predisposition to ME/CFS we conducted genome-wide single-nucleotide polymorphism (SNP) analysis to identify possible variants.

Methods: 383 ME/CFS participants underwent DNA testing using the commercial company 23andMe. The deidentified genetic data was then filtered to include only non-synonymous and nonsense SNPs from exons and microRNAs, and SNPs close to splice sites. The frequencies of each SNP were calculated within our cohort and compared to frequencies from the Kaviar reference database. Functional annotation of pathway sets containing SNP genes with high frequency in ME/CFS was performed using over-representation analysis via ConsensusPathDB. Furthermore, these SNPs were also scored using the Combined Annotation Dependent Depletion (CADD) algorithm to gauge their deleteriousness.

Results: 5693 SNPs were found to have at least 10% frequency in at least one cohort (ME/CFS or reference) and at least two-fold absolute difference for ME/CFS. Functional analysis identified the majority of SNPs as related to immune system, hormone, metabolic, and extracellular matrix organization. CADD scoring identified 517 SNPs in these pathways that are among the 10% most deleteriousness substitutions to the human genome.

Source: Perez M, Jaundoo R, Hilton K, Del Alamo A, Gemayel K, Klimas NG, Craddock TJA, Nathanson L. Genetic Predisposition for Immune System, Hormone, and Metabolic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Study. Front Pediatr. 2019 May 24;7:206. doi: 10.3389/fped.2019.00206. eCollection 2019. https://www.ncbi.nlm.nih.gov/pubmed/31179255

Endometriosis as a Comorbid Condition in Chronic Fatigue Syndrome (CFS): Secondary Analysis of Data From a CFS Case-Control Study

Abstract:

Background: Endometriosis (EM) is a recognized co-morbid condition in women with chronic fatigue syndrome (CFS). This analysis evaluates the impact of EM on the health of women with CFS by comparing selected health characteristics and laboratory parameters in women with CFS with and without EM (CFS+EM and CFS-only).

Methods: This secondary analysis included all 36 women with CFS from a cross-sectional study of CFS in Wichita, KS, conducted between 2002 and 2003. The health characteristics and laboratory parameters of interest included functioning, fatigue, CFS-related symptoms, gynecologic history, routine laboratory parameters, inflammatory markers, cortisol levels, allostatic load, and sleep parameters (overnight polysomnography). We used parametric or non-parametric tests to compare group differences in the selected health characteristics and laboratory parameters. For examining the association between EM and variables of interest, logistic regression models were performed and odds ratios (OR) with 95% confidence intervals (CI) were reported for the magnitude of associations. Statistical significance was set at 0.05 (two-sided).

Results: The mean age of this study sample was 50.9 years. Of women with CFS, 36.1% reported having EM. Age and body mass index (BMI) did not differ between CFS+EM and CFS-only groups. When examining the impact of EM, compared to women with CFS-only, women with both CFS and EM were more likely to report chronic pelvic pain [OR = 9.00 (95% CI, 1.47-55.25)] and hysterectomy [OR = 10.3 (1.82-58.39)], had more CFS symptoms (6.8 ± 0.3 vs. 5.5 ± 0.3, p = 0.02), younger mean age at menopause onset (36.4 ± 3.0 vs. 47.0 ± 2.7 years, p = 0.03), higher mean number of obstructive apnea episodes per hour (20.3 vs. 4.4, p = 0.05) and reported more negative life events (15.8 vs. 4.4, p = 0.05). Other parameters did not differ significantly between the two groups.

Conclusions: We found more than a third of women with CFS reported endometriosis as a comorbid condition. The endometriosis comorbidity was associated with chronic pelvic pain, earlier menopause, hysterectomy, and more CFS-related symptoms. However, endometriosis in women with CFS did not appear to further impact functioning, fatigue, inflammatory markers, or other laboratory parameters. Further investigations including younger women are warranted.

Source: Boneva RS, Lin JS, Wieser F, Nater UM, Ditzen B, Taylor RN, Unger ER. Endometriosis as a Comorbid Condition in Chronic Fatigue Syndrome (CFS): Secondary Analysis of Data From a CFS Case-Control Study. Front Pediatr. 2019 May 21;7:195. doi: 10.3389/fped.2019.00195. eCollection 2019. https://www.ncbi.nlm.nih.gov/pubmed/31179251

Patients with fibromyalgia and chronic fatigue syndrome show increased hsCRP compared to healthy controls

Abstract:

Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are both chronic disorders that have a devastating effect on the lives of the affected patients and their families. Both conditions have overlapping clinical features that partly resemble those of inflammatory disorders. The etiology is still not understood, and it is suggested that the immune system might be a contributing factor. So far, the results are inconclusive. The purpose of this study was to compare the two conditions and investigate the level of the inflammatory marker high-sensitivity CRP (hsCRP) in CFS and FM patients compared to healthy controls.

Female participants aged 18-60 years were enrolled in this study. The group consisted of 49 CFS patients, 57 FM patients, and 54 healthy controls. hsCRP levels were significantly higher for both the CFS and the FM groups compared to healthy controls when adjusting for age, smoking, and BMI (p < .001).

There was no difference between the two patient groups. The level of hsCRP was affected by BMI but not by age and smoking. Patients with CFS and FM have higher concentrations of hsCRP compared to healthy controls. This remains significant even after adjusting for BMI. CFS and FM cannot be distinguished from each other on the basis of hsCRP in our study.

Copyright © 2019. Published by Elsevier Inc.

Source: Groven N, Fors EA, Klæbo Reitan S. Patients with fibromyalgia and chronic fatigue syndrome show increased hsCRP compared to healthy controls. Brain Behav Immun. 2019 Jun 6. pii: S0889-1591(19)30208-9. doi: 10.1016/j.bbi.2019.06.010. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31176728

Neuropsychological dysfunction in chronic fatigue syndrome and the relation between objective and subjective findings

Abstract:

OBJECTIVE: This study aimed to explore the relationship between self-reported cognitive difficulties, objective neuropsychological test performances, and subjective health complaints in chronic fatigue syndrome (CFS) and to examine the degree of impaired cognitive functions.

METHOD: A total of 236 consecutively recruited outpatients, 18-62 years of age, completed the tests. Self-administered questionnaires were used for assessing fatigue, pain, depression, anxiety and subjective cognitive complaints (Everyday Memory Questionnaire [EMQ]). Also, neuropsychological tests, that is, Stroop I-IV, California Verbal Learning Test-Second Edition (CVLT-II) learning and delay, Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) Letter Number (L-N) Sequencing, and the Paced Auditory Serial Addition Task were performed to examine whether these objective measures correlated with subjective complaints and were compared with normative data.

RESULTS: There was a trend of association (p < .05) between the unadjusted EMQ with Stroop IV (inhibition and shifting attention), the CVLT-II learning and delay (verbal learning and memory), and the WAIS-III L-N Sequencing (working memory), but none were statistically significant at the .001 level. The EMQ was positively associated with fatigue, pain, and depression (p < .001). The PASAT (working memory) was negatively associated with pain (p < .001). Between 21% and 38% of the patients performed below the 1.5-SD cutoff for clinically significant impairment on the Stroop tests.

CONCLUSION: The self-reported cognitive performance was not strongly associated with the objective cognitive performances on any domains in patients with CFS. Patients with higher fatigue, pain, and depression levels reported greater subjective cognitive difficulties, as well as higher pain related to lower objective working memory function. The CFS patients had problems mainly in the domains of psychomotor speed and attention measured by the objective neuropsychological tests. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

TRIAL REGISTRATION: ClinicalTrials.gov NCT00920777.

Source: Rasouli O, Gotaas ME, Stensdotter AK, Skovlund E, Landrø NI, Dåstøl P, Fors EA. Neuropsychological dysfunction in chronic fatigue syndrome and the relation between objective and subjective findings. Neuropsychology. 2019 Jun 6. doi: 10.1037/neu0000550. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31169386

Abnormal blood lactate accumulation during repeated exercise testing in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Post-exertional malaise and delayed recovery are hallmark symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Studies on repeated cardiopulmonary exercise testing (CPET) show that previous exercise negatively affects oxygen uptake (VO2 ) and power output (PO) in ME/CFS. Whether this affects arterial lactate concentrations ([Laa ]) is unknown.

We studied 18 female patients (18-50 years) fulfilling the Canadian Consensus Criteria for ME/CFS and 15 healthy females (18-50 years) who underwent repeated CPETs 24 h apart (CPET1 and CPET2 ) with [Laa ] measured every 30th second. VO2 at peak exercise (VO2 peak) was lower in patients than in controls on CPET1 (P < 0.001) and decreased in patients on CPET2 (P < 0.001).

However, the difference in VO2peak between CPETs did not differ significantly between groups. [Laa ] per PO was higher in patients during both CPETs (Pinteraction < 0.001), but increased in patients and decreased in controls from CPET1 to CPET2 (Pinteraction < 0.001). Patients had lower VO2 (P = 0.02) and PO (P = 0.002) at the gas exchange threshold (GET, the point where CO2 production increases relative to VO2 ), but relative intensity (%VO2peak ) and [Laa ] at GET did not differ significantly from controls on CPET1 .

Patients had a reduction in VO2 (P = 0.02) and PO (P = 0.01) at GET on CPET2 , but no significant differences in %VO2peak and [Laa ] at GET between CPETs. Controls had no significant differences in VO2 , PO or %VO2peak at GET between CPETs, but [Laa ] at GET was reduced on CPET2 (P = 0.008).

In conclusion, previous exercise deteriorates physical performance and increases [Laa ] during exercise in patients with ME/CFS while it lowers [Laa ] in healthy subjects.

© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Source: Lien K, Johansen B, Veierød MB, Haslestad AS, Bøhn SK, Melsom MN, Kardel KR, Iversen PO. Abnormal blood lactate accumulation during repeated exercise testing in myalgic encephalomyelitis/chronic fatigue syndrome. Physiol Rep. 2019 Jun;7(11):e14138. doi: 10.14814/phy2.14138. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6546966/ (Full article)

Orthostatic intolerance in chronic fatigue syndrome

Abstract:

BACKGROUND: Orthostatic intolerance (OI) is a significant problem for those with chronic fatigue syndrome (CFS). We aimed to characterize orthostatic intolerance in CFS and to study the effects of exercise on OI.

METHODS: CFS (n = 39) and control (n = 25) subjects had recumbent and standing symptoms assessed using the 20-point, anchored, ordinal Gracely Box Scale before and after submaximal exercise. The change in heart rate (ΔHR ≥ 30 bpm) identified Postural Orthostatic Tachycardia Syndrome (POTS) before and after exercise, and the transient, exercise-induced postural tachycardia Stress Test Activated Reversible Tachycardia (START) phenotype only after exercise.

RESULTS: Dizziness and lightheadedness were found in 41% of recumbent CFS subjects and in 72% of standing CFS subjects. Orthostatic tachycardia did not account for OI symptoms in CFS. ROC analysis with a threshold ≥ 2/20 on the Gracely Box Scale stratified CFS subjects into three groups: No OI (symptoms < 2), Postural OI (only standing symptoms ≥ 2), and Persistent OI (recumbent and standing symptoms ≥ 2).

CONCLUSIONS: Dizziness and Lightheadedness symptoms while recumbent are an underreported finding in CFS and should be measured when doing a clinical evaluation to diagnose orthostatic intolerance. POTS was found in 6 and START was found in 10 CFS subjects. Persistent OI had symptoms while recumbent and standing, highest symptom severity, and lability in symptoms after exercise.

Trial registration: The trial was registered at the following: https://clinicaltrials.gov/ct2/show/NCT03567811.

Source: Garner R, Baraniuk JN. Orthostatic intolerance in chronic fatigue syndrome. J Transl Med. 2019 Jun 3;17(1):185. doi: 10.1186/s12967-019-1935-y.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547462/ (Full article)

Genetic Predisposition for Immune System, Hormone, and Metabolic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Study

Abstract:

Introduction: Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a multifactorial illness of unknown etiology with considerable social and economic impact. To investigate a putative genetic predisposition to ME/CFS we conducted genome-wide single-nucleotide polymorphism (SNP) analysis to identify possible variants.

Methods: 383 ME/CFS participants underwent DNA testing using the commercial company 23andMe. The deidentified genetic data was then filtered to include only non-synonymous and nonsense SNPs from exons and microRNAs, and SNPs close to splice sites. The frequencies of each SNP were calculated within our cohort and compared to frequencies from the Kaviar reference database. Functional annotation of pathway sets containing SNP genes with high frequency in ME/CFS was performed using over-representation analysis via ConsensusPathDB. Furthermore, these SNPs were also scored using the Combined Annotation Dependent Depletion (CADD) algorithm to gauge their deleteriousness.

Results: 5693 SNPs were found to have at least 10% frequency in at least one cohort (ME/CFS or reference) and at least two-fold absolute difference for ME/CFS. Functional analysis identified the majority of SNPs as related to immune system, hormone, metabolic, and extracellular matrix organization. CADD scoring identified 517 SNPs in these pathways that are among the 10% most deleteriousness substitutions to the human genome.

Source: Melanie Perez, Rajeev Jaundoo, Kelly Hilton, Ana Del Alamo, Kristina Gemayel, Nancy G. Klimas, Travis J. A. Craddock and Lubov Nathanson. Genetic Predisposition for Immune System, Hormone, and Metabolic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Study. Front. Pediatr., 24 May 2019 | https://doi.org/10.3389/fped.2019.00206 (Full article)

Healthcare Utilization in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Analysis of US Ambulatory Healthcare Data, 2000-2009

Abstract:

Background: ME/CFS is a complex and disabling illness with substantial economic burden and functional impairment comparable to heart disease and multiple sclerosis. Many patients with ME/CFS do not receive appropriate healthcare, partially due to lack of diagnostic tests, and knowledge/attitudes/beliefs about ME/CFS. This study was to assess the utility of US ambulatory healthcare data in profiling demographics, co-morbidities, and healthcare in ME/CFS.

Methods: Data came from the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) in the U.S. Weighted analysis was performed. We examined 9.06 billion adult visits from 2000 to 2009 NAMCS/NHAMCS data. ME/CFS-related visits were identified by ICD-9-CM code, 780.71, up to tertiary diagnosis.

Results: We estimated 2.9 million (95% CI: 1.8-3.9 million) ME/CFS-related visits during 2000-2009, with no statistical evidence (p-trend = 0.31) for a decline or increase in ME/CFS-related visits. Internists, general and family practitioners combined provided 52.12% of these visits. Patients with ME/CFS-related visits were mostly in their 40 and 50 s (47.76%), female (66.07%), white (86.95%), metropolitan/urban residents (92.05%), and insured (87.26%). About 71% of ME/CFS patients had co-morbidities, including depression (35.79%), hypertension (31.14%), diabetes (20.30%), and arthritis (14.11%). As one quality indicator, physicians spent more time on ME/CFS-related visits than non-ME/CFS visits (23.62 vs. 19.38 min, p = 0.065). As additional quality indicators, the top three preventive counseling services provided to patients with ME/CFS-related visits were diet/nutrition (8.33%), exercise (8.21%), and smoking cessation (7.24%). Compared to non-ME/CFS visits, fewer ME/CFS-related visits included counseling for stress management (0.75 vs. 3.14%, p = 0.010), weight reduction (0.88 vs. 4.02%, p = 0.002), injury prevention (0.04 vs. 1.64%, p < 0.001), and family planning/contraception (0.17 vs. 1.45%, p = 0.037).

Conclusions: Visits coded with ME/CFS did not increase from 2000 to 2009. Almost three quarters of ME/CFS-related visits were made by ME/CFS patients with other co-morbid conditions, further adding to complexity in ME/CFS healthcare. While physicians spent more time with ME/CFS patients, a lower proportion of ME/CFS patients received preventive counseling for weight reduction, stress management, and injury prevention than other patients despite the complexity of ME/CFS. NAMCS/NHAMCS data are useful in evaluating co-morbidities, healthcare utilization, and quality indicators for healthcare in ME/CFS.

Source: Bae J, Lin JS. Healthcare Utilization in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Analysis of US Ambulatory Healthcare Data, 2000-2009. Front Pediatr. 2019 May 14;7:185. doi: 10.3389/fped.2019.00185. eCollection 2019. https://www.frontiersin.org/articles/10.3389/fped.2019.00185/full (Full article)

Shared microglial mechanisms underpinning depression and chronic fatigue syndrome and their comorbidities

Abstract:

In 2011, it was reviewed that a) there is a strong co-occurrence between major depression and chronic fatigue syndrome (CFS), with fatigue and physio-somatic symptoms being key symptoms of depression, and depressive symptoms appearing during the course of CFS; and b) the comorbidity between both disorders may in part be explained by activated immune-inflammatory pathways, including increased translocation of Gram-negative bacteria and increased levels of pro-inflammatory cytokines, such as interleukin (IL)-1. Nevertheless, the possible involvement of activated microglia in this comorbidity has remained unclear.

This paper aims to review microglial disturbances in major depression, CFS and their comorbidity. A comprehensive literature search was conducted using the PubMed / MEDLINE database to identify studies, which are relevant to this current review. Depressed patients present neuroinflammatory alterations, probably related to microglial activation, while animal models show that a microglial response to immune challenges including lipopolysaccharides is accompanied by depressive-like behaviors. Recent evidence from preclinical studies indicates that activated microglia have a key role in the onset of fatigue. In chronic inflammatory conditions, such as infections and senescence, microglia orchestrate an inflammatory microenvironment thereby causing fatigue.

In conclusion, based on our review we may posit that shared immune-inflammatory pathways and especially activated microglia underpin comorbid depression and CFS. As such, microglial activation and neuro-inflammation may be promising targets to treat the overlapping manifestations of both depression and CFS.

Copyright © 2019. Published by Elsevier B.V.

Source: Filho AJMC, Macedo DS, de Lucena DF, Maes M. Shared microglial mechanisms underpinning depression and chronic fatigue syndrome and their comorbidities. Behav Brain Res. 2019 May 25:111975. doi: 10.1016/j.bbr.2019.111975. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31136774