CNS – American ME and CFS Society

In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome

Abstract:

BACKGROUND: Central sensitisation entails several top-down and bottom-up mechanisms, all contributing to the hyperresponsiveness of the central nervous system to a variety of inputs. In the late nineties, it was first hypothesised that chronic fatigue syndrome (CFS) is characterised by hypersensitivity of the central nervous system (i.e. central sensitisation). Since then, several studies have examined central sensitisation in patients with CFS. This study provides an overview of such studies.

MATERIALS AND METHODS: Narrative review.

RESULTS: Various studies showed generalised hyperalgesia in CFS for a variety of sensory stimuli, including electrical stimulation, mechanical pressure, heat and histamine. Various tissues are affected by generalised hyperalgesia: the skin, muscle tissue and the lungs. Generalised hyperalgesia in CFS is augmented, rather than decreased, following various types of stressors like exercise and noxious heat pain. Endogenous inhibition is not activated in response to exercise and activation of diffuse noxious inhibitory controls following noxious heat application to the skin is delayed.

CONCLUSIONS: The observation of central sensitisation in CFS is in line with our current understanding of CFS. The presence of central sensitisation in CFS corroborates with the presence of several psychological influences on the illness, the presence of infectious agents and immune dysfunctions and the dysfunctional hypothalamus-pituitary-adrenal axis as seen in these severely debilitated patients.

Source: Nijs J, Meeus M, Van Oosterwijck J, Ickmans K, Moorkens G, Hans G, De Clerck LS. In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome. Eur J Clin Invest. 2012 Feb;42(2):203-12. doi: 10.1111/j.1365-2362.2011.02575.x. Epub 2011 Jul 27. https://www.ncbi.nlm.nih.gov/pubmed/21793823

Hormonal alterations in adolescent chronic fatigue syndrome

Abstract:

AIM: The chronic fatigue syndrome is associated with alterations in the hypothalamus-pituitary-adrenal axis and cardiovascular autonomic nervous activity, suggesting a central dysregulation. This study explored differences among adolescent chronic fatigue syndrome patients and healthy controls regarding antidiuretic hormone, the renin-angiotensin-aldosterone-system, sex hormones and cardiac peptides.

METHODS: We included a consecutive sample of 67 adolescents aged 12-18 years with chronic fatigue syndrome diagnosed according to a thorough and standardized set of investigations, and a volunteer sample of 55 healthy control subjects of equal gender and age distribution. Hormones were assayed with standard laboratory methods.

RESULTS: Among patients, plasma antidiuretic hormone was significantly decreased and serum osmolality and plasma renin activity were significantly increased (p < or = 0.001). Serum concentration of aldosterone, cortisol, NT-proBNP and sex hormones were not significantly different in the two groups.

CONCLUSION: Chronic fatigue syndrome in adolescents is associated with alterations in hormonal systems controlling osmolality and blood volume, possibly supporting a theory of central dysregulation.

Source: Wyller VB, Evang JA, Godang K, Solhjell KK, Bollerslev J. Hormonal alterations in adolescent chronic fatigue syndrome. Acta Paediatr. 2010 May;99(5):770-3. doi: 10.1111/j.1651-2227.2010.01701.x. Epub 2010 Mar 1. https://www.ncbi.nlm.nih.gov/pubmed/20199497

Neuroendocrine mechanisms in fibromyalgia-chronic fatigue

Abstract:

Fibromyalgia and chronic fatigue syndrome are poorly understood disorders that share similar demographic and clinical characteristics. Because of the clinical similarities between both disorders it was suggested that they share a common pathophysiological mechanism, namely, central nervous system dysfunction.

This chapter presents data demonstrating neurohormonal abnormalities, abnormal pain processing and autonomic nervous system dysfunction in fibromyalgia and chronic fatigue syndrome. The possible contribution of the central nervous system dysfunction to the development and symptomatology of these conditions is discussed. The chapter concludes by reviewing the effect of current treatments and emerging therapeutic modalities in fibromyalgia and chronic fatigue syndrome.

Source: Buskila D, Press J. Neuroendocrine mechanisms in fibromyalgia-chronic fatigue. Best Pract Res Clin Rheumatol. 2001 Dec;15(5):747-58. http://www.ncbi.nlm.nih.gov/pubmed/11812019

Comparison of SPET brain perfusion and 18F-FDG brain metabolism in patients with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome is a clinically defined condition of uncertain aetiology.

We compared 99Tcm-HMPAO single photon emission tomography (SPET) brain perfusion with dual-head 18F-FDG brain metabolism in patients with chronic fatigue syndrome. Eighteen patients (14 females, 4 males), who fulfilled the diagnostic criteria of the Centers for Disease Control for chronic fatigue syndrome, were investigated.

Thirteen patients had abnormal SPET brain perfusion scans and five had normal scans. Fifteen patients had normal glucose brain metabolism scans and three had abnormal scans. We conclude that, in chronic fatigue syndrome patients, there is discordance between SPET brain perfusion and 18F-FDG brain uptake. It is possible to have brain perfusion abnormalities without corresponding changes in glucose uptake.

Source: Abu-Judeh HH, Levine S, Kumar M, el-Zeftawy H, Naddaf S, Lou JQ, Abdel-Dayem HM. Comparison of SPET brain perfusion and 18F-FDG brain metabolism in patients with chronic fatigue syndrome. Nucl Med Commun. 1998 Nov;19(11):1065-71. http://www.ncbi.nlm.nih.gov/pubmed/9861623

Chronic fatigue syndrome: an immunological perspective

Abstract:

OBJECTIVE: The aim of this study is to review research examining an immunological basis for chronic fatigue syndrome (CFS) and to discuss how a disturbance in immunity could produce central nervous system (CNS)-mediated symptoms.

METHOD: Data relevant to the hypothesis that abnormal cytokine release plays a role in the pathogenesis of CFS are reviewed as well as recent evidence relating to potential mechanisms by which immune products may enter the brain and produce a disturbance in CNS processes.

RESULTS: Examinations of cytokine levels in patients with CFS have produced inconclusive results. Recent evidence suggests that abnormal release of cytokines within the CNS may cause neural dysfunction by a variety of complex mechanisms.

CONCLUSION: Neuropsychiatric symptoms in patients with CFS may be more closely related to disordered cytokine production by glial cells within the CNS than to circulating cytokines. This possibility is discussed in the context of unresolved issues in the pathogenesis of CFS.

Source: Vollmer-Conna U, Lloyd A, Hickie I, Wakefield D. Chronic fatigue syndrome: an immunological perspective. Aust N Z J Psychiatry. 1998 Aug;32(4):523-7. http://www.ncbi.nlm.nih.gov/pubmed/9711366

Alteration of spatial-temporal parameters of gait in Chronic Fatigue Syndrome patients

Abstract:

Chronic Fatigue Syndrome (CFS) has been widely studied and a lot of information is available in the literature regarding the immunological, virological, neuroendocrinal and psychiatric aspects of the disease, but its aetiology is still poorly understood. Great attention has also been paid to the alteration of the muscular function caused by CFS.

The aim of the present work was to study CFS patients’ gait in order to find out objective measures which can better characterize the pathology. Spatial and temporal parameters of gait were collected from a group of 12 CFS informed volunteers by using the typical instrumentation of movement analysis, and raw data were statistically elaborated.

Comparisons with reference data from a population of healthy subjects revealed significant abnormalities in the symmetry indices of the bilateral parameters and in the linear relationships among parameters, and between these parameters and the physical characteristics of the patients.

Interestingly, the abnormalities were present as from the beginning of the gait, which indicates that they are unlikely to be caused by the rapid increasing fatigue. This strengthens the hypothesis of a direct involvement of the central nervous system (CNS) in the onset of the disease.

Source: Saggini R, Pizzigallo E, Vecchiet J, Macellari V, Giacomozzi C. Alteration of spatial-temporal parameters of gait in Chronic Fatigue Syndrome patients. J Neurol Sci. 1998 Jan 21;154(1):18-25. http://www.ncbi.nlm.nih.gov/pubmed/9543318

Susceptibility to immunologically mediated fatigue in C57BL/6 versus Balb/c mice

Abstract:

Proinflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha have been proposed to play a role in the pathogenesis of fatigue. In the present study we compared the susceptibility of two mouse strains to immunologically induced fatigue.

Daily running of two strains of mice, Balb/c and C57BL/ 6, was assessed after a single injection of Corynebacterium parvum antigen (2 mg/mouse). Spontaneous running activity of each animal was compared to mean running distance prior to injection. To evaluate the involvement of cytokines in fatigue development, C57BL/6 mice were treated with antibodies to specific cytokines at the time of challenge with C. parvum antigen. Also, cytokine mRNA expression was analyzed in the brains of mice at different time periods after immunologic challenge.

A significant difference in running activity between the two mice strains was observed after C. parvum antigen inoculation: C57BL/6 mice showing a greater (P < 0.05) reduction in running activity (relative to preinjection levels) and slower recovery to baseline than Balb/c mice. Injection of antibodies specific to either IL-1beta or TNF-alpha did not alter immunologically induced fatigue, suggesting a lack of involvement of these cytokines produced outside of the central nervous system (CNS).

However, increased TNF-alpha and IL-1beta mRNA expression was found in the brains of C57BL/6 compared to that seen in Balb/c mice at 6, 10, and 15 days after C. parvum antigen injection. The elevated CNS cytokine mRNA expression corresponded to development of fatigue. These findings are consistent with the hypothesis that expression of proinflammatory cytokines within the CNS plays a role in the pathogenesis of immunologically mediated fatigue.

Source: Sheng WS, Hu S, Lamkin A, Peterson PK, Chao CC. Susceptibility to immunologically mediated fatigue in C57BL/6 versus Balb/c mice. Clin Immunol Immunopathol. 1996 Nov;81(2):161-7. http://www.ncbi.nlm.nih.gov/pubmed/8906747

Randomized, double blind, controlled placebo-phase in trial of low dose phenelzine in the chronic fatigue syndrome

Abstract:

Because of the striking similarity of the clinical manifestations produced by use of the drug reserpine and seen in patients with the chronic fatigue syndrome (CFS), we theorized that CFS was a disorder of reduced central sympathetic drive. Because of the pharmacology of control of this central sympathetic system, we further postulated that CFS symptoms would respond quickly to low dose treatment with a monamine oxidase inhibitor. To test these hypotheses, we designed a randomized, double blind placebo controlled study using phenelzine.

No patient in the trial had a diagnosis of lifetime or current psychiatric disorder and none had depressed mood in the range of clinically depressed patients on a paper and pencil test of depression. Patients in the placebo group received placebo for 6 weeks while those in the drug treatment group were treated in three 2-week segments-placebo, 15 mg phenelzine every other day, and then 15 mg daily. This treatment regimen produced a significant pattern of improvement compared to worsening in 20 self report vehicles of CFS symptoms, illness severity, mood or functional status.

Thus the data support our hypothesis of reduced sympathetic drive, although an alternative hypothesis of pain alleviation is also possible. The study design also allowed us to evaluate patients for a placebo effect: no evidence for this was found, suggesting that CFS is not an illness due to patients’ being overly suggestible.

Source: Natelson BH, Cheu J, Pareja J, Ellis SP, Policastro T, Findley TW. Randomized, double blind, controlled placebo-phase in trial of low dose phenelzine in the chronic fatigue syndrome. Psychopharmacology (Berl). 1996 Apr;124(3):226-30. http://www.ncbi.nlm.nih.gov/pubmed/8740043

Gait abnormalities in chronic fatigue syndrome

Abstract:

To evaluate our clinical impression that patients with the chronic fatigue syndrome (CFS) did not walk normally, we assessed gait kinematics at slow walking speeds (i.e., 0.45, 0.89 and 1.34 m/sec) and 30 m run time speeds on CFS patients and on a comparison group of sedentary controls.

Run time was significantly slower for CFS than control subjects (p < 0.001). There was a significant interaction (p < 0.01) between group and speed for maximum hip angle during stance and swing phase with hip angle being significantly larger at 1.34 m/sec for CFS than controls subjects for both cases (p < 0.05). Knee flexion during stance and swing phases was significantly larger for controls than CFS subjects at 0.45 m/sec (p < 0.01). Ratio of stride length divided by leg length was significantly larger for the control subjects than for the CFS subjects with differences occurring at 0.45 and 0.89 m/sec (p < 0.01) but not 1.34 m/sec.

The data indicate that CFS patients have gait abnormalities when compared to sedentary controls. These could be due to balance problems, muscle weakness, or central nervous system dysfunction; deciding which will require further research. Evaluation of gait may be a useful tool to measure outcome following therapeutic interventions.

Source: Boda WL, Natelson BH, Sisto SA, Tapp WN. Gait abnormalities in chronic fatigue syndrome. J Neurol Sci. 1995 Aug;131(2):156-61. http://www.ncbi.nlm.nih.gov/pubmed/7595641

GPs’ attitudes to a self diagnosis of myalgic encephalomyelitis. Evidence supports presence of encephalitis

Comment on: General practitioners’ attitudes to patients with a self diagnosis of myalgic encephalomyelitis. [BMJ. 1995]

EDITOR,-Although the precise pathoaetiology of myalgic encephalomyelitis remains the subject of debate, Shonagh Scott and colleagues are incorrect in asserting that “no evidence exists” of encephalitis. Buchwald et al carried out a large cohort study in which neurological symptoms, results of magnetic resonance imaging, and lymphocyte phenotyping suggested that the patients were experiencing “a chronic, immunologically mediated inflammatory process of the central nervous system.”2 More recently, Schwartz et al, who used single photon emission computed tomography, described abnormalities that were consistent with the hypothesis that “a chronic viral encephalitis” may be present.3 Furthermore, in the only postmortem study to have been published the polymerase chain reaction showed enteroviral sequences (compatible with coxsackie virus B3) in samples from the hypothalamus and brain stem,4 indicating that viral persistence within selective parts of the central nervous system may also play a part.

Given the uncertainties surrounding both the pathoaetiology and the diagnostic criteria for myalgic encephalomyelitis, it is not surprising to learn that self diagnosis produces difficulties in the doctor-patient relationship. The conclusions of and motives behind Scott and colleagues’ study must, however, be questioned in view of the fact that the fictitious patients had a list of vague symptoms that failed to satisfy diagnostic criteria for either a chronic fatigue syndrome (as defined by the International Chronic Fatigue Syndrome Study Group)5 or a postinfectious fatigue syndrome (as defined by current British criteria).6 Neither did the symptoms accord with those that patient support organisations would agree constitute a satisfactory diagnosis of myalgic encephalomyelitis.

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2549699/pdf/bmj00593-0058b.pdf

Source: Shepherd C. GPs’ attitudes to a self diagnosis of myalgic encephalomyelitis. Evidence supports presence of encephalitis. BMJ. 1995 May 20;310(6990):1330. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2549699/