Tag: review

Parallels between post-polio fatigue and chronic fatigue syndrome: a common pathophysiology?

Abstract:

Fatigue is the most commonly reported and most debilitating of post-polio sequelae affecting the >1.8 million North American polio survivors. Post-polio fatigue is characterized by subjective reports of difficulty with attention, cognition, and maintaining wakefulness. These symptoms resemble those reported in nearly 2 dozen outbreaks of post-viral fatigue syndromes (PVFS) that have recurred during this century and that are related clinically, historically, anatomically, or physiologically to poliovirus infections.

This article reviews recent studies that relate the symptoms of post-polio fatigue and chronic fatigue syndrome (CFS) to clinically significant deficits on neuropsychologic tests of attention, histopathologic and neuroradiologic evidence of brain lesions, impaired activation of the hypothalamic-pituitary-adrenal axis, increased prolactin secretion, and electroencephalogram (EEG) slow-wave activity.

A possible common pathophysiology for post-polio fatigue and CFS, based on the Brain Fatigue Generator Model of PVFS, and a possible pharmacotherapy for PVFS based on replacement of depleted brain dopamine, will be described.

 

Source: Bruno RL, Creange SJ, Frick NM. Parallels between post-polio fatigue and chronic fatigue syndrome: a common pathophysiology? Am J Med. 1998 Sep 28;105(3A):66S-73S. http://www.ncbi.nlm.nih.gov/pubmed/9790485

 

Neuroimaging in chronic fatigue syndrome

Abstract:

The diagnosis of chronic fatigue syndrome (CFS) is made difficult by the absence of specific biomedical markers, and depends primarily on determining whether subjective information provided by the patient meets the clinical case definition of this syndrome. Reported cognitive difficulties and/or complaints of headache may instigate referral for brain imaging.

This article will discuss the value of neuroimaging in evaluating CFS, specifically reviewing studies that (1) used static magnetic resonance imaging (MRI) to assess structural abnormalities; and (2) assessed regional cerebral blood flow (rCBF) via detection of Tc-99m hexamethylpropyl-eneamine oxime distribution by single-photon emission computed tomography (SPECT). Future research design considerations are explored including (1) the utilization of positron emission tomography (PET) and other emerging neuroimaging technologies; and (2) methodological concerns, i.e., the influence of psychopathology (such as depression) and neurologic disease (such as multiple sclerosis) as possible confounding factors.

 

Source: Lange G, Wang S, DeLuca J, Natelson BH. Neuroimaging in chronic fatigue syndrome. Am J Med. 1998 Sep 28;105(3A):50S-53S. http://www.ncbi.nlm.nih.gov/pubmed/9790482

 

Stress-associated immune modulation: relevance to viral infections and chronic fatigue syndrome

Abstract:

The frequent association of an active viral infection with the symptoms of CFS led researchers to hypothesize that chronic fatigue syndrome (CFS) is induced by a virus. Results of these studies indicated that despite clinical support for this hypothesis, there were no clear data linking viruses to CFS. In this overview, we will explore the interrelation of the immune, endocrine, and central nervous systems, and the possibility that stress and/or the reactivation/replication of a latent virus (such as Epstein Barr virus) could modulate the immune system to induce CFS. Relevant research conducted in the developing field of psychoneuroimmunology will be reviewed, with a particular focus on cytokine synthesis, natural killer (NK) cell activity, and T-lymphocyte function, as they relate to CFS.

 

Source: Glaser R, Kiecolt-Glaser JK. Stress-associated immune modulation: relevance to viral infections and chronic fatigue syndrome. Am J Med. 1998 Sep 28;105(3A):35S-42S. http://www.ncbi.nlm.nih.gov/pubmed/9790480

 

Natural killer cells and natural killer cell activity in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is associated with insidious and persistent immunologic abnormalities that have proved difficult to reproduce. The heterogeneity of CFS, the variable quality of immunologic assays and their performance, along with an almost complete absence of longitudinal studies of cellular immune abnormalities in CFS may explain this difficulty. However, in a significant proportion of cases, low levels of natural killer (NK) cell activity have been reported.

This article will explore the mechanisms responsible for low NK cell activity, discuss the relation between levels of NK cell activity and health/disease, describe new findings on NK cell-brain interactions, and put forth a specific hypothesis for the role of NK cells in the pathogenesis of CFS.

 

Source: Whiteside TL, Friberg D. Natural killer cells and natural killer cell activity in chronic fatigue syndrome. Am J Med. 1998 Sep 28;105(3A):27S-34S. http://www.ncbi.nlm.nih.gov/pubmed/9790479

 

Neurally mediated hypotension and chronic fatigue syndrome

Abstract:

 

A substantial body of clinical evidence now supports an association between various forms of hypotension and both idiopathic chronic fatigue and the chronic fatigue syndrome (CFS). Patients with CFS have a high prevalence of neurally mediated hypotension, and open treatment of this autonomic dysfunction has been associated with improvements in CFS symptoms. Randomized trials are now in progress to evaluate the efficacy of treatments directed at neurally mediated hypotension in those with CFS patients, and the results of these trials should help guide more basic inquiries into the mechanisms of orthostatic intolerance in affected individuals.

 

Source: Rowe PC, Calkins H. Neurally mediated hypotension and chronic fatigue syndrome. Am J Med. 1998 Sep 28;105(3A):15S-21S. http://www.ncbi.nlm.nih.gov/pubmed/9790477

 

Chronic fatigue and chronic fatigue syndrome: shifting boundaries and attributions

Abstract:

The subjective symptom of “fatigue” is one of the most widespread in the general population and is a major source of healthcare utilization. Prolonged fatigue is often associated with neuropsychological and musculoskeletal symptoms that form the basis of several syndromal diagnoses including chronic fatigue syndrome, fibromyalgia, and neurasthenia, and is clearly not simply the result of a lack of force generation from the muscle.

Current epidemiologic research in this area relies predominantly on self-report data to document the prevalence and associations of chronic fatigue. Of necessity, this subjective data source gives rise to uncertain diagnostic boundaries and consequent divergent epidemiologic, clinical, and pathophysiologic research findings.

This review will highlight the impact of the case definition and ascertainment methods on the varying prevalence estimates of chronic fatigue syndrome and patterns of reported psychological comorbidty. It will also evaluate the evidence for a true postinfective fatigue syndrome.

 

Source: Lloyd AR. Chronic fatigue and chronic fatigue syndrome: shifting boundaries and attributions. Am J Med. 1998 Sep 28;105(3A):7S-10S. http://www.ncbi.nlm.nih.gov/pubmed/9790475

 

Chronic fatigue syndrome and fibromyalgia. Dilemmas in diagnosis and clinical management

Abstract:

There has been a resurgence of interest in recent years in both chronic fatigue syndrome and fibromyalgia. These perplexing and common clinical conditions are a source of significant patient morbidity and frame one of the more enduring dilemmas of contemporary Western medical thought, namely the ambiguous interface between mind and body. In this article, the current definitions are reviewed, and a framework for an emerging psychobiological model of these syndromes is presented. These issues are synthesized into a pragmatic approach to clinical management.

 

Source: Demitrack MA. Chronic fatigue syndrome and fibromyalgia. Dilemmas in diagnosis and clinical management. Psychiatr Clin North Am. 1998 Sep;21(3):671-92, viii. http://www.ncbi.nlm.nih.gov/pubmed/9774804

 

Chronic fatigue syndrome or just plain tired?

The complaint of unremitting fatigue has been around for centuries. Over the years, people with fatigue have been said to suffer from myalgic encephalomyelitis, Icelandic disease, neurasthenia, nervous exhaustion, febricula and Yuppie flu.1,2 Interest in the illness known today as chronic fatigue syndrome (CFS) grew when a cluster of patients in Nevada were found to have a chronic mononucleosis-like syndrome associated with persistently high titres of antibodies to Epstein–Barr virus (EBV) in the late 1980s.2 Today, the role of EBV and other potential viral and immunologic triggers of CFS remains unclear, and even in the wake of a recent flurry of research, the pathophysiology of CFS is poorly understood and no single diagnostic test can confirm its presence.

While CFS support groups lobby for disability coverage for individuals with CFS and insurance companies fight the claims, neither the public nor the medical community unanimously agrees on the existence of CFS as a real clinical entity. Some believe it is merely a presentation of depression or other psychosomatic illness; others argue that individuals claiming to have CFS have seized upon a convenient diagnosis to explain the effects of overwork or “normal” fatigue.

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1229654/pdf/cmaj_159_5_519.pdf

Comment in:

What causes chronic fatigue? [CMAJ. 1999]

What causes chronic fatigue? [CMAJ. 1999]

 

Source: Caplan C. Chronic fatigue syndrome or just plain tired? CMAJ. 1998 Sep 8;159(5):519-20. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1229654/

 

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

 

Reviewing the reviews: the example of chronic fatigue syndrome

Abstract:

OBJECTIVE: To test the hypothesis that the selection of literature in review articles is unsystematic and is influenced by the authors’ discipline and country of residence.

DATA SOURCES: Reviews in English published between 1980 and March 1996 in MEDLINE, EMBASE (BIDS), PSYCHLIT, and Current Contents were searched.

STUDY SELECTION: Reviews of chronic fatigue syndrome (CFS) were selected. Articles explicitly concerned with a specialty aspect of CFS and unattributed, unreferenced, or insufficiently referenced articles were discarded.

DATA EXTRACTION: Record of data sources in each review was noted as was the departmental specialty of the first author and his or her country of residence. The references cited in each index paper were tabulated by assigning them to 6 specialty categories, by article title, and by assigning them to 8 categories, by country of journal publication.

DATA SYNTHESIS: Of 89 reviews, 3 (3.4%) reported on literature search and described search method. Authors from laboratory-based disciplines preferentially cited laboratory references, while psychiatry-based disciplines preferentially cited psychiatric literature (P = .01). A total of 71.6% of references cited by US authors were from US journals, while 54.9% of references cited by United Kingdom authors were published in United Kingdom journals (P = .001).

CONCLUSION: Citation of the literature is influenced by review authors’ discipline and nationality.

 

Source: Joyce J, Rabe-Hesketh S, Wessely S. Reviewing the reviews: the example of chronic fatigue syndrome. JAMA. 1998 Jul 15;280(3):264-6. http://www.ncbi.nlm.nih.gov/pubmed/9676676