Tag: review

The chronic fatigue syndrome

Abstract:

The chronic fatigue syndrome (CFS) was formally defined in 1988 to describe disabling fatigue of at least 6 months’ duration of uncertain etiology. Reports of CFS have emerged from the United States, Canada, the United Kingdom, Australia, New Zealand, Israel, Spain, and France. The disease primarily affects individuals between 20 and 50 years of age, and there is a preponderance of females.

Although a triggering infectious illness is reported by most patients with CFS, there is no convincing evidence causally linking any currently recognized infectious agent to CFS. Multiple minor immunologic aberrations are frequent but inconsistent and of uncertain significance. There is no consistent evidence for myopathy or physical deconditioning.

Depression is found in approximately 50% of CFS patients, with depression preceding the physical symptoms in half of the cases. No therapy has been proved effective in controlled clinical trials with prolonged follow-up, although antidepressants have not been formally evaluated.

The long-term prognosis of patients with CFS has not been well studied, but CFS appears to be a disease of prolonged duration with considerable morbidity but no mortality. Further research into the pathogenesis and treatment of CFS is necessary.

 

Source: Shafran SD. The chronic fatigue syndrome. Am J Med. 1991 Jun;90(6):730-9. http://www.ncbi.nlm.nih.gov/pubmed/2042689

 

Human herpesvirus-6 (HHV-6) (short review)

Abstract:

Human Herpesvirus-6 is the etiological agent of Roseola infantum and approximately 12% of heterophile antibody negative infectious mononucleosis. HHV-6 is T-lymphotropic, and readily infects and lyses CD4+ cells. The prevalence rate of HHV-6 in the general population is about 80% (as measured by IFA) with an IgG antibody titer of 1:80. A lower prevalence, however, is observed in some countries.

HHV-6 is reactivated in various malignant and non-malignant diseases as well as in Chronic Fatigue Syndrome and transplant patients. Furthermore, elevated antibody titers were also observed in lymphoproliferative disorders, auto-immune diseases and HIV-1 positive AIDS patients. There appears to be some strain variability in HHV-6 isolates.

The GS isolates of HHV-6 (prototype) was resistant to Acyclovir, Gancyclovir, but its replication was inhibited by Phosphonoacetic acid and Phosphoformic acid. HHV-7 isolated from healthy individuals showed, by restriction analysis, that 6 out of 11 probes derived from two strains of HHV-6, cross-hybridized with DNA fragments, derived from HHV-7.

 

Source: Ablashi DV, Salahuddin SZ, Josephs SF, Balachandran N, Krueger GR, Gallo RC. Human herpesvirus-6 (HHV-6) (short review). In Vivo. 1991 May-Jun;5(3):193-9. http://www.ncbi.nlm.nih.gov/pubmed/1654146

 

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome

Abstract:

There continues to be an emerging body of literature related to fibromyalgia and the related conditions chronic fatigue syndrome and myofascial pain.

During the past year, the most notable contributions included a large multicenter study providing new diagnostic criteria for the classification of fibromyalgia and clinical studies describing the overlap of fibromyalgia, chronic fatigue syndrome, and myofascial pain.

Pathophysiologic studies were often preliminary and uncontrolled but the focus of these studies on abnormal nociception, neurohormones, and muscle metabolism provides an exciting hypothesis to unify pain, fatigue, and sleep disturbances, the primary symptoms of fibromyalgia. Unfortunately, new therapeutic trials were neither innovative nor especially encouraging.

 

Source: Goldenberg DL. Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome. Curr Opin Rheumatol. 1991 Apr;3(2):247-58. http://www.ncbi.nlm.nih.gov/pubmed/2064904

 

Physiologic measurement of exercise and fatigue with special reference to chronic fatigue syndrome

Abstract:

Oxidative metabolism is the major source of energy for muscle activity, and maximal oxygen uptake (VO2max), the product of maximal cardiac output and maximal arteriovenous oxygen difference, indicates individual capacity for oxidative metabolism and performance of exercise by the large muscles.

Strength, a function of muscle cross-sectional area, motor-unit recruitment, and neuromuscular coordination, is the ability to develop force in a single, brief, maximal-effort voluntary contraction of rested muscle. Weakness is a diminished ability of rested muscle to exert maximal force. Fatigue is a loss of maximal force-generating capacity that develops during muscular activity, likely originates within muscle itself, and persists until muscle is fully recovered. Individual perception of motor effort can be determined with standardized rating scales.

These concepts are discussed in detail, their relevance to the pathophysiology of exercise in chronic fatigue syndrome is analyzed, and a general strategy of exercise evaluation pertinent to chronic fatigue syndrome is presented.

 

Source: Lewis SF, Haller RG. Physiologic measurement of exercise and fatigue with special reference to chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S98-108. http://www.ncbi.nlm.nih.gov/pubmed/2020810

 

Validation of biologic markers for use in research on chronic fatigue syndrome

Abstract:

Unresolved aspects of chronic fatigue syndrome can be addressed by research involving biologic markers. These may be any molecular, biochemical, physiological, or other biologic parameter obtainable from biologic specimens. The use of biologic markers in research requires their validation as dependent or independent variables. Additionally, other characteristics of markers such as reliability of assays, background level, confounding factors, interpretations, and legal and ethical implications should be considered before the use of markers in research. A checklist is provided for evaluating a biologic marker before its inclusion in research.

 

Source: Schulte PA. Validation of biologic markers for use in research on chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S87-9. http://www.ncbi.nlm.nih.gov/pubmed/2020808

 

Symptoms and signs of chronic fatigue syndrome

Abstract:

This review summarizes the symptoms and signs seen in patients with chronic fatigue syndrome (CFS). It is based on the authors’ experience with two cohorts of approximately 510 patients with chronic debilitating fatigue and on the reported experience of other investigators with similar patients.

The most characteristic symptoms of CFS are the sudden onset of an infectious-type illness, the subsequent chronic and debilitating fatigue, and postexertional malaise; many patients also have recurrent fevers, pharyngitis, adenopathy, myalgias, sleep disorders, and cognitive impairment.

 

Source: Komaroff AL, Buchwald D. Symptoms and signs of chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S8-11. http://www.ncbi.nlm.nih.gov/pubmed/2020806

 

Chronic fatigue syndrome: issues in the diagnosis and estimation of incidence

Abstract:

This article critiques the current working definition of chronic fatigue syndrome. The concerns raised about the current working definition are the following: prolonged or excessive exertion is not addressed explicitly; duration and quality of bed rest are not specified; a socioeconomic ascertainment bias is present; data from history and physical findings are not clearly separated and are relegated to minor criteria; and the rigor of neurologic and psychiatric evaluations is not specified.

We propose a flow chart that addresses the possible modes of evolution of chronic fatigue syndrome for patients; this chart may yield more homogeneous subgroups of individuals with this syndrome or enable some patients to avert the syndrome.

 

Source: Armon C, Kurland LT. Chronic fatigue syndrome: issues in the diagnosis and estimation of incidence. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S68-72. http://www.ncbi.nlm.nih.gov/pubmed/2020804

 

Issues and problems in the conduct of epidemiologic research on chronic fatigue syndrome

Abstract:

The epidemiologic research approach is perhaps most appropriate for initial studies of chronic fatigue syndrome since the syndrome is vaguely defined, scientific knowledge about it is limited, and an infectious etiology is suspected.

Several priority needs appropriate for epidemiologic research are identified, including a refinement of diagnostic criteria; a greater understanding of the natural history of the syndrome; basic incidence, prevalence, and mortality statistics; information on whether asymptomatic cases exist; etiologic studies of possible heterogeneity of cases; investigations of clusters of cases; and determinations of whether patients with the syndrome have an increased risk of malignancy.

Because of the lack of cogent etiologic hypotheses regarding the syndrome, case-control studies are identified as a high priority for research. The many difficulties encountered in conducting such research are discussed and approaches to dealing with these problems are suggested.

 

Source: Grufferman S. Issues and problems in the conduct of epidemiologic research on chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S60-7. http://www.ncbi.nlm.nih.gov/pubmed/2020803

 

Assessment of depression in patients with chronic fatigue syndrome

Abstract:

Assessment of the relationship of depression to chronic fatigue syndrome (CFS) is a complicated but important topic. This relationship may range from the misdiagnostic (i.e., depression misidentified as CFS) to the etiologic (i.e., CFS causes an organic affective syndrome). Assessment should focus on the symptoms and syndromes of depressive disorder, utilization of a single rating scale to assess presumed depression is discouraged, and alternate approaches to classification that allow for symptomatic overlap of a major depressive disorder and CFS are suggested. Careful attention needs to be given to the use of external validating criteria in empiric studies, such as natural history, clinical course (including treatment response), and family history.

 

Source:  Thase ME. Assessment of depression in patients with chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S114-8. http://www.ncbi.nlm.nih.gov/pubmed/2020797

 

Testing of vestibular function: an adjunct in the assessment of chronic fatigue syndrome

Abstract:

Patients with chronic fatigue syndrome (CFS) often complain of dysequilibrium that is nonspecific. The basis of this complaint is unknown but may be related to vestibular system abnormalities, in that an association between inner-ear deficits and infectious mononucleosis has been established in the medical literature. An overview of quantitative vestibular function testing is given, including vestibulo-ocular and vestibulospinal tests. The basic principles of caloric and rotational testing are provided, including the interaction between vision and the vestibular system. Moving-platform posturography is described. Preliminary results from quantitative vestibular function testing of a small group of individuals with CFS are provided.

 

Source:  Furman JM. Testing of vestibular function: an adjunct in the assessment of chronic fatigue syndrome. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S109-11. http://www.ncbi.nlm.nih.gov/pubmed/2020795