Chronic fatigue syndrome
In medicine, chronic fatigue syndrome is "a syndrome characterized by persistent or recurrent fatigue, diffuse musculoskeletal pain, sleep disturbances, and subjective cognitive impairment of 6 months duration or longer. Symptoms are not caused by ongoing exertion; are not relieved by rest; and result in a substantial reduction of previous levels of occupational, educational, social, or personal activities. Minor alterations of immune, neuroendocrine, and autonomic function may be associated with this syndrome. There is also considerable overlap between this condition and fibromyalgia."[1][2]
Definition
Various definitions for chronic fatigure syndrome have been proposed and they have been summarized.[3]
In 1994, the International Chronic Fatigue Syndrome Study Group proposed:[4]
"Chronic fatigue is defined as self-reported persistent or relapsing fatigue lasting 6 or more consecutive months"
"A case of idiopathic chronic fatigue is defined as clinically evaluated, unexplained chronic fatigue that fails to meet criteria for the chronic fatigue syndrome."
"A case of the chronic fatigue syndrome is defined by the presence of the following:
- clinically evaluated, unexplained, persistent or relapsing chronic fatigue that is of new or definite onset [has not been lifelong]; is not the result of ongoing exertion; is not substantially alleviated by rest; and results in substantial reduction in previous levels of occupational, educational, social, or personal activities; and
- the concurrent occurrence of four or more of the following symptoms, all of which must have persisted or recurred during 6 or more consecutive months of illness and must not have predated the fatigue:
- self-reported impairment in short-term memory or concentration severe enough to cause substantial reduction in previous levels of occupational, educational, social, or personal activities;
- sore throat;
- tender cervical or axillary lymph nodes;
- muscle pain, multijoint pain without joint swelling or redness;
- headaches of a new type, pattern, or severity;
- unrefreshing sleep; and
- postexertional malaise lasting more than 24 hours."
Prevalence
Among outpatients in a health maintenance organization in the Northwestern United States:[4]
- Chronic fatigue 19% of patients or 1775 to 6321 cases per 100 000 persons
- Of the 19%, about two thirds "had a medical or psychiatric condition that could account for the fatigue"
- Of the 19%, about 4% have chronic fatigue syndrome or 75 to 267 cases per 100 000 persons
Etiology
According to twin studies, chronic fatigue syndrome may have a genetic susceptibility[5] with heritability as high as 51%[6]. This compares to a heritability for major depression of about a third.[7]
Xenotropic murine leukemia virus-related virus (XMRV), a human gammaretrovirus, may contribute to infection.[8]In one study, the virus was found "in nearly 98 percent of about 300 patients with the syndrome" while only 3.7 percent of 218 healthy people were infected.[9]
References
- ↑ Anonymous (2024), Chronic fatigue syndrome (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A (1994). "The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group.". Ann Intern Med 121 (12): 953-9. PMID 7978722.
- ↑ Anonymous. About CFS: What is Chronic Fatigue Syndrome? National Institutes of Health
- ↑ 4.0 4.1 Buchwald D, Umali P, Umali J, Kith P, Pearlman T, Komaroff AL (1995). "Chronic fatigue and the chronic fatigue syndrome: prevalence in a Pacific Northwest health care system.". Ann Intern Med 123 (2): 81-8. PMID 7778839.
- ↑ Sullivan PF, Evengård B, Jacks A, Pedersen NL (2005). "Twin analyses of chronic fatigue in a Swedish national sample.". Psychol Med 35 (9): 1327-36. DOI:10.1017/S0033291705005222. PMID 16168155. Research Blogging.
- ↑ Buchwald D, Herrell R, Ashton S, Belcourt M, Schmaling K, Sullivan P et al. (2001 Nov-Dec). "A twin study of chronic fatigue.". Psychosom Med 63 (6): 936-43. PMID 11719632.
- ↑ Sullivan PF, Neale MC, Kendler KS (2000). "Genetic epidemiology of major depression: review and meta-analysis.". Am J Psychiatry 157 (10): 1552-62. PMID 11007705.
- ↑ Lombardi, Vincent C.; Francis W. Ruscetti, Jaydip Das Gupta, Max A. Pfost, Kathryn S. Hagen, Daniel L. Peterson, Sandra K. Ruscetti, Rachel K. Bagni, Cari Petrow-Sadowski, Bert Gold, Michael Dean, Robert H. Silverman, Judy A. Mikovits (2009-10-08). "Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome". Science: 1179052. DOI:10.1126/science.1179052. Retrieved on 2009-10-09. Research Blogging.
- ↑ Grady, Denise. Virus Is Found in Many With Chronic Fatigue Syndrome, The New York Times, 2009-10-09. Retrieved on 2009-10-09.