Chronic fatigue syndrome
Is defined as a long standing, severe, disabling fatigue without demonstrable muscle weakness.
Underlying disorders that could explain the fatigue are absent. Depression, anxiety and other psychologic diagnoses are typically absent.
Treatment is rest and psycho-logic support, often including antidepressant.
This definition of chronic fatigue syndrome (CFS) has several variants, and heterogeneity among patients who meets the criteria of this definition is considerable.
Prevalence is impossible to state precisely.
It varies from 7 to 38/100,000 people.
Prevalence may vary because of differences in diagnostic evaluation, physician – patient attitude, social acceptability, risk of exposure to an infectious or toxic agent, or definition and case finding.
CFS occurs slightly more often in women or females.
In office based studies, prevalence is highest among whites, however community surveys indicate a higher prevalence among blacks, Hispanics and American Indians than among whites
Etiology and Pathophysiology
Etiology is controversial and the precise cause remains unknown. Psycho-logic factors may be the cause in an unknown percentage of cases, however CFS seems to be distinct from typical depression, anxiety, or other psychological disorders.
A chronic viral infection has been proposed as a cause because many patients relate on set of CFS to an event similar to influenza or mononucleosis.
Epstein-Barr virus has also been proposed as a cause, but immunologic markers of exposure don’t appear to be sensitive or specific.
Other possible but unproven viral causes include enteroviruses, human herpesvirus 6, and human T-cell lymphotropic virus.
Allergic reactions has also been proposed, about 65 percent reports previous allergies, and the rate of cutaneous reactivity to inhalants or foods is 25 - 50 percent higher in this group than in the general population
Various immunologic abnormalities have been reported, they include low levels of lgG, decrease lymphocytic proliferation, low interferon-ϒ levels in response to mitogens and poor cytotoxicity of natural killer cells.
Some patients have abnormal lgG with circulating auto antibodies and immune complexes.
Many other immunologic abnormalities have been studied but none provide adequate sensitivity and specificity for defining the syndrome.
Additionally, no consistent or readily reproducible pattern of immunologic abnormalities has been identified.
Other proposed mechanism include neuroendocrine abnormalities, abnormal levels of neurotransmitters, inadequate cerebral circulation and elevated levels of ACE
Data indicate that relatives of patients with CFS have an increased risk of developing the syndrome, suggesting a familial or genetic component.
Symptoms,signs and diagnosis
Onset is usually abrupt and many patients report an initial viral-like illness with swollen lymph nodes,extreme fatigue,fever,and upper respiratory symptoms.
The main is severe fatigue (usually for >= six mo) that interfere with daily activities.
Usually no signs of muscle weakness, arthritis, neuropathy, or organomegaly are present, however some definitions require the presence of low grade-fever,nonexudative pharyngitis,or palpable or tender lymph nodes
Because the cause is unknown, diagnosis is by clinical criteria.
Further evaluation aims to exclude treatable disorders .A reasonable assessment includes CBC and measurement of electrolytes, ESR and thyroid –stimulating hormone.
In some cases chest-x-ray and tests for antinuclear antibody, rheumatoid factor, hepatitis and HIV should be added.
Other viral antibody and other expensive tests are unlikely to shed light on the diagnosis or cause.
Obvious depression or severe anxiety excludes the diagnosis of CES
Diagnostic criteria for chronic fatigue syndrome
Unexplained, persistent, or relapsing chronic fatigue that is new or has a definite onset:
That is not due to ongoing exertion.
That is not substantially alleviated by rest.
And that substantially reduces occupational, educational, social, or personal activities.
At least four of the following for > = six mo (must not predate the fatigue)
Impaired short term memory (self reported) severe enough to substantially reduce occupational, educational, social, or personal activities
- Sore throat
- Low grade fever
- Tender, enlarged, painful cervical or axilillary lymph nodes.
- Muscle pain
- Abdominal pain
- Multijoint pain without joint without joint swelling or tenderness (arthralgia).
- Headaches those are new in type, pattern or severity
- Unrefreshing sleep
- Postexertional malaise lasting >= 24 hours.
- Cognitive difficulties especially with concentrating and sleeping.
Nonsedating and antidepressants are commonly prescribed, although their values is undetermined
Antiviral treatments with acyclovir and amantadine do not appear effective
Studies of immunologic treatments including high dose immune globulins, dialyzable WBC extract, amphigen, interferons, Isoprinosine, and corticosteroids, have been inconclusive and mostly disappointing
Dietary supplements and high-dose vitamins are commonly used,but their usefulness have not been substantiated .
Psychological intervention whether individual or group therapy may help some patients.
Formal structured physical rehabilitation programs may help.
Persistent or prolonged rest should be firmly discouraged because it can worsen deconditioning and promote progressive frailty
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