Chronic fatigue syndrome (CFS), also known as chronic fatigue and immune dysfunction syndrome, is a mysterious medical condition that affects approximately 500,000 Americans (CDC 2005a). The disease has no known cause and there is no test that can measure for it.
Rather, CFS is defined as a set of symptoms that include prolonged, overwhelming fatigue that begins upon awakening and lasts throughout the day. The fatigue may worsen with exercise or physical activity. Other symptoms associated with CFS include mood swings, muscle spasms, pain, headache, sleep disturbances, and loss of appetite (Afari 2003; Balch 2000). There is typically no evidence of muscle weakness, joint or nerve abnormalities. Also, CFS is not considered a primary psychological disorder, although it may have psychological elements (e.g., depression) (CFIDS 2005).
Chronic fatigue syndrome primarily affects women age 25 to 45, but can affect anyone. While the cause of CFS is unknown, it can be triggered by a number of factors, including infectious agents, mental or physical stress, nutrient deficiencies, immune system abnormalities or allergies, hormonal abnormalities, and low blood pressure. It tends to run in families, so some researchers have hypothesized there may be a genetic predisposition. Oxidative stress may also play a role in the disease (Afari 2003; Borish 1998).
Several famous clusters of cases have occurred, such as an outbreak in Los Angeles County Hospital in 1934, but no common environmental or infectious cause was ever discovered (Kasper 2005). In recent years, as researchers have learned more about the disease, some clinicians have begun calling for CFS to be classified into different subgroups, depending upon other factors present (e.g., family history, viral status, and socio-demographic factors) (Jason 2005). This thinking reflects the idea that CFS may have multiple, interlocking causes or triggers, including the following:
- Infectious disease. To date there is no specific correlation between any infectious agent and CFS (Kasper 2005). Anecdotally, many CFS sufferers believe that their condition began with a flu-like illness, although for others the disease arises spontaneously (CFIDS 2005).
- Immune disorders. Many patients with CFS have impaired immune function, as indicated by increased production of cytokines, decreased natural killer cells, alterations in T cell expression, or increased allergies or autoimmune diseases—although it is unclear whether these conditions were caused by CFS itself (Gerrity 2004; Patarca 2001; Tirelli 1994; Tomoda 2005; Ur 1992; Vernon 2005; Visser 1998; Vollmer-Conna 1998).
- Dental amalgam toxicity. Some research shows a possible correlation between dental amalgam, metal toxicity, and CFS symptoms. In one study, 83 patients (76 percent) reported long-term health improvement following the removal of dental metal. This effect is believed to be related to a hypersensitive allergic response (Stejskal 1999).
- Oxidative stress. Studies suggest that oxidative stress may play a role in the development of CFS (Fulle 2000; Logan 2001; Richards 2000).
- Endocrine system disorders. Stress, both physical and emotional, can lead to increased levels of cortisol and other hormones. An article in the Journal of Affective Disorders concluded that CFS may be associated with low cortisol levels and increased serotonin function (Cleare 1995). Aluminum is increased in CFS, while DHEA and iron are reduced in female patients (van Rensburg 2001; Scott 1999a).
- Low blood pressure. Low blood pressure is a common finding in CFS. In one study, neurally-mediated low blood pressure was documented in 96 percent of CFS patients (Bou-Holaigah 1995). Medications for the treatment of neurally-mediated low blood pressure resulted in improvement in two-thirds of patients (Calkins 1998). Orthostatic hypotension (low blood pressure that occurs when going from a lying to a standing position) is also a common symptom in chronic fatigue patients (Streeten 1998).