Chronic Fatigue

Chronic fatigue syndrome (CFS) is the most common name used to specify a disorder or group of disorders generally defined by persistent fatigue unrelated to exertion, not substantially relieved by rest and accompanied by other specific symptoms for a minimum of six months. The disorder may also be referred to as post-viral fatigue syndrome (PVFS), myalgic encephalomyelitis (ME), or several other terms. Although classified by the World Health Organization under Diseases of the nervous system, the etiology (cause or origin) of CFS is currently unknown and there is no diagnostic laboratory test or biomarker. Fatigue is a common symptom in many illnesses, but CFS is a multi-systemic disease and is relatively rare by comparison. Symptoms of CFS include post-exertional malaise; unrefreshing sleep; widespread muscle and joint pain; cognitive difficulties; chronic, often severe, mental and physical exhaustion; and other characteristic symptoms in a previously healthy and active person. CFS patients may report additional symptoms including muscle weakness, increased sensitivity to light, sounds and smells, orthostatic intolerance, digestive disturbances, depression, poor immune response, and cardiac and respiratory problems. It is unclear if these symptoms represent co-morbid conditions or are produced by an underlying etiology of CFS. All diagnostic criteria require that the symptoms must not be caused by other medical conditions.