The diagnosis of chronic fatigue syndrome (CFS) means that the sufferer has experienced fatigue for at least six months in the absence of known medical causes as well as had other characteristic symptoms. The Institute of Medicine (IOM) committee recommends the name systemic exertion intolerance disease (SEID) for this disease, and it has also been referred to as myalgic encephalomyelitis (ME), even though no evidence of inflammation of the brain (encephalitis) has been demonstrated with this condition. Characteristic symptoms in addition to fatigue include
- significant impairment in short-term memory,
- poor concentration,
- tender lymph nodes,
- sore throat,
- muscle pain,
- joint pain without swelling or redness,
- non-refreshing sleep,
- malaise lasting more than 24 hours after exertion,
- headaches of a new type, pattern, or severity.
Other signs and symptoms may also be present, like
- mild fever,
- double vision.
Dizziness, balance problems, fainting, food sensitivities, night sweats, chills, vision disturbances, mood changes, and depression have also been reported. The symptoms can be generalized and may occur due to many different causes; therefore, the diagnosis of chronic fatigue syndrome relies upon excluding other medical causes of the symptoms.