Chronic Fatigue Syndrome (CFS) or Systemic Exertion Intolerance Disease (SEID)

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Chronic fatigue syndrome (CFS) or systemic exertion intolerance disease (SEID) facts

  • Chronic fatigue syndrome (CFS) is defined by two major criteria, chronic severe fatigue for at least six months not caused by a diagnosable disease or relieved with rest and at least four other specific symptoms that occur at the same time or after the development of severe fatigue. In 2015, the Institute of Medicine proposed a new name for this syndrome -- systemic exertion intolerance disease (SEID).
  • The cause of chronic fatigue syndrome (CFS or SEID) is unknown.
  • Risk factors are not clearly understood, but the majority of adults diagnosed are adult women from 40-50 years of age; pediatric patients diagnosed are usually teenagers.
  • The symptoms and signs of chronic fatigue syndrome (CFS or SEID) are relatively specific: chronic severe fatigue for at least five to six months not caused by a diagnosable disease and at least four other specific symptoms such as cognitive impairment, muscle and/or joint pains, new types of headaches, tender lymph nodes, sore throat, unrefreshing sleep, and malaise after exercise that occur at the same time or after the development of severe fatigue.
  • The estimated prevalence in the U.S. is about 836,000 to 2.5 million people.
  • Chronic fatigue syndrome or SEID is diagnosed about four times more often in women than men.
  • CFS/SEID is diagnosed by five to six symptoms or signs; there is no definitive test for CFS/SEID.
  • Treatment of chronic fatigue syndrome (CFS or SEID) is based on treating the symptoms patients exhibit.
  • Although there is no known cure for CSF or SEID, symptoms may be markedly reduced.
  • The prognosis for chronic fatigue syndrome (CFS or SEID) in adults is only fair to poor; children have a better or good prognosis with treatment.
  • Adopting a healthy lifestyle is the usual preventive advice given by clinicians that treat chronic fatigue syndrome (CFS or SEID) patients.
  • Additional sources of information and support groups are available for chronic fatigue syndrome (CFS or SEID).
Medically Reviewed by a Doctor on 2/27/2015

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Living with Chronic Fatigue Syndrome

One Patient's Story

At 21 years of age, Sarah Jones* felt like she was falling apart.

Once an energetic cheerleader and member of a professional dance team, full of energy and life, Jones gradually found herself bedridden and unable to work. As time went on she became more confused as to why she was feeling constantly tired.