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Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) refers to severe, continued tiredness (fatigue). It does not get better with rest and is not directly caused by other medical problems.


The exact cause of chronic fatigue syndrome (CFS) is unknown. It may be due to:

  • Epstein-Barr virus or human herpes virus-6 (HHV-6); however, no specific virus has been identified as the cause
  • Inflammation in the nervous system, because of a faulty immune system response

The following may also play a role in the development of CFS:

  • Age
  • Previous illnesses
  • Stress
  • Genetics
  • Environmental factors

CFS is most common in women ages 30 to 50.


The hallmark symptom is persistent and profound fatigue, which often worsens after physical or mental exertion.

Symptoms may also include muscle aches, headache, and extreme fatigue.

The main symptom of CFS is extreme tiredness, which is:

  • New
  • Lasts at least 6 months
  • Not relieved by bed rest
  • Severe enough to keep you from participating in certain activities
  • Worsened when in upright position

Other symptoms include:

  • Feeling extremely tired for more than 24 hours after exercise that would normally be considered easy
  • Feeling unrefreshed after sleeping for a proper amount of time
  • Forgetfulness
  • Concentration problems
  • Confusion
  • Joint pain, but no swelling or redness
  • Headaches that differ from those you have had in the past
  • Irritability
  • Mild fever  - 101°F (38.3°C) or less)
  • Muscle aches (myalgias)
  • Muscle weakness, all over or multiple locations, not explained by any known disorder
  • Sore throat
  • Sore lymph nodes in the neck or under the arms

Exams and Tests

The Centers for Disease Control (CDC) describes CFS as a distinct disorder with specific symptoms and physical signs. Diagnosis is based on ruling out other possible causes.

Your health care provider will try to rule out other possible causes of fatigue, including:

A diagnosis of CFS must include:

  • Absence of other causes of chronic fatigue
  • At least four CFS-specific symptoms
  • Extreme, long-term fatigue

There are no specific tests to confirm the diagnosis of CFS. However, there have been reports of CFS people having abnormal results on the following tests:

  • Brain MRI
  • White blood cell count


There is currently no cure for CFS. The goal of treatment is to relieve symptoms.

Treatment includes a combination of the following:

  • Cognitive-behavioral therapy (CBT) and graded exercise for certain people
  • Healthy diet
  • Sleep management techniques
  • Medicines to reduce pain, discomfort, and fever
  • Medicines to treat anxiety (anti-anxiety drugs)
  • Medicines to treat depression (antidepressant drugs)

Some drugs can cause reactions or side effects that are worse than the original symptoms of the disease.

People with CFS are encouraged to maintain an active social life. Mild physical exercise may also be helpful. Your health care team will help you figure out how much activity you can do, and how to slowly increase your activity. Tips include:

  • Avoid doing too much on days when you feel tired
  • Balance your time between activity, rest, and sleep
  • Break big tasks into smaller, more manageable ones
  • Spread out your more challenging tasks through the week

Relaxation and stress-reduction techniques can help manage chronic (long-term) pain and fatigue. They are not used as the primary treatment for CFS. Relaxation techniques include:

  • Biofeedback
  • Deep breathing exercises
  • Hypnosis
  • Massage therapy
  • Meditation
  • Muscle relaxation techniques
  • Yoga

Newer medicine approaches are being researched. 

Support Groups

Some people may benefit from taking part in a CFS support group.

Outlook (Prognosis)

The long-term outlook for people with CFS varies. It is hard to predict when symptoms first start. Some people completely recover after 6 months to a year.

About 1 in 4 people with CFS are so severely disabled that they cannot get out of bed or leave their home. Symptoms can come and go in cycles, and even when people feel better, they may experience a relapse triggered by exertion or an unknown cause.

Some people never feel like they did before they developed CFS. Studies suggest that you are more likely to get better if you receive extensive rehabilitation.

Possible Complications

Complications may include:

  • Depression
  • Inability to take part in work and social activities, which can lead to isolation
  • Side effects from medicines or treatments

When to Contact a Medical Professional

Call your provider if you have severe fatigue, with or without other symptoms of this disorder. Other more serious disorders can cause similar symptoms and should be ruled out.

Alternative Names

CFS; Fatigue - chronic; Immune dysfunction syndrome; Myalgic encephalomyelitis (ME); Myalgic encephalopathy chronic fatigue syndrome (ME-CFS); Systemic exertion intolerance disease (SEID)


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Update Date 1/20/2015

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