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Chronic fatigue syndrome

Chronic fatigue syndrome refers to severe, continued tiredness (fatigue). It is not relieved by rest and is not directly caused by other medical conditions.


The exact cause of chronic fatigue syndrome (CFS) is unknown. Some theories suggest CFS 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 most commonly occurs in women ages 30 to 50.


Symptoms of CFS are similar to those of the flu and other common viral infections. Symptoms may include muscle aches, headache, and extreme fatigue. However, symptoms of CFS last for 6 months or more. CFS may be similar to fibromyalgia in many cases.

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

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 degrees F 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 patients 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. Many people with CFS have depression and other psychological disorders that may improve with treatment.

Treatment includes a combination of the following:

  • Cognitive-behavioral therapy (CBT) and graded exercise for certain patients
  • 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 active social lives. 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:

  • Avoiding doing too much on days when you feel tired
  • Balancing your time between activity, rest, and sleep
  • Breaking big tasks into smaller, more manageable ones
  • Spreading out more challenging tasks throughout the week

Relaxation and stress-reduction techniques can help manage chronic 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

Support Groups

Some people may benefit from taking part in a chronic fatigue syndrome support group.

Outlook (Prognosis)

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

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

  • Depression
  • Inability to participate in work and social activities, which can lead to isolation
  • Side effects from medication or treatments

When to Contact a Medical Professional

Call your health care 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)


Cush JJ, Dao KH. Polyarticular arthritis. In: Firestein GS, Budd RC, Gabriel SE, et al, eds.Kelley's Textbook of Rheumatology

Bennett RM. Fibromyalgia and chronic fatigue syndrome. In: Goldman L, Schafer AI, eds.Cecil Medicine

Engleberg NC. Chronic fatigue syndrome. In: Mandell GL, Bennett JE, Dolin R, eds.Principles and Practice of Infectious Diseases

Santhouse A, Hotopf M, David AS. Chronic fatigue syndrome. BMJ

Nijs J, Roussel N, Van Oosterwijck J, De Kooning M, Ickmans K, Struyf F, et al. Fear of movement and avoidance behaviour toward physical activity in chronic-fatigue syndrome and fibromyalgia: state of the art and implications for clinical practice.Clin Rheumatol

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Update Date 1/22/2014

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