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Chronic fatigue syndrome

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


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 that 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 an 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:

  • Drug dependence
  • Immune or autoimmune disorders
  • Infections
  • Muscle or nerve diseases (such as multiple sclerosis )
  • Endocrine diseases (such as hypothyroidism )
  • Other illnesses (such as heart, kidney, or liver diseases)
  • Psychiatric or psychological illnesses, particularly depression
  • Tumors

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 people with CFS 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:

  • Counseling therapy - cognitive-behavioral therapy (CBT)
  • Graded exercise
  • 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.




Bennett RM. Fibromyalgia, chronic fatigue syndrome, and myofascial pain. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 274.

Engleberg NC. Chronic fatigue syndrome. In: Bennett JE, ed. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases . 8th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2015:chap 133.

IOM (Institute of Medicine). Beyond myalgic encephalomyelitis/chronic fatigue syndrome: redefining an illness. Washington, DC: The National Academies Press; 2015. www.nationalacademies.org/hmd/~/media/Files/Report%20Files/2015/MECFS/MECFS_ReportBrief.pdf . Accessed April 20, 2016.

Nijs J, Roussel N, Van Oosterwijck J, 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 . 2013;32(8):1121-1129. PMID: 23639990 www.ncbi.nlm.nih.gov/pubmed/23639990 .

Santhouse AM, Hotopf M, David AS. Chronic fatigue syndrome. BMJ . 2010;340:c738. PMID: 20150199 www.ncbi.nlm.nih.gov/pubmed/20150199 .

Smith ME, Haney E, McDonagh M, et al. Treatment of myalgic encephalomyelitis/chronic fatigue syndrome: a systematic review for a National Institutes of Health Pathways to Prevention Workshop. Ann Intern Med. 2015;162:841. PMID: 26075755 www.ncbi.nlm.nih.gov/pubmed/26075755 .


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              Review Date: 1/16/2016

              Reviewed By: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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