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Diseases reference index «Chronic fatigue syndrome»

Chronic fatigue syndrome is a condition of prolonged and severe tiredness or weariness (fatigue) that is not relieved by rest and is not directly caused by other conditions.

See also: Fatigue


The exact cause of chronic fatigue syndrome (CFS) is unknown. Some researchers suspect it may be caused by a virus, such as Epstein-Barr virus or human herpes virus-6 (HHV-6). However, no specific virus has been identified as the cause.

Studies suggest that CFS may be caused by inflammation along the nervous system, and that this inflammation may be some sort of immune response or process.

Other factors such as age, prior illness, stress, environment, or genetics may also play a role.

CFS most commonly occurs in women ages 30 to 50.

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

CFS is diagnosed after the health care provider rules 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


Symptoms of CFS are similar to those of most common viral infections (muscle aches, headache, and fatigue). They come on within a few hours or days and last for 6 months or more.

Main symptoms:

  • Fatigue or tiredness, never experienced to this extent before (new onset), lasting at least 6 months and not relieved by bed rest
  • Fatigue that is severe enough to restrict activity (serious fatigue develops with less than one-half of the exertion compared with before the illness)

Other symptoms:

  • Fatigue lasting more than 24 hours after an amount of exercise that would normally be easily tolerated
  • Feeling unrefreshed after sleeping an adequate amount of time
  • Forgetfulness or other similar symptoms including difficulty concentrating, confusion, or irritability
  • Headaches, different from previous headaches in quality, severity, or pattern
  • Joint pain, often moving from joint to joint (migratory arthralgias), without joint swelling or redness
  • Lymph node tenderness in the neck or armpit
  • 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

Exams and Tests

Physical examination may show:

  • Fever
  • Lymph node swelling
  • Lymph node tenderness
  • Redness in the throat without drainage or pus

A diagnosis of CFS must include:

  • Absence of other causes of chronic fatigue (excluding depression)
  • At least four of the other symptoms listed
  • Extreme, long-term fatigue

There are no specific tests to confirm the diagnosis of CFS, although a variety of tests are usually done to rule out other possible causes of the symptoms.

There have been reports of CFS patients being found positive on the following tests:

  • Brain MRI showing swelling in the brain or destruction of part of the nerve cells (demyelination)
  • Higher levels of specific white blood cells (CD4 T cells) compared with other types of white blood cells (CD8 T cells)
  • Specific white blood cells (lymphocytes) containing active forms of EBV or HHV-6


There is currently no cure for CFS. Instead, the symptoms are treated. Many people with CFS experience depression and other psychological problems that may improve with treatment.

Overall, the best strategy for treatment includes a combination of the following:

  • A healthy diet
  • Antidepressant drugs in some cases, usually low-dose tricyclic antidepressants
  • Cognitive-behavioral therapy (CBT) and graded exercise for certain patients
  • Medication
  • Sleep management techniques

Work with your health care provider to find a level of activity you can handle. Then gradually increase your activity level. Activity management should involve:

  • 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 be helpful in managing chronic pain and fatigue. They are not useful, however, as the primary treatment for CFS. A number of relaxation techniques are available, including:

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

Some of the proposed treatments include:

  • Medications to reduce pain, discomfort, and fever
  • Medications to treat anxiety (anti-anxiety drugs)
  • Medications to treat depression (antidepressant drugs)

Some medications can cause adverse reactions or side effects that are worse than the original symptoms of chronic fatigue syndrome.

Patients with CFS are encouraged to maintain active social lives. Mild physical exercise may also be helpful.

Outlook (Prognosis)

The long-term outlook for patients with CFS varies and is difficult to predict when symptoms first start. Some patients completely recover after 6 months to a year. Others may take longer for a complete recovery.

Some patients never return to their pre-illness state. Most studies report that patients who are treated in an extensive rehabilitation program are more likely to recover completely than those patients who don't seek treatment.

Possible Complications

  • Depression (related both to symptoms and lack of diagnosis)
  • Lifestyle restrictions (some people are so fatigued that they are essentially disabled during the course of the illness)
  • Side effects and adverse reactions to medication treatments
  • Social isolation caused by fatigue

When to Contact a Medical Professional

Call for an appointment with your health care provider if you experience persistent, severe fatigue, with or without other symptoms of this disorder. Other more serious disorders can cause similar symptoms and should be ruled out.

See also:Chronic fatigue syndrome - resources

Alternative Names

CFS; Fatigue - chronic; Immune dysfunction syndrome; Myalgic encephalomyelitis (ME)

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