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

See also: Fatigue

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

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:

• Your 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, and include muscle aches, headache, and extreme fatigue. However, symptoms of CFS last for 6 months or more.

The main symptom of CFS is extreme tiredness (fatigue), 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

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.

CFS is diagnosed after your 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

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

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

Patients 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

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.

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

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

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

Firestein GS, Budd RC, Harris ED Jr., et al., eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2008.

Engleberg NC. Chronic fatigue syndrome. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 131.

Santhouse A, Hotopf M, David AS. Chronic fatigue syndrome. BMJ. 2010;340:c738.