Overview

Chronic fatigue syndrome (CFS) is a complicated disorder characterized by extreme fatigue that lasts for at least six months and that can't be fully explained by an underlying medical condition. The fatigue worsens with physical or mental activity, but doesn't improve with rest.

Other characteristic symptoms include:

  • Sleep that isn't refreshing
  • Difficulties with memory, focus and concentration
  • Dizziness that worsens with moving from lying down or sitting to standing

This condition is also known as myalgic encephalomyelitis (ME). Sometimes it's abbreviated as ME/CFS. The most recent term proposed is systemic exertional intolerance disease (SEID).

The cause of chronic fatigue syndrome is unknown, although there are many theories — ranging from viral infections to psychological stress. Some experts believe chronic fatigue syndrome might be triggered by a combination of factors.

There's no single test to confirm a diagnosis of chronic fatigue syndrome. You may need a variety of medical tests to rule out other health problems that have similar symptoms. Treatment for chronic fatigue syndrome focuses on improving symptoms.

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Symptoms

Symptoms of chronic fatigue syndrome can vary from person to person, and the severity of symptoms can fluctuate from day to day. Signs and symptoms may include:

  • Fatigue
  • Problems with memory or concentration
  • Sore throat
  • Headaches
  • Enlarged lymph nodes in your neck or armpits
  • Unexplained muscle or joint pain
  • Dizziness that worsens with moving from lying down or sitting to standing
  • Unrefreshing sleep
  • Extreme exhaustion after physical or mental exercise

When to see a doctor

Fatigue can be a symptom of many illnesses, such as infections or psychological disorders. In general, see your doctor if you have persistent or excessive fatigue.

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Causes

The cause of chronic fatigue syndrome is still unknown. Some people may be born with a predisposition for the disorder, which is then triggered by a combination of factors. Potential triggers include:

  • Viral infections. Because some people develop chronic fatigue syndrome after having a viral infection, researchers question whether some viruses might trigger the disorder. Suspicious viruses include the Epstein-Barr virus, human herpes virus 6. No conclusive link has yet been found.
  • Immune system problems. The immune systems of people who have chronic fatigue syndrome appear to be impaired slightly, but it's unclear if this impairment is enough to actually cause the disorder.
  • Hormonal imbalances. People who have chronic fatigue syndrome also sometimes experience abnormal blood levels of hormones produced in the hypothalamus, pituitary glands or adrenal glands. But the significance of these abnormalities is still unknown.
  • Physical or emotional trauma. Some people report that they experienced an injury, surgery or significant emotional stress shortly before their symptoms began.

Risk factors

Factors that may increase your risk of chronic fatigue syndrome include:

  • Age. Chronic fatigue syndrome can occur at any age, but it most commonly affects young to middle-aged adults.
  • Sex. Women are diagnosed with chronic fatigue syndrome much more often than men, but it may be that women are simply more likely to report their symptoms to a doctor.

Complications

Possible complications of chronic fatigue syndrome include:

  • Lifestyle restrictions
  • Increased work absences
  • Social isolation
  • Depression

July 06, 2022
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  2. Gluckman SJ. Clinical features and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome. https://www.uptodate.com/contents/search. Accessed Feb. 4, 2020.
  3. Ferri FF. Chronic fatigue syndrome. In: Ferri's Clinical Advisor 2020. Elsevier; 2020. https://www.clinicalkey.com. Accessed Feb. 4, 2020.
  4. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Information for Healthcare Providers. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/me-cfs/healthcare-providers/index.html. Accessed Feb, 4, 2020.
  5. Chronic fatigue syndrome. Merck Manual Professional Version. https://www.merckmanuals.com/professional/special-subjects/chronic-fatigue-syndrome/chronic-fatigue-syndrome?query=chronic%20fatigue. Accessed Feb. 4, 2020.
  6. Goldman L, et al., eds. Fibromyalgia, chronic fatigue syndrome and myofascial pain. In: Goldman-Cecil Medicine. 26th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Feb. 4, 2020.
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  8. Bierle DM (expert opinion). Mayo Clinic. July 31, 2020.
  9. Chon TY (expert opinion). Mayo Clinic. July 31, 2020.

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