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Chronic Fatigue Syndrome (CFS) Symptoms and Diagnosis

Reviewed on 6/1/2016


A woman suffers from chronic fatigue syndrome (CFS).

Chronic fatigue syndrome (CFS, also called chronic fatigue immune dysfunction syndrome, or CFIDS) is a chronic disorder characterized by several debilitating conditions including severe fatigue. Other symptoms include weakness, impaired memory or concentration, insomnia, muscle pain, and fatigue following exertion that lasts more than 24 hours. The causes of CFS are unknown, and there is no specific test to diagnose the condition. It is diagnosed through exclusion, that is, ruling out other illnesses with similar symptoms.

What Is Chronic Fatigue Syndrome?

A woman suffers from chronic fatigue syndrome (CFS).

Chronic fatigue syndrome can be difficult to diagnose, and also hard to define. A diagnosis of CFS is made when a patient meets at least two of the criteria described on the following slides.

Chronic Fatigue Syndrome – Criteria #1

To be diagnosed with chronic fatigue syndrome (CFS), you must have severe chronic fatigue of six months or longer duration.

In order to be diagnosed with chronic fatigue syndrome, a patient must have severe and chronic fatigue that lasts six months or more, and other medical conditions that could cause the fatigue must be excluded. The fatigue must significantly interfere with work or daily activities.

Chronic Fatigue Syndrome – Criteria #2

To be diagnosed with chronic fatigue syndrome (CFS), you must concurrently have four or more of the eight defining symptoms.

In addition to prolonged fatigue, patients must have four or more of the following symptoms to be diagnosed with chronic fatigue syndrome:

  • impairment in short-term memory or concentration
  • sore throat
  • tender lymph nodes
  • muscle pain
  • joint pain without swelling or redness
  • headaches of a new type, pattern, or severity
  • unrefreshing sleep
  • post-exertional malaise lasting more than 24 hours.

Similar Medical Conditions

A doctor examines a woman's X-ray.

Fatigue is a symptom that is often associated with many other medical conditions. Before being diagnosed with chronic fatigue syndrome a doctor will often try to rule out:

  • fibromyalgia syndrome
  • myalgic encephalomyelitis (ME)
  • neurasthenia
  • multiple chemical sensitivities
  • chronic mononucleosis

Other Conditions That May Cause Similar Symptoms

Numerous conditions may cause similar symptoms to chronic fatigue syndrome (CFS).

There are many other illnesses that are treatable that need to be ruled out to arrive at a diagnosis of chronic fatigue syndrome. It is possible to have these other conditions and also have CFS; if the conditions are treated and the patient still has chronic fatigue then CFS may be considered as a diagnosis. Conditions that can be treated that may have similar symptoms include:

  • hypothyroidism
  • sleep apnea or narcolepsy
  • major depressive disorders, bipolar affective disorders, schizophrenia
  • eating disorders
  • cancer
  • autoimmune disease
  • hormonal disorders
  • subacute infections
  • obesity
  • alcohol or substance abuse
  • vitamin D deficiency
  • reactions to medications.

Other Commonly Observed Symptoms in CFS

A woman describeA woman describesrs chronic fatigue syndrome (CFS) symptoms to her doctor.

There are a number of secondary symptoms that are also associated with chronic fatigue syndrome. Up to half of patients with CFS may experience symptoms including abdominal pain, alcohol intolerance, bloating, chest pain, chronic cough, diarrhea, dizziness, dry eyes or mouth, earaches, irregular heartbeat, jaw pain, morning stiffness, nausea, night sweats, psychological problems (depression, irritability, anxiety, panic attacks), shortness of breath, skin sensations, tingling sensations, and weight loss.

Prevalence of CFS

Chronic fatigue syndrome (CFS) affects more than one 1 million people in the United States.

More than 1 million Americans have been diagnosed with chronic fatigue syndrome. Many others have symptoms of severe fatigue but do not meet the diagnostic criteria for CFS.

Risk Factors for CFS

There are a variety of risk factors for chronic fatigue syndrome (CFS).

People of all ethnicities and ages can develop CFS. Risk factors for developing chronic fatigue syndrome include:

  • Female gender – women are four times more likely to develop CFS
  • Age 40s and 50s
  • There may be a genetic link

Diagnosis of CFS

A doctor explains a patient's diagnosis.

There are no specific tests that will diagnose chronic fatigue syndrome. To complicate matters, patients often may not appear ill, and the disease may go into remission and then relapse. To make a diagnosis, a doctor will first rule out other conditions that have similar symptoms that can be tested for, including mononucleosis, Lyme disease, thyroid conditions, diabetes, multiple sclerosis, various cancers, depression, vitamin D deficiency, and bipolar disorder. The Centers for Disease Control (CDC) estimates fewer than 20% of people who have CFS are actually diagnosed.

Treatment of CFS

A doctor prescribes medication treatment for a CFS patient.

There is no cure for chronic fatigue syndrome, so treatment is aimed at managing symptoms. Treatment usually involves a combination of medication and lifestyle changes such as preventing overexertion, reducing stress, managing diet, and nutritional supplements. Physical therapy may also be recommended. It is believed that the earlier the diagnosis is made and the sooner treatment starts, the better the outcome will be for patients.

Recovery From CFS

A woman with chronic fatigue syndrome (CFS) stares through a window.

Chronic fatigue syndrome symptoms vary from patient to patient. Some people are severely disabled and unable to work or carry out daily activities. Others may be able to work while still experiencing symptoms. Some patients cycle through periods of relative wellness and periods of illness. The number of patients who recover from CFS is unknown, but management is symptoms early on seems to be associated with better outcomes.

Possible Causes of CFS

CFS researchers work in a laboratory.

The causes of chronic fatigue syndrome are unknown. Causes may be infectious, physical, psychological, genetic, or environmental – or a combination of these factors.

Chronic Fatigue Syndrome (CFS) Symptoms and Diagnosis

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