Chronic Fatigue Syndrome or Myalgic Encephalomyelitis

Chronic Fatigue Syndrome or Myalgic Encephalomyelitis

By Catherine Seton, MD and Lori Montgomery, MD, CCFP


Chronic Fatigue Syndrome and Myalgic Enchephalomyelitis (say: my-AL-jic en-sef-uh-loh-may-ug-LAHY-tis) are terms used in place of each other. In Canada, this complex, often debilitating medical disorder is known as ME/CFS. In 2003, Health Canada wrote a clinical case definition of ME/CFS. It is: “an acquired illness that affects all body systems, predominantly (mostly) the neurological, endocrine, and immune systems.” ME/CFS is grouped with neurological diseases in the WHO International Classification of Diseases. It is very poorly understood by patients, health care professionals, and researchers.


We think that about 20,000 to 30,000 Canadians have ME/CFS. These numbers may not be accurate, partly because many people do not see a doctor for their symptoms. Another problem is that some people think they have ME/CFS, but have never been tested for some of the things that cause similar symptoms, like infection, diabetes, or thyroid disease.

Some researchers now believe that ME/CFS happens in people who are genetically predisposed to have the disease, although others have shown evidence that a viral infection of some kind or an impaired immune system might be the reason for it. When these people are exposed to a trigger event such as infection, traumatic injury, emotional trauma, hormonal change, or chemical exposure, their body’s ability to cope with physiologic stress is impaired.

Signs and symptoms

This abnormal stress response, plus the wear and tear on the body from the trigger event, is thought to cause the wide range of symptoms that may occur such as:

  • sudden onset of lasting, severe fatigue that severely reduces the patient’s activity level; may combine extreme tiredness, weakness, exhaustion, heaviness, and slowed response time
  • feeling very tired, lasting more than 24 hours after very little physical or mental work
  • non-restorative sleep (sleep after which they do not feel rested)
  • muscle pain that moves around, sometimes without a clear reason; joint pain without redness or swelling
  • headache
  • impaired memory or concentration
  • recurrent sore throat
  • tender lymph nodes: most often at sides of neck and under arms
  • feeling dizzy or weak upon standing
  • not tolerant to heat or cold
  • sensitive to light, noise, odors
  • new sensitivities to food/medicines/chemicals
  • gastrointestinal problems such as irritable bowel syndrome

Diagnostic tests

There is no blood test or other exam that makes the diagnosis of ME/CFS. Many people with ME/CFS do not look sick despite profound disability. Symptoms may vary from person to person and even from day to day in one person. Fatigue and other ME/CFS symptoms are common in many other illnesses. For these and other reasons, ME/CFS is a challenge to diagnose.

Other diseases are ruled out
The first step is to rule out other diseases that cause similar symptoms. Blood, urine, and stool samples, and possibly other tests like X-rays, magnetic resonance imaging (MRIs) or a sleep study may be ordered based on your symptoms. Remember that endocrine diseases and infections are common conditions that cause similar symptoms to ME/CFS. If no other cause of the problem is found and you have a number of the symptoms listed above, you fit the criteria for diagnosis of ME/CFS.

Some tests are done not to make a diagnosis, but to figure out the severity of disease. A Tilt Table Test, for example, can decide whether there is an abnormality in the nervous system’s ability to control heart rate and blood pressure, which happens sometimes in this disorder. If this is the case, more tests will be done to figure out the severity of the problem.

Blood tests
Some people advocate for a special blood test (called 37-kDa 2-5A Rnase L immunoassay). Levels of this enzyme fluctuate (go up and down) a lot in normal people, so it is not a specific diagnostic test. There are a number of other tests being studied, which may some day allow ME/CFS to be diagnosed based on urine or blood tests. However, none is endorsed by medical authorities at this time.

When a clear diagnosis is made, one of the most important parts of treatment is to educate the patient, family, friends, co-workers, and employers about what having the disease means to the person’s life. Many health care providers still doubt that this condition is a distinct disease. Patients will therefore find speaking with those providers difficult unless armed with enough information. It is also important that the patient have a good therapeutic alliance with a health professional who is educated about ME/CFS.

Treatment approach

It is critical that patients become as active as able without making the symptoms worse. It is therefore important to learn to plan, pace, and prioritize activities. This is part of pain self-management, which is described in more detail elsewhere on this site. Acupuncture, aquatic therapy, gentle massage, meditation, deep breathing, biofeedback, yoga, tai chi, and massage therapy help some patients as well.

Other lifestyle changes
Other lifestyle changes, like improving your sleep quality, eating a balanced diet, and stopping smoking, are important as well. Coping strategies can be learned to manage problems with memory, concentration, and attention.
Medical treatment will focus on managing the symptoms of the disorder. Pain can often be managed with anti-inflammatory medicines or acetaminophen, for example. Patients with ME/CFS are often very sensitive to medicines, so initial doses will be very low, with increases planned if side effects are able to be managed. It may be tempting to treat fatigue with stimulants, but many patients find that this allows them to increase activity in an unplanned and unpaced way, and this causes a “crash” afterwards. Some patients may benefit from:

  • tricyclic antidepressants, which treat pain, sleep, and mood
  • antihistamines, which may help allergy-like symptoms
  • medicines like zopiclone and L-tryptophan may be used to help regulate sleep, but note that zopiclone and medicines like it can cause sleep dependence if used for more than 14 days
  • serotonin-norepinephrine reuptake inhibitors (SNRIs) if the patient is depressed

Treating low blood pressure
Low blood pressure, if severe and causing symptoms, may need to be treated with fluids and salt along with support stockings, or in rare cases, with medicine.


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