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Specialist Advice — 13 minutes

The mystery of chronic fatigue syndrome

March 15th 2022

Sleep care team
Sleep care team

Have you been experiencing severe fatigue accompanied by muscle and joint pain for more than six months? Does your condition prevent you from going about your daily activities, or does it leave you bedridden after the slightest effort? You may be suffering from myalgic encephalomyelitis (ME), also known as chronic fatigue syndrome (CFS). However, this diagnosis is difficult to establish because symptoms can vary from person to person and day to day.

Temporary exhaustion or chronic fatigue?  

Everyone feels fatigue from time to time. When the causes are known, such as an excessive workload, a lack of sleep, a major physical effort, a period of intense emotions or an illness, we speak of asthenia. This condition generally goes away with time and rest, or by treating the illness causing it.  

Asthenia becomes abnormal when it continues despite sleep and rest. But this does not necessarily mean you have chronic fatigue. Because the causes of CFS are not well understood, the syndrome’s definition varies from one group of experts to another.

According to the 2003 Canadian Consensus Criteria for ME and CFS,[1] chronic fatigue syndrome is a serious and chronic illness that affects multiple systems of the body.  

  • The individual is unable to carry out daily activities and often has to stay in bed.
  • Physical activity may result in severe fatigue and non-restorative sleep, as well as joint and muscle pain. 
  • Depending on the case, the individual may have problems with functions such as neurological (cognitive), autonomic (dizziness when changing position), neuroendocrine (body temperature regulation) and immune system (swollen lymph nodes).    

Who is most at risk?  

In a 2017 survey conducted by Statistics Canada, more than 560,000 Canadians reported suffering from chronic fatigue syndrome, an increase of 37% compared to a similar survey done three years earlier.[2,3] In Quebec, roughly 70,000 people reportedly suffer from this condition. CFS occurs mainly in middle-aged individuals and affects twice as many women as men.[4] 

What are the causes?  

The precise causes of CFS are unknown, but certain factors may be associated with its onset:[4]  

  • Infections, such as those caused by the Epstein-Barr virus (EBV) and possibly SARS-CoV-2, which causes COVID-19. Infections caused by other viruses or bacteria, such as those responsible for Lyme disease or Q fever, are also suspected. 
  • Immune system disorders: Although people with chronic fatigue syndrome do not have an immune deficiency (vulnerability to infection), regulation of the immune system in affected individuals differs from that of normal individuals. 
  • Endocrine and metabolic disorders (hypometabolic state, abnormalities in energy generated through cellular metabolism, defective cortisol secretion, low blood pressure, etc.) 
  • Depression does not appear to cause chronic fatigue syndrome, but it is important to treat it before focussing on treating chronic fatigue.  
  • Sleeping problems or non-restorative sleep.
  • Genetics: Changes in the sequence of genes associated with brain function, stress response or emotions may make some individuals more prone to developing chronic fatigue syndrome. 

What are the symptoms? 

The symptoms reported by patients can vary from person to person and day to day. They include the following:[5]  

  • Pathological fatigue: persistent and unexplained tiredness, forcing the person to reduce their activities and not improving through rest 
  • Fatigue or dizziness following physical effort
  • Sleep disorders and non-restorative sleep
  • Unexplained muscle or joint pain (myalgia) 
  • Neurocognitive disorders (impairment of memory, concentration, verbal skills, etc.) 
  • Neurological or cognitive disorders (confusion, poor concentration, memory loss, disorientation, etc.) 
  • Autonomic nervous system disorders (orthostatic hypotension, dizziness when changing position, palpitations, etc.) 
  • Neuroendocrine disorders (fluctuating body temperature during the day, eating disorders, etc.) 
  • Immune system disorders (tenderness in the neck or armpit lymph nodes, sore throat, new intolerances or allergies, etc.)

How is it diagnosed?

Until we have a specific diagnostic test for chronic fatigue syndrome, the diagnosis is first based on ruling out other illnesses, or the lack of any identifying cause for the symptoms the patient reports. Diagnostic tests can help rule out some of the more common causes of fatigue, including tests for sleep disorders, or blood tests for anemia, cancer or endocrine disorders.[5]

To establish a diagnosis of CFS, the patient must experience some of the symptoms described above: pathological fatigue, dizziness after exercise, trouble sleeping, pain, two neurocognitive symptoms, and at least one symptom in two of the following systems: autonomic nervous, neuroendocrine and immune. In addition, the symptoms must last for more than six months.[5] 

The first blood test to diagnose CFS?  

In the fall of 2020, a promising diagnostic test was proposed by a group of researchers led by Dr. Alain Moreau from CHU Sainte-Justine in Montreal.[6] This blood test, performed post-exercise following 90 minutes of arm muscle stimulation, reveals typical and reproducible variations of microRNAs in the blood of individuals with CFS. However, this tool is still in the experimental stage.

Is there a treatment? 

Unfortunately, there is currently no treatment that cures chronic fatigue syndrome. The treatments available are aimed at relieving the symptoms and improving quality of life. Some individuals report an improvement in symptoms over time, while the opposite is true for many others. 

Because the disease presents differently in each individual, treatment should be tailored to each person and focus on relieving the most debilitating symptoms.[5,7] This includes medications to treat pain and promote sleep, as well as maintaining a certain level of physical activity, if possible.   

Several other treatments have been proposed, but their efficacy has not been proven:  

  • Cognitive behavioural therapy  
  • Medication with antibiotic and antiviral agents, as well as steroids and antihistamines 
  • Herbal and vitamin supplements of all types  
  • Dietary restrictions

Learning to live with chronic fatigue syndrome   

Living with chronic fatigue syndrome can be frustrating when the symptoms impact quality of life and cannot be controlled by treatment. It is even more frustrating when health care professionals do not recognize CFS because of difficulties in diagnosing it. Some groups involved with individuals suffering from chronic fatigue syndrome, such as the Association québécoise de l'encéphalomyélite myalgique (AQEM), can be very helpful.

For professional support, we’re here for you.

We provide services that can help your doctor diagnose eliminate some of the more common causes of chronic fatigue and determine the appropriate treatment.

Do you have a medical prescription for any of these tests? Book an appointment online or contact Biron Health Group’s customer service at 1 833 590-2712.

  1. B. M. Carruthers et al. (2003). “Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical Working Case Definition, Diagnostic and Treatment Protocols. A Consensus Document,” Journal of Chronic Fatigue Syndrome, 11(1):7-115.  
  2. Bruce M. Carruthers and Marjorie I. van de Sande (2006). “Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Clinical Case Definition and Guidelines for Medical Practitioners. An Overview of the Canadian Consensus Document,” Carruthers and van de Sande,
  3. Canadian Institutes for Health Research. “Working with patients and their families to improve health outcomes for people living with ME/CFS,” [accessed on February 28, 2022]. 
  4. Stephen J. Gluckman (2021). “Clinical features and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome,” UpToDate,   
  5. Fred Friedberg et al. (2012). “Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: A Primer for Clinical Practitioners,” International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis,   
  6. E. Nepotchatykh, W. Elremaly, I. Caraus I. et al. (2020). “Profile of Circulating MicroRNAs in Myalgic Encephalomyelitis and Their Relation to Symptom Severity, and Disease Pathophysiology,” Nature Scientific Reports, 10(19620),
  7. Stephen J. Gluckman (2020). “Patient education: Myalgic encephalomyelitis/chronic fatigue syndrome (Beyond the Basics),” UpToDate,  
Sleep care team
Sleep care team