Dr. Mersad Alimoradi 29 Jun 2021

Chronic fatigue syndrome (CFS) is an elusive syndrome whose hallmark symptom is unexplained chronic tiredness. It is also called myalgic encephalopathy (ME) or systemic exertion intolerance disease (SEID).

Sleepiness, joint pain, brain fog, concentration troubles, sleeping disorders, and others have all been described as symptoms of chronic fatigue syndrome. The severity of CFS can be very variable, however, in some people, the disorder can become debilitating.

CFS symptoms are often dismissed as a natural result of work and stress and therefore, almost 90% of people with CFS go undiagnosed. Doctors often have to do extensive testing to rule out other illnesses before arriving at chronic fatigue syndrome/myalgic encephalopathy (CFS/ME).

The exact cause of CFS/ME syndrome is not known. Treatment, therefore, aims to improve the symptoms and elevate the quality of life rather than cure the disease.

What is Chronic Fatigue Syndrome?

A few decades ago, chronic fatigue syndrome was not considered a real medical diagnosis. The variability and non-specific nature of symptoms had led many doctors to dismiss the diseases and regard them as mental (and not physical) disturbances.

Nevertheless, following immense investigations and numerous research, the medical community accepted Chronic Fatigue Syndrome as an independent medical diagnosis.

In 2015, the Institute of Medicine (USA) reported that up to 2.5 million Americans might suffer from chronic fatigue syndrome, 90% of whom are still not diagnosed. The disease can affect anyone in any age group, however, it is mostly seen in middle-aged women.

The hallmark symptom of CFS/ME is chronic fatigue (> 6 months) that is otherwise not explained by another illness and is not relieved by rest.

Patients always feel physically and mentally tired and have no energy to perform routine daily tasks. Many other symptoms like memory disturbances, sleep troubles, and brain fog can prevent patients with chronic fatigue from living a healthy life.

What are the symptoms?

Many varying symptoms have been reported as symptoms of myalgic encephalopathy, and they include:

  • Constantly feeling tired and lacking energy
  • Trouble concentrating (brain fog)
  • Memory disturbances
  • Sleep disturbances (e.g. insomnia)
  • Exhaustion after a physical or mental effort
  • Headache
  • Sore throat
  • Muscle aches
  • Joint pain
  • Dizziness especially when getting up from a sitting or sleeping position

The severity of CFS/ME symptoms varies between different periods of time. Some days they might be unbearable or debilitating, and other days you might barely notice them.

Many patients report extreme exhaustion and a flare-up of CFS/ME symptoms after intense physical or mental effort (like work stress or performing sports).

The symptoms usually start at a specific point in time and have not been there since forever (which suggests a possible trigger).

What causes chronic fatigue syndrome?

The exact cause of CFS/ME is still not known. Doctors believe that chronic fatigue syndrome is a result of an interplay between several factors. Certain events can trigger CFS in people who might be genetically predisposed to developing it. And as such, the possible causes of chronic fatigue syndrome include:

  • Genetics: It is thought that people with CFS have a genetically determined predisposition to the disease, and once triggered by an external factor, the disease ensues.
  • Viral infections: Many studies have already speculated about possible links between common viruses and CFS. It is thought that these viruses trigger a certain immune reaction that ignites the disease process. Some viruses suggested as causing CFS/ME include the Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and possibly the SARS-CoV-2 (Post COVID-19 syndrome).
  • Bacterial infections: It has been suggested that bacterial infections (like pneumonia) might act as a trigger for CFS/ME.
  • Abnormal Immune Function: Some scientists suggest that an unbalanced immune response might contribute to the development of CFS syndrome.
  • Hormonal abnormalities: Pituitary and adrenal hormonal imbalances have been suggested as causes of chronic fatigue syndrome, however, this is still not confirmed
  • Trauma: In some cases, CFS/ME symptoms are triggered by an intense physical or emotional/psychological trauma.

Risk Factors

It’s still not clear what puts you at risk of developing chronic fatigue syndrome, however, the following factors have been suggested:

  • Gender: Women seem to be more prone to develop CFS/ME compared to men
  • Age: CFS usually occurs in middle-aged women and men (40-50)
  • Allergies
  • Mental stress
  • Genetic factors (still not clearly established)


The road to diagnosing CFS/ME can be more tiring and frustrating to patients than the disease itself. Since chronic fatigue syndrome can cause symptoms similar to many other diseases, extensive testing, and multiple medical referrals are usually done before arriving at a diagnosis of CFS/ME.

Indeed, symptoms like constant tiredness and joint pain can be associated with more serious illnesses (like rheumatoid arthritis for example). Hence, before settling for a diagnosis of CFS/ME, your treating physicians will need to rule out other conditions. This translates to:

  • Blood tests: routine blood tests and auto-immune disease workup are usually ordered to rule out autoimmune diseases and other possible illnesses
  • Imaging: If you have specific body pains, your physician will likely order an X-ray, CT scan, or MRI, depending on the location of the pain.
  • Other tests: These might include anything from electroencephalography (EEG) to endoscopic imaging depending on your specific case.

Some diseases (like Lyme disease, lupus, multiple sclerosis, and others) can cause symptoms similar to those of CFS/ME. Certain drugs, like antihistamines, can also cause tiredness and sleepiness.

If all of these tests are normal and do not point at any specific disease that can be causing your symptoms, then you will be diagnosed with chronic fatigue syndrome if:

  • You’re suffering from the typical symptoms of CFS (fatigue, sleep disturbances, joint pain, etc.)
  • The symptoms have started at a specific point in time
  • The symptoms have been there for more than 6 months
  • The symptoms are not relieved by rest


Unfortunately, there’s still no definite treatment for chronic fatigue syndrome. Most methods and medications aim at relieving symptoms and improving the quality of life. The goal is to control the disease so that you could go on with your life undisturbed by CFS symptoms.

  • Drugs: Since CFS can be associated with stress and depression, many patients might benefit from low-dose antidepressants. Anti-inflammatory drugs (NSAIDs) and paracetamol can be prescribed to deal with joint and muscle pain.
  • Therapy: Counselling can help you deal with stress that can both be a cause and an effect of chronic fatigue syndrome.
  • Lifestyle changes: Following a normal healthy sleep pattern can give you a needed energy boost and help reduce the symptoms of chronic fatigue syndrome.
  • Exercising: Although intense exercise can worsen CFS/ME symptoms, maintaining some degree of physical activity is necessary to not lose your exercise ability in the long term
  • Finding support: You can join one of the growing CFS/ME support groups and initiatives to share your experiences and learn from other people who suffer from the same illness.

Although living with chronic fatigue is sometimes exhausting, you should not give up. Different bodies respond to different therapies, and there’s a good chance you’ll find something to help you lead a healthy and (nearly) symptom-free life. Stay positive, share your experiences, get help from others, and help others cope with this elusive and largely under-diagnosed disease.

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About the Author:
Dr. Mersad is a medical doctor, author, and editor based in Germany. He's managed to publish several research papers early in his career. He is passionate about spreading medical knowledge. Thus, he spends a big portion of his time writing educational articles for everyone to learn.



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