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Chronic fatigue syndrome

Síndrome de la fatiga crònica Vall d'Hebron

Chronic fatigue syndrome, also known as myalgic encephalomyelitis, is a condition characterised by chronic and incapacitating fatigue when exerting little effort, which does not improve with rest. Over time this causes dysfunction of the neurological, immune, endocrine and metabolic systems. Its severity is very variable. In some cases physical and cognitive capacity may be significantly affected, disabling patients and limiting their quality of life. In other cases, people with the condition may lead a relatively active life.



Even through the cause of chronic fatigue syndrome is not yet known, it is being actively researched. It is thought the condition may be brought on by a combination of physical and psychological factors. These include viral or bacterial infections, recent negative or traumatic experiences, mental stress, depression and nutritional deficiencies. It is important to study the accompanying symptomatology: pain, sleep disorders, headaches; and cognitive, neurological, neurovegetative and immunological symptomatology in order to reach a proper diagnosis.




The most typical symptom is intense tiredness and fatigue that is not cured by rest and that limits daily life. Fatigue should last more than six months for diagnosis to be confirmed.

Other common symptoms are:


  • Muscle and joint pain.
  • Muscle weakness
  • Difficulty concentrating and memory loss.
  • Headache.
  • Pins and needles, mainly in the hands.
  • Gastrointestinal disorders.
  • Neck ache.
  • Sleep disorders (feeling tired upon waking).



Who is affected by the condition?


It affects young people, mainly women, between twenty and forty years old. Although there are no studies of its prevalence in the Spanish population, in other countries it affects 0.07% to 0.3% of people.




A general blood test is used along with imaging tests to carry out a differential diagnosis with other causes of persistent fatigue. The basic imaging tests are a chest x-ray and an abdominal ultrasound. A psychopathological assessment is required prior to definitive diagnosis to:


  • Rule out particular psychiatric processes
  • Study the psychopathological comorbidity
  • Start the appropriate pharmacological or non-pharmacological treatment.

In the case of CFS, as with many immunoinflammatory diseases, there is no specific diagnostic test available; a diagnosis is therefore reached by fulfilling the Fukuda criteria.


Primary criteria (both must be present):

Unexplained and persistent or recurring chronic fatigue (minimum 6 months), which appears again or comes on suddenly and which is not as a result of recent exertion. Does not significantly improve with rest. Produces a considerable decrease in levels of occupational, educational, social or personal activity. Exclusion of other illnesses that may cause prolonged fatigue.


Additional symptoms (occurring concurrently, 4 or more of the related signs and symptoms must be present and be persistent or recurring over 6 months following the onset of fatigue):

  • Short-term memory or concentration is impaired
  • Odynophagia (sore throat)
  • Painful cervical or axillary adenopathies
  • Muscle pain
  • Polyarthralgia with no signs of inflammation
  • Unrefreshing sleep
  • Headaches of a new type or intensity
  • Fatigue after exercise lasting more than 24 hours. It is important to study the accompanying symptomatology: pain; sleep disorders; headaches; cognitive, neurological, neurovegetative and immunological symptoms.

There is no treatment to cure chronic fatigue syndrome, but the symptoms can be improved:

  • Measures to do this include sleep hygiene and nutritional advice.
  • Gradually increasing aerobic exercise in line with tolerance. It is essential to personalise treatment according to the patient’s individual characteristics and the evolutionary phases of the condition.
  • Cognitive behavioural therapy
  • Pharmacological treatment of the main symptoms and associated comorbidities



Typical treatment


There is currently no treatment to cure chronic fatigue syndrome, but symptoms can be improved:

  • Including sleep hygiene measures and nutritional advice
  • Gradually increasing aerobic exercise, according to tolerance It is essential to personalise treatment to fit the individual characteristics of the patient and the evolutionary stage of the clinical condition
  • Cognitive behavioural therapy
  • Pharmacological treatment of the main symptoms and related comorbidities


Typical test:


Diagnosis of chronic fatigue syndrome (CFS) is purely clinical, but a general blood test and imaging tests are useful to carry out a differential diagnosis with other causes of persistent fatigue.

The general blood test should include:


  • Basic biochemistry
  • Creatine kinase
  • Thyroid-stimulating hormone and free thyroxine
  • Proteinogram
  • Haemogram
  • Iron, ferritin, vitamin B12 and folates
  • Vitamin D
  • Acute phase reactants
  • Antibodies 




• Appropriate physical exercise.

• Relaxation techniques.

• Avoiding physical and emotional stress.

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