Chronic Fatigue Syndrome (CFS/ME)


Chronic Fatigue Syndrome or Myalgic Encephalomyelitis (CFS/ME) is a complex and debilitating disorder characterized by extreme fatigue that does not improve with rest and that may worsen with physical or mental activity. Moreover, people affected by CFS show numerous non specific symptoms which include, among others, weakness, muscle pain, loss of memory and/or concentration, insomnia and extreme fatigue lasting more than 24 hours after physical or mental strain.

Most people who suffer from CFS/ME are forced to significantly reduce the activities they used to perform before the disorder appeared.

The cause or causes have not been identified and there is no definitive diagnosis evidence. On the other hand, since many other illnesses have disabling fatigue as a symptom, care must be taken to exclude them before a diagnosis of CFS/ME is made.



An international panel of CFS/ME research experts was called in 1994 to draft a definition of CFS that would be useful both to researchers and to CFS/ME correct diagnosis. In order to be diagnosed with CFS/ME, the patient must essentially satisfy the following two criteria:

1. Having had severe fatigue of six months or longer duration, with a clinical diagnosis excluding other health disorders that could have caused such fatigue.

2. Concurrently have four or more of the following symptoms: substantial impairment in short-term memory or concentration; sore throat; painful or sensitive lymph nodes in neck and armpits; inexplicable muscle pain; multi- joint pain without redness or swelling; headaches which differ from the ones suffered before, with a different pattern or severity; lack of refreshing sleep; fatigue that lasts more than 24 hours after physical effort.

Symptoms must have persisted or recurred during six or more consecutive months and must not have predated the fatigue.

Chronic Fatigue Syndrome (CFS/ME) is classified by the WHO with code G93.3 into the chapter of Central Nerve System Disorders.


Other many symptoms, whose frequency varies depending on the patient, may appear alongside with the eight principal symptoms that define CFS/ME: abdominal pain, intolerance to alcohol, bloating, chest pain, chronic cough, diarrhea, dizziness, dry eyes and dry mouth, earache, arrhythmia, jaw pain, morning stiffness, nausea, night sweats, psychological problems (depression, irritability, anxiety disorders, panic attacks, etc.), shortness of breath, skin sensitivity, tingling sensation, weight loss, etc.



· Diagnosis of CFS/ME is essentially based on the patient's clinics.

· People with CFS/ME symptoms must be carefully evaluated by a specialist doctor in order to establish a differential diagnosis with respect to other pathologies whose symptoms are similar, such as mononucleosis, Lyme illness, hormone disorders, diabetes, multiple sclerosis, various types of cancer, severe depression and bipolar disorder.

· Recent research indicates that less than 20% of the patients with CFS/ME have been diagnosed.



Due to its unknown aetiology, CFS/ME still has no cure and therefore its treatment is focused on improving the symptomatology. A unique treatment does not exist and it should be personalized. In the majority of cases a combination of several therapeutic measures is recommended.

In order to improve the patients' quality of life, some changes in the life style are recommended; for instance, preventing excessive efforts, reducing stress, performing mild stretching exercises and some changes with respect to the diet in combination with certain nutritional supplies. Effective communication between doctor and patient is a good starting point from which to develop a programme adapted to the patient's needs and that can provide him or her with the maximum perception of improvement.

Specific physical therapies, adapted to every patient, can be part of the treatment for CFS/ME. Mild exercise, avoiding excessive efforts, is recommended, preferably under the supervision of an expert on this pathology.

A delay on the diagnosis and treatment has been associated to a worse prognosis of the illness. For example, recent research on this aspect proves that people suffering from CFS/ME for two or less years have better perspectives. It is unknown whether this fact is due to a premature diagnosis; however, the more time goes by between early symptoms and diagnosis, the worst the progress of the disorder.



CFS/ME affects each person in a different way and its course cannot be foreseen, alternating remission and crisis or outbreak periods. While there are cases in which the disorder becomes totally disabling, forcing the patients to live secluded in their homes, in other cases it may evolve favourably and patients can even perform some activities or carry out with a job although they still suffer from some symptoms.

Data on recovery from CFS/ME are not clear. Improvement percentages vary between an 8% and a 63% in studies published in 2005, with an average of 40% of patients who improve in a major o minor degree. In any case, a full recovery is very rare with an average of only 5% of cases with total remission.



In spite of an intensive, nearly 20-year search, the cause of CFS/ME remains unknown. Diverse infectious agents, chemical agents, psychological causes, etc. have been considered and the search continues.

Much of the ongoing research has focused on the roles the immune, endocrine and nervous systems may play in CFS/ME. More recently, interactions among these factors are under evaluation.

Genetic and environmental factors can also play an important role in the appearance and/or development of the condition, although more evidence is needed.

CFS/ME is not caused by depression although both disorders usually coexist (like in other chronic illnesses, depression can appear as a reaction to the suffering and the disabling process lived by the patient).



In 2007, the CFS Name Change Advisory Committee suggested that the name 'chronic fatigue syndrome' became 'chronic fatigue syndrome - myalgic encephalomyelitis (CFS/ME), since such denomination reflects the disorder more clearly avoiding any trivialization suggested by its original name. The term used in Canada to refer to chronic fatigue syndrome is ME/CFS (myalgic encephalomyelitis / chronic fatigue syndrome) while in the United Kingdom is ME (myalgic encephalomyelitis).

Source: Centers for Disease Control and Prevention (CDC). EEUU (2020)


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