Chronic fatigue syndrome

The cause of chronic fatigue syndrome is not yet fully understood, and its pathophysiology remains the subject of ongoing research. Possible mechanisms and predisposing factors are being investigated, including neurological, metabolic and immune system abnormalities, as well as a possible genetic contribution. Available genetic studies have produced preliminary findings and do not yet allow a definitive genetic basis for the condition to be established. Infections have also been linked to the onset of some cases, although the mechanisms involved are not yet fully understood.

Clinical assessment should take into account the full range of symptoms and how they develop over time, including post-exertional malaise, sleep disturbances, cognitive difficulties, pain and possible autonomic and immune system manifestations. Management aims to provide individualised care, control symptoms and improve quality of life, taking into account each person's needs and abilities.

Symptoms

Chronic fatigue syndrome is characterised by a range of symptoms that can vary in intensity and frequency between affected individuals and over time. The main symptoms include debilitating fatigue that does not improve substantially with rest and significantly reduces the ability to carry out everyday activities, post-exertional malaise, unrefreshing sleep and cognitive difficulties.

Post-exertional malaise is the worsening of symptoms following physical, cognitive, emotional or social activities that were previously better tolerated. This worsening may be disproportionate to the activity undertaken, may be delayed (occurring hours or even days afterwards) and may last for days or longer.

Other symptoms may include:

• Muscle and joint pain
• Headaches
• Difficulties with concentration, attention and memory
• Unrefreshing sleep and other sleep disturbances
• Dizziness, palpitations or worsening of symptoms when standing, which may be associated with orthostatic intolerance
• Digestive symptoms
• Sore throat or tender lymph nodes, in some people

Who does the condition affect?

The condition can affect people of any age, including children, adolescents and adults. In adults, it is diagnosed more frequently in women than in men, although it can affect people of any sex.

The prevalence of the condition varies depending on the diagnostic criteria used and the methodology of epidemiological studies. It is also thought to be significantly underdiagnosed, meaning that prevalence estimates may not reflect the actual number of people affected. When interpreting these figures, it is important to take into account the population studied and the criteria used in each study.

Diagnosis

Diagnosis is clinical and is based on an assessment of the symptoms, how they develop over time and their impact on functional capacity. There is currently no laboratory or imaging test that can, on its own, confirm the condition.

Further investigations are selected on an individual basis according to each person's clinical presentation. Their purpose is to support the diagnostic assessment, investigate other conditions that may explain the symptoms and identify any coexisting conditions.

Myalgic encephalomyelitis should be suspected in people who experience debilitating fatigue that does not improve substantially with rest, a significant reduction in their ability to carry out everyday activities, post-exertional malaise, unrefreshing sleep or other sleep disturbances, and cognitive difficulties. The diagnosis can be confirmed when symptoms have persisted for three months, established diagnostic criteria are met and no other clinical explanation for the symptoms is identified.

The assessment should include a detailed medical history, a physical examination and an assessment of mental state when clinically indicated. It is important to establish when the symptoms began and how they have developed, their impact on everyday life, whether post-exertional malaise is present and whether there are other associated symptoms, as well as to identify any possible coexisting conditions.

Treatment

There is currently no curative treatment for this condition. Management should be individualised and, where possible, interdisciplinary. It should focus on controlling the main symptoms, preventing them from worsening and improving quality of life, taking into account the severity of the condition and each person's needs.

The main care measures include:

• Information and education about the condition: understanding the symptoms, how they develop and post-exertional malaise can help people make informed decisions about their everyday activities.
• Energy management and activity adjustment: adapting physical, cognitive, emotional and social activities to individual capacity, taking into account fluctuations in symptoms and the need for rest. Increasing activity through fixed, predetermined increments is not recommended.
• Attention to sleep and nutrition: identifying and addressing sleep disturbances and possible nutritional difficulties according to individual needs.
• Treatment of symptoms and coexisting conditions: selecting pharmacological and non-pharmacological interventions according to each person's clinical situation and needs.
• Psychological support: cognitive behavioural therapy may be offered, if the person wishes, to help manage symptoms and improve quality of life. It is not a curative treatment and should not be based on the assumption that beliefs or behaviours considered abnormal are the underlying cause of chronic fatigue syndrome.

Clinical follow-up should be adapted to the severity and progression of the condition, with decisions made jointly by the person and their healthcare professionals.

Graded exercise therapy based on fixed, predetermined increases in physical activity is not recommended.

Prevention

No effective measures have currently been shown to prevent the onset of the condition. However, it is important to recognise its symptoms, ensure appropriate clinical assessment and establish an early diagnosis. Once the condition has been diagnosed, individualised follow-up and adapting activities to each person's capacity may help manage symptoms and reduce the risk of post-exertional malaise.

General recommendations 

• Look for reliable sources of information. Having access to reliable information about chronic fatigue syndrome, its symptoms and how it develops can help people understand their individual needs and take part in decisions about their healthcare.
• Adapt activities to individual capacity. It is important to take into account physical and cognitive limitations, fluctuations in symptoms and the need for rest. Post-exertional malaise may occur after physical, cognitive, emotional or social activity, sometimes with a delay, and may last for days.
• Respect individual limits. Increasing activity through fixed, predetermined increments is not recommended. Activities should be adjusted to each person's circumstances and how their symptoms respond.
• Pay attention to sleep disturbances. If sleep problems occur, it is advisable to discuss them with healthcare professionals so that possible causes and treatment options can be assessed.
• Maintain a balanced diet. Nutritional recommendations should be tailored to individual needs. Supplements or restrictive diets are not recommended unless clinically indicated.
• Seek medical advice if your clinical condition changes. The onset of new symptoms or a significant worsening of existing symptoms requires medical assessment; these changes should not automatically be attributed to chronic fatigue syndrome.

Follow-up should be adapted to the severity and progression of the condition. Decisions about care and treatment should be made jointly by the person and their healthcare professionals, taking into account their needs, preferences and priorities.