Chronic Fatigue Syndrome

What is chronic fatigue syndrome?

Myalgic encephalomyelitis, also called chronic fatigue syndrome, is a long term condition whose central feature is post exertional malaise, a disproportionate worsening of symptoms after physical or mental effort that can be delayed by hours or days. It is a recognised physical illness, not deconditioning or a psychological disorder, and graded exercise that pushes through symptoms can cause harm.

Causes

• Frequently follows a viral or other infection
• Immune system dysregulation
• Autonomic nervous system dysfunction
• Impaired cellular energy metabolism
• Genetic predisposition
• No single cause identified to date

Symptoms

• Profound fatigue not relieved by rest
• Post exertional malaise after minimal activity
• Unrefreshing sleep
• Cognitive difficulty with memory and concentration
• Orthostatic intolerance with symptoms on standing
• Muscle and joint pain
• Headaches and sore throat
• Sensitivity to light, sound and temperature

Risk factors

• Preceding infection such as Epstein Barr virus or COVID-19
• Female sex
• Age between 20 and 45 at onset
• Family history
• Significant physical or emotional stress before onset

Diagnosis

• Clinical criteria requiring post exertional malaise
• Symptoms persisting more than three months with substantial functional reduction
• Blood tests to exclude anaemia, thyroid, coeliac and inflammatory disease
• Assessment for sleep disorders and depression
• Orthostatic testing where indicated
• Diagnosis of exclusion combined with positive symptom criteria

Treatment

• Activity pacing to stay within the individual energy envelope
• Avoiding graded exercise programmes that provoke post exertional malaise
• Sleep management strategies
• Symptomatic treatment of pain and orthostatic symptoms
• Managing coexisting conditions
• Practical support with work, education and daily living
• Psychological support for adjustment, not as a cure

Self care

• Pace activity and stay within your energy envelope
• Plan rest before, not after, demanding activity
• Break tasks into short blocks with genuine rest between
• Keep an activity and symptom diary to find your baseline
• Do not push through post exertional malaise
• Manage orthostatic symptoms with fluids, salt if advised and compression
• Accept practical help and adapt the home to reduce effort

When to see a doctor

Book an appointment if:

• New or changing symptoms that could indicate another condition
• Worsening function despite careful pacing
• Symptoms on standing that are limiting
• Low mood or difficulty coping
• To discuss workplace or education adjustments
• For a formal diagnosis, since it opens access to support

Some symptoms need emergency care rather than an appointment. See the warning signs listed above.

Prevention

• No proven way to prevent it currently
• Rest properly during and after significant infections rather than rushing back
• Avoid pushing through early post viral fatigue
• Seek assessment early if fatigue persists beyond a few months

Outlook

Course varies considerably. Some people improve substantially over months to years, others stabilise at a reduced level, and a minority remain severely affected. Careful pacing and avoiding repeated post exertional crashes are associated with better outcomes. Children and adolescents generally have a better recovery rate than adults.

Related conditions

Common questions