2nd February 2024

Chronic Fatigue Syndrome/Myalgia Encephalomyelitis

What is it?

Also known as Myalgia Encephalomyelitis, it is a complex disorder with chronic fatigue and multiple other somatic symptoms. It is accompanied by cognitive dysfunction and an inability to carry on with day-to-day activities. For a diagnosis to be reached, symptoms should last for 6 months. It is included in the ICD 11 under the section on Neurological problems. It is not a psychological illness. 

Epidemiology

It can affect both sexes but is 2-4 times more common in females.

Pathophysiology

The pathophysiology has not been established yet, but it is postulated that it could be neuro-immuno-endocrine related. 

NICE guidelines recommend a diagnosis if there is persistent fatigue for at least 6 weeks or longer and debilitating an individual’s functioning, which cannot be explained by another illness and also has all of the following:

• Debilitating fatigue, which is worsened by activity. It is not caused by excessive cognitive, physical, emotional or social exertion and is not relieved by rest.
• Post-exertional malaise in which worsening of symptoms is often delayed in onset by hours to days and, is disproportionate to the activity, and has a prolonged recovery time.
• Unrefreshing sleep, disturbed sleep, or both.
• Cognitive difficulties, including word-finding difficulties, slowed responsiveness, poor concentration and memory problems.

Risk factors

• Female sex
• Lower socio-economic status
• Lower physical activity
• Lower educational status
• Poor social adjustment
• Adverse childhood experiences
• Poor sleep and nutrition
• Genetics

Differential diagnosis

• Endocrinological causes- Diabetes, Cushing’s syndrome, Thyroid problems
• Haematological causes- Anaemia
• Malignancy
• Infections- HIV, Hepatitis, Tuberculosis
• Neurological- Parkinson’s, Dementia
• Mental illness
• Autoimmune conditions

Reference

• Afari, N. and Buchwald, D. (2003). Chronic Fatigue Syndrome: A Review. American Journal of Psychiatry, [online] 160(2), pp.221–236. doi:10.1176/appi.ajp.160.2.221.
• Sharpe, M. and Wessely, S. (2012). Chronic fatigue syndrome. New Oxford Textbook of Psychiatry, pp.1036–1043. doi:10.1093/med/9780199696758.003.0133.