Background
ME/CFS
PEM
Assessment
NAM Quick Reference Diagnostic Algorithm
Management
Referral
About myalgic encephalomyelitis/chronic fatigue syndrome
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is a chronic multi-system disease of variable and fluctuating severity and of uncertain aetiology. There is ample evidence of pathophysiological changes causing immunological, metabolic, neurologic, and autonomic dysfunction. There is no evidence the disorder is psychological, functional, or due to somatisation.
The cause of ME/CFS is not known. Recognised aetiological factors or triggers include:
- infection with viruses, bacteria, or protozoa (e.g., Epstein-Barr virus (EBV), influenza, COVID‑19, Giardia)
- immunisation
- physical trauma (e.g., surgery, motor vehicle accident)
- general anaesthesia
- genetic susceptibility
- major life stressors
- environmental toxin exposure.
The estimated prevalence of ME/CFS is 0.2 to 1% in Australia. It affects people of all ages. Peak incidence occurs in ages 11 to 19 years and 30 to 39 years. It is 3 times more common in girls or women.
ME/CFS is a lifelong illness for the majority of patients, with no cure or specific treatment. Young people with ME/CFS have a more favourable prognosis than adults.
Symptom severity can vary and fluctuate, and ranges from mild (50% reduction in premorbid functioning) to very severe (totally bed‑bound).
Patients often experience delayed or incorrect diagnosis for several years. Up to 90% of patients with symptoms meeting the diagnostic criteria remain undiagnosed.
The prevalence of anxiety and depression in ME/CFS is similar to that seen in any chronic illness.
ME/CFS is diagnosed based on clinical assessment criteria.
Common features are post-exertional malaise (PEM), fatigue, sleep disturbances, cognitive difficulties, and orthostatic intolerance symptoms.
About post-exertional malaise (PEM)
Significant worsening of fatigue and other symptoms after even minor physical, mental, or emotional exertion that is disproportionate to the activity, and would not have caused a problem before the illness.
PEM onset can be immediate or delayed by hours or days following overexertion.
PEM symptoms may last days or weeks after the activity, or sometimes even longer.
PEM is not substantially relieved by normal amounts of rest.
Sensory overload (light, sound, or touch), and orthostatic stress can induce PEM in some patients.
Other features can include muscle weakness, flu-like symptoms, temperature intolerance, pain, sensory sensitivities, neuroendocrine disturbances, immune system abnormalities, and cellular metabolism abnormalities.
Routine physical examination and investigations are frequently normal or non-specifically mildly abnormal (e.g., red throat, swollen lymph nodes), except for signs of orthostatic intolerance.
Cognitive behaviour therapy (CBT) and graded exercise therapy (GET) are not recommended treatments to treat the underlying ME/CFS but may be considered as adjunct therapies with caution, to address secondary sequelae of the condition.
