ME/CFS (Myalgic Encephalomyelitis / Chronic Fatigue Syndrome)
A long-term condition of profound, post-exertional fatigue not relieved by rest.
Overview
ME/CFS is a complex multi-system condition. The cardinal feature is post-exertional malaise — a delayed worsening after even modest activity. Severity ranges from mild (working with adjustments) to very severe (bed-bound, tube-fed).
Symptoms
- • Disabling fatigue lasting ≥3 months
- • Post-exertional malaise (delayed crash after activity)
- • Unrefreshing sleep
- • Cognitive dysfunction ('brain fog')
- • Orthostatic intolerance, light/sound sensitivity, pain
Risk factors
- • Female sex (2–3× higher)
- • Recent viral illness
- • Family history
Causes
- • Often post-infectious (EBV, COVID-19, enteroviruses)
- • Likely immune, autonomic and metabolic dysregulation
- • Genetic susceptibility under investigation
🚨 Red flags — seek urgent care
- • New neurological signs, weight loss, night sweats — investigate alternatives
- • Suicidal ideation in severe disease
- • Rapid deterioration after exertion ('crash')
When to seek care
- • Persistent fatigue >6 weeks with post-exertional malaise
- • Functional decline
- • Severe symptoms requiring home support
Diagnosis
- • Clinical diagnosis using NICE 2021 / IOM criteria — no confirmatory test
- • Rule out anaemia, hypothyroidism, coeliac, sleep apnoea, depression, autoimmune disease
- • Bloods: FBC, U&E, LFT, TFT, ferritin, CRP, coeliac screen, vitamin D, B12, glucose, creatine kinase
Treatment
- • Pacing and energy-envelope management — NEVER graded exercise therapy (NICE 2021)
- • Symptom-targeted care: orthostatic intolerance, pain, sleep
- • Multidisciplinary support (occupational therapy, dietetics, mental-health support for impact)
- • Specialist ME/CFS service referral where available
Prevention
- • Early rest after viral illness may reduce risk
- • Avoid 'push-crash' cycles during recovery
Complications
- • Severe deconditioning and disability
- • Loss of employment and education
- • Co-existing depression and anxiety
Prognosis
Variable — some recover partially over years, others remain severely affected. Pacing and avoiding overexertion are the strongest predictors of stability.
Education & self-care
ME/CFS is a real, biological illness. Pacing, validation and symptom-targeted care help most people stabilise and gradually improve function.
Frequently asked questions
Is exercise the cure?
No. Graded exercise therapy is no longer recommended — it can cause lasting harm. Pacing within your energy envelope is the cornerstone.
Is ME/CFS the same as long COVID?
There is significant overlap; many long-COVID patients meet ME/CFS criteria.
Is there a blood test for ME/CFS?
No single diagnostic test exists. Diagnosis is clinical and based on persistent fatigue plus post-exertional malaise lasting over 3 months, after excluding other causes such as anaemia, thyroid disease and sleep disorders.
Will graded exercise help or harm?
Recent NICE guidance no longer recommends graded exercise therapy. Activity should be paced within the patient's energy envelope, with rest planned before symptoms worsen.
What helps most day-to-day?
Pacing, sleep hygiene, treating any orthostatic intolerance, and addressing co-existing depression or anxiety. Realistic activity planning prevents the boom-bust pattern that worsens symptoms.