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Chronic Pain Syndrome (Myalgic Encephalomyelitis)

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Overview

Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME) is a complex chronic medical condition of unknown aetiology affecting multiple body systems. It presents with severely debilitating physical and mental fatigue.

Around 50-80% of patients with CFS/ME start suddenly with a flu-like illness

Epidemiology

  • More common in women

Risk Factors & Associations

  • Female sex
  • EBV infection
  • COVID-19
  • Life stressors

Presentation

  • Flu-like symptoms (malaise, myalgia
  • Persistent disabling fatigue
    • This is not relieved by sleep, rest, or reduced activity
    • This is usually over 3 months
    • Fatigue may show remissions
    • Fatigue must be moderate-severe and persistent >50% of the time
  • Post-exertional malaise or fatigue
  • Short-term memory impairment
  • Concentration impairment
  • Sore throat
  • Generalised arthralgia without inflammation
  • Headache or migraine onset after fatigue
  • Sleep problems
    • Unrefreshing sleep
    • Insomnia/hypersomnia
    • Disturbed sleep-wake cycle
  • Dizziness/light-headedness/malaise after standing up from sitting
  • Diffuse muscular pain
  • Tender but non-enlarged lymph nodes may be felt, but this is uncommon

Differential Diagnoses

Major depressive disorder

  • Features of depression present
  • Low mood
  • Anhedonia
  • Hopelessness
  • Suicidal ideation

Sleep apnoea

  • Excess sleepiness is present
  • Morning headaches
  • The patient may snore at night

Fibromyalgia

  • Widespread pain which has localised tenderness at specific anatomical points
  • There is considerable overlap between fibromyalgia and CFS

Dehydration

Infectious mononucleosis

  • Spleno- and/or hepatomegaly
  • More likely in adolescents
  • Positive serology for EBV

Hypothyroidism

  • Cold sensitivity
  • Brittle nails/hair

Anaemia

Diabetes

  • Polyuria present
  • Polydipsia present

Underlying neoplasia for lymphadenopathy

Multiple sclerosis (MS)

  • Fatigue is a cardinal symptom of MS
  • Optic neuritis may be present
  • Neurological signs may be present

Investigations

NICE recommend carrying out a large panel of blood tests to exclude other pathologies. These involve FBC, ESR, CRP, glucose, TFTs, ANA, RF, HIV, U&Es, calcium, CK, coeliac screening, ferritin etc.

Diagnosis

Suspect diagnosis if the patient has all four of the following features for a minimum of 6 weeks in adults and 4 weeks in children and young people:

  • Post-exertional malaise
  • Debilitating fatigue
  • Cognitive difficulties
  • Unrefreshing sleep/sleep disturbance

Management

  • Cognitive behavioural therapy
  • Management of symptoms:
    • SSRIs for depression
    • Low-dose tricyclic antidepressants/trazodone for sleep problems 

Monitoring

  • Patients should be periodically assessed for depression as untreated and more severe depression may worsen symptoms

Patient Advice

  • Patients should try exercise therapy to help improve stamina and rebuild self-confidence but must be balanced with being able to carry out activities of daily living and not inducing exertional malaise.

Complications

  • Major depressive disorder

Prognosis

  • Prognosis varies significantly
  • Children can be severely affected, but the outlook is generally better in children and young people than in adults

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