The basics - Chronic fatigue syndrome

Chronic fatigue syndrome has many symptoms and can be hard to diagnose, says Dr Laurence Knott.

Chronic fatigue syndrome (CFS) is also known as myalgic encephalopathy (ME) and the two terms are used interchangeably. The causes of the condition are not known, although factors including infection, endocrine, metabolic and psychogenic factors have been implicated.

Based on population statistics from other countries, the NICE review in August 2007 concluded that the likely UK incidence of CFS was 0.2-0.4 per cent. This means that an average practice of 10,000 patients will have up to 40 people with CFS on their list.

The average age of presentation is 30 years, and it affects twice as many women as men.

Diagnosis
The condition should be considered in any patient who presents with fatigue that is new or that had a specific onset, that is persistent or recurrent, unexplained by other conditions, that has resulted in a substantial reduction in activity level and is characterised by post-exertional malaise or fatigue. This is typically delayed by at least 24 hours, with slow recovery over several days.

NICE recommends that the diagnosis should be considered once fatigue has persisted for four months in adults and three months in children.

CFS is an unusual diagnosis to make in children, and should usually be done in liaison with a paediatrician.

In order to fulfil the NICE criteria, at least one of the following features should also be present:

  • Sleep disturbance.
  • Muscle and/or joint pain that is multi-site with no evidence of inflammation.
  • Headaches.
  • Painful lymph nodes without pathological enlargement.
  • Sore throat.
  • Cognitive dysfunction (for example, an inability to concentrate or impaired short-term memory).
  • Symptoms that become worse after physical or mental exertion.
  • General malaise or flu-like symptoms.
  • Dizziness or nausea.
  • Palpitations in the absence of identified cardiac pathology.

A number of other possible CFS symptoms have been described. These include general symptoms such as night sweats, weight loss and alcohol intolerance, GI symptoms such as abdominal pain, diarrhoea and respiratory/cardiovascular symptoms such as chronic cough, neurally mediated hypotension on tilting and shortness of breath.

Psychological symptoms such as anxiety, panic attacks, depression and irritability may also present in patients with CFS.

The differential diagnosis depends on the clinical presentation, but should include neoplasia, thyroid disease, autoimmune conditions, psychogenic disorders, diabetes, anaemia, inflammatory bowel disease, and myopathies. If chest pain or dyspnoea are features, cardiological and respiratory causes will also need to be ruled out.

Investigations
NICE recommends that patients with red flag features should be thoroughly investigated before they are diagnosed with CFS.

The minimum set of investigations recommended by NICE includes FBC, U&E, liver and thyroid function and ESR or plasma viscosity testing. CRP, random blood glucose, serum creatinine, serum calcium and creatine kinase should be measured.

Blood tests for gluten sensitivity should be carried out, and serum ferritin levels should be assessed in children.

Symptom management
Patients and their carers should be involved in decisions about care. Early symptomatic treatment is recommended, even before diagnosis is confirmed.

Advice should be given about sleep patterns. Daytime napping is not recommended, but rest periods are an essential component of CFS management.

These should be limited to 30 minutes and interspersed with low-level physical or cognitive exercises. Relaxation therapy may be helpful.

Diet should be well balanced and include slow-release starch foods. Dry starchy foods and sipping fluids can be recommended for patients with nausea.

Supplements are unlikely to be helpful unless the patient is on a very restrictive diet.

Mobility support such as wheelchairs, blue badges and stair-lifts may be needed.

Occupational and educational needs should be considered, and liaison with employers, occupational health services, and social and education services is important.

Referral
NICE recommends offering all patients with a presumptive diagnosis of CFS referral to a specialist within six months if their symptoms are mild, within three to four months if they are moderate, and immediately if they are severe.

Specialist management includes cognitive behaviour therapy (CBT), graded exercise therapy and activity management. Pain control may need the intervention of a pain management specialist.

NICE recommends the use of a low dosage tricyclic antidepressant such as amitriptyline for patients suffering from pain or sleep disturbance, providing they are not already taking an SSRI.

Melatonin may be helpful in children with sleep disorder.

SSRIs to boost energy levels and NSAIDs for relief of pain can been helpful in some patients. However, they are not mentioned in the NICE guidelines, and there are no systematic reviews to support the use of either.

There is no evidence to support the use of complimentary therapies, but accepting that some patients find them helpful for symptom control is consistent with involving patients in their own care.

Prognosis
No large studies on CFS have been carried out, but those that have been done suggest that 50 per cent of patients will improve over time.

Unsurprisingly, lower recovery rates and higher relapse rates are associated with patients who have had their symptoms for many years.

Dr Laurence Knott is a GP in Enfield.

Key points
  • In an average practice of 10,000, there will be around 40 patients with CFS.
  • Diagnosis is made on the basis of symptoms, and exclusion of other conditions by physical examination and investigation.
  • Early symptomatic treatment is recommended, even before diagnosis is confirmed.
  • Management includes advice on sleep hygiene, rest periods, relaxation techniques, activity management, occupational and educational issues, dietary advice and mobility support.
  • Specialist treatment includes CBT, graded exercise therapy and pharmacological interventions.

Red flags
CFS symptoms that should be thoroughly investigated:

  • Localising/focal neurological signs.
  • Signs of inflammatory arthritis or connective tissue disease.
  • Signs of cardiorespiratory disease.
  • Significant weight loss.
  • Sleep apnoea.
  • Significant lymphadenopathy.

References

  • NICE. Clinical Guideline CG53 (2007) Chronic fatigue syndrome/myalgic encephalomyelitis (or encephalopathy); diagnosis and management.
  • Carruthers B, Jain A, De Meirleir K et al. Myalgic encephalomyelitis/chronic fatigue syndrome: clinical working case definition, diagnostic and treatment protocols. J Chronic Fatigue Syndrome 2003; 11: 7-115.

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