Health Centres - Chronic fatigue syndrome (Myalgic encephalomyelitis)
The problem of 'fatigue'
Fatigue is a very common feeling that occurs in a host of circumstances, sometimes as a symptom of illness, at other times as an emotion or as a reaction to life events.
Much confusion surrounds the medical use of the term 'fatigue'. Here we use the term 'CFS/ME' to refer to a profoundly disabling condition in which there is marked difficulty in carrying out effort-related tasks.
Its full title is 'chronic fatigue syndrome/myalgic encephalomyelitis'.
What is fatigue?
In normal circumstances the feeling of physical tiredness is related to a cause such as excess effort. It may be enough to force us to rest but it then improves in a short time.
Repeated physical effort tends to improve our fitness and ability to carry out heavy or sustained work. The severity and impact of the symptoms experienced by the majority of people with CFS/ME is vastly greater than the symptoms of what one might call 'ordinary' fatigue.
There is usually a delay of anything from hours to days between the effort and the exhaustion in CFS/ME and repeated activity does not lead to adaptation and improvement in strength or stamina – usually the reverse occurs.
The size of the problem
CFS/ME is a major world-wide public health problem. There are considerable difficulties in establishing good figures for the number of people affected, but accepting that the figures are approximate, the following generalisations can be made regarding the UK:
- CFS/ME affects between 2 and 4 people per 1000 of the population
- it affects people of all ages, including children as young as five years old
- the commonest age of onset is between the early twenties to mid-forties
- CFS/ME is diagnosed about twice as often in women compared to men
- it affects all social classes.
There are therefore as many as 200,000 people with CFS/ME in the UK alone – a staggering number for a condition that has attracted so little serious enquiry until recently.
Definitions
From the point of view of conducting research on a condition, it is essential that agreement exists on what it is that is being studied, or conclusions made in one centre will have no relevance to anywhere else.
Several groups around the world have therefore worked to produce definitions of CFS/ME that attempt to encapsulate the necessary features of the condition. The most widely used are those of the Centre for Disease Control (1994) in the USA, which are:
- Fatigue of definite or new onset that is not the result of exertion, is not significantly improved by sleep or rest and which results in substantial reduction in overall performance for a consecutive period of six months or longer.
- self-reported significant impairment of short term memory or concentration.
- sore throat.
- tender lymph glands (small swellings under the skin which are part of the immune system) in the neck region or under the armpits.
- muscle pain.
- headaches of a new type, pattern or severity.
- unrefreshing sleep.
- malaise following effort that lasts more than 24 hours
- pains in several joints occurring without joint swelling or redness.
There are several problems using such a system as this. For a start the requirement for the fatigue to be present for six months takes no account of the fact that the disability from CFS/ME starts on day one of the illness, which is often abrupt.
In practice no caring doctor would wave a patient out of the consulting room and ask them to make an appointment once the six months were up so that he could then start discussing the symptoms for real.
In the early weeks of CFS/ME it can be difficult or impossible to distinguish it from other conditions that can cause similar symptoms but which have a different outcome, and it is necessary to search for these. The purpose of these diagnostic criteria therefore should be seen as mainly an aid to research. People who fulfil them are therefore similar at least to a certain extent, so it becomes possible to compare how they fare with different types of treatment.
It is quite possible to have CFS/ME and not have all of these symptoms – an individual's experience of CFS/ME is essentially unique.
International criteria
The 'Oxford Criteria' (1990) therefore defined CFS/ME as a syndrome in which:
- there is a definite onset (ie it is not lifelong)
- fatigue is the main symptom
- the fatigue is severe, disabling and affects both physical and mental functioning
- the fatigue has been present for at least six months, during which time it has been present more than 50 per cent of the time
- other symptoms may be present, particularly myalgia, mood and sleep disturbance.
Tests
In making a diagnosis of CFS/ME it is important to exclude other conditions that can cause some or all of the symptoms although there are really no other conditions that look exactly like it in all its aspects.
Fatigue, of a generally smaller degree is however a common accompaniment of anaemia (lack of blood), underactivity of the thyroid gland, diabetes, disturbance of kidney or liver function and persistent infection, especially with some viruses and more unusual bacterial infections.
Rarer causes include immune system diseases such as lymphoma, 'auto-immune' diseases such as SLE (systemic lupus erythematosus) in which many organs become inflamed, or underproduction of hormones from the pituitary gland of the brain.
Simple blood and urine tests can screen for the majority of these conditions and are well within the scope of the GP to arrange.
The diagnostic approach
In the majority of people who have CFS/ME it is possible to make a positive diagnosis of the condition based on its own features, in which case extra tests help to confirm that nothing else has been missed.
An unhelpful line of thinking among 'dinosaur doctors' is to say to a fatigued patient, on receipt of a normal set of blood reports, that there is 'nothing wrong'.
To the patient sitting in the chair and feeling completely whacked by the effort of getting to the surgery nothing could be more obviously wrong with such a view.
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