If you ask most people what causes chronic fatigue syndrome (CFS), they will either tell you that some doctors consider it to be physical and that others regard it as psychological. However, what they probably won't know is that those doctors aren't talking about the same illness. The problem is that the name CFS is no longer used to describe one disorder (myalgic encephalopathy or ME), but several.

Over the past ten years, it has become an umbrella term for a variety of different conditions, all of which feature persistent, unexplained fatigue. Unexplained in this context means that the symptoms can not be attributed to a generally recognised medical disease like anaemia, rheumatoid arthritis or multiple sclerosis. Using the same name for different conditions has caused a lot of confusion and misunderstanding, so it has been decided to change the name. The final decision is expected at the end of 2001 and will probably be announced by the American minister for Health. In the meantime, it may be useful to know the type of conditions which currently come under the heading of CFS.

For those of you who are wondering why other specialists haven't discussed subgroups, let me explain that many doctors in Britain, particularly psychiatrists, do not regard the differences between them to be of clinical significance. In their opinion, the conditions overlap to such a degree that one can give general advice about treatment which will suit everyone. However, specialists like myself aren't so sure.

We tend to approach unexplained fatigue in the same way as headaches. We know there are different types, such as tension headaches, cluster headaches and migraines. They all have features in common, not least pain, but we have learnt that the treatment which works for one is not necessarily effective for the others. Moreover, we don't refer to 'acute headache syndrome' and limit our advice to taking paracetamol and recommending more relaxation. Admittedly, that will help the majority of sufferers, but it ignores a sizeable minority. To cut a long story short, we want to treat fatigue syndromes in a similar way. Unlike some of my colleagues, I cannot recommend gradually increasing activity for everyone with CFS because I regard it rather like paracetamol. It helps a large number of patients, but that is not a good enough reason not to mention the alternatives. My approach may not be better –only time and research will tell – but Netdoctor-co-uk felt that unless you hear both sides of the story, you cannot make a truly informed decision. So compare and contrast. This is a complex subject, so if you don't understand something, leave it for a while and come back to it later.

The information below comes from papers dating back to 1938, as well as my own research and the clinical experiences of a wide range of experts.

Myalgic encephalopathy or myalgic encephalomyelitis?

Myalgic encephalopathy (ME) is a neurological disease triggered by an infection. The illness used to be called myalgic encephalomyelitis but that is no longer considered to be accurate. It's not that the name was wrong when it was introduced (1956), but that the condition has changed since then. Prior to 1960, patients with ME sometimes developed paralysis and other symptoms which suggested an inflammation of the central nervous system and spinal cord. Hence the term encephalomyelitis. However, following the introduction of the polio vaccine, those symptoms became much less common and although there is still evidence of a disease in the brain, i.e. encephalopathy, very few patients today show signs of an inflammatory process in the spinal cord. That why we amended the name.

The link with polio may not be coincidental. Several of the early epidemics of ME occurred just prior to, during, or after an outbreak of polio. Indeed, it was sometimes referred to as 'atypical polio' and it has several features in common with post-polio syndrome. There are also other similarities but at the moment, we know too little about ME to do anything more than speculate. Whatever the cause, the majority of cases start between May and November. And although almost anyone can get it, it is more common amongst older individuals, either in their late thirties or forties.

How can doctors tell the difference between ME and CFS?

CFS is defined according to two sets of criteria. The British definition devised by Dr. Michael Sharpe and his colleagues (1991), requires the presence of unexplained physical and mental fatigue for a minimum of six months. About 1 or 2 per 100 people meet these criteria.

The American definition formulated for the Centers for Disease Control and Prevention (1994) also requires the presence of fatigue for six months, but in addition, patients must have four other symptoms from a list of eight. They are:

1. impaired memory or concentration

2. sore throat

3. tender cervical or axillary lymph nodes

4. muscle pain

5. multi-joint pain

6. new headaches

7. unrefreshing sleep

8. post-exertional malaise.

Patients also have to undergo a thorough medical examination before a diagnosis can be made. According to the estimates, between .4 and 1% of the population meet these criteria.

ME is different. The main problem in ME is not normal fatigue but a reduction in muscle strength after minimal exertion AND a delay in the return of normal muscle power after exertion ends. As far as I know, the latter is peculiar to ME.

The delay in recovery from exercise can last anything from 24 hours to five days. That's why we believe that the emphasis on the word fatigue when discussing ME is misleading. As one well respected consultant explained in an interview: "it's not really fatigue at all, which is defined as a normal recovery state from exertion, and that is precisely what does not happen in this illness. Anyone who works a 20-hour day will be fatigued but they'll recover from it – it's not the same thing". Others have likened having ME to a battery which runs flat very quickly and which takes longer than normal to recharge. In a nutshell, the essence of ME is not normal tiredness or lethargy.

There are two other characteristics of ME which are worth noting. Firstly, there must be evidence of central nervous system involvement, such as lack of balance, visual disturbances (e.g. blurred vision, sensitivity to light), frequency of micturition (passing urine more often), as well as transient difficulties with memory and concentration and emotional fragility. Secondly, there are often signs of impaired circulation. This might manifest itself as a ghastly pallor just before feeling unwell (ask relatives if they have noticed this), or feeling cold even when it's very warm.

Except during the acute phase or a relapse, all the symptoms of ME tend to worsen following exertion. This means that these patients are not 'tired-all-the-time' but that the severity of their symptoms fluctuates, often from hour to hour as well as from day to day. It's the variability of ME which differentiates it from the fatigue syndrome associated with chronic stress and depression. In both these cases, patients experience far fewer fluctuations during the day and in depression, the symptoms are generally not exacerbated by activity. Indeed, patients usually feel better following exercise.

Another difference between ME and either stress or depression is that the vast majority of ME patients (90% plus) cannot tolerate alcohol. One glass of white wine is usually as much as they can stand. Many also develop problems with normal doses of antibiotics and antidepressants. At this moment, we really don't know why.

Aside from the protracted recovery following exercise and the fluctuations in the severity of the symptoms, ME differs from CFS in other ways. For one thing, ME is far less common (at most, affecting 1 per 1000 of the population). Secondly, patients with ME cannot increase their activity levels every week, even gradually, as they tend to reach a plateau and going above that invariably causes a relapse. Patients who are able to follow this kind of activity programme either have another fatigue syndrome, or are well on the way to recovery. And the cognitive deficits (problems with memory and concentration) are more pronounced than in most cases of CFS*.

ME may not be identical to CFS, but in many respects, it is difficult to distinguish from post-viral (fatigue) syndrome. This is partly because ME is often triggered by an infection but also because many definitions of post-viral syndrome include the presence of fatigue following exertion. At the moment, ME and postviral syndrome are listed together in the World Health Organisation's International Classification of Diseases Volume 10 under 'Diseases of the Nervous System'.

Other fatigue syndromes

Glandular Fever .

[Ed. Note: Glandular Fever is also known as mononucleosis.]  This is an infection caused by the Epstein-Barr virus. It's easily diagnosed using a blood test, and tends to be more common among the young (late teens and early twenties).

The characteristics of glandular fever include fatigue, sore throats, malaise and swollen and tender glands. There may also be a fever during the early days. Recovery is often protracted but most people will recover within a few months.

A small percentage of sufferers may continue to feel unwell for longer and it is not uncommon to suffer a relapse after a period or stress or following another infection. However, not everyone who develops post-viral fatigue after glandular fever will fulfil the criteria for ME. In my experience, many patients feel totally drained and without any energy for a while and this is not related to exertion. (In that sense, it is more like an ongoing flu than ME). This is also one of the viruses which can make people feel terribly depressed. The best advice to avoid post-viral fatigue, is not to treat glandular fever like a cold. Rest in the early stages, try to avoid stress and eat a good diet. Follow the doctor's orders about alcohol, and if you feel depressed, get help (see below). Don't try to work through it and don't underestimate it. This is one of those viruses which should be treated with respect!

Chronic stress

This refers to the exhaustion and other symptoms experienced during or after periods of ongoing distress. Symptoms include profound fatigue, fear, irritability, anger, indigestion, disturbed sleep, sweating, pain in muscle and joints, sensitivities to foods, and poor concentration. Some patients also become more susceptible to colds and flu, or they find them harder to shake off.

People who are suffering from stress tend to feel tired-all-the-time (i.e. they show fewer fluctuations linked to exertion) but most can drink as they used to. (Indeed, some probably drink too much).

A few individuals collapse following a viral infection and therefore attribute their illness to ME. However, when one takes a history, it becomes clear that the infection was merely the last straw after months, and sometimes years of stress, emotional problems, and various stress-related symptoms. It's important to recognise this aspect of the illness, as ongoing stress can undermine the functioning of the adrenal gland and it may help to support adrenal function with supplements or drugs as part of the treatment programme.

Strictly-speaking, this condition should not be diagnosed as CFS (since the history of stress can explain the fatigue), but there are indications, particularly from psychiatric assessments and studies of cortisol levels, that this has happened. Hence its inclusion here.

Do note that having either ME or glandular fever can be so distressing that patients may develop the symptoms of chronic stress as well. That's why I recommend that everyone who finds it hard to cope with their ME or post-viral syndrome should try and find an experienced and qualified counsellor to provide the necessary support. The most effective therapists are those with a special interest in disability in general, and ME in particular (ask your local health authority if they have a community psychologist for disabled people, or contact a local self-help group).

Phobic avoidance

In a small proportion of patients with CFS, there is evidence that ME or a post-viral syndrome has been complicated or exacerbated by unhelpful beliefs both about the illness and its treatment. For example, some individuals may hear or read that complete bed rest is the only way to treat fatigue (which is a myth), or that a restricted diet is essential in order to recover (which is both contentious and potentially dangerous). The problem is that those who follow this advice may become physically unfit or terribly malnourished and this just makes them feel even weaker and sicker.

Another trap which many patients fall into, and not just those with ME, is that of fear. For instance, the fear of getting worse (again) can stop some people from trying something different, so they end up sticking with a strategy which worked in the past but which is now actually impeding their recovery. In my view, many of these psychological problems are the result of misinformation and the shortage of expertise within the NHS. This makes too many patients turn to complementary practitioners who are sympathetic and promise a cure but who are not qualified and can't deliver. Watch out for generalisations such as 'any exercise can cause permanent damage' or 'ME is caused by candida'. If you are unsure about any advice, call the ME Association helpline. They are a reliable source of medical information in the UK.

One can tell if phobic avoidance is a problem by the way in which patients talk about their illness. There will be evidence of fear and of having followed dubious advice. Some will also develop the symptoms of clinical depression. From a research perspective, these patients rarely show signs of immune activation (sore throats, tender glands) and the severe cognitive impairment found in ME and post-infectious CFS. Neurological symptoms are also more limited, and can often be explained in terms of stress and hyperventilation. Common ones include dizziness, feeling faint, trembling hands and tingling sensations in hands and feet.

The best advice for this subgroup is not to avoid anything simply because of fear and to keep trying new things, starting slowly, gently and in the case of drugs, at low doses. As far as exercise goes, patients with all fatigue syndromes should keep as active as they can be (i.e. up to the point where they feel unpleasantly tired or weak.) There is no evidence of permanent damage following gentle exercise and it's important to avoid the 'complications' caused by a lack of activity.

If you suspect that you have become sensitive to foods, don't start by excluding them from your diet. You may be able to avoid a reaction simply by preparing the item in a different way (grilling instead of frying), or by eating the food at lunchtime rather than in the evening. If that doesn't help, please consult a qualified nutritionist, dietician or naturopath before embarking on an exclusion diet. Or contact your GP.

Misdiagnosed conditions

As most CFS specialists know, a small but significant number of people with unexplained chronic fatigue are wrongly diagnosed. I myself recently acted as a second opinion for a person who had been told that she had ME but whose symptoms were really due to Coeliac's Disease. Other conditions which may be misdiagnosed as CFS include fibromyalgia (a rheumatological condition dominated by pain), subclinical hypothyroidism, primary food sensitivities, the after-effects of pesticide poisoning and a variety of psychosomatic disorders.

Of course, having one condition does not confer immunity from others. Any ongoing illness can cause chronic stress. And there is nothing to stop people with ME and post-viral syndrome from developing other immunological disorders (including sensitivities to foods and chemicals). That's why it's important to tell your doctor when symptoms occur and what makes them worse. Also, don't attribute every new symptom to CFS.

Pedersen's Syndrome

This is typically triggered by something resembling a normal cold and the main symptom is vertigo. Although the vast majority of patients recover quickly, 5-10% will continue to experience symptoms for months or years.

The vertigo presents in different ways. Some people feel like the room, or they, are spinning around but others may sense movement or rotation but not spinning. People also report feeling unbalanced or unsteady when walking, and they say that the floor is coming up, or that they are being pushed towards one side when they walk. It's often accompanied by significant fatigue as well as visual disturbances, anxiety and depression. Attacks tend to become less frequent over months but they may persist in some form for several years.

The vertigo can be triggered during the chronic stage by anything, but many link it to movement of the head and neck or rapid changes of posture. In women, it may be worse premenstrually, and some have more pronounced symptoms early morning.

Other possible subgroups

The term CFS has also been applied to some cases of Gulf War Syndrome (Haley et al 2000), the illness following exposure to organophosphates (Davies et al 2000), back problems (e.g. Perrin 1993) and Vitamin D deficiency (Hock 1997).

All the above may present with chronic fatigue and other symptoms suggestive of ME.

Management.

Since fatigue is common to all the subgroups, the basic advice is to get sufficient rest, to eat a good diet and to avoid stress as much as possible. However, the following gives a summary of more specific advice on activity, drugs and supplements .

ME and post-viral fatigue

ME should be managed as follows:

Pacing of activities, which means stopping when feeling unpleasantly tired or when one develops nausea or weakness. Either rest, or switch to an activity which uses a different muscle group.

Eat a varied diet, low on sugar and fat, and if feeling nauseous, change to white meat and fish with fruit and vegetables and limit red meat and anything fried. Suffice to say, don't drink alcohol or just have one glass of white wine occasionally.

Optional: vitamin C, E and selenium in recommended doses. Other anti-oxidants are worth trying but please get expert advice from a qualified nutritionist, dietician or naturopath first.

Counselling is useful if severely affected but cognitive behavioural therapy (CBT) may be more appropriate for those who have developed phobias or depression. (It's hard to cope with an illness like ME on your own, so don't be afraid or feel guilty about seeking outside help.)

Don't believe some of the media articles on antidepressants. This is a versatile group of drugs and some have a beneficial effect on the immune system. Low doses can help pain, sleep problems and 'brain fog'. For mild to moderate depression associated with ME, you can also try the herb St. John's Wort. It's particularly good for post-viral fatigue as it also has antibacterial and anti-viral properties. However, if you are on other drugs, please inform your GP.

Glandular Fever.

Same basic rules apply. Do not ignore depression. This is not about mind over matter but mind AND matter. Try St. Wohn's Wort (see above), but drugs like amitripyline or fluoxetine can also be helpful.

Take your time to convalesce properly. Rest, relax and slowly increase your activity levels. If that doesn't work, try pacing.

Chronic stress

Try psychotherapy or counselling to identify stressors.

Eat a healthy, well-balanced diet.

Learn new ways of relaxing.

Supplements which may help include licorice (if cortisol levels are low) and the herb kava kava.

Graded activities where you slowly increase what you do every week may be more helpful than pacing.

Phobic avoidance

The treatment of choice for this subgroup is cognitive-behavioural therapy plus graded exercise. Also, don't be afraid of anti-depressants. Start on a low dose but try and take the full amount suggested.

Pedersen's syndrome

There is no research on this so the information is based on the literature on vertigo, anecdotal reports and other people's clinical experience. Vertigo can be treated with drugs like betahistine and stemetil. Also useful are some anti-histamines.

Try vestibular exercises if offered.

Diazepam (1-2 mg every morning) is used by some experts in the US, but because of potential addiction, be guided by a doctor. (It may be more helpful to keep this drug for special events). Others use the antidepressant sertraline.

A few consultants recommend vitamin C with bioflavanoids. Look for a good quality brand and try 1000 mg a day.

Supplements which may be helpful include gingko biloba.

Conclusion

As long as we continue to use the same name for different conditions, confusion and controversy is inevitable. It means that the psychiatrists are probably right when they attribute the illness to psychological factors. The neurologists and virologists are probably right when they claim that infection may play a major role in CFS. And doctors who specialise in nutritional medicine are probably right when they link the illness to deficiencies or sensitivities. The solution is to recognise the differences and not to dismiss them. We should compare and contrast, not ignore and assume. Some subgroups may be identical e.g. ME and post-viral syndrome, but without the research, we cannot be sure.

I know that subgrouping complicates matters, but isn't accuracy more important than simplicity?

*Footnote

When the term CFS was first introduced (1988), the diagnostic criteria resembled those for ME and post-viral fatigue. However, when doctors adopted broader criteria in 1991 and 1994, they included an increasingly larger proportion of people with other problems. This meant that an abnormality of the immune system detected in 80% of patients selected using the older criteria was found in only 40% of those diagnosed using the 1994 version. Similarly, rates of psychiatric disorders are higher in broadly-defined samples than in patients who fulfil the stricter definitions.

Shepherd, C. Living With ME. Vermilion. 1998.

Campling, F and Sharpe, M. CFS: The Facts. Oxford University Press. 2000.

Ash-Bernal, R et al. Acta Otolaryngology, 1995, 115, 9-17. (On vestibular problems in CFS).

Borok, G. Journal of Chronic Fatigue Syndrome, 1998, 4, 3, 39-57. (Food sensitivities and fatigue).

Chaudhuri, A and Behan, PO. Journal of Chronic Fatigue Syndrome, 2000, 51-68. (Good on the neurological aspects of CFS and ME).

Davies, R et al. Advances in Psychiatric Treatment, 2000, 6, 5, 356-361. (On effects of organophosphate poisoning).

Haley, RW et al. Radiology, 2000, 215, 807-817). (On possible causes of Gulf War syndrome).

Heim, C et al. The potential role of hypocortisolism in the pathophysiology of stress-related bodily disorders. Psychoneuroendocrinology, 2000, 25, 1-35.

Hock, AD. Journal of Chronic Fatigue Syndrome, 1997, 3, 3, 17-27. (This links some cases of chronic fatigue to vitamin D deficiency).

Ho-Yen, DO. British Journal of General Practice, 1990, 40, 37-39. (British criteria for post-viral syndrome).

Paul L et al. European Journal of Neurology, 1999, 6, 63-69. (This study shows the loss of muscle strength in ME patients and the prolonged recovery).

Pedersen, E. Epidemic vertigo. Brain, 1959, 82, 566-580. (Basis for information on Pedersen's syndrome.)

Perrin, RN. British Osteopathic Journal, 1993, 11, 15-23. (On the relationship between CFS and back problems).

Pruessner, JC et al. Psychosomatic Medicine, 1999, 61, 197-204. (A recent paper on the relationship between chronic stress and cortisol)

Ramsay, MA. Postgraduate Medical Journal, 1978, 54, 718-721. (A classic paper on ME.)

Richardson, J. Journal of Chronic Fatigue Syndrome, 2000, 6, 2, 11-21. (Paper on the misdiagnosis of ME and treatment of pesticide poisoning).

Skinner, GRB et al. J. Nutritional and Environmental Medicine, 2000, 10, 2, 115-124. (On hypothyroidism and CFS)

Wilson, A et al. BMJ, 1994, 308, 756-759. (More on misdiagnosis of CFS).

Contacts:

ME Association., 4 Corringham Road, Stanford le Hope, Essex SS17 0AH.  Please enclose SAE.  

Check local CAB for the nearest independent or AfME affiliated patient support group. Some are good, some not so good. (AfME is Action for ME).

Ellen Goudsmit