Published by the M.E./Chronic Fatigue Syndrome Society of Victoria Inc.
What is Chronic Fatigue Syndrome?
Chronic Fatigue Syndrome (CFS) is a serious and debilitating illness that can last for years, and sometimes for life. CFS is a recognised syndrome, the cardinal feature of which is profound exhaustion, accompanied by a range of other symptoms. In some cases the illness causes persistent disability, while in others it follows a relapsing and remitting course.
People with CFS are not just 'tired for a long time'; CFS is not just 'chronic fatigue'. Many people complain of fatigue (up to 30% of the population at any one time!), but of all people reporting to doctors with the complaint of fatigue, fewer than 10% will have CFS. In CFS, the exhaustion or fatigue is usually accompanied by other flu-like symptoms which can be extremely distressing.
What are the symptoms of CFS?
- profound exhaustion exacerbated by minor exercise - everyone has this symptom
Other symptoms which occur commonly are:
- memory and concentration impairment
- an intense, flu-like feeling
- muscle pain
- sleep disturbance
- headaches
- disturbance of balance
Less frequently reported, but still common:
sore throat, painful lymph nodes, depression, nausea, mild fever or chills etc.
The experience of CFS is best described by relating it to a severe dose of influenza or other viral illness which either does not improve, or only partially improves, and lasts for a minimum of six months.
What causes CFS?
The cause of CFS is unknown, although several research groups around the world believe that the symptoms may be caused by a continuing immune response, due either to a persisting infection or to the failure of the immune system to 'turn off' after an initial infection. Other researchers are focusing on disturbances in brain chemistry which may contribute to the symptoms, and some are examining alterations in cellular metabolism which could also be of significance.
In 75% of cases, CFS begins with a viral infection, or what is apparently a viral infection. It begins suddenly, with typical 'viral-like' symptoms. Occasionally CFS begins with a bacterial or parasitic infection, or with a vaccination, or exposure to a toxic chemical - ie., some sort of challenge to the immune system. Frequently associated with this immune system challenge are other factors, such as strenuous physical activity or psychological stress. In up to 25% of cases, the onset of CFS is gradual, with no recognisable precipitating event.
Many people in the community experience 'viral' infections under similar circumstances, but what distinguishes CFS is that the symptoms remain - for a minimum of six months, and frequently for many years. For this reason, researchers are examining whether people with CFS have a genetic pre-disposition to developing the illness; and whether certain viruses which can evade the immune system are present in people with CFS.
Researchers at the University of Newcastle and University of Sydney have found a new chemical in the urine of a high percentage of people with CFS which is present only in a minority of healthy people, and then in much lower concentrations than in people with CFS. This chemical is believed to be of non-human origin, and is similar in structure to known neurotoxic compounds. Its role in the illness is being studied. These researchers have also found that alterations in the levels of certain biochemicals in people with CFS correlate strongly with particular symptoms of the illness.
An internationally recognised research team at The Prince Henry Hospital in Sydney is investigating the following model of the illness:
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Cytokines are chemical messengers of the immune system. They play an important role in the communication between different immune system cells, and in the destruction of some organisms which invade the body. Some cytokines, such as interferon and interleukin, are used to treat diseases such as cancer and hepatitis B. When these cytokines are administered to patients, they develop symptoms very similar to CFS. It has been postulated that continual production of cytokines by the immune system is the cause of many of the symptoms of CFS; this hypothesis is now being tested by research groups around the world. Some studies indicating altered cytokine production in people with CFS have already been published.
Who gets CFS, and how many people have it?
An epidemiological study which looked at the prevalence of CFS (ie. how many people have it at one time) was conducted by Dr Andrew Lloyd and colleagues of The Prince Henry Hospital in Sydney. This study (published in the Medical Journal of Australia) found that CFS can affect people of all ages, but most commonly affects people under the age of 45. Over 25% of people affected are under the age of 20, and just under 10% are over the age of 45. Females develop CFS slightly more frequently than males, in a ratio of 1.3:1.0. It has been estimated, based on the results of the epidemiological study, that a minimum of 37.1 per 100,000 people have CFS, ie. 6700 Australians, or 1700 Victorians. This estimate yields a minimum figure for several reasons:
- people with a mild form of CFS were not included in the study
- the study only identified people with CFS who had presented to doctors
- some doctors in the study region didn't believe in the existence of CFS, so may not have alerted the research team to the existence of some patients with CFS
- there may be a tendency for people who have had CFS for a long time to cease reporting to doctors with their symptoms.
The epidemiological study also found that CFS affects people from all socioeconomic groups, in a similar distribution to that found in the community.
This study was conducted in the Richmond Valley, near Lismore in NSW. The estimate of 37.1 cases of CFS per 100,000 people is very similar to the prevalence of multiple sclerosis (MS) in NSW, based on a study of MS done in Newcastle.
--Epidemiological studies conducted in the United States have been published more recently, and they indicate a prevalence of CFS of between 1 and 2 cases per 1000 people, ie. between 18,000 and 36,000 Australians with the illness. These estimates are more accurate since they are based on random community samples.
How long does CFS last?
There are very few published studies which have documented the natural history of CFS. The illness can have a spectrum of possible outcomes, ranging from a relatively mild illness lasting just six months, to a severe illness lasting for many years. The consensus amongst researchers seems to be that most people improve over time, although the percentage of people who regain their pre-illness level of health is unknown. Based on the epidemiological study conducted in the Richmond Valley, 'full-blown' CFS lasts for more than five years in 33% of people.
In a recent study published in the British Medical Journal, 103 CFS patients who had already been ill for several years were followed up for an average period of three years. At the end of the study, only six out of 103 patients had recovered completely.
Is there a treatment for CFS?
No effective treatment for CFS has been developed. Several substances have been tested in double-blind, placebo-controlled trials, with mixed results. These include:
- vitamin B12/liver extract
- Acyclovir (an antiviral drug)
- intravenous gammaglobulin
- evening primrose oil/fish oil mixture
- magnesium injections
- transfer factor
- Ampligen (an antiviral drug)
Ampligen and evening primrose oil have shown benefit for people with CFS in their original trials, but results need to be confirmed through additional trials before the role these substances in treating CFS becomes clear. Gammaglobulin and magnesium have shown some success with alleviating symptoms in their initial trials, but the results of subsequent trials have contradicted the original findings. We are still waiting for larger trials of these substances to be completed before we will know if they have any role in the treatment of the illness. In Australia, supplies of gammaglobulin are limited, and regardless of efficacy, this drug is unlikely to be available for treating CFS. At present, CFS cannot be treated; rather it is managed.
What are the management strategies for CFS?
Management of CFS relies on rest, with gentle graded exercise where appropriate; lifestyle modification, and treatment of some symptoms. Medications can be used to treat sleeping difficulties, headaches, muscle pain, depression and allergies, all of which may be experienced by people with CFS. Total bed-rest is not considered to be an appropriate management strategy, although there are times when some people with the illness are simply too sick to get out of bed. People with CFS are encouraged to maintain involvement in activities within the limits imposed by the illness.
How is CFS diagnosed?
There is no laboratory test which can be used to diagnose CFS. Instead, diagnosis relies on careful evaluation of the patient's history and exclusion of other conditions by the doctor. The patient must then fulfil the case definition for CFS. Laboratory tests can be used where indicated to exclude other conditions. Some laboratory tests (eg. immunological tests) can be used as evidence to support the diagnosis, but alone have no diagnostic value in the syndrome. Sophisticated laboratory tests are research tools, and are not used in routine diagnosis of the illness. The patient's history (eg. sudden onset of a 'viral' illness and typical symptoms) often points to the likelihood of CFS.
There are three sets of diagnostic criteria for CFS in use, which are generally similar. The criteria devised and used by the researchers at The Prince Henry Hospital are as follows:
The patient must have:
1) Chronic persisting or relapsing fatigue of a generalised nature, exacerbated by minor exercise, causing significant disruption of usual daily activities, and present for greater than six months.
2) Neuropsychiatric dysfunction including impairment of concentration evidenced by difficulty in completing mental tasks which were easily accomplished before the onset of the syndrome; and new onset of short term memory impairment.
3) No alternative diagnosis reached by history, physical examination or investigations over a six month period.
Researchers have decided that people with the symptoms of CFS must be unwell for a minimum of six months before being given the diagnosis of CFS. While somewhat arbitrary, this requirement recognises the fact that delayed recovery after viral or other infections is very common in the community, and serves to distinguish those with short-term illness from those with longer-term (or chronic) illness, ie. CFS.
What other diseases have some symptoms similar to CFS?
Before the diagnosis of CFS can be arrived at, other conditions which can have similar symptoms to CFS must be excluded. These include cancer, HIV disease, autoimmune diseases, neuromuscular diseases, endocrine diseases, and a range of psychiatric illnesses, to name some. The early stages of multiple sclerosis and systemic lupus erythematosus can resemble CFS, and must be carefully excluded.
What are the latest research findings?
The most significant recent finding is that CFS appears to be associated with a cardiac abnormality known as 'neurally mediated hypotension' (NMH). This condition is well known to cardiologists, and involves a mis-communication between the heart and the brain which causes an abnormal lowering of blood pressure, leading to symptoms such as fatigue, dizziness and nausea. Preliminary studies have indicated that a majority of people with CFS suffer from NMH, and some respond well to treatment. To better assess the association between CFS and NMH, and to explore potential treatment options, researchers from Johns Hopkins University and the National Institute of Allergy and Infectious Diseases in the USA are currently undertaking a large study. The researchers do not believe that NMH is the cause of CFS, or that it is reponsible for all symptoms.
In published studies looking at immune system functioning in CFS, immune system abnormalities have been found in most patients. Activation of the immune system - as if it were responding to a foreign organism - is consistently reported. Also consistently reported is poor functioning of natural killer cells, which are important as a first line of defence against viruses. There is now some evidence of abnormal production of cytokines (immune system chemicals) in people with CFS. However, no specific abnormality has yet been found in all people with CFS. Studies of muscles conducted at different centres indicate that muscle function is normal in CFS.
Sleep disturbance, documented in laboratory studies, has been recognised as an important feature of the syndrome. In the last few years, studies reporting abnormalities in hormonal levels and neurochemicals have appeared, opening up new avenues for research. Several reports of SPECT scans (a brain imaging technique) have been published, showing reduced blood flow and/or altered cellular metabolism in regions of the brain in people with CFS. Magnetic resonance imaging (MRI - another brain imaging technique) has revealed 'unidentified bright objects' in the brain in a significant percentage of people with CFS. In tests of memory and concentration, people with CFS perform more poorly in particular aspects than healthy people, and people with some other diseases.
Biochemical studies have documented metabolic disturbances in CFS, for example abnormalities in blood levels of angiotensin-converting enzyme (ACE) and acyl-carnitine.
Research into CFS is still in its very early stages when compared with other diseases. Published research studies - while few in number - have generally been of high quality. Research is now focusing on the immune system, the brain, metabolic factors and the role of viruses in CFS.
Who is doing research into CFS?
In Australia: The team at The Prince Henry Hospital/University of NSW has been studying CFS since 1987. Team members include Associate Professor Andrew Lloyd, Associate Professor Ian Hickie, and Professor Denis Wakefield (and several others). This group has looked at immunological, neurophysiological, epidemiological, virological, genetic, psychiatric and economic aspects of the illness, and has conducted several treatment trials.
In 1994, a team from the University of Newcastle and the University of Sydney received substantial publicity relating to their discovery of a novel chemical compound in the urine of people with CFS. This group has also found multiple biochemical abnormalities in CFS, and currently has underway a study looking at urinary metabolites, hormones, red blood cells, symptoms and psychology in CFS. A group at the Royal Adelaide Hospital is studying potassium levels in people with CFS, and another researcher in Adelaide is looking at red blood cell structure and function in CFS patients.
Dr Kathy Rowe at the Royal Children's Hospital in Melbourne has been working with adolescents with CFS for more than six years, and has conducted a treatment trial and devised management strategies for sufferers in this age group.
In the United States: Researchers at the National Institutes of Health, and the Centers for Disease Control and Prevention (CDC) have been investigating CFS since the mid-1980's and earlier. These are government funded agencies. The CDC has listed CFS in the category of 'Priority 1 New, Reemerging and Drug Resistant Infectious Diseases', along with diseases such as malaria, tuberculosis, hepatitis C and measles. Researchers from Harvard Medical School, the University of Miami, the University of Minnesota and other universities and hospitals are actively involved in CFS research. One of the world's leading AIDS researchers (Professor Jay Levy) of the University of California in San Francisco is also studying CFS.
In the United Kingdom: Professor Peter Behan of the Institute of Neurological Sciences at the Southern General Hospital in Glasgow, Scotland, heads the largest research team. Researchers from Oxford University, Kings College School of Medicine, the Royal Free Hospital and St Mary's Hospital are among those investigating CFS.
Elsewhere: Research is also taking place in Belgium, Canada, Denmark, Germany, Italy, Japan, New Zealand, South Africa, Spain, Sweden and The Netherlands.
Is CFS a new illness?
Researchers from around the world tell us that an illness with symptoms very similar to CFS has been reported since the mid-1700's. Reports continued through the 19th century, and into the 20th century. CFS is not a new illness. However, some researchers believe that the incidence of CFS has increased significantly since 1980.
Names of the illness
'Chronic Fatigue Syndrome' is the name adopted for the illness in 1988 by the medical research community. They prefer this name since it doesn't imply anything about the cause of the syndrome, while highlighting the principal symptom. 'Post-Viral Fatigue Syndrome' (or, more commonly in Australia, 'Post-Viral Syndrome') implies a viral cause or trigger, which is not always the case. 'Myalgic Encephalomyelitis' (ME) means myalgia (muscle pain) plus inflammation of the brain and nerves (encephalomyelitis). While myalgia is common in the syndrome, inflammation of the brain and nerves is rarely - if ever - present.
Chronic Fatigue Syndrome as a name for the illness is intensely disliked by people with CFS, since it trivialises the illness. It is equivalent to calling diabetes 'chronic thirst syndrome', or Parkinson's disease 'chronic shaking syndrome'. Although the name emphasises the main symptom, it does not convey the potential severity of the illness or the distress that other prominent associated symptoms can cause.
In the United Kingdom and Canada, patient self-help groups retain the name Myalgic Encephalomyelitis, while in the United States, 'Chronic Fatigue and Immune Dysfunction Syndrome' (CFIDS) is common.
Is CFS more than one illness?
It has been suggested by some researchers that people with CFS may not be a homogeneous group, ie. the label of 'CFS' may cover more than one disease. Some others believe that CFS may cover different diseases which have a common final pathway in the body. To date, little good evidence has been produced to demonstrate that CFS does in fact represent more than one disease. One study published recently found that two separate subgroups could be identified in a large group of people with CFS, based on their reported symptoms. Further studies looking at this issue are currently underway.
Does exposure to chemicals play a role in the onset of CFS?
The team at the University of Newcastle/University of Sydney have reported (in the Medical Journal of Australia) finding elevated levels of certain pesticides in some people with CFS. The significance of this finding remains unknown. Apart from this, there are no published studies which have looked at the role of chemicals (eg. solvents, pesticides) or heavy metals in the onset or continuation of CFS. It has been stated by a number of researchers that chemical exposure may play a role in triggering CFS.
What is the financial cost of CFS?
Based on the epidemiological study done by the research team in Sydney, it has been estimated by Dr Lloyd (in another paper published in the Medical Journal of Australia) that CFS costs the Australian community a minimum of $59 million per year (1988/89 dollars), including a minimum cost to the Federal government of $26 million per year (1988/89 dollars). Using the consumer price index (CPI), these figures can be inflated up to give the minimum costs as at the end of 1995. The cost to the community then becomes $75.5 million per year (1995 dollars), and the cost to the Federal government becomes $33.3 million per year (1995 dollars).
This is probably a substantial under-estimate of minimum current costs, since while the CPI rose approximately 28% from 1988/89 to the end of 1995, the more relevant Health and Personal Care Index rose over 50% in the same period. Both these indices are compiled by the Australian Bureau of Statistics.
Why has CFS been ignored for so long by the medical profession?
There are several reasons for this:
- CFS is not fatal, so the urgency for research and better understanding has not been as great as with some other diseases.
- Tests performed on CFS patients in the past usually showed no abnormality. It is only with very modern medical tests and techniques that definite abnormalities have been observed in CFS patients.
- Research money was (and still is) very difficult to obtain for those wishing to study this illness. Therefore, little work has been done and the understanding of the illness has remained poor.
- Medical 'dogma' was that people did not remain unwell after viral infections for more than six months, so Post-Viral Fatigue Syndrome or CFS was ignored by many in the medical profession.
Why is there renewed interest in CFS?
There has been renewed interest in CFS since 1985, when three important events occurred.
1) Dr Peter Behan in Scotland published a paper called "The postviral fatigue syndrome - an analysis of findings in 50 cases", which showed a variety of immunological, muscular and virological abnormalities in people with PVFS. The authors concluded that PVFS "is associated with disordered regulation of the immune system and persistent viral infection."
2) Dr Stephen Straus of the National Institute of Allergy and Infectious Diseases (USA), and Dr James Jones, then of the University of Arizona, both published papers linking the Epstein-Barr virus (which causes glandular fever) to persistent ill-health in patients who had what is now called CFS. These papers challenged the medical 'dogma' that illness after viral infections doesn't last more than six months. (Since then, it has been shown that the persistent ill-health that is characteristic of CFS is not caused by the Epstein-Barr virus).
3) The outbreak of illness at Incline Village, Nevada, and northern California reached its peak in 1985, while another outbreak occurred at Lyndonville, New York State, in the same year. Many of the people affected remained ill for extended periods of time, with what is now known as Chronic Fatigue Syndrome. These outbreaks attracted significant media attention in the USA, as well as the interest of the Centers for Disease Control and Prevention.
What are some of the myths about CFS?
- CFS is a 'Yuppie Flu' This name implied that CFS affected only young, upwardly-mobile professional people (yuppies) who couldn't handle the stress of their daily lives, and who used CFS as an excuse to opt out of the 'rat-race'. Essentially, it implied that they were malingerers, since no-one really believed that a disease specifically affected 'yuppies'. Studies have demonstrated that CFS affects people of all socioeconomic categories, and does not disproportionately affect people from any one socioeconomic group.
- CFS is a form of depression In the last few years, some psychiatrists and others have promoted the belief that CFS is a form of depression which causes symptoms in the body ('somatised' depression). However, extensive testing, including studies of immune function, hormones, brain chemicals, memory and concentration, brain blood flow and sleeping difficulties indicates, without exception, that CFS is different from depression.
Furthermore, based on the epidemiological study conducted in NSW, only 29% of people with CFS suffer from depression at any one time. Characteristics of major depression, such as feelings of guilt, loss of pleasure in life, etc. are not present in CFS. In addition, children and adolescents represent a higher percentage of patients in CFS than in depression.
- CFS mainly affects 'high achievers' CFS does not single out high achievers. It affects people of all levels of achievement, of all socioeconomic groups, and of all ages (although most commonly people under age 45). Some high-level athletes do get CFS. This may be because strenuous exercise can be a co-factor in triggering CFS. This co-factor is not related to athletic ability.
- CFS is a form of stress or 'burnout' Stress in its broadest medical sense can be a co-factor in triggering CFS. This 'stress' on the body may be strenuous physical exercise, psychological stress, chemical exposure, etc. However, many people in the community experience one or more of these co-factors in conjunction with a viral infection, yet do not develop CFS. This is why researchers are investigating whether people with CFS have a genetic pre-disposition to developing the illness, or whether some viruses can evade the body's defences and cause ill-health. Stress is not responsible for the symptoms of CFS; it does not cause CFS. When someone has CFS, removal of any stress does not remove the illness, although it may help with management. CFS is not some form of 'burnout'.
A recent study followed a group of patients with glandular fever for six months from the time they became ill. It was found that social adversity in the six months prior to illness onset was not associated with the subsequent development of CFS (diagnosed six months after illness onset in those who remained unwell).
- CFS is a 20th Century disease This is not true. An illness with symptoms similar to CFS has been reported as far back as 1750. We do not know if more people have CFS now than in the past, since it is only recently that studies have looked at the prevalence and incidence of CFS. We do know that there is now greater awareness of CFS, and this is leading to more frequent diagnosis of the illness. Even so, some researchers believe that the incidence of CFS has increased significantly in the last 15 years.
- Everyone recovers from CFS eventually There are as yet few published studies which have looked at the natural history of CFS. Researchers around the world generally agree that most people improve over time, and few get progressively worse. However, based on published studies, the percentage of people who regain their pre-illness level of health appears to be small. It is believed that the chances of complete recovery diminish the longer the illness lasts. Indeed, there are many people whose condition has improved over the years, but who still suffer permanently from some symptoms of CFS. Studies published in international medical journals have included people who have had CFS for 20 or 30 years. This information sheet is Copyright 1996 M.E./Chronic Fatigue Syndrome Society of Victoria Inc.