CHRONIC FATIGUE SYNDROME INFORMATION SHEET
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 biochemical's 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:



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.