Around 75% of people with ME/CFS can trace back the onset of their condition to an acute viral infection. This could be a specific infection such as chickenpox, glandular fever, or rubella. However, it may be a non-specific flu-like illness or bronchitis. ME/CFS occasionally occurs following other types of infection such as mycoplasma, Q fever, salmonella or toxoplasmosis (ME/CFS – Diagnosis Delay Harms Health – Early Diagnosis Why it is so Important – A report from the ME Alliance – Dr Charles Shepherd).
It has also been reported that ME/CFS has been triggered by a vaccination, or exposure to toxins or pesticides. Other conditions such as MCS can begin on an initial exposure to a toxic compound, see also multiplechemicalsensitivity.org and aessra.org.
One of the conclusions contained in the 2002 UK independent ME/CFS working group report to the (British) Chief Medical Officer (see also Annexes to the Report) was that:
- ‘…six months duration of symptoms should be viewed as an endpoint for the diagnostic process…’
A key principle for effective management is to establish a provisional diagnosis early on, and certainly before symptoms have persisted for several months. The person then has a name for their various symptoms, an explanation, and a plan of management, such as the all important pacing, can be put into place as soon as it becomes apparent that they are not recovering from the initial infection.
It is no longer acceptable for people to be left feeling abandoned by the medical profession because of a lack of willingness to make a diagnosis.
The following timeline is suggested:
- At four to six weeks of persisting undue fatigue and other ME/CFS-like symptoms following an acute infection, a diagnosis of a post-viral/infectious fatigue syndrome should be considered.
- After three to four months of persisting symptoms, and where other possible causes of ME/CFS-like symptoms have been excluded through investigation (eg. various blood tests), a provisional diagnosis of ME/CFS should be considered. Initial approaches to clinical management (eg. pacing) can be instituted at this stage.
- By six months, if symptoms persist, the provisional diagnosis should be confirmed (perhaps at this stage by a specialist eg immunologist or a physician), provided all other explanations have been properly excluded, and further advice on management given (perhaps further referrals to exercise physiologists/clinical psychologists etc).
- In children, a positive diagnosis can often be made earlier, at around three months – as recommended in the RCPCH (UK Royal College of Paediatrics and Child Health) guideline 2004.