Consensus Document for ME/CFS
Consensus Document should be read
and studied by every medical provider."
-David S. Bell, MD, FAAP- (USA)
[UPDATE: This definition has provided the foundation for a
new set of clinical and research criteria as of July 2012,
Myalgic Encephalomyelitis: International Consensus Criteria,
for both adult and pediatric cases.
Its authors have followed with Physician's Guidelines,
2012 ICC Primer.
We will continue to provide access to this and other definitions
pages for historic reference.]
This 2003 ME/CFS Clinical Working Case Definition is the
predecessor to the 2011 International
Consensus Criteria. Health Canada selected an eleven member
International Expert Consensus Panel who collectively "had
diagnosed and/or treated more than twenty thousand patients.
There was 100% consensus by the panel members on the final
Consensus Document. The Consensus Document has become known
Canadian Consensus Document for ME/CFS." Also available
is the excellent comprehensive yet concise
Overview of the Canadian Consensus Document.
felt there was a need for the criteria to encompass more symptoms
in order to reflect ME/CFS as a distinct entity and distinguish
it from other clinical entities that have overlapping
symptoms. As fatigue is an integral part of many illnesses,
the panel concurred that more other prominent symptoms should be
definition places the hallmark symptom of post-exertional malaise
and neurological features as major criteria--much like the
historic definitions, Ramsay's, Dowsett's, Hyde's and Hooper's
descriptions of and definitional criteria for M.E.--unlike the US
CDC and UK Oxford definitions that, in Elizabeth G. Dowsett's words,
elevated "...glandular enlargement and fatigue to unreal
importance, while overlooking the characteristic encephalitic
features of the genuine illness [M.E.]."
criteria in the Consensus Document that must be present are:
significant degree of new onset, unexplained, persistent, or
recurrent physical and mental fatigue that substantially reduces
Malaise and/or Fatigue: There is an inappropriate loss of
physical and mental stamina, rapid muscular and cognitive
fatigability, post exertional malaise and/or fatigue and/or pain
and tendency for other associated symptoms with the patient's
cluster of symptoms to worsen. The is a pathologically slow
recovery period--usually 24 hours or longer.
Dysfunction: There is unrefreshed sleep or sleep
quantity or rhythm disturbances such as reversed or chaotic
diurnal sleep rhythms.
There is significant degree of myalgia. Pain can
be experienced in the muscles and/or joints, and is often
widespread and migratory in nature. Often there are
significant headaches of new type, pattern or severity.
"Neurological/Cognitive Manifestations: Two or more
of the following difficulties should be present:
confusion, impairment of concentration and short-term memory
consolidation, disorientation, difficulty with information
processing, categorizing and word retrieval, and perceptual and
sensory disturbances--e.g., spatial instability and
disorientation and inability to focus vision. Ataxia,
muscle weakness and fasciculations are common. There may
be overload phenomena [hypersensitivities to stimuli that have
changed form pre-illness status]: cognitive, senory--e.g.,
photophobia and hypersensitivity to noise--and or emotional
overload, which may lead to "crash" periods and or anxiety.
Least One Symptom from Two of the Following Categories:
Overview of the Canadian Consensus Document
a specific listing of these manifestations.)
definition also includes a brief segment on ME/CFS in children.
(See also Pediatric ME/CFS)