“ME/CFS (Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome) is a complex illness affecting multiple systems of the body and, in particular, the nervous and immune systems. It has many symptoms, made worse by physical and mental activity beyond personal limits and recuperation after exertion is prolonged. ME/CFS can be severely debilitating and can disrupt significantly the lives of those affected. Myalgic Encephalomyelitis is classified as a neurological disorder in the World Health Organisation's International Classification of Diseases (ICD 10 G93.3).” ME/CFS Australia

The Canadian Consensus Definition

The ME/CFS Canadian Consensus Document, published in 2005, was a breakthrough for defining this misunderstood and poorly diagnosed condition. It provides the meet most specific and comprehensive clinical case definition to date.

In order to be diagnosed with ME/CFS, a patient must all of the following criteria:

1. Fatigue (significant, unexplained, persistent physical and mental fatigue)
2. Post-Exertional Malaise and/or Fatigue (pathologically slow recovery period after exertion)
3. Sleep Dysfunction
4. Pain (in muscles or joints, widespread and migratory)
5. Two or more of the following Neurological/Cognitive Manifestations: Confusion; impairment of concentration and short-term memory consolidation; disorientation; difficulty with information processing, categorizing and word retrieval; and perceptual and sensory disturbances.
6. At least one symptom from two of the following categories:
1. Autonomic Manifestations: Orthostatic intolerance; light-headedness; extreme pallor; nausea and irritable bowel syndrome; urinary frequency of bladder dysfunction; palpitations; exertional dyspnea
2. Neuroendocrine Manifestations: loss of thermostatic stability; intolerance to extremes of heat and cold; marked weight change; worsening of symptoms of stress
3. Immune Manifestations: Tender lymph nodes; recurrent sore throat; recurrent flu-like symptoms; general malaise; new sensitivities to food, medications or chemicals
7. The illness persists for at least six months

For more details on each of these, click here to download a copy of the Canadian Consensus Document.

Mythbusting quiz

Read Linda MacDonald's excellent ME/CFS Mythbusting quiz for the facts about ME/CFS!