London criteria

The London criteria is a definition of Myalgic Encephalomyelitis for use in research, first published in 1994 and updated in 2014.

Authors

• 2014 authors: Sandra Howes, Ellen Goudsmit, and Charles Shepherd
• 1994 authors: Elizabeth Dowsett, Ellen Goudsmit, Anne Macintyre, and Charles Shepherd

Definition

All patients should fulfill the following five criteria:

1. A new onset of significantly abnormal levels of muscle fatigability and/or muscle weakness, precipitated by relatively minor levels of activity. Symptoms typically worsen during the next 24-48 hours.
2. The presence of symptoms indicating the involvement of the brain and central nervous system (e.g. impaired short-term memory and concentration, disturbed sleep patterns, balance problems).
3. Periods of impaired circulation compatible with autonomic dysfunction (e.g. facial pallor, disturbances in thermoregulation including inappropriate sweating and sensitivity to both heat and cold; postural hypotension and/or orthostatic intolerance).
4. Fluctuation of symptoms, from hour to hour and day to day.
5. These symptoms must have been present during the past three months (to exclude patients with the debility which often follows illnesses such as influenza).

Learn more

• A Comparison of Case Definitions for Myalgic Encephalomyelitis and Chronic Fatigue Syndrome (2017)
• Myalgic Encephalomyelitis (ME). Criteria and clinical guidelines 2014.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.