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.