Myalgic Encephalomyelitis (ME)

Mark Douet/Getty Images

Definition:

Myalgic encephalomyelitis, abbreviated as ME, is one of several alternate names for the disease that's commonly known as chronic fatigue syndrome (CFS). It's common to see the abbreviations combined, as ME/CFS or CFS/ME.

The word myalgic means muscle pain or tenderness.

  • my is a shortened form of myo, which means muscle
  • algic is the adjective form of algia, which means pain

The word encephalomyelitis means inflammation of the central nervous system (the brain and spinal cord.)

  • encephalo refers to the brain
  • myel means spinal cord and medula oblongata
  • itis means inflammation

Pronunciation: Myalgic: my-AL-jik
Encephalomyelitis: en-SEF-uh-lo-MY-uh-LY-tis

Several countries around the world currently call the condition myalgic encephalomyelitis. This term appears to be gaining traction in the U.S. among researchers, advocates, and people with the disease. Some people use the terms interchangeably, while others consider them separate conditions.

Patients, advocates, and some researchers in the U.S. have pushed for ME/CFS due to the widespread belief that the name "chronic fatigue syndrome" trivializes the condition and leads to misconceptions about it. They hope to eventually drop the "CFS" portion altogether and just use ME.

However, a major report from the Institute of Medicine has called for the name of this condition to be systemic exertion intolerance disease, or SEID.

That's based on the widespread abnormalities associated with the illness and one of its distinguishing symptoms, post-exertaional malaise (an extreme negative reaction to exertion and inability to repeat the activity the following day.)

It remains to be seen whether than name SEID will find acceptance.

It faces an up-hill battle, since many researchers have transitioned to myalgic encephalomyelitis/chronic fatigue syndrome in their published papers.

Additionally, a lot of people with the disease have formed a strong emotional attachment to ME, since it was the first alternative name to gain traction that didn't involve "fatigue." A common sentiment is that the public doesn't understand the difference between clinically significant fatigue and just being tired, such as from a lack of sleep.

Another reason for leaving behind "chronic fatigue syndrome" is that the name has become inaccurate. The Institute of Medicine report concluded that it is a disease, not a syndrome, as is made clear in the name "systemic exertion intolerance disease."

Critics of the name ME and its variations say that we don't have adequate evidence of inflammation in the brain and spinal cord to re-name the disease for it. However, a small 2014 study did appear to provide some evidence that encephalomyelitis is a feature of the condition.

We'll need more research to be certain.

Sources:

Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board of the Health of Select Populations; Institute of Medicine. The National Academies Collection: Reports funded by National Institutes of Health. Beyond myalgic encephalomyelitis/chronic fatigue syndrome: redefining an illness. Washington (DC): National Academies Press (US); 2015 Feb.

Nakatomi Y, et al. Journal of nuclear medicine. 2014 Jun;55(6):945-50. Neuroinflammation in patients with chronic fatigue syndrome/myalgic encephalmylitis: An 11C-(R)-PK11195 PET study.

Continue Reading