Last week the Journal of Internal Medicine published “Myalgic Encephalomyelitis: International Consensus Criteria” online ahead of the print version.  The new criteria was developed by an impressive panel of 26 ME/CFS experts from 13 different countries.  Notably, there was 100% agreement among panel members on the final criteria presented.

Two of the many controversies that have swirled around ME/CFS (myalgic encephalomyelitis / chronic fatigue syndrome) for years are what to call it and how to diagnose it correctly. 

The Name

What to call this illness has been the subject of numerous disagreements in the ME/CFS community.  You can read more about the many name iterations in “A Disease in Search of a Name: The History of CFS and the Efforts to Change Its Name.” 

I was pleasantly surprised to see that the consensus panel, in the first three sentences of the abstract, attempted to settle the argument once and for all. 

“The label “chronic fatigue syndrome” (CFS) has persisted for many years because of lack of knowledge of the etiological agents and of the disease process. In view of more recent research and clinical experience that strongly point to widespread inflammation and multisystemic neuropathology, it is more appropriate and correct to use the term “myalgic encephalomyelitis”(ME) because it indicates an underlying pathophysiology. It is also consistent with the neurological classification of ME in the World Health Organization’s International Classification of Diseases (ICD G93.3).” 

The Criteria

A disease criteria serves several functions:

• It defines the illness.
• It makes research both possible and more accurate by grouping patients with a specific set of similar symptoms together.
• It can often be used to help diagnose patients. 

Over the years, a number of different criteria have been used for ME/CFS.  The problem is that some, like the Reeves Empirical Criteria, are so broadly inclusive that a large number of patients with Major Depressive Disorder end up being included, which significantly skews the results of any research done using that criteria. 

Following is the new International Consensus Criteria:

A patient 

• will meet the criteria for post-exertional neuroimmune exhaustion (A), 
• will have at least one symptom from three neurological impairment categories (B), 
• will have at least one symptom from three immune/gastro-intestinal/genitourinary impairment categories (C), and 
• will have at least one symptom from energy metabolism/transport impairments (D).

A. Post-Exertional Neuroimmune Exhaustion (PENE pen ׳-e) 
 
Compulsory 
 
This cardinal feature is a pathological inability to produce sufficient energy on demand with prominent symptoms primarily in the neuroimmune regions. 
 
Characteristics are:

1.  Marked, rapid physical and/or cognitive fatigability in response to exertion, which may be minimal such as activities of daily living or simple mental tasks, can be debilitating and cause a relapse.