What is Chronic Fatigue Syndrome (or CFIDS)?

There are many different opinions about chronic fatigue syndrome (CFS).   The name “fatigue syndrome” certainly sounds harmless.   After all, fatigue is very common.   Everyone, at some point, experiences fatigue.    Yet, CFS is a unique and devastating.   The clinical symptoms of CFS can be summed up quickly: 

The Symptoms of CFS

1.     Prolonged and Disabling Fatigue  - This is the hallmark symptom of CFS.   Small tasks, once taken for granted, can cause exacerbation of symptoms for days or weeks.   Since the price for activity is often paid after the event, many people with CFS have a difficult time avoiding relapses.  Most people with CFS must slowly learn to pace their activity.   

Exercise and activity may temporarily worsen CFS.   These symptoms are:

a.      Flu-like symptoms - Swollen lymph nodes and flu-like muscle aches are common in CFS. Many people with CFS report that their illness began with an acute viral infection.    

b.      Orthostatic Intolerance -  Sitting or standing is something most people take for granted.   For many who suffer from CFS, remaining stationary and upright can be very uncomfortable.   After sitting or standing, pain in the legs and diminished mental clarity are common.   Many theories abound as to what causes orthostatic intolerance in people with CFS.  Neurological dysfunction, cardiomyopathy, and hypovolemia (low blood volume) have each been suggested as possible culprits.

3.  Neurological Dysfunction - Neurological symptoms vary greatly from person to person.   Some of the more prominent neurological symptoms are diminished mental clarity, extreme mental fatigue, insomnia, and chronic migraines.  Digestive problems and tachycardia (rapid heart rate, especially upon sitting or standing) are also common.  

What is the Center Disease for Controls CFS case definition?

The most widely used definition for CFS is 1994 CDC CFS case definition.  The definition is more complex, focusing on eight symptoms.   According to the authors, the goal of the definition was to integrate many fatiguing illnesses under one umbrella.   The downside of this integrative approach has been conflicting research results.   There is now widespread consensus that the CDC’s 1994 revised case definition is deeply flawed, catching a heterogeneous group.   Despite the controversy, the research definition was broadened once again in 2003.

Where did the terms CFIDS and Myalgic Encephalitis come from?

CFIDS stands for “chronic fatigue and immune dysfunction syndrome”.    The largest advocacy group in the United States, the CFIDS Association of America, uses this name.   Many people with CFS feel that the name “Chronic Fatigue Syndrome” severely trivializes and broadens the illness.  This view led to the eventual merging of the phrase ”immune dysfunction” into the name, yielding the frequently utilized acronym, CFIDS.   The tendency of the illness to be precipitated by a virus also contributed to the popularity of the term CFIDS. 

The name M.E., or Myalgic Encephalomyelitis, is commonly used in the United Kingdom and Australia.   This name is used widely in the U.S as well.   The name also has some historical footing and is associated with distinct definition.