ME and CFS definitions
Overview
ME/CFS is a complex multi-system chronic illness which varies greatly from person to person and has several different case definitions. The severity can range from mild debilitating symptoms to severely disabling affects which confine people to bed for months or years, sometimes with almost no mental ability or tolerance of normal sounds and lighting.
ME – ‘Myalgic Encephalomyelitis’ technically means an illness that causes inflammation in the brain and spinal cord, and results in pain in the muscles. The ME Association in the UK believes that Myalgic Encephalopathy is currently a more suitable name as so far research has only made preliminary findings of neuro-inflammation.
ME has been classified by the World Health Organisation (ICD 10 G 93.3) as a neurological illness since 1969.
However, increasing research is finding evidence that other bodily systems involved affected including the immune, cardiovascular, digestive system and energy production/transport.
It is estimated that ME (ICC criteria) effects approximately 250,000 individuals within the UK. In many cases, onset is linked to a viral infection. Other triggers may include an operation or an accident, although some people experience a slow, insidious onset.
It can cause pain, which is sometimes severe, anywhere in the body, inability to concentrate, mental fog, memory problems, muscles weakness, post-exertional malaise and debility, profound tiredness/exhaustion, immunological symptoms, faintness, etc.
An estimated 25% are severely affected and confined to bed or home.
Currently diagnoses can usally only be made by a process of elimination, to exclude other conditions, and seeing whether certain criteria are met. The International Consensus Criteria for ME is currently favoured by many, including most medical specialists in the field.
Explanation of the label ‘Chronic Fatigue Syndrome’.
Chronic Fatigue Syndrome (CFS) is an ‘heterogeneous’ or ‘umbrella’ label for a collection of symptoms. Some people of the case definitions for CFS are different to those for ME, especially the ICC criteria. The department of health in the UK (at time of writing 03/2015) refers to CFS/ME because of currently lack of clarity and agreement over definitions of CFS and ME. Many people, including some physicians and researchers would like ME to be either separated from the name CFS or recognised as a distinct sub-group.
SEID?
America’s IOM – Institute of Medicine as produced a new case definition with the name SEID – systemic exertion intolerance disease. However many believe this is only a suitable replacement for CFS but falls way short of defining ME with the depth and accuracy of International Consensus Criteria for ME . An increasing amount of research is suggesting there are multiple versions of the illness, or distinct types and there is a need for research to produce biomarkers to clearly distinguish between these.
Functional PET imaging showing neuroinflammation of patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)
Radiology researchers find multiple brain abnormalities in ME/CFS 2014
In this video Prof Julia Newton talks about patients with ME having upto 20 times the normal amount of acid being produced by muscle cells
Main Symptoms
(If diagnosed according the ICC – International Consensus Criteria)
Post-exertional malaise and debility – worsening of symptoms and/or ability which can sometimes be delayed hours or days and have a slow recovery lasting days or weeks.
Unusual muscle weakness – can vary dramatically day to day, hour to hour and often accompanied by pain (see research links).
Lack of physical and mental stamina.
Neurological symptoms:
Pain – anywere in the body and can be severe. Multiple types of pain including “new headaches.”
Cognitive problems – inability to concentrate, “brain-fog”, memory problems; can be severe.
Sleep disturbance.
Immunological:
Flu-like symptoms may be recurrent or chronic and typically activate or worsen with exertion. Susceptibility to viral infections with prolonged recovery periods.
Gastointestinal problems.
Sensitivities to food, medications, odours or chemicals.
Energy production/transport:
1. Cardiovascular: Faintness and dizziness – especially when in upright position. Sometimes diagnosed as POTS – postural orthostatic tachycardia syndrome – causing rapid pulse and a wide range of symptoms with an upright posture.
2. Respiratory problems.
3. Loss of thermostatic stability – i.e. feeling cold or hot at room temperature, with swings between the two.
4. Intolerance of extremes of temperature.
This is not an exhaustive list of symptoms.
Testable effects of ME
Just a few among many tests that can show the effects of ME are: (Links to details on research)
Natural Killer Cell Function test
Spinal fluid protein abnormalities
There are an increasing number of research findings of immunological nature such as trials of drug Rituximab and a recent pilot study which may have revealed cytokine biomarkers.
In this video ME Association advisor Dr Charles Shepherd gives his view on the difference between ME and CFS, and also explains his proposal for using the name Myalgic Encephalopathy instead of Myalgic Encephalomyelitis
In this video Professor Leonard Jason explains why the label CFS can be unhelpful as well as describing developements in the area of diagnosis.