ME Awareness: What you need to know about M.E. | 01 May 2020

May 1, 2020

Dr Charles Shepherd, Hon. Medical Adviser, ME Association.

M.E. (myalgic encephalopathy or encephalomyelitis) is a complex multisystem disease with a wide range of disabling symptoms.

This free download provides information to help in the understanding of M.E, its symptoms, treatments and the current research situation.

M.E. is estimated to affect around 0.2-0.4% of the population (c.265,000 people in the UK) – including children and adolescents.

What you need to know about M.E.

M.E. can cause greater functional impairment and poorer quality of life than many other serious medical conditions, including multiple sclerosis and cancer.

M.E. has a characteristic clinical feature known as post-exertional malaise – a delayed exacerbation of symptoms that can follow even minor physical or mental exertion.

M.E. research has determined significant abnormalities in the central nervous system, immune system, endocrine (hormone producing) system, and in muscle (causing energy metabolism impairment).

M.E. is classified by the World Health Organisation (WHO) as a neurological disease. WHO classification is recognised by the Department of Health, the Medical Research Council and NICE (National Institute for Health and Care Excellence).

The NICE clinical guideline, which is aimed primarily at the NHS, is currently being rewritten. This follows stakeholder pressure – including from the ME Association – that the existing guideline was unfit for purpose. The new guideline has been delayed due to the coronavirus but is expected in 2021.

  • M.E. affects all social classes and ethnic groups.
  • M.E. is the commonest cause of long-term sickness absence from school.
  • M.E. can affect more than one family member – suggesting that genetic factors are involved.
  • M.E. has been estimated to cost the UK economy £3.3bn each year.
M.E. is not a minor ailment and there is a wide spectrum of severity.

M.E. is diagnosed following careful assessment of clinical history, physical examination, exclusion of other possible causes of symptoms and the application of diagnostic criteria. There are currently no blood or other diagnostic tests available.

M.E. is not a minor ailment and there is a wide spectrum of severity. Around 25% of people are severely affected – being housebound, or bedbound and often requiring a wheelchair if they can mobilise – at various stages during the illness.

M.E. can affect some people very severely, leading to atypical seizures, speech and swallowing difficulties and extreme intolerance to light and sound. These people will be bedbound, they require continuous 24-hour care and may need tube-feeding.

M.E. in most cases is triggered by a known event such as an acute infection. People with M.E. often report that they don’t feel as though they have recovered from the symptoms even after the infection has passed. In other cases, M.E. can develop following different triggers.

M.E. is considered a fluctuating condition – meaning that the symptoms can vary in form and intensity throughout the day, from day to day, and week to week – making it very unpredictable and hard to manage.

M.E. is a devastating disease with no established biomarker.

ME research funding has been woefully inadequate from central sources with much knowledge coming from studies funded by the charity sector. The ME Association has invested over £1million in biomedical research and continues to believe research offers the best hope for greater understanding and effective treatment.


M.E. is diagnosed following a significant reduction in pre-illness activity levels and an inability to return to normal function. The most important diagnostic symptoms are:

  • Post-exertional malaise/symptom exacerbation (PEM) – often with a delayed impact, lasting days or weeks before function is restored. PEM can also trigger a relapse.
  • Activity-induced muscle fatigue precipitated by trivially small exertion (physical or mental) relative to the patient’s previous activity tolerance.
  • Cognitive dysfunction – problems with short-term memory, concentration, word-finding.
  • Sleep problems – sleeping too little or too much, vivid-dreams, unrefreshing sleep.
  • Ongoing flu-like symptoms – including sore throats and enlarged glands, fever-like sweats, lethargy.
  • Orthostatic intolerance – problems with pulse and blood pressure control leading to feeling faint/dizzy when upright.

Other common symptoms include:

  • Pain – which can involve muscle, joints and nerves.
  • Problems with balance and with temperature control.
  • Sensitivity to light and sound.
  • Alcohol intolerance.
  • Gastrointestinal symptoms.


Most people with M.E. will make some degree of improvement over time.

Drugs can be prescribed to help manage or control some symptoms such as pain and sleep disturbance. There is no curative treatment – although several drugs are being assessed in clinical trials.

The most important aspect of ongoing care is activity management– which involves striking the right balance between activity and rest so as not to exacerbate symptoms. This is known as Pacing.

Most people with M.E. will make some degree of improvement over time. However, a significant minority remain permanently and severely affected and many will see fluctuations in severity over a period, with some getting progressively worse.

Nomenclature and definitions of M.E.

M.E. (myalgic encephalomyelitis) is the medical name that was introduced by The Lancet to describe an outbreak of the illness at the Royal Free Hospital in London in 1955. M.E. is the name that is preferred by people with the disease.

M.E. was renamed as CFS (chronic fatigue syndrome) by doctors in both the UK and USA during the 1980s. People with M.E., as well as patient support charities and a significant number of health professionals, do not feel that CFS is an appropriate name to use as it trivialises the level of suffering, ignores the multisystem symptomatology and can encompass people with ‘chronic fatigue’.

The term ‘encephalomyelitis’ is not a pathologically proven explanation for what may be happening within the nervous system. Consequently, it often causes dissent among doctors.

The ME Association therefore proposed the term ‘encephalopathy’, meaning a significant disorder of brain function, and Myalgic Encephalopathy has been accepted by NICE and others as an alternative.

In 2015 the influential Institute of Medicine (now the National Academy of Medicine) in America published a fully encompassing report – Beyond ME/CFS: Redefining an illness – that concluded:

‘ME/CFS is a serious, chronic, complex, and systemic disease that frequently and dramatically limits the activities of affected patients.  

‘In its most severe form, this disease can consume the lives of those whom it afflicts. It is “real.”

‘It is not appropriate to dismiss these patients by saying, “I am chronically fatigued, too.”’
M.E. is estimated to cost the UK economy, £3.3 billion each year.

In 2017 a 2020 Health report – Counting the Cost – estimated the economic cost of ME/CFS to the UK economy is around £3.3 billion per annum.

The 2007 NICE Guideline on ME/CFS is currently being re-written following criticism from the patient community that it was no longer fit for purpose. The ME Association is a stakeholder in the review process and Dr Charles Shepherd is an expert witness on the guideline committee. A new guideline has been delayed due to the coronavirus but is expected in 2021.

The Medical Research Council (MRC) regards ME/CFS as a research priority and issued a highlight notice to encourage research applications – especially in relation to immune system dysfunction and neuropathology.

In January 2020, a major new application from the ME/CFS Biomedical Partnership was submitted to the MRC that would result in a genetics study on 20,000 people with the condition. This £3.5million bid could provide answers to important questions about causation.

The ME Association has been involved in this vital initiative since the beginning and we hope to share some good news about the funding very soon. Please register your interest in the study as it will need the full support of the M.E. community if it is to succeed.

However, in general, research remains severely underfunded in the UK with most of the contribution still coming from the small charity sector. The ME Association Ramsay Research Fund has invested over £1million in biomedical research in recent years and continues to seek good quality applications.

Factsheets in this series

The ME Association

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