What is Myalgic Encephalomyelitis/Chronic Fatigue Syndrome?


Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, complex, neuroimmune disease that profoundly limits people’s lives. It is often triggered by an infection and is relapsing-remitting. It is not well understood and there are no test or cure. It is estimated that about 15-30 million people globally have ME/CFS.

ME/CFS is often a hidden illness, and people with the condition are frequently ignored or dismissed by doctors and other healthcare professionals. It can cause significant loss of function and is associated with a lower quality of life than many other serious diseases such as multiple sclerosis, stroke, heart disease, or diabetes. People with ME/CFS are more likely to be unemployed and to have poorer outcomes than people without the disease.

A key symptom of ME/CFS is post-exertional malaise, which is the sharp and debilitating worsening of symptoms and/or fatigue following physical or cognitive activity. It can occur immediately after an event or it may be delayed by up to 24 hours. It can be triggered by a range of activities from going for a jog to brushing teeth, and it is recurrent. People with ME/CFS often have other symptoms such as persistent or widespread muscle pain, unrefreshing sleep, difficulty concentrating, orthostatic intolerance (problems with balance and blood pressure) and periods of bloating and constipation, or problems regulating body temperature. Some people with ME/CFS have comorbidities, which are illnesses that occur alongside ME/CFS. These include fibromyalgia (widespread muscle pain), sleep disordered breathing, irritable bowel syndrome, postural orthostatic tachycardia, and anxiety and depression.

It is a relapsing-remitting illness that can vary in intensity from day to day, week to week, and month. It can become severe and disabling, and some people are bedbound.

The cause of ME/CFS is unknown, but it is thought to be an autoinflammatory disease and involves inflammation of the brain and spinal cord. It is a multisystemic, chronic condition that affects the brain and the rest of the body.

ME/CFS can be triggered by a variety of infections, including glandular fever and Epstein-Barr virus (EBV), herpes viruses (including herpes simplex, varicella zoster, and hepatitis A, B, or C). There is also some evidence that it can be triggered by vaccinations, particularly the measles, mumps, and rubella vaccine, or by bacterial meningitis.

The most recent formal definitions of ME/CFS suggest that it is a distinct illness that is not the same as other conditions. ME/CFS is a complex and complexly overlapping illness, and research is required to identify diagnostic biological markers and develop effective treatments. The name of the illness has changed over time, and it is currently known as ME, but it is sometimes referred to as chronic fatigue syndrome or CFS in the USA and some other countries. However, this can lead to confusion and misunderstandings with healthcare professionals, which is why Solve ME/CFS uses the term ME only. The charity aims to provide clarity on this matter and encourages the use of the most recent definitions of ME by governments and clinicians.