Myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome
Other names	Post-viral fatigue syndrome (PVFS), systemic exertion intolerance disease (SEID)[1]: 20
The four primary symptoms of ME/CFS according to the National Institute for Health and Care Excellence
Specialty	Rheumatology, rehabilitation medicine, endocrinology, infectious disease, neurology, immunology, general practice, paediatrics, other specialists in ME/CFS[2]: 58
Symptoms	Worsening of symptoms with activity, long-term fatigue, sleep problems, others[3]
Usual onset	Peaks at 10–19 and 30–39 years old[4]
Duration	Long-term[5]
Causes	Unknown[6]
Risk factors	Being female, family history, viral infections[6]
Diagnostic method	Based on symptoms[7]
Treatment	Symptomatic[8]
Prevalence	About 0.17% to 0.89% (pre-pandemic)[9]

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious long-term illness. People with ME/CFS experience a profound fatigue that does not go away with rest, sleep issues and problems with memory or concentration. They are able to do much less than before they became ill. Further common symptoms include dizziness, nausea and pain.^[3] The hallmark symptom is a worsening of the illness hours to days after minor physical or mental activity. This "crash" can last less than a day to several months.^[10]

The cause or causes of the disease are unknown.^[11] ME/CFS often starts after an infection, such as mononucleosis.^[12] ME/CFS can run in families, but the genes that contribute to ME/CFS risk are not known.^[13] ME/CFS is associated with changes in the nervous and immune systems, as well as in energy production.^[14] Diagnosis is based on symptoms because no diagnostic test is available.^[7]

The illness can improve or worsen over time, but full recovery is uncommon.^[12] Treatment is aimed at relieving symptoms, as no therapies or medications are approved to treat the condition.^[2]: 29 Pacing one's activities can help avoid flare-ups and counselling may help in coping with the illness.^[8] Before the COVID-19 pandemic, ME/CFS affected roughly one in every 150 people, although estimates varied widely.^[9] However, many people with long COVID fit ME/CFS diagnostic criteria.^[15] ME/CFS occurs more often in women than in men. It most commonly affects adults between ages 40 and 60 but can occur at other ages, including childhood.^[16]

ME/CFS has a large social and economic impact. About a quarter of individuals are severely affected and unable to leave their bed or home.^[10]: 3 The disease can be socially isolating.^[17] People with ME/CFS often face stigma in healthcare settings and care is complicated by controversies around the cause and treatments of the illness.^[18] Doctors may be unfamiliar with ME/CFS, as it is often not covered in medical school.^[15] Historical research funding for ME/CFS has been far below that of diseases with comparable impact.^[19]