Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an umbrella term that includes both myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). It is a serious, chronic and complex disease that affects many systems of the body and can profoundly impact daily activities. The main symptom is disabling fatigue that does not improve with rest and lasts at least 6 months. Fatigue may get worse after activity, which is known as post-exertional malaise. Other signs and symptoms may include muscle pain, joint pain, concentration and memory problems, headaches, sleep problems, fever, sore throat, and/or tender lymph nodes. ME/CFS generally occurs in young adults (20 to 40 years of age) and is twice as common in women.
The exact cause is not known, but symptoms may be triggered by an infection. Diagnosis can be difficult as there are no specific laboratory tests and the symptoms are common to a number of different illnesses. There is no cure or effective treatment for this condition but there are several clinical trials.
While the term ME/CFS is widely used, there is still a debate in the medical literature about the relationship between myalgic encephalomyelitis and chronic fatigue syndrome and there is no universally accepted definition. The term “systemic exertion intolerance disease” has been proposed as new term for both diseases.
Last updated: 4/14/2020
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine. Source Washington (DC): National Academies Press (US). Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. The National Academies Collection: Reports funded by National Institutes of Health. February, 2015; http://www.ncbi.nlm.nih.gov/pubmed/25695122.
Twisk FN. Replacing Myalgic Encephalomyelitis and Chronic Fatigue Syndrome with Systemic Exercise Intolerance Disease Is Not the Way forward. Diagnostics (Basel). February 5, 2016; 6(1):