Myalgic encephalomyelitis, formerly known as chronic fatigue syndrome and now often referred to as ME/CFS, was recently redefined and renamed to more accurately reflect the brain inflammation and multisystem symptoms of the disease.
With the renaming came new guidelines from the National Academy of Medicine to help primary and specialty care providers more readily diagnose and manage a condition that has traditionally been difficult to diagnose and manage.
Symptoms leading to a diagnosis of ME/CFS now include: an impairment in activities of daily living that persist for more than six months; an onset of unexplained profound fatigue that isn't helped by rest; a general feeling of discomfort after exertion; unrefreshing sleep; and either cognitive impairment (memory or learning problems) or symptoms that occur only when standing. See the Diagnosis section for more details.
ME/CFS affects women at three to four times the rate that it affects men, and the illness is diagnosed more often in people in their 40s and 50s. It can affect any sex, race or socioeconomic class. Research shows that it is at least as common in Hispanics and African Americans as it is in Caucasians. And although ME/CFS is less common in children than in adults, children can develop the illness, particularly during the teen years. It can be as disabling as multiple sclerosis and chronic obstructive pulmonary disease.
ME/CFS is estimated to affect between 826,000 and 2.5 million people in the United States, according to the Centers for Disease Control and Prevention. ME/CFS is sometimes seen in members of the same family, suggesting there may be a genetic link; more research is needed to prove this link.
ME/CFS does not appear to be a new illness. Outbreaks of similar disorders have been described in medical literature since the 1930s. Furthermore, case reports of comparable illnesses date back several centuries.
Interest in ME/CFS was renewed in the mid-1980s after several studies found slightly higher levels of antibodies to the Epstein-Barr virus (EBV) in people with ME/CFS-like symptoms than in healthy individuals. Most of these people had experienced an episode of infectious mononucleosis (sometimes called mono or the "kissing disease") a few years before they began to experience the chronic, incapacitating symptoms of ME/CFS. As a result, for a time, the ME/CFS illness became popularly termed "chronic EBV."
Further investigation revealed that elevated EBV antibodies were not indicative of ME/CFS, since healthy people have EBV antibodies and some people with ME/CFS don't have elevated levels of EBV antibodies.
ME/CFS may begin suddenly or come on gradually. The sudden onset frequently follows a respiratory, gastrointestinal or other acute infection, including mononucleosis. Other cases develop after emotional or physical traumas such as serious accidents, bereavement or surgery.
There are no indications that ME/CFS is contagious or that it can be transmitted through intimate or casual contact. Research continues to determine the safety of blood donation by people with ME/CFS. The AABB, an organization representing blood banking centers in the United States and around the world, has recommended the indefinite deferral of potential blood donors with a past or current history of ME/CFS. This recommendation has been adopted by the American Red Cross and America's Blood Centers, the two largest blood collectors in the United States.
Although ME/CFS can persist for many years, long-term studies indicate that ME/CFS generally is not a progressive illness. Symptoms are usually most severe in the first year or two. Thereafter, the symptoms typically stabilize, then persist chronically, wax and wane or improve. For some people with ME/CFS, however, symptoms can get worse over time.
It appears that while the majority of people with ME/CFS partially recover, only a few fully recover, while others experience a cycle of recovery and relapse. There's no way to predict which category you might fall into. There is some evidence that the sooner a person is diagnosed with ME/CFS and symptoms are managed and treated, the better the chances of improvement, which illustrates the importance of early diagnosis and treatment.