myalgic encephalomyelitis/chronic fatigue syndrome
medical condition
myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), condition characterized by persistent debilitating
fatigue that has no identifiable cause. ME/CFS is a remarkably complex
illness and remains incompletely understood. These factors complicate its accurate
diagnosis and have raised questions regarding its naming and description.
Epidemiology and characteristics
Worldwide, an estimated 0.2 to 2.8 percent of people are affected by ME/CFS. However,
prevalence rates likely are much higher because an estimated 90 percent of persons living with ME/CFS may be undiagnosed. There are various reasons for such drastic underdiagnosis; some examples include limited access to
health care, a lack of knowledge about ME/CFS among health care providers, a lack of acceptance by some members of the medical
community, the absence of tests to detect ME/CFS, and fatigue being a
ubiquitous symptom of illness. Indeed, while fatigue can undermine a person’s ability to work and carry out day-to-day tasks, physicians generally consider fatigue to be a nonspecific symptom, causing it to be readily overlooked. Moreover, although anyone can be affected by ME/CFS, it is most common in adults between ages 40 and 60 and tends to affect women more often than men; this age range and gender difference presents significant challenges, particularly in
differentiating ME/CFS from symptoms of early
menopause.
Some of the first reports of “outbreaks” of fatigue syndrome were made in the 1930s and often involved
polio patients. Such clusters of fatigue onset among hospitalized patients instilled the idea that the condition was potentially infectious. In 1970 a review of reported outbreaks led to the conclusion that fatigue syndrome, then known as
benign myalgic encephalomyelitis, was a psychosocial phenomenon, rather than a specific physical disorder. In the mid-1980s the term
benign was discarded, and diagnosis of myalgic encephalomyelitis (ME) was based on prolonged muscle fatigue following mild physical effort. Shortly thereafter health officials in the
United States renamed the condition chronic fatigue syndrome (CFS), leaving ME as a synonym.
Through much of the 1990s and into the early 2000s, the validity of CFS as a distinct disorder was questioned, especially because of the considerable overlap with other functional somatic syndromes, such as
fibromyalgia and
Gulf War syndrome. In addition, some patients felt stigmatized by use of the term
fatigue, and, because
symptoms arise in multiple body systems and involve more than fatigue, there was considerable pressure to rename the condition. Additionally, some experts considered ME and CFS to be two distinct conditions. Today, because of the condition’s complexity, it is generally referred to by using the umbrella term
ME/CFS, though, in the view of some, this remains inadequate.
Suspected causes, diagnosis, and treatment
Multiple theories about the cause of ME/CFS have been advanced, but none have been proved. Suggested causes include bacterial or viral infections, genetic factors (the condition appears to run in families), physical injury or emotional trauma, metabolic disorders, and altered immune function.
Diagnosis of ME/CFS is based primarily on two criteria: severe
fatigue lasting six months or longer and the coexistence of any four other characteristic symptoms, which are mild fever,
sore throat, tender
lymph nodes, muscle
pain and weakness,
joint pain,
headache,
sleep disorders, confusion, and
memory loss. Symptoms are often similar in appearance to those of other conditions and tend to come and go or may fluctuate in severity over time. Thus, diagnosis of ME/CFS further requires all other illnesses or medical conditions associated with the same symptoms to be ruled out clinically.
There is no cure for ME/CFS. Patients can be treated with drugs to control their most severe symptoms; for example, some patients are treated with
antihistamines to control allergy-like symptoms or with
sedatives to treat
sleep disorders. Many patients respond positively to a range of nondrug therapeutic approaches, including exercise therapy,
counseling, and stress reduction. In addition, studies have shown promising responses to
cognitive behavioral therapy, in which patients learn to develop strategies that help them cope with their condition and that improve the quality of their lives. While some persons with ME/CFS become progressively worse, most improve gradually, and some eventually achieve full recovery.
