Chronic fatigue syndrome (CFS) is an illness characterized by prolonged, debilitating fatigue that does not improve with rest and worsens with physical or mental activity. It is also characterized by multiple nonspecific symptoms such as headaches, recurrent sore throats, muscle and joint pains, and memory and concentration difficulties.
CFS can be hard to diagnose, and its cause or causes are unknown. Even its name can be confusing: CFS is also known as myalgic encephalomyelitis (ME or ME/CFS or CFS/ME), as well as chronic fatigue and immune dysfunction syndrome (CFIDS).
Profound fatigue, the hallmark of the disorder, can come on suddenly or gradually and persists or recurs throughout the period of illness. Unlike the short-term disability of an illness such as the flu, by definition CFS symptoms must have lasted for at least six months. They often linger for years.
CFS affects women at about 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 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.
The prevalence of CFS is difficult to measure because the illness can be difficult to diagnose, but, in general, it is estimated that at least 1 million people in the United States have CFS, according to the CDC. 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.
CFS does not appear to be a new illness, although it only recently was assigned a name. Relatively small outbreaks of similar disorders have been described in medical literature since the 1930s. Furthermore, case reports of comparable illnesses date back several centuries.
The international group organized by the CDC named the illness chronic fatigue syndrome because the name reflects the most common symptom: long-term, persistent fatigue. It is important to note, however, that the word “fatigue” may be extremely misleading. Fatigue is but one symptom among many that make up this illness, and it doesn’t reflect the significance of other disabling symptoms. The word also adds to generalized misunderstanding and trivialization of the illness..
There are no indications that 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 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 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.
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.
Although CFS can persist for many years, long-term studies indicate that 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 CFS, however, symptoms can get worse over time.
It appears that while the majority of people with 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 CFS and symptoms are managed and treated, the better the chances of improvement, which illustrates the importance of early diagnosis and treatment