Chronic fatigue syndrome, also known as chronic fatigue and immune dysfunction syndrome, is a puzzling medical condition that usually strikes women ages 30 to 50, though the condition can affect anyone, according to the National Institutes of Health. Up to 1 million people in the United States are affected by chronic fatigue syndrome, or CFS, according to the Solve ME/CFS Initiative (formerly the Chronic Fatigue and Immune Dysfunction Syndrome Association of America).
Because there is no known cause or even specific diagnosis for the malady, doctors and the general public have historically puzzled over whether CFS is real. But many doctors today view the syndrome as a serious medical condition requiring treatment, according to Dr. Richard Podell, a clinical professor in the department of family medicine at Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey.
Chronic fatigue syndrome is characterized by extreme fatigue that lasts for at least six consecutive months and that is made worse by physical activity and stress, according to the Centers for Disease Control (CDC). This fatigue isn't the normal tiredness that might result from not getting enough rest or engaging in strenuous physical activity. Those with CFS feel fatigue regardless of the amount of rest they get, and this condition gets in the way of everyday life, making normal daily activities and work difficult, Podell told Live Science.
Many of those with CFS also experience bouts of intense exhaustion — sometimes accompanied by other symptoms — after engaging in physical activity. Known as post-exertional malaise, these periods of exhaustion can last for 24 hours or more, according to the CDC. In addition to such exhaustion, the CDC uses the following list of symptoms to diagnose CFS:
- Impaired short-term memory and concentration
- Muscle pain
- Joint pain not accompanied by swelling or redness
- Tender lymph nodes in the neck or armpit
- Frequent or recurring sore throat
There are also many other symptoms of chronic fatigue syndrome that the CDC does not always use to diagnose the condition. These include:
- Irritable bowel syndrome
- Depression or other psychological problems
- Chills and night sweats
- Dizziness and balance problems
- Sensitivity to certain smells, noises or foods
- Insomnia and other sleep problems
The cause of chronic fatigue syndrome is still something of a mystery to researchers. Over the past several decades, medical studies examined if the condition was contagious (spread person-to-person or animal-to-person), but found no evidence that it is. Studies have also failed to support an association between the condition and a number of transmissible diseases.
However, one study conducted in 2009 by researchers with the National Institutes of Health found a connection between CFS and a newly discovered virus, xenotropic murine leukemia virus-related virus, or XMRV. Subsequent research linked CFS to other, similar viruses. But four studies published in 2010 suggested that the original study by NIH-funded scientists was flawed. By 2011, all research connecting CFS to viral diseases had been retracted by the scientific journals that had originally published the findings, according to the journal Nature (opens in new tab).
Researchers are still exploring possible links between other infectious agents and chronic fatigue syndrome. According to the CDC, some of the possible infectious agents that have been studied in the past or which are still under investigation include:
- Epstein-Barr virus infection, also known as mononucleosis
- Human herpesvirus 6 infection, which commonly affects AIDS patients and organ transplant recipients taking immune-suppressant drugs
- Enterovirus infection, a virus that targets the gastrointestinal tract
- Rubella, or German measles
- Candida albicans, a fungus that causes yeast infections
- Bornaviruses, which result in an infectious neurological syndrome
- Mycoplasma, which causes a type of pneumonia
- Ross River virus, which causes a type of mosquito-borne disease
- Coxiella burnetii, which causes Q fever, a bacterial infection that can affect the lungs, liver, heart and other parts of the body
Some studies also suggest that CFS may be caused by an inflammation along the nervous system as a response to the immune system, according to the NIH. The agency additionally cites age, stress, the environment and genetics as possible causes. Hypotension (chronic low blood pressure), depression, anemia and allergies are among the causes proposed by the Mayo Clinic.
Diagnosis & tests
A doctor will only diagnose chronic fatigue syndrome after ruling out all other reasons for fatigue in a process known as a diagnosis of exclusion. Factors that must first be ruled out include immune disorders, drug dependence, infection, endocrine disorders, tumors, and psychiatric and psychological illnesses like depression and muscle or nerve disease, according to the NIH.
A number of factors complicate diagnosis, including the fact that there is no laboratory test or biomarker for CFS. Fatigue and many of the other symptoms of the condition resemble those associated with a range of other illnesses, further complicating diagnosis. The condition is characterized by periods of remission and relapse, which means that patients who have the syndrome may not always appear to be suffering from it. And because symptoms vary widely, it is difficult for medical professionals to pin down exact diagnostic criteria.
Treatment & medication
No known medication or treatment can completely cure chronic fatigue syndrome. The Centers for Disease Control encourages people with the condition to create a support group of doctors, therapists and family members. That's because not only do patients with the syndrome have to deal with extreme tiredness, but also the uncertainty of when a certain symptom will take place, potential loss of independence, mood swings, changes in relationships with friends and family as a result of the tiredness and potential irritability, decreased sexual appetite, and poor memory, according to the CDC.
Though no cure for CFS has yet been identified, research into treating the condition is ongoing. Podell listed several researchers — including Dr. Jose Montoya at Stanford School of Medicine in California — who are exploring the effectiveness of using antiviral medication to treat CFS patients who have abnormally high levels of antibodies for Epstein-Barr virus and herpes virus.
Even though it's not possible to cure the syndrome, it is possible to treat the symptoms. Keeping a healthy diet, taking antidepressants (if relevant), learning good sleep management techniques, taking necessary medication for pain and undergoing cognitive behavioral therapy can improve the condition, according to the NIH. It's also a good idea to know your limits in stressful or challenging activity and your tiredness levels.
Reducing stress and promoting relaxation through biofeedback, deep breathing, massage, meditation and yoga also help patients cope with chronic fatigue syndrome, according to the NIH.
This article is for informational purposes only, and is not meant to offer medical advice.
- Based on five studies, a systematic review published by the Cochrane Database of Systematic Reviews cautiously concludes that exercise therapy is a promising treatment for chronic fatigue syndrome.
- Some people with CFS cannot work and can apply for disability benefits through the Social Security Administration.
- The Solve ME/CFS Initiative (SMCI) offers a webinar series on CFS research. The series is archived on SMCI's website.