Chronic fatigue syndrome

Definition

Chronic fatigue syndrome (CFS) is a condition that causes extreme tiredness. People with CFS have debilitating fatigue that lasts for six months or longer. They also have many other symptoms. Some of these are pain in the joints and muscles, headache, and sore throat. CFS does not have a known cause, but appears to result from a combination of factors.

Description

CFS is the most common name for this disorder, but it also has been called chronic fatigue and immune disorder (CFIDS), myalgic encephalomyelitis, low natural killer cell disease, post-viral syndrome, Epstein-Barr disease, and Yuppie flu. CFS has so many names because researchers have been unable to find out exactly what causes it and because there are many similar, overlapping conditions. Reports of a CFS-like syndrome called neurasthenia date back to 1869. Later, people with similar symptoms were said to have fibromyalgia because one of the main symptoms is myalgia, or muscle pain. Because of the similarity of symptoms, fibromyalgia and CFS are considered to be overlapping syndromes.

In the early to mid-1980s, there were outbreaks of CFS in some areas of the United States. Doctors found that many people with CFS had high levels of antibodies to the Epstein-Barr virus (EBV), which causes mononucleosis, in their blood. For a while they thought they had found the culprit, but it turned out that many healthy people also had high EBV antibodies. Scientists have also found high levels of other viral antibodies in the blood of people with CFS. These findings have led many scientists to believe that a virus or combination of viruses may trigger CFS.

CFS was sometimes referred to as Yuppie flu because it seemed to often affect young, middle-class professionals. In fact, CFS can affect people of any gender, age, race, or socioeconomic group. Although anyone can get CFS, most patients diagnosed with CFS are 25-45 years old, and about 80% of cases are in women. Estimates of how many people are afflicted with CFS vary due to the similarity of CFS symptoms to other diseases and the difficulty in identifying it. The Centers for Disease Control and Prevention (CDC) has estimated that 4-10 people per 100,000 in the United States have CFS. According to the CFIDS Foundation, about 500,000 adults in the United States (0.3% of the population) have CFS. This probably is a low estimate since these figures do not include children and are based on the CDC definition of CFS, which is very strict for research purposes.

Causes & symptoms

There is no single known cause for CFS. Studies have pointed to several different conditions that might be responsible. These include:

• Viral infections
• Chemical toxins
• Allergies
• Immune abnormalities
• Psychological disorders.

Although the cause is still controversial, many doctors and researchers now think that CFS may not be a single illness. Instead, they think CFS may be a group of symptoms caused by several conditions. One theory is that a microorganism, such as a virus, or a chemical injures the body and damages the immune system, allowing dormant viruses to become active. About 90% of all people have a virus in the herpes family dormant (not actively growing or reproducing) in their bodies since childhood. When these viruses start growing again, the immune system may overreact and produce chemicals called cytokines that can cause flu-like symptoms. Immune abnormalities have been found in studies of people with CFS, although the same abnormalities are also found in people with allergies, autoimmune diseases, cancer, and other disorders.

The role of psychological problems in CFS is very controversial. Because many people with CFS are diagnosed with depression and other psychiatric disorders, some experts conclude that the symptoms of CFS are psychological. However, many people with CFS did not have psychological disorders before getting the illness. Many doctors think that patients become depressed or anxious because of the effects of the symptoms of their CFS. One recent study concluded that depression was the result of CFS and was not its cause.

Having CFS is not just a matter of being tired. People with CFS have severe fatigue that keeps them from performing their normal daily activities. They find it difficult or impossible to work, attend school, or even to take part in social activities. They may have sleep disturbances that keep them from getting enough rest or they may sleep too much. Many people with CFS feel just as tired after a full night's sleep as before they went to bed. When they exercise or try to be active in spite of their fatigue, people with CFS experience what some patients call "payback"--debilitating exhaustion that can confine them to bed for days.

Other symptoms of CFS include:

• Muscle pain (myalgia)
• Joint pain (arthralgia)
• Sore throat
• Headache
• Fever and chills
• Tender lymph nodes
• Trouble concentrating
• Memory loss.

A recent study at Johns Hopkins University found an abnormality in blood pressure regulation in 22 of 23 patients with CFS. This abnormality, called neurally mediated hypotension, causes a sudden drop in blood pressure when a person has been standing, exercising or exposed to heat for a while. When this occurs, patients feel lightheaded and may faint. They often are exhausted for hours to days after one of these episodes. When treated with salt and medications to stabilize blood pressure, many patients in the study had marked improvements in their CFS symptoms.

Diagnosis

CFS is diagnosed by evaluating symptoms and eliminating other causes of fatigue. Doctors carefully question patients about their symptoms, any other illnesses they have had, and medications they are taking. They also conduct a physical examination, neurological examination, and laboratory tests to identify any underlying disorders or other diseases that cause fatigue. In the United States, many doctors use the CDC case definition to determine if a patient has CFS.

To be diagnosed with CFS, patients must meet both of the following criteria:

• Unexplained continuing or recurring chronic fatigue for at least six months that is of new or definite onset, is not the result of ongoing exertion, and is not mainly relieved by rest, and causes occupational, educational, social, or personal activities to be greatly reduced.
• Four or more of the following symptoms: loss of short-term memory or ability to concentrate; sore throat; tender lymph nodes; muscle pain; multi-joint pain without swelling or redness; headaches of a new type, pattern, or severity; unrefreshing sleep; and post-exertional malaise (a vague feeling of discomfort or tiredness following exercise or other physical or mental activity) lasting more than 24 hours. These symptoms must have continued or recurred during six or more consecutive months of illness and must not have started before the fatigue began.

Treatment

There is no cure for CFS, but many treatments are available to help relieve the symptoms. Treatments usually are individualized to each person's particular symptoms and needs. The first treatment most doctors recommend is a combination of rest, exercise, and a balanced diet. Prioritizing activities, avoiding overexertion, and resting when needed are key to maintaining existing energy reserves. A program of moderate exercise helps to keep patients from losing physical conditioning, but too much exercise can worsen fatigue and other CFS symptoms. Counseling and stress reduction techniques also may help some people with CFS.

Many medications, nutritional supplements, and herbal preparations have been used to treat CFS. While many of these are unproven, others seem to provide some people with relief. People with CFS should discuss their treatment plan with their doctors, and carefully weigh the benefits and risks of each therapy before making a decision.

Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, may be used to relieve pain and reduce fever. Another medication that is prescribed to relieve pain and muscle spasms is cyclobenzaprine (sold as Flexeril).

Many doctors prescribe low dosages of antidepressants for their sedative effects and to relieve symptoms of depression. Antianxiety drugs, such as benzodiazepines or buspirone may be prescribed for excessive anxiety that has lasted for at least six months.

Other medications that have been tested or are being tested for treatment of CFS are:

• Fludrocortisone (Florinef), a synthetic steroid, which is currently being tested for treatment of people with CFS. It causes the body to retain salt, thereby increasing blood pressure. It has helped some people with CFS who have neurally mediated hypotension.
• Beta-adrenergic blocking drugs, often prescribed for high blood pressure. Such drugs, including atenolol (Tenoretic, Tenormin) and propranolol (Inderal), are sometimes prescribed for neurally mediated hypotension.
• Gamma globulin, which contains human antibodies to a variety of organisms that cause infection. It has been used experimentally to boost immune function in people with CFS.
• Ampligen, a drug which stimulates the immune system and has antiviral activity. In one small study, ampligen improved mental function in people with CFS.

Alternative treatment

A variety of nutritional supplements are used for treatment of CFS. Among these are vitamin C, vitamin B₁₂, vitamin A, vitamin E, and various dietary minerals. These supplements may help improve immune and mental functions. Several herbs have been shown to improve immune function and have other beneficial effects. Some that are used for CFS are astragalus (Astragalus membranaceus), echinacea (Echinacea spp.), garlic (Allium sativum), ginseng (Panax ginseng), gingko (Gingko biloba), evening primrose oil (Oenothera biennis), shiitake mushroom extract (Lentinus edodes), borage seed oil , and quercetin.

Many people have enhanced their healing process for CFS with the use of a treatment program inclusive of one or more alternative therapies. Stress reduction techniques such as biofeedback, meditation, acupuncture, and yoga may help people with sleep disturbances relax and get more rest. They also help some people reduce depression and anxiety caused by CFS.

Prognosis

The course of CFS varies widely for different people. Some people get progressively worse over time, while others gradually improve. Some individuals have periods of illness that alternate with periods of good health. While many people with CFS never fully regain their health, they find relief from symptoms and adapt to the demands of the disorder by carefully following a treatment plan combining adequate rest, nutrition, exercise, and other therapies.

Prevention

Because the cause of CFS is not known, there currently are no recommendations for preventing the disorder.

Key Terms

Arthralgia

Joint pain.

Cytokines

Proteins produced by certain types of lymphocytes. They are important controllers of immune functions.

Depression

A psychological condition, with feelings of sadness, sleep disturbance, fatigue, and inability to concentrate.

Epstein-Barr virus (EBV)

A virus in the herpes family that causes mononucleosis.

Fibromyalgia

A disorder closely related to CFS. Symptoms include pain, tenderness, and muscle stiffness.

Lymph node

Small immune organs containing lymphocytes. They are found in the neck, armpits, groin, and other locations in the body.

Lymphocytes

White blood cells that are responsible for the actions of the immune system.

Mononucleosis

A flu-like illness caused by the Epstein-Barr virus.

Myalgia

Muscle pain.

Myalgic encephalomyelitis

An older name for chronic fatigue syndrome; encephalomyelitis refers to inflammation of the brain and spinal cord.

Natural killer (NK) cell

A lymphocyte that acts as a primary immune defense against infection.

Neurally mediated hypotension

A rapid fall in blood pressure that causes dizziness, blurred vision, and fainting, and is often followed by prolonged fatigue.

Neurasthenia

Nervous exhaustion--a disorder with symptoms of irritability and weakness, commonly diagnosed in the late 1800s.

Further Reading

For Your Information

Books

• Demitrack, Mark A., and Susan E. Abbey. Chronic Fatigue Syndrome: An Integrative Approach to Evaluation and Treatment. New York: The Guilford Press, 1996.
• Fisher, Gregg Charles. Chronic Fatigue Syndrome: A Comprehensive Guide to Symptoms, Treatments, and Solving the Practical Problems of CFS. New York: Warner Books, 1997.
• Hoffman, Ronald L. Tired All the Time: How to Regain Your Lost Energy. New York: Poseidon Press, 1993.
• Johnson, Hillary. Osler's Web: Inside the Labyrinth of the Chronic Fatigue Syndrome Epidemic. New York: Crown Publishers, 1996.

  Periodicals

• Cannon JG, et al. "Interleukin-1 beta, Interleukin-1 Receptor Antagonist, and Soluble Interleukin-1 Receptor Type II Secretion in Chronic Fatigue Syndrome." Journal of Clinical Immunology 17 (May 1997): 253-61.
• Houde, Susan Crocker, and Renee Kampfe-Leacher. "Chronic Fatigue Syndrome: An Update for Clinicians in Primary Care."The Nurse Practitioner 22 (July 1997): 30-40.
• Lerner, A. Martin, et al. "Hypothesis: A Unified Theory of the Cause of Chronic Fatigue Syndrome." Infectious Diseases in Clinical Practice 6 (1997): 239-243.
• "New Treatment for Chronic Fatigue Syndrome." Tufts University Diet & Nutrition Letter 13 (February 1996): 1-2.
• Weiss, Rick. "A Cure for Chronic Fatigue? If New Research Proves Right, Some Sufferers Have Nothing More than an Easy-to-Fix Blood Pressure Problem." The Nurse Practitioner 22 (July 1997): 30-40.

  Organizations

• American Association for Chronic Fatigue Syndrome. 7 Van Buren Street, Albany, NY 12206. (518) 435-1765. http://weber.u.washington.edu/~dedra/aacfs1.html.
• The CFIDS Association. Community Health Services, P.O. Box 220398, Charlotte, NC 28222-0398. (704) 362-2343.
• The National CFS Association. 919 Scott Avenue, Kansas City, KS 66105. (913) 321-2278.
• The National CFIDS Foundation. 103 Aletha Road, Needham, MA 02192. (781) 449-3535. http://www.cfidsfoundation.org/

  Other

• Centers for Disease Control and Prevention "The Facts about Chronic Fatigue Syndrome." CFS Research group, Mailstop A15, Centers for Disease Control and Prevention, Atlanta, GA 30333. (404) 639-1338. http://www.cdc.gov/ncidod/diseases/cfs/facts1.htm.
• National Institutes of Health, Public Service Resources "Chronic Fatigue Syndrome." http://www.niaid.hih.gov/publications/cfs/complete.htm.

Gale Encyclopedia of Medicine. Gale Research, 1999.