Chronic fatigue syndrome is a complicated disorder characterized by extreme fatigue that can't be explained by any underlying medical condition. The fatigue may worsen with physical or mental activity, but doesn't improve with rest.
The cause of chronic fatigue syndrome is unknown, although there are many theories — ranging from viral infections to psychological stress. Some experts believe chronic fatigue syndrome might be triggered by a combination of factors.
There's no single test to confirm a diagnosis of chronic fatigue syndrome. You may need a variety of medical tests to rule out other health problems that have similar symptoms. Treatment for chronic fatigue syndrome focuses on symptoms.
Symptoms
Chronic fatigue syndrome has eight official signs and symptoms, plus the central symptom that gives the condition its name:
Fatigue
Loss of memory or concentration
Sore throat
Enlarged lymph nodes in your neck or armpits
Unexplained muscle pain
Pain that moves from one joint to another without swelling or redness
Headache of a new type, pattern or severity
Unrefreshing sleep
Extreme exhaustion lasting more than 24 hours after physical or mental exercise
When to see a doctor
Fatigue can be a symptom of many illnesses, such as infections or psychological disorders. In general, see your doctor if you have persistent or excessive fatigue.
Causes
Scientists don't know exactly what causes chronic fatigue syndrome. It may be a combination of factors that affect people who were born with a predisposition for the disorder.
Some of the factors that have been studied include:
Viral infections. Because some people develop chronic fatigue syndrome after having a viral infection, researchers question whether some viruses might trigger the disorder.
Suspicious viruses include Epstein-Barr virus, human herpes virus 6 and mouse leukemia viruses. No conclusive link has yet been found.
Immune system problems. The immune systems of people who have chronic fatigue syndrome appear to be impaired slightly, but it's unclear if this impairment is enough to actually cause the disorder.
Hormonal imbalances. People who have chronic fatigue syndrome also sometimes experience abnormal blood levels of hormones produced in the hypothalamus, pituitary glands or adrenal glands. But the significance of these abnormalities is still unknown.
Resource: www.mayoclinic.org
