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Chronic Fatigue Syndrome Health Center

Chronic Fatigue Syndrome

Chronic fatigue syndrome, or CFS, causes you to feel so tired that you can’t complete normal, daily activities. While chronic fatigue syndrome has no known cause and is difficult to diagnose, its major symptoms can be treated.

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What Happens

In some cases, chronic fatigue syndrome (CFS) develops after a flu-like illness such as mononucleosis (mono) or after a period of unusual stress. But it may also occur without warning, even if you have not been sick.

The fatigue may come upon you gradually or quite suddenly. Because fatigue can be vague and can be caused by many things, you might not pay attention to the problem for several weeks or months. It is hard to say what is normal with CFS. That's because the diagnosis often is not clear for some time.

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