Symptoms

The main symptom of chronic fatigue syndrome (CFS) is a devastating tiredness or exhaustion that has lasted at least 6 months and does not improve much with rest. This fatigue also is so severe that it interferes with your work, your play, and your social activities. The fatigue and other symptoms described below may begin suddenly or they may develop gradually over weeks or months.

Other long-term symptoms include:

• Forgetfulness, memory loss, confusion, or difficulty concentrating.
• Sore throat.
• A fever.
• Tender lymph nodes in the neck or armpits.
• Muscle pain.
• Joint pain without redness or swelling.
• Headaches that are different from other headaches you have had in the past.
• Unrefreshing sleep (waking up feeling tired or not rested).
• Feeling unwell after exercise or other physical activities.

Because CFS is not easily diagnosed, health experts have established some rules to help them recognize the disease. To be diagnosed with CFS, you must have fatigue and at least four of the symptoms listed above. At least four of your symptoms must have started at the same time as or after your fatigue began, and they must have lasted for at least 6 months.

But if you have symptoms of CFS, such as often feeling very tired for no clear reason, you may still get treatment even if you don't quite meet these criteria. For instance, your doctor may decide you need treatment even if you have had symptoms for less than 6 months.

Some people with CFS develop a condition in which their heart rate increases and their blood pressure drops when they stand or sit up from a reclining position. This is often described as feeling "lightheaded" or feeling faint or dizzy. This condition is called orthostatic hypotension.

Depression is common and can make your other symptoms worse. Antidepressant medicines can help you feel better.

CFS causes symptoms that are the same as many other diseases, especially early on. For this reason, it can be diagnosed only after a thorough evaluation has ruled out other conditions with similar symptoms.