This is the second installment in Pain.com’s Chronic Fatigue Syndrome series. The topics of focus for this article are the causes and symptoms of chronic fatigue syndrome.
The cause of Chronic Fatigue Syndrome remains unknown. Chronic Fatigue Syndrome is not a well-understood condition in general, although it has a well-defined list of symptoms. A diagnosis of Chronic Fatigue Syndrome is made by ruling out other conditions that cause severe fatigue, so it often seems like a “diagnosis of last resort” for a patient when doctors can’t find anything else wrong with them.
A wide variety of causes have been implicated for Chronic Fatigue Syndrome. One hypothesis is that the condition is caused by a virus that has yet to be identified. The basis for this idea is that the symptoms of Chronic Fatigue Syndrome resemble in some ways the symptoms of known viral infections that can cause severe fatigue, such as Epstein-Barr virus or herpesvirus 6. Some doctors think that Chronic Fatigue Syndrome is caused by immune dysfunction, or a combination of an unknown viral infection with an immune dysfunction component. Other causes have been proposed, such as allergies, genetic factors, chronic low blood pressure, low blood sugar levels, iron-deficiency anemia, clinical depression, autoimmune disease, disrupted circadian rhythms, physical or chemical abnormalities in the brain, and dysfunction of endocrine organs that produce hormones.
These ideas have varying degrees of support, and it is not at all clear which, if any, of these hypotheses are correct. To complicate things, some scientists think that multiple factors need to come together for Chronic Fatigue Syndrome to develop, or that Chronic Fatigue Syndrome can be caused by different factors in different individuals. For instance, there may be some people in which Chronic Fatigue Syndrome is caused by a viral infection and others in which non-viral factors play a bigger role. With a difficult diagnostic process and without an identified cause, identifying and treating Chronic Fatigue Syndrome is difficult.
The main symptom that is present in Chronic Fatigue Syndrome is, obviously, chronic fatigue. Chronic fatigue is defined as fatigue that lasts for at least six months. The symptoms of Chronic Fatigue Syndrome usually come on suddenly over a period of a few days, not gradually over weeks or months. The fatigue associated with Chronic Fatigue Syndrome is often debilitating to the point of the affected person’s activity level being cut in half. This unrelenting fatigue is not improved after sleeping.
Fatigue is not the only symptom of Chronic Fatigue Syndrome. People with Chronic Fatigue Syndrome may also have difficulty concentrating or remembering things. If a person with Chronic Fatigue Syndrome tries to exercise or do something requiring strenuous mental activity, the resulting exhaustion can last for over a day after the activity. Physical symptoms such as lymph node swelling or tenderness, sore throat, muscle pain, joint pain without swelling, and headache also occur frequently in people with Chronic Fatigue Syndrome.
The symptoms listed above are the main symptoms that define Chronic Fatigue Syndrome. However, people with Chronic Fatigue Syndrome may also report other symptoms that are not part of the medical definition of the syndrome. These symptoms include: weight gain, weight loss, dizziness, fainting, irregular heartbeat, digestive upset, nausea, cough, and chest pain. Depression, irritability, and anxiety problems have also been reported.