Causes of Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disorder or a group of disorders characterized by persistent fatigue for a period of at least six months. This condition may be accompanied by other symptoms like muscle pain, cognitive difficulties like impaired memory, insomnia, depression, poor immune response, cardiac problems, etc. Fatigue, being the characteristic feature of this condition, is worsened by physical or mental exertion and cannot be relieved by rest.

Fatigue is a common symptom associated with many diseases, so it is very important to rule out the possibility of other diseases before zeroing in on chronic fatigue syndrome. As there is no specific method to diagnose this condition, tests should be done to find out whether the symptoms are caused by any other disease.

There are many controversies regarding the name of the condition, its definition, causes and treatment. However, in 1994, an international committee of researchers convened a meeting of experts and drafted a definition. According to these experts, the symptoms of the affected person must come under the following criteria, to be diagnosed with chronic fatigue syndrome. The first condition is that the fatigue must last for a period of at least six months and the possibility of other diseases must be ruled out. The second criteria is that the affected person must experience four or more of the following symptoms concurrently. The symptoms are sore throat, problems with memory and concentration, muscle pain, swollen lymph nodes, a different pattern of headache, joint pain without redness or swelling, discomfort after some kind of exertion, etc. The symptoms must be persistent or recurring during the period of illness (six months or more) and should not precede this period of fatigue.

Till date, no specific reason has been identified to cause chronic fatigue syndrome. Researches are underway to find out the causes of this disorder. Several possible causes like action of infectious agents, physiological and psychological conditions, etc. have been suggested by researches. This disorder may be due to one or more such causes. Current research is more concentrated on the role of the immune system, the nervous system and the endocrine system.

It is also said that genetic and environmental factors play a role in the occurrence of this disease. Even though, there is no specific primary cause for this disorder, some experts believe that a convergence of the following factors can lead to this disorder:

• Genetic variations may play an important role in the occurrence of this disorder. A study of people affected with chronic fatigue syndrome revealed that there were alterations in some specific genes involved in immune function and communication between the cells. The link between chronic fatigue syndrome and genetic variation is still not proved.
• Some experts project brain abnormalities as the reason behind this disorder. According to them, abnormal levels of certain chemicals, controlled by the nervous system is responsible for the symptoms caused by chronic fatigue syndrome. Important functions like sleep, response to stress and depression, etc, are controlled by the chemicals produced by the hypothalamus-pituitary-adrenal axis. This factor is also not proved.
• Some suggestions favor a hyper-reactive immune system as the cause for chronic fatigue syndrome. Their contention is that irregularities of the immune system can cause this disorder. The immune system can be over-reactive and under-reactive at the same time. While some symptoms are caused by an over-reactive system, some are the resultants of an under-reactive immune system. There is no evidence to prove this contention though.
• It is also suggested that this disorder may be the result of some viral infections, but it is observed that only some patients show signs and symptoms of viral infection. This contention is based on the observations that the onset of this disease is with flu-like symptoms and there are reports of cluster outbreaks of chronic fatigue syndrome in people living in a particular area or household. There is no conclusive evidence to prove the role of any infectious agent in the occurrence of this disease.

Apart from the above said possibilities, several other causes have been put forward. They are iron deficiency anemia, low blood pressure, autoimmune disease causing inflammation of nervous system pathways, history of allergies, depression, etc.

Studies show that this disorder can affect people of all ages and from all walks of life. It is more common in people in the age group of 40 to 50, especially women. Chronic fatigue syndrome can affect children too and teenagers are more likely to develop this disorder. Early diagnosis and treatment is very important for recovery from this disorder.