Chronic fatigue syndrome is the medical term used to describe several health conditions which leads to persistent tiredness in the affected person and this particular symptom characteristically last for at least 6 months in adults and for at least 3 months in children. Unlike tiredness (fatigue) caused by other illness tiredness associated with chronic fatigue syndrome is not relieved by taking rest and the tiredness worsen with mental and physical stress.

Other than tiredness other associated symptoms of chronic fatigue syndrome include sleep without any refreshment, pain in different joints and muscles of the body, poor tolerance to light, loud sound, depression, breathing troubles etc.The exact underlying cause of chronic fatigue syndrome is not known however infection by certain viruses, exposure to psychological stress may be responsible and as per some experts the symptoms of chronic fatigue syndrome may precipitate due to interplay of different factors.There is no single test which can confirm chronic fatigue syndrome but several diagnostic tests are to be done before coming to the final diagnosis of chronic fatigue syndrome.

Treatment usually depends upon relieving of symptoms. Common treatment options include drugs like antidepressants, sleeping pills, etc. and certain therapies which include both psychological counseling along with gentle exercise.Chronic fatigue syndrome is quite rare. It is estimated that in every 100,000 adults about 7 to 3000 cases of chronic fatigue syndrome are diagnosed. In the US about 1 million people and in the UK about a quarter of a million people suffer from chronic fatigue syndrome. This condition is more common in females and rarely occurs in children and in adolescents.
Other medical terms used interchangeably with chronic fatigue syndrome include chronic fatigue immunodysfunction syndrome, myalgic encephalomyelitis, post viral fatigue syndrome, etc.

Symptoms
In most of the patients of chronic fatigue syndrome, the initial symptoms start suddenly and usually along with flu like symptoms characterized by fever, generalized body pain, malaise, cough etc. The most common preceding event in chronic fatigue syndrome is exposure to severe degree of stress within few months.
Commonly occurring symptoms include:
1) New onset episode of severe degree of tiredness usually lasting for at least 6 months, which occurs without any relation to exertion, is not relieved by taking rest and no other contributing medical conditions can be found associated with the episodes of tiredness.
2) Te tiredness is so severe that it interferes with daily routine and reduces the activity of the person to some extent
3) Other associated symptoms are loss of memory, poor concentration, no refreshment even after sleep, pain in the muscle (myalgia), pain in the joints, headache (either new onset or change in the character and severity), frequent episodes of sore throat, painful swelling of neck glands and glands located in the armpit ( cervical and axillary lymph nodes).
4) Other common symptoms include mental fogging, difficulty in maintain particular balance, posture, repeated episodes of black out, dizziness, lightheadedness, episodes of allergy, alteration of bowel movements, pain in the abdomen, bloated feeling, nausea, vomiting, episodes of chill, night sweat, intolerability to light, loud noise, blurring of vision, pain in the eyes, episodes of depression, mood swings, irritability, frustration, etc.
5) Sometimes decline in cognitive function like decrease in attention span, poor memory, delayed reaction time, etc.
The common complications associated with chronic fatigue syndrome include depression, social isolation, interruption in normal routine leading to difficulty in maintaining normal family and social relationships, poor performance at school, colleges and at work place etc.

Causes
The exact underlying cause of chronic fatigue syndrome is not yet understood clearly but several possible explanations are proposed. These are
1) Viral infections: infection by certain viruses namely Epstein Barr virus, human herpes virus 6, mouse leukemia virus, etc. may predispose the person to the symptoms of chronic fatigue syndrome. Although no conclusive evidence to support the association is there.
2) Impairment of the immune system may increase the susceptibility to the disease although this association is not also established.
3) Imbalance in the circulating hormones may lead to chronic fatigue syndrome in the future.

Risk factors
Common risk factors include
1) Age: usually people in between 40 and 50 years of age are at increased risk
2) Being women
3) Exposure stress

Treatment
Common treatment options include certain drugs to relieve symptoms like sleeping pills, anti depressant drugs, etc. undergoing therapy which include both psychiatric counseling and enrolling in graded exercise program.