This syndrome presents with a sudden onset of flu-like symptoms with no prior history of severe exhaustion. With the onset of flu-like symptoms, the patient complains of severe exhaustion and postexertional malaise even after minimal physical exertion [8]. Along with severe fatigue, there may be other general symptoms like anorexia, nausea, and vomiting. There may be nightly drenching sweats and unrefreshing sleep.

Cognitive symptoms are very prominent and mainly include long- and short-term memory loss, poor concentration, and lack of alertness. Intelligence, language, and the power of reasoning are not affected. Cognitive symptoms are very important for a diagnosis, without this the disorder cannot be concluded. Mood fluctuations mainly anxiety, irritability, and comorbid depression might be seen.

Though the symptom presentation will be more or less similar in most of the patients, the functional capacity varies. Some can lead fairly normal lives while others are bedridden. Due to severe physical and mental exhaustion, work and social activities are greatly reduced.

There is no single symptom or test to diagnose this condition. Diagnosis is mainly based on the exclusion of other medical conditions that can produce fatigue mainly AIDS, malignancy, and thyroid or adrenal conditions. When a patient presents with fatigue after any physical activity as the main complaint, a thorough physical examination and blood examination must be done to exclude any other systemic disease.

For a clinical diagnosis there are certain essential criteria that should be present for an accurate diagnosis mainly:

• Short term memory loss/concentration difficulties
• Physical or mental exertion brings about severe malaise
• Altered and unrefreshing sleep
• Myalgia
• Arthralgia
• Sore throat which is persistent or recurring
• Tender lymph nodes mainly cervical and axillary

At least four of these criteria should be met along with dysfunctional cognitive symptoms.

Blood examination will show a low ESR, thus showing no signs of inflammation or infection. MRI and CT scans show no abnormality. Blood tests may be done to detect any antibodies if there was any prior infection. On clinical examination, crimson crescent discoloration of both anterior tonsillar pillars may be present. Since mood-related symptoms are often seen, other mental health conditions like schizophrenia, depression, bipolar disorder need to be ruled out. A psychiatrist will be able to diagnose if any one of the above conditions is causing undue fatigue.

As there is no known etiology for this condition there is no well-established mode of treatment. The treatment is mainly symptomatic. The objective is to improve the functional capacity of the patients so that they are able to carry out their daily activities with minimal fatigue.

The physician should plan the treatment according to the personal needs and status of the patient. This treatment should be modified from time to time depending on the medical condition and symptoms.

Recovery rates are good with proper treatment. Individuals are able to resume their daily activities. Relapses and remissions occur [6]. With treatment patients can recover within two years. Severe persistent cases show poor prognosis. Children and adolescents show better recovery rates. Regular monitoring is necessary as treatment requires modification according to status and symptoms of the condition [7].

Chronic fatigue syndrome is supposed to have multiple factors responsible but the exact etiology still remains unknown. Several theories have been postulated but there is no documented evidence. Viruses have been implicated in the causation of chronic fatigue syndrome; the most common associated viruses are Epstein-Barr virus (EBV) and herpes simplex 6 virus. Other immunosuppressive conditions like AIDS, malignancy, and thyroid disorders also have a certain role to play. These conditions also produce symptoms similar to chronic fatigue syndrome. Any abnormality in the immune system can trigger off this condition.

Genetic predisposition and familial tendency seem to play a role in this disorder. Depression, emotional instability, and mental fatigue are seen in cases with the condition but there is an uncertainty whether it’s a result or causation.

Recent studies show any period of stress, trauma, or emergency situations cause the hypothalamic-pituitary-adrenal axis (HPA) to fluctuate resulting in abnormal hormonal response causing a decreased production of cortisol [3]. There is no single causative agent, but the interplay of all the above factors produces this syndrome.

Since there are various definitions for the condition, the exact prevalence also varies. The condition affects all races and ethnic backgrounds. There is a female preponderance usually affecting women between 30-50 years of age. Children and young adults are rarely affected [4]. It is not a contagious disease but shows a familial tendency.

The pathogenesis still remains unknown in spite of many years of research. Many theories have been postulated, but no single theory has been pointed out in the etiopathogenesis.

On the basis of the clinical presentation, etiopathogenesis has been documented. Other investigations demonstrated abnormalities in other aspects including human brain functioning, immune responses, neuroendocrine responses and psychological tendencies [5]. Genetic predisposition is also considered vital for the manifestation of chronic fatigue syndrome.

Several investigations reveal the role of central nervous system due to several symptoms including difficulty in concentration, memory loss and lack of alertness. Various imaging techniques like MRI show significant changes in the subcortical white matter of the affected individuals. Other tests show decreased cerebral blood flow.

Imbalance in hypothalamic-pituitary-adrenal axis is also implicated including serotonin pathways. Abnormal response to stress or trauma is considered as a reason. Many patients also show decreased cortisol.

Viral infections like EBV virus or Herpes 6 virus have been implicated as patient’s blood shows antibodies to these infections. So post viral infection, patients present with chronic fatigue. Immune system also seems to play a role in the etiology, mainly immunocompromised states.

However, the outcome and medical utility of these findings still remains elusive. Chronic fatigue syndrome is a complex syndrome with varied pathophysiological abnormalities manifesting similar signs.

Due to a wide spectrum of symptoms and a number of physiological, pathological and psychological pathways playing a role, it makes the pathogenesis multifactorial.

There is no known prevention for chronic fatigue syndrome as the exact cause is not known.

Once diagnosed, prevention of aggravation of symptoms includes avoiding stimulants, stress and too much sleep. These factors are known to trigger the symptoms. Too much overexertion should be avoided.

Chronic fatigue syndrome is a state of of persistent fatigue that remains without any explanation for a minimum duration of 6 months. The cardinal symptoms are fatigue, memory loss, poor concentration, irritability, altered sleep patterns and muscle aches [1].

This syndrome was earlier known as myalgic encephalomyelitis (ME) and has been attributed to a viral infection. There is however no documented evidence of any infective cause of this condition at present. Laboratory investigations are normal.

The syndrome usually disables the individual to perform daily activities due to profuse exhaustion, lack of concentration and memory loss. This leads to depression in the patients. Genetic and psychological mechanisms also seem to play a role in this condition. The severity of symptoms varies from individual to individual.

The proportion of patients with organic disease remains uncertain [2]. Recent studies suggest that two thirds of patients with symptom duration of more than 6 months have an underlying psychiatric disorder.

Chronic fatigue syndrome is a condition that causes severe fatigue. This fatigue persists even after periods of rest. Any physical or mental exertion brings about exhaustion, which restricts the individual from doing their daily activities. There is no known cause for this condition. Viral infections are thought to cause this condition.

This syndrome mainly shows fatigue which should be present for a minimum of 6 months to confirm this medical condition. Along with this, the patient will show memory loss, problems in sleeping, muscle and joint pains, and sore throat. These symptoms are important to confirm chronic fatigue syndrome.

This syndrome mainly affects women, and usually occurs between 30- 50 years of age. There are no specific tests for this condition and thus hard to detect by the physician. The exclusion of other medical conditions helps in the diagnosis.

Since the cause remains unknown, there is no specific treatment. Treatment is mainly directed towards relieving the symptoms shown by the patient. The aim of the treatment is to enable the individual to carry out daily activities and prevent from being totally bedridden. There is no total cure for this condition; periods of relapse and remission are common.

Regular monitoring and follow-up are important as the treatment will also be modified according to the condition of the patient. Total recovery is not possible, but lifestyle modifications and therapy can help the patient lead a fairly normal life.

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