Chronic Fatigue Syndrome

According to the CDC, chronic fatigue syndrome (CFS) is defined by the presence of:
unexplained, persistent fatigue that is of new onset; is not the result of ongoing exertion; is not alleviated by rest; and results in substantial reduction in previous levels of occupational, educational, social, or personal activities AND

a. impairment in short term memory or concentration
b. sore throat or tender lymph nodes in the neck or under the arms
c. muscle pain or multijoint pain without redness or swelling
d. headache of a new pattern or severity
e. 2 of the above
f. 4 of the above

Correct answer is F - chronic fatigue syndrome is diagnosed by persistent fatigue and the presence of four or more of the above symptoms that persist during six or more consecutive months and that have not been present prior to the onset of the CFS. Other symptoms which are also included in making the diagnosis are unrefreshing sleep, low grade fever or post-exertional malaise lasting more than 24 hours.

Patients who have chronic fatigue but who do not have these criteria are defined as having idiopathic chronic fatigue. Less than 10 percent of patients who complain of fatigue meet the criteria for CFS. It is twice as more likely to occur in women.


CFS is a difficult diagnosis to make due to the lack of physical or laboratory findings. The history is the most important part of the evaluation. Simple blood tests for blood count, thyroid, sugar, kidney and liver function and HIV and tuberculosis may be done to rule out other causes, but in general more extensive testing for conditions such as Lyme disease or EBV (Epstein Bar Virus) is not recommended.

The cause remains unclear. From the 1930's to the 1950's, the cause was assumed to be due to chronic brucellosis infection, and from 1950's to 1970's it was hypoglycemia. More recently research has focused on chronic Epstein Barr virus (EBV) infection, Lyme disease, allergies, candidiasis, and immune system disorders. However, scientific data does not support any of these hypotheses. Another controversial factor is the role of depression in this condition. Three studies verified that two-thirds or more of patients with CFS meet criteria for anxiety disorders or depression. However, it is debated if this is a primary cause or a secondary symptom as a result of chronic fatigue.

Several treatment strategies including multiple medications have been tried, but the only regimens which have been shown to have a positive impact are cognitive behavior therapy (CBT) and graded exercise therapy. The behavior therapy consists of a series of one hour sessions designed to modify behavior that may delay recovery. Support groups were not as beneficial as individual sessions. Ideally this is done in combination with exercise therapy. Although exercise can initially worsen the symptoms, it is not advised to increase rest. Patients are encouraged to gradually push themselves by doing cardiopulmonary exercises such as walking on a treadmill. Finally another important factor in long term treatment management is the rapport that exists between the physician and patient.

Patient resources: Center for Disease Control, National CFS and Fibromyalgia Association, Up To Date Patient Information.

References:
The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group.
Psychiatric diagnoses in patients who have chronic fatigue syndrome.
Interventions for the treatment and management of chronic fatigue syndrome: a systematic review.
Cognitive behaviour therapy for the chronic fatigue syndrome: a randomized controlled trial.