Chronic Fatigue Syndrome

Introduction:
Severe fatigue is a common complaint among patients. Often, the fatigue is transient or can be attributed to a definable organic illness. Some patients present with persistent and disabling fatigue, but show no abnormalities on physical examination or screening laboratory tests. In these cases, the diagnosis of chronic fatigue syndrome (CFS) should be considered.

According to Centers for Disease Control and Prevention (CDC, USA) Chronic fatigue syndrome (CFS) currently is defined as:
(1) fatigue of at least 6 months' duration, seriously interfering with the patient's life; and (2) without evidence of various organic or psychiatric illnesses that can produce chronic fatigue.

The World Health Organization classifies myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) as a nervous system disease. Together with other diseases under the G93 heading, ME/cfs shares a triad of abnormalities involving elevated oxidative and nitrosative stress (O&NS), activation of immuno-inflammatory pathways, and mitochondrial dysfunctions with depleted levels of adenosine triphosphate (ATP) synthesis.

Clinical features:
Elaborately CFS is characterized by debilitating fatigue with associated myalgias, tender lymph nodes, arthralgias, chills, feverish feelings, and postexertional malaise. According to Komaroff there may be abrupt onset with an 'infectious-like' illness, intermittent unexplained fevers, arthralgias and 'gelling' (stiffness), sore throats, cough, photophobia, night sweats, and post-exertional malaise with systemic symptoms.

According to Clauw 4 of the following criteria need to be present: sore throat, impaired memory or cognition, unrefreshing sleep, postexertional fatigue, tender glands, aching stiff muscles, joint pain, and headaches.

Prevalence:
While chronic, debilitating fatigue is common in medical outpatients, CFS is relatively uncommon. Prevalence depends substantially on the case definition used.

Etiology:
It is known that CFS is a heterogeneous disorder possibly involving an interaction of biologic systems. Medical research continues to examine the many possible etiologic agents for CFS (infectious, immunologic, neurologic, and psychiatric), but the answer remains elusive.

Diagnosis:
Diagnosis of CFS is primarily by exclusion with no definitive laboratory test or physical findings.

Differential diagnosis should be considered carefully as similarities with fibromyalgia & teperomadibular joint disorder exist and concomitant illnesses include irritable bowel syndrome, depression, and headaches.
Course of CFS:

According to Komaroff the illness can last for years and is associated with marked impairment of functional health status.

Treatment:
Therefore, treatment of CFS may be variable and should be tailored to each patient. Therapy should include graded exercise (SF-36 is useful in assessing functional status), diet, good sleep hygiene, antidepressants, and other medications, depending on the patient's presentation.

It is noteworthy that for graded exercises to be implemented one need to assess the exercise capacity of the individual.