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Chronic Fatigue Syndrome

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Signs and Symptoms

The problem that researchers, doctors, and patients face in identifying and diagnosing CFS is that its cause is unknown and symptoms may be invisible and unmeasurable. For many years, CFS was simply defined as an idiopathic chronic fatigue (fatigue of unknown origin). In the late 1980s, the Centers for Disease Control and Prevention (CDC), in conjunction with an international panel of CFS research experts, adopted a definition that was reviewed and updated in 1994. According to this definition, which is in current use, a diagnosis of CFS requires the following:

  1. Severe chronic fatigue of six consecutive months or longer with other known medical conditions excluded by clinical diagnosis
  2. Significant interference with daily activities and work
  3. Concurrently four or more of the following 8 symptoms:
    • Substantial impairment in short-term memory or concentration
    • Sore throat that is frequent or recurring
    • Tender lymph nodes in the neck or armpit
    • Muscle pain
    • Multi-joint pain without swelling or redness
    • Headaches of a new type, pattern or severity
    • Unrefreshing sleep
    • Post-exertional malaise lasting more than 24 hours

These symptoms must have persisted or recurred during six or more consecutive months of illness and must not have predated the fatigue.

Although this definition is now widely accepted and used by researchers and physicians to both study and diagnose CFS, there is still no consensus as to a cause. While a single cause may yet be identified, many researchers believe that CFS has multiple triggers. These include:

  • Viral infection such as Epstein Barr virus, although no microorganism has been isolated as the instigator
  • Immune dysfunction provoked by trauma, stress, or allergy, which in turn triggers CFS
  • Nutritional deficiency
  • Abnormally low blood pressure (neurally mediated hypotension) that can cause fainting
  • Stress that activates the HPA axis where the hypothalamus, pituitary and adrenal glands interact

While most researchers agree that CFS is not contagious, they have observed family patterns and believe there may be a tendency to an inherited predisposition of the condition. Some investigators feel that further research will reveal that CFS is not a single condition at all but a group of different disorders with a similar end point.

It is known that those affected by CFS have a definite onset of symptoms, that is, a time before which they felt well and had the energy for normal daily tasks. About 75% of the time, CFS is preceded by what appears to be a flu-like illness. Other cases of CFS arise following a period of intense physical or emotional stress, and some emerge slowly with those affected noticing a gradual decline in their energy and sense of well-being.

Besides the primary symptoms of CFS, a variety of other symptoms may be commonly seen. These include:

  • Abdominal pain
  • Allergies and sensitivities to foods, odors, chemicals, medication and sound
  • Bloating
  • Chest pain
  • Chills and night sweats
  • Chronic cough
  • Depression and anxiety
  • Irritable bowel or diarrhea
  • Dizziness
  • Dry eyes or mouth
  • Earaches
  • Irregular heartbeat
  • Jaw pain
  • Low grade fever
  • Morning stiffness
  • Nausea and loss of appetite
  • Numbness, tingling or burning sensation in the face hands or feet
  • Shortness of breath

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