C–E

chronic fatigue syndrome A constellation of
symptoms that exist within a framework of pro-
found, persistent fatigue and generalized PAIN. Nei-
ther the fatigue nor other symptoms improve with
rest. Chronic fatigue syndrome often debilitates
those who have it and confounds the doctors try-
ing to treat them. Researchers have as yet been
unable to identify clear pathologic (disease
process) reasons that account for the symptoms of
chronic fatigue syndrome. Proposed causes
include viral INFECTION(such as with EPSTEIN-BARR
VIRUS or human herpesvirus 6), HYPERSENSITIVITY
REACTION(ALLERGY), autoimmune disorder or other
IMMUNE SYSTEMdysfunction, hormonal imbalance,
chronic intermittent HYPOTENSION(low BLOOD PRES-
SURE), subclinical ANEMIA, and HYPOGLYCEMIA(low
blood sugar). In many people chronic fatigue syn-
drome appears after a serious viral infection or
after an event that causes significant stress.

Symptoms and Diagnostic Path
In many people, the initial symptoms of chronic
fatigue syndrome are those of a viral infection
such as INFLUENZA. But the symptoms do not go
away after the typical timeline for such an infec-
tion. Because ongoing symptoms are widely vari-
able and often without apparent physical cause,
medical experts have established two basic criteria
for a diagnosis of chronic fatigue syndrome. For
six months or longer the person must have

• severe, chronic fatigue for six months or longer
  with diagnostic evaluation unable to find a
  medical reason for the fatigue


• four or more of the eight additional key symp-
  toms: sore THROAT, MUSCLEpain, tender LY M P H
  nodes, noticeable difficulty with concentration
  and short-term memory; pain in numerous

joints; headaches; difficulty sleeping or unrest-

ful sleep; feeling of overwhelming exhaustion

after physical exertion.

In addition to these core symptoms, most peo-

ple have numerous other symptoms that may

include

• ABDOMINAL PAIN
  
  
  • CHEST PAINand shortness of breath
  
  
  
  


• chronic COUGH
  
  
  • NAUSEA, gastrointestinal discomfort, and DIAR-
    RHEA
  
  
  • night sweats
  
  
  • DEPRESSION, anxiety, or panic attacks
  
  
  
  


• jaw pain


• earaches


• “pins and needles” sensations


• dizziness

There are no diagnostic procedures that define

chronic fatigue syndrome. Rather, the doctor

orders certain diagnostic tests to rule out other

potential causes for the symptoms. These include

BLOODtests to measure thyroid HORMONE levels,

blood cell types and counts, electrolytes, globulins,

and GLUCOSElevels in the blood circulation. The

doctor may desire additional blood tests and uri-

nalysis. Abnormal findings point in a different

clinical direction; a diagnostic criterion for chronic

fatigue syndrome is that such routine tests are

normal.

Diagnostic imaging procedures such as MAG-

NETIC RESONANCE IMAGING (MRI) and COMPUTED

TOMOGRAPHY(CT) SCAN may rule out other sus-

pected conditions though do not help the doctor

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