An examination of the working case definition of Chronic Fatigue Syndrome (CFS)

PURPOSE: Chronic fatigue syndrome (CFS) currently is defined

by a working case definition developed under the leadership of

the United States Centers for Disease Control and Prevention

(CDC) based on a consensus among experienced clinicians. We

analyzed the experience from one large center to examine the

adequacy of the case definition.


Predefined clinical and laboratory data were collected

prospectively from 369 patients with debilitating fatigue, of

whom 281 (76%) met the major criteria of the original CDC case

definition for CFS: (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 same clinical

data were obtained from 311 healthy control subjects and two

comparison groups with diseases that can present in a similar

fashion; relapsing-remitting multiple sclerosis (n = 25) and

major depression (n = 19).

RESULTS: All of the minor criteria

symptoms from the original CDC case definition distinguished

patients with debilitating chronic fatigue from healthy

control subjects, and many distinguished the patients with

chronic fatigue from the comparison groups with multiple

sclerosis and depression: myalgias, postexertional malaise,

headaches, and a group of infectious-type symptoms (ie,

chronic fever and chills, sore throat, swollen glands in the

neck or underarm areas). In addition, two other symptoms not

currently part of the case definition discriminated the

chronic fatigue patients from the control/comparison groups:

anorexia and nausea. Physical examination criteria only

infrequently contributed to the diagnosis. Patients meeting

the CDC major criteria for CFS also met the minor criteria in

91% of cases.

CONCLUSION: Patients meeting the major criteria

of the current CDC working case definition of CFS reported

symptoms that were clearly distinguishable from the experience

of healthy control subjects and from disease comparison groups

with multiple sclerosis and depression. Eliminating three

symptoms (ie, muscle weakness, arthralgias, and sleep

disturbance) and adding two others (ie, anorexia and nausea)

would appear to strengthen the CDC case definition of CFS.

MCM: Evaluates 281 Pts meeting original CDC *major* criteria

for CFS– they are termed “chronic fatigue” patients and were

evaluated to see to what extent they met the minor criteria.

All of the minor criteria were found much more commonly in CF

compared to NL pts.

The following symptoms significantly differentiated the CF pts

vs muliple sclerosis MS and major depression MD: myalgias (89%

vs 68% vs 68%), postexertional malaise (79% vs 52% vs 19%),

headache (59 vs 28 vs 22), and infectious-type symptoms:

fever/chills (43 vs 4 vs 10), sore throat (64 vs 8 vs 11),

swollen neck glands (60 8 11) or swollen arm glands (32 8 0).

MD pts had similar incidence of difficulty concentrating (83

52 79) or thinking (31 48 68), photophobia (58 68 42),

irritability (70 44 74), and sleep disturbances (98 72 95).

Early morning awakening (19 24 58) appeared characteristic of


The definition could be strengthened by eliminating muscle

weakness (68% in CF vs 71% in MS and 28% in MD), arthralgia

(73% CF vs 68% MS vs 50% MD), and sleep disturbance (98% vs

72% in MS and 95% in MD) and by adding anorexia (35 4 5) and

nausea (58 8 16).

Komaroff AL, Fagioli LR, Geiger AM, Doolittle TH, Lee J, Kornish RJ,

Gleit MA, Guerriero RT

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