An examination of the working case definition of chronic fatigue syndrome

Abstract:

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.

PATIENTS AND METHODS: 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.

 

Source: Komaroff AL, Fagioli LR, Geiger AM, Doolittle TH, Lee J, Kornish RJ, Gleit MA, Guerriero RT. An examination of the working case definition of chronic fatigue syndrome. Am J Med. 1996 Jan;100(1):56-64. http://www.ncbi.nlm.nih.gov/pubmed/8579088

 

Reducing heterogeneity in chronic fatigue syndrome: a comparison with depression and multiple sclerosis

Abstract:

Chronic fatigue syndrome (CFS) is a heterogeneous illness characterized by a high prevalence of psychiatric problems. We reasoned that we could reduce heterogeneity by excluding patients with psychiatric problems preceding CFS.

We compared the functional status, mood, fatigue level, and psychiatric status of this more homogeneous group of CFS patients with the same parameters in patients with mild multiple sclerosis and in patients with major depression or dysthymia.

Patients with CFS and those with multiple sclerosis were similar in terms of level of anger, severity of depression, level of anxiety, and frequency of current psychiatric diagnoses. Patients with CFS resembled depressed patients in having impaired vigor and experiencing substantial fatigue and confusion–problems constituting part of the case definition of CFS.

The group with CFS was not psychologically vulnerable before the development of this condition and maintained adequate networks of social support despite disabling illness.

Stratification to exclude patients with prior psychiatric disease and those with mild CFS allowed us to define a group of patients with CFS who more resembled patients with mild MS than patients with major depression or dysthymia and thus were more likely to have illness with an infectious or immunologic cause. Use of such a stratification strategy should prove important in testing of the viral/immunologic hypothesis of the etiology of CFS.

 

Source: Natelson BH, Johnson SK, DeLuca J, Sisto S, Ellis SP, Hill N, Bergen MT. Reducing heterogeneity in chronic fatigue syndrome: a comparison with depression and multiple sclerosis. Clin Infect Dis. 1995 Nov;21(5):1204-10. http://www.ncbi.nlm.nih.gov/pubmed/8589144

 

Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Disentangling common characteristics is not so easy

Comment on: “Abnormal” illness behaviour in chronic fatigue syndrome and multiple sclerosis. [BMJ. 1995]

 

EDITOR,-Over the past few years I have seen a growing number of patients with the chronic fatigue syndrome who have been told by psychiatrists and psychologists that abnormal illness behaviour and psychosocial factors are the main factors perpetuating their disability. Few patients have accepted or believed this explanation; neither have I. The ME Association now has evidence that the fashionable theory of abnormal illness behaviour linked to somatisation is being used by several agencies as a convenient excuse for turning down applications for financial benefits or for putting pressure on vulnerable patients to undergo speculative “rehabilitation” programmes, which they may be reluctant to participate in.

Although Peter Trigwell and colleagues conclude that patients with the chronic fatigue syndrome and multiple sclerosis have virtually identical patterns of illness behaviour without any form of shared aetiology, their study suggests that the two conditions may have more in common than just central fatigue and uncertainty about long term prognosis.’ When DeLuca et al examined patients with the chronic fatigue syndrome, patients with multiple sclerosis, and healthy controls using a paced auditory serial addition test (a method of assessing processing of complex auditory information) they found that both groups of patients scored significantly below the controls, indicating similar difficulties with tasks that require simultaneous processing of cognitive information.2

You can read the full comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551397/pdf/bmj00615-0064a.pdf

 

Source: Shepherd C. Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Disentangling common characteristics is not so easy. BMJ. 1995 Oct 21;311(7012):1093. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551397/pdf/bmj00615-0064a.pdf

 

Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Choice of multiple sclerosis as comparison condition was inappropriate

Comment on: “Abnormal” illness behaviour in chronic fatigue syndrome and multiple sclerosis. [BMJ. 1995]

 

EDITOR,-Peter Trigwell and colleagues compared patients with the chronic fatigue syndrome with patients with multiple sclerosis and report similar responses on Pilowsky’s illness behaviour questionnaire.’ There is accumulating evidence that the chronic fatigue syndrome is a functional disorder, with psychological, social, and physical factors implicated in its cause, whereas in multiple sclerosis the primary cause is physical. Wood et al compared patients with the chronic fatigue syndrome with patients with various muscle diseases and found a threefold increase in psychiatric diagnoses in the group with the chronic fatigue syndrome.2 Wessely et al describe an important prospective cohort study and conclude that common infections play little part in causing the chronic fatigue syndrome but that both previous psychological disorder and previous fatigue are associated with its development.3

We agree with Trigwell and colleagues that illness behaviour is highly relevant to the chronic fatigue syndrome, but we share their reservations about the particular method of assessing this. We also suggest that the choice of multiple sclerosis as a comparison condition was inappropriate. Multiple sclerosis, in contrast to muscle diseases, follows a relapsing and remitting course, often manifests sensory (subjective) rather than motor (objective) signs, and might therefore lead to illness behaviour that is abnormal, albeit for different reasons from those that might apply in the chronic fatigue syndrome.

You can read the full comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551396/pdf/bmj00615-0063c.pdf

 

Source: Campion PD, Dowrick CF, Edwards RH. Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Choice of multiple sclerosis as comparison condition was inappropriate. BMJ. 1995 Oct 21;311(7012):1092-3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551396/pdf/bmj00615-0063c.pdf

“Abnormal” illness behaviour in chronic fatigue syndrome and multiple sclerosis

Abstract:

OBJECTIVE: To investigate the presence of abnormal illness behaviour in patients with a diagnosis of chronic fatigue syndrome.

DESIGN: A cross sectional descriptive study using the illness behaviour questionnaire to compare illness behaviour scores and illness behaviour profiles of patients with chronic fatigue syndrome and patients with multiple sclerosis.

SETTING: A multidisciplinary fatigue clinic and a teaching hospital neurology outpatient clinic.

SUBJECTS: 98 patients satisfying the Oxford criteria for chronic fatigue syndrome and 78 patients with a diagnosis of multiple sclerosis.

MAIN OUTCOME MEASURE: Responses to the 62 item illness behaviour questionnaire.

RESULTS: 90 (92%) patients in the chronic fatigue syndrome group and 70 (90%) in the multiple sclerosis group completed the illness behaviour questionnaire. Both groups had significantly high scores on the general hypochondriasis and disease conviction subscales and significantly low scores on the psychological versus somatic concern subscale, as measured in relation to normative data. There were, however, no significant differences in the subscale scores between the two groups and the two groups had identical illness behaviour profiles.

CONCLUSION: Scores on the illness behaviour questionnaire cannot be taken as evidence that chronic fatigue syndrome is a variety of abnormal illness behaviour, because the same profile occurs in multiple sclerosis. Neither can they be taken as evidence that chronic fatigue and multiple sclerosis share an aetiology. More needs to be known about the origins of illness beliefs in chronic fatigue syndrome, especially as they are important in determining outcome.

Comment in:

Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Choice of multiple sclerosis as comparison condition was inappropriate.[BMJ. 1995]

Illness behaviour in the chronic fatigue syndrome and multiple sclerosis. Disentangling common characteristics is not so easy. [BMJ. 1995]

 

Source: Trigwell P, Hatcher S, Johnson M, Stanley P, House A. “Abnormal” illness behaviour in chronic fatigue syndrome and multiple sclerosis. BMJ. 1995 Jul 1;311(6996):15-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2550080/pdf/bmj00599-0019.pdf (Full article)

 

Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression

Abstract:

To examine the degree and nature of cognitive impairments in chronic fatigue syndrome, a comprehensive neuropsychological battery was given to patients with chronic fatigue syndrome, multiple sclerosis, depressed patients, and healthy controls. The battery included tests of attention and concentration, information processing speed, verbal and visual memory, intellectual ability, and concept formation. Measures of depression and anxiety were also obtained.

The chronic fatigue syndrome group did not differ from the depressed group in overall neuropsychological performance, but differed from the multiple sclerosis and control groups. The most significant impairment was in information processing speed in the chronic fatigue syndrome group. Depression and anxiety were not related to neuropsychological performance. The influence of reduced information processing on other areas of cognition is discussed.

 

Source: DeLuca J, Johnson SK, Beldowicz D, Natelson BH. Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression. J Neurol Neurosurg Psychiatry. 1995 Jan;58(1):38-43. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1073266/ (Full article)

 

Fatigue secondary to chronic illness: postpolio syndrome, chronic fatigue syndrome, and multiple sclerosis

Abstract:

Estimates of the percentage of patients with postpolio syndrome, chronic fatigue syndrome, and multiple sclerosis who experience fatigue range from approximately 75% to 100%. In this study we describe the severity of fatigue and its impact on subjects with these three diagnoses.

The Fatigue Severity Scale, the Human Activity Profile, and the Nottingham Health Profile were used to measure fatigue, activity, and health status respectively of each diagnostic group as well as a control group. Using a Kruskal-Wallis one-way analysis of variance followed by a Bonferroni-adjusted Mann Whitney U test all diagnostic groups reported significantly higher levels (p = .0000 to p = .002) of fatigue and lower perceived health status than the control group.

Subjects with chronic fatigue and multiple sclerosis also had significantly reduced activity levels (p = .002 to p = .01) compared with the control group. Further attention should be directed toward understanding the relationship between fatigue and ability to engage in activities as well as strategies for remediation and/or compensation of the fatigue.

 

Source: Packer TL, Sauriol A, Brouwer B. Fatigue secondary to chronic illness: postpolio syndrome, chronic fatigue syndrome, and multiple sclerosis. Arch Phys Med Rehabil. 1994 Oct;75(10):1122-6. http://www.ncbi.nlm.nih.gov/pubmed/7944918

 

Cognitive functioning and depression in patients with chronic fatigue syndrome and multiple sclerosis

Abstract:

OBJECTIVE: To assess cognitive function in patients with chronic fatigue syndrome (CFS) and multiple sclerosis (MS) and to evaluate the role of depressive symptoms in cognitive performance.

DESIGN: Case-control. All subjects were given a neuropsychological battery, self-report measures of depression and fatigue, and a global cognitive impairment rating by a neuropsychologist “blinded” to clinical diagnosis. Patients with MS and CFS were additionally evaluated with a Structured Clinical Interview for DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition) disorders.

SETTING: Institutional and private neurological practices and the community at large.

PATIENTS: Twenty patients with CFS diagnosed in accord with the Centers for Disease Control and Prevention-revised criteria who had cognitive complaints; 20 patients with clinically definite MS who were ambulatory and were matched for fatigue severity, age, and education to CFS subjects; and 20 age- and education-matched healthy controls.

RESULTS: Patients with CFS had significantly elevated depression symptoms compared with patients with MS and healthy controls (P < .001) and had a greater lifetime prevalence of depression and dysthymia compared with MS subjects. Patients with CFS, relative to controls, performed more poorly on the Digit Symbol subtest (P = .023) and showed a trend for poorer performance on logical memory (P = .087). Patients with MS compared with controls had more widespread differences of greater magnitude on the Digit Span (P < .004) and Digit Symbol (P < .001), Trail Making parts A (P = .022) and B (P = .037), and Controlled Oral Word Association (P = .043) tests. Patients with MS also showed a trend of poorer performance on the Booklet Category Test (P = .089). When patients with CFS and MS were directly compared, MS subjects had lower scores on all measures, but the differences reached significance only for the Digit Span measure of attention (P = .035).

CONCLUSIONS: Patients with CFS compared with MS have more depressive symptoms but less cognitive impairment. Relative to controls, a subset of CFS subjects did poorly on tests of visuomotor search and on the logical memory measure of the Wechsler Memory Scale-revised. Poor performance of logical memory in CFS appears to be related to depression, while visuomotor deficits in CFS are unrelated. Cognitive deficits in patients with MS are more widespread compared with those in patients with CFS and are independent of depressive symptoms.

 

Source: Krupp LB, Sliwinski M, Masur DM, Friedberg F, Coyle PK. Cognitive functioning and depression in patients with chronic fatigue syndrome and multiple sclerosis. Arch Neurol. 1994 Jul;51(7):705-10. http://www.ncbi.nlm.nih.gov/pubmed/8018045

 

Neuropsychiatric status of patients with chronic fatigue syndrome: an overview

Abstract:

Chronic fatigue syndrome (CFS) is an illness that results in debilitating fatigue as well as rheumatological, infectious, and neuropsychiatric symptoms. The present paper is a brief overview of the neuropsychological and psychiatric research on CFS. Studies from our laboratory contrasting CFS with patients with multiple sclerosis, depression, and healthy controls are detailed. Our hypothesis of neuropsychological impairments in CFS is discussed.

 

Source: Deluca J, Johnson SK, Natelson BH. Neuropsychiatric status of patients with chronic fatigue syndrome: an overview. Toxicol Ind Health. 1994 Jul-Oct;10(4-5):513-22. http://www.ncbi.nlm.nih.gov/pubmed/7778111

 

Measuring the functional impact of fatigue: initial validation of the fatigue impact scale

Abstract:

The fatigue impact scale (FIS) was developed to improve our understanding of the effects of fatigue on quality of life. The FIS examines patients’ perceptions of the functional limitations that fatigue has caused over the past month. FIS items reflect perceived impact on cognitive, physical, and psychosocial functioning.

This study compared 145 patients referred for investigation of chronic fatigue (ChF) with 105 patients with multiple sclerosis (MS) and 34 patients with mild hypertension (HT). Internal consistency for the FIS and its three subscales was > .87 for all analyses. Fatigue impact was highest for the ChF group although the MS group’s reported fatigue also exceeded that of the HT group. Discriminant function analysis correctly classified 80.0% of the ChF group and 78.1% of the MS group when these groups were compared.

This initial validation study indicates that the FIS has considerable merit as a measure of patient’s attribution of functional limitations to symptoms of fatigue.

 

Source: Fisk JD, Ritvo PG, Ross L, Haase DA, Marrie TJ, Schlech. Measuring the functional impact of fatigue: initial validation of the fatigue impact scale. Clin Infect Dis. 1994 Jan;18 Suppl 1:S79-83. http://www.ncbi.nlm.nih.gov/pubmed/8148458