Can the chronic fatigue syndrome be defined by distinct clinical features?

Abstract:

To determine whether patients diagnosed as having chronic fatigue syndrome (CFS) constitute a clinically homogeneous class, multivariate statistical analyses were used to derive symptom patterns and potential patient subclasses in 565 patients. The notion that patients currently diagnosed as having CFS constitute a single homogeneous class was rejected.

An alternative set of clinical subgroups was derived. The validity of these subgroups was assessed by sociodemographic, psychiatric, immunological and illness behaviour variables. A two-class statistical solution was considered most coherent, with patients from the smaller class (27% of the sample) having clinical characteristics suggestive of somatoform disorders. The larger class (73% of sample) presented a more limited combination of fatigue and neuropsychological symptoms, and only moderate disability but remained heterogeneous clinically. The two patient groups differed with regard to duration of illness, spontaneous recovery, severity of current psychological morbidity, utilization of medical services and CD8 T cell subset counts. The distribution of symptoms among patients was not unimodal, supporting the notion that differences between the proposed subclasses were not due simply to differences in symptom severity.

This study demonstrated clinical heterogeneity among patients currently diagnosed as CFS, suggesting aetiological heterogeneity. In the absence of discriminative clinical features, current consensus criteria do not necessarily reduce the heterogeneity of patients recruited to CFS research studies.

 

Source: Hickie I, Lloyd A, Hadzi-Pavlovic D, Parker G, Bird K, Wakefield D. Can the chronic fatigue syndrome be defined by distinct clinical features? Psychol Med. 1995 Sep;25(5):925-35. http://www.ncbi.nlm.nih.gov/pubmed/8588011

 

Cell-mediated immune function and the outcome of chronic fatigue syndrome

Abstract:

This study examined the importance of cell-mediated immunity in determining the long-term outcome of patients diagnosed with chronic fatigue syndrome (CSF).

A total of 103 patients (74%) of 139 previously enrolled in one of two treatment trials conducted within a university hospital referral center was reviewed a mean of 3.2 yr after trial entry. Ongoing symptom severity, levels of disability and immunological function were assessed at follow-up. The relationship between immunological function at trial entry and measures of outcome was also evaluated.

Sixty-five patients (63%) had improved, while only 6 (6%) reported no current symptoms. Thirty-one subjects (30%) were unable to perform any form of work and 26 (25%) were on a disability benefit directly attributable to CFS. Cell-mediated immune function, as measured at trial entry or follow-up, did not appear to affect outcome.

Whilst improvement occurred in the majority of patients with CFS, a substantial proportion (37%) remained functionally impaired. Impairment of cell-mediated immunological function measured during the course of the illness may not be an important factor in determining long-term outcome.

 

Source: Wilson A, Hickie I, Lloyd A, Hadzi-Pavlovic D, Wakefield D. Cell-mediated immune function and the outcome of chronic fatigue syndrome. Int J Immunopharmacol. 1995 Aug;17(8):691-4. http://www.ncbi.nlm.nih.gov/pubmed/8847164

 

Are cytokines associated with neuropsychiatric syndromes in humans?

Abstract:

Traditional aetiological models in neuropsychiatry have placed little emphasis on the abnormal behavioural responses (decreased psychomotor activity, anorexia, weight loss, decreased social exploration and sexual behaviour, impaired cognitive function and increased somnolence) that are common to both psychiatric syndromes, notably depression, and the illness behaviour of sick animals.

In recent years, the possible role of cytokines, as mediators of not only the immunological and metabolic responses to infection and inflammation but also a co-ordinated behavioural response, has been described. Further, a range of possible mechanisms for these effects has been postulated, notably involving corticotropin releasing factor (CRF) and prostaglandins of the E series (PgE) with the central nervous system (CNS).

Here we outline a series of human clinical conditions where neuropsychiatric syndromes co-occur with a host response to infection or inflammation. These may be characterized by cytokine production (e.g. acute, recurrent and chronic viral illness, systemic autoimmune diseases and chronic fatigue syndrome).

Other clinical situations characterized by exposure to or in vivo production of cytokines (e.g. treatment of chronic infections and malignancies, progression and/or recurrence of malignancies) are also discussed.

We postulate that the stereotyped behavioural repertoire observed is mediated by cytokine-dependent mechanisms within the CNS. Systematic studies of the behavioural responses of such patient groups are suggested, noting specifically correlations between the time course and severity of immune and neuroendocrine and behavioural responses and dose-response effects.

 

Source: Hickie I, Lloyd A. Are cytokines associated with neuropsychiatric syndromes in humans? Int J Immunopharmacol. 1995 Aug;17(8):677-83. http://www.ncbi.nlm.nih.gov/pubmed/8847162

 

The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group

Abstract:

The complexities of the chronic fatigue syndrome and the methodologic problems associated with its study indicate the need for a comprehensive, systematic, and integrated approach to the evaluation, classification, and study of persons with this condition and other fatiguing illnesses. We propose a conceptual framework and a set of guidelines that provide such an approach. Our guidelines include recommendations for the clinical evaluation of fatigued persons, a revised case definition of the chronic fatigue syndrome, and a strategy for subgrouping fatigued persons in formal investigations.

Comment in:

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

 

Source: Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group. Ann Intern Med. 1994 Dec 15;121(12):953-9. http://www.ncbi.nlm.nih.gov/pubmed/7978722

 

The treatment of chronic fatigue syndrome: science and speculation

Abstract:

The chronic fatigue syndrome (CFS) is a heterogeneous disorder characterized by fatigue, neuropsychiatric symptoms, and various other somatic complaints. Treatment studies to date reflect both the diversity of medical disciplines involved in the management of patients with CFS and the multiple pathophysiologic mechanisms proposed.

There have been few attempts to study integrated treatment programs, and although several controlled studies have been reported, no treatment has been shown clearly to result in long-term benefit in the majority of patients. Good clinical care integrating medical and psychologic concepts, together with symptomatic management, may prevent significant secondary impairment in the majority of patients.

Future treatment studies should examine differential response rates for possible subtypes of the disorder (eg, documented viral onset, concurrent clinical depression), evaluate the extent of any synergistic effects between therapies (ie, medical and psychologic), and employ a wide range of biologic and psychologic parameters as markers of treatment response.

 

Source: Wilson A, Hickie I, Lloyd A, Wakefield D. The treatment of chronic fatigue syndrome: science and speculation. Am J Med. 1994 Jun;96(6):544-50. http://www.ncbi.nlm.nih.gov/pubmed/8017453

 

Longitudinal study of outcome of chronic fatigue syndrome

Abstract:

OBJECTIVE: To examine the predictors of long term outcome for patients with the chronic fatigue syndrome.

DESIGN: Cohort study.

SUBJECTS: 139 subjects previously enrolled in two treatment trials; 103 (74%) were reassessed a mean of 3.2 years after start of the trials.

SETTING: University hospital referral centre.

MAIN OUTCOME MEASURES: Age at onset, duration of illness, psychological and immunological status at initial assessment. Ongoing symptom severity, levels of disability, and immunological function at follow up.

RESULTS: 65 subjects had improved but only six reported no current symptoms. An alternative medical diagnosis had been made in two and psychiatric illness diagnosed in 20. The assignment of a primary psychiatric diagnosis at follow up and the strength of the belief that a physical disease process explained all symptoms at entry to the trials both predicted poor outcome. Age at onset of illness, duration of illness, neuroticism, premorbid psychiatric diagnoses, and cell mediated immune function did not predict outcome.

CONCLUSION: Though most patients with the chronic fatigue syndrome improve, a substantial proportion remain functionally impaired. Psychological factors such as illness attitudes and coping style seem more important predictors of long term outcome than immunological or demographic variables.

Comment in:

Chronic fatigue syndrome. Distinguish between syndromes… [BMJ. 1994]

Chronic fatigue syndrome. Immunological findings vary between populations. [BMJ. 1994]

Chronic fatigue syndrome. Role of psychological factors overemphasised. [BMJ. 1994]

 

Source: Wilson A, Hickie I, Lloyd A, Hadzi-Pavlovic D, Boughton C, Dwyer J, Wakefield D. Longitudinal study of outcome of chronic fatigue syndrome. BMJ. 1994 Mar 19;308(6931):756-9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2539669/

You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2539669/pdf/bmj00432-0032.pdf

 

Immunologic and psychologic therapy for patients with chronic fatigue syndrome: a double-blind, placebo-controlled trial

Abstract:

PURPOSE: To evaluate the potential benefit of immunologic therapy with dialyzable leukocyte extract and psychologic treatment in the form of cognitive-behavioral therapy (CBT) in patients with chronic fatigue syndrome (CFS).

PATIENTS AND METHODS: Immunologic and psychologic treatments were administered to 90 adult patients who fulfilled diagnostic criteria for CFS in a double-blind, randomized, and placebo-controlled study. A four-cell trial design allowed the assessment of benefit from immunologic and psychologic treatment individually or in combination. Outcome was evaluated by measurement of global well-being (visual analogue scales), physical capacity (standardized diaries of daily activities), functional status (Karnofsky performance scale), and psychologic morbidity (Profile of Mood States questionnaire), and cell-mediated immunity was evaluated by peripheral blood T-cell subset analysis and delayed-type hypersensitivity skin testing.

RESULTS: Neither dialyzable leukocyte extract nor CBT (alone or in combination) provided greater benefit than the nonspecific treatment regimens.

CONCLUSIONS: In this study, patients with CFS did not demonstrate a specific response to immunologic and/or psychologic therapy. The improvement recorded in the group as a whole may reflect both nonspecific treatment effects and a propensity to remission in the natural history of this disorder.

Comment in:

Treatment for chronic fatigue syndrome. [Am J Med. 1994]

Cognitive behavior therapy for chronic fatigue syndrome. [Am J Med. 1995]

Cognitive behavior therapy for chronic fatigue syndrome. [Am J Med. 1995]

 

Source: Lloyd AR, Hickie I, Brockman A, Hickie C, Wilson A, Dwyer J, Wakefield D. Immunologic and psychologic therapy for patients with chronic fatigue syndrome: a double-blind, placebo-controlled trial. Am J Med. 1993 Feb;94(2):197-203. http://www.ncbi.nlm.nih.gov/pubmed/8430715

 

Immunity and the pathophysiology of chronic fatigue syndrome

Abstract:

The pathophysiology of chronic fatigue syndrome (CFS) remains unknown. The syndrome often follows a recognized or presumed infection and the disorder may therefore result from a disordered immune response to a precipitating infection or antigenic challenge.

Abnormalities of both humoral and cellular immunity have been demonstrated in a substantial proportion of patients with CFS. The most consistent findings are of impaired lymphocyte responses to mitogen and reduced natural killer cell cytotoxicity. Cutaneous anergy and immunoglobulin G subclass deficiencies have also been found.

Further studies are needed examining cytokine levels in serum and cerebrospinal fluid, and cytokine production in vitro in patients with CFS. Interpretation of the findings of published studies of immunity is limited by probable heterogeneity in the patient groups studied, and by the lack of standardization and reproducibility in the assays used.

The pattern of abnormalities reported in immunological testing in patients with CFS is consistent with the changes seen during the resolving phases of acute viral infection. These data provide circumstantial support for the hypothesis that CFS results from a disordered immune response to an infection. Longitudinal studies of immunity in patients developing CFS after defined infectious illnesses will provide the best means of further examining this hypothesis.

 

Source: Lloyd AR, Wakefield D, Hickie I. Immunity and the pathophysiology of chronic fatigue syndrome. Ciba Found Symp. 1993;173:176-87; discussion 187-92. http://www.ncbi.nlm.nih.gov/pubmed/8491097

 

Immunological and psychological dysfunction in patients receiving immunotherapy for chronic fatigue syndrome

Abstract:

Associations between immunological and psychological dysfunction in 33 patients with Chronic Fatigue Syndrome (CFS) were examined before and in response to treatment in a double blind, placebo-controlled trial of high dose intravenous immunoglobulin. Only those patients who received active immunotherapy demonstrated a consistent pattern of correlations between improvement in depressive symptoms and markers of cell-mediated immunity (CMI).

This finding lends some support to the hypothesis that depressive symptoms in patients with CFS occur secondary to, or share a common pathophysiology with, immunological dysfunction. This pattern and the lack of strong associations between depression and immunological disturbance prior to treatment are less supportive of the view that CFS is primarily a form of depressive disorder or that immunological dysfunction in patients with CFS is secondary to concurrent depression.

 

Source: Hickie I, Lloyd A, Wakefield D. Immunological and psychological dysfunction in patients receiving immunotherapy for chronic fatigue syndrome. Aust N Z J Psychiatry. 1992 Jun;26(2):249-56. http://www.ncbi.nlm.nih.gov/pubmed/1642616

 

Cell-mediated immunity in patients with chronic fatigue syndrome, healthy control subjects and patients with major depression

Abstract:

The chronic fatigue syndrome (CFS) is characterized by severe persistent fatigue and neuropsychiatric symptoms. It has been proposed that the abnormalities in cell-mediated immunity which have been documented in patients with CFS may be attributable to a clinical depression, prevalent in patients with this disorder.

Cell-mediated immune status was evaluated in patients with carefully defined CFS and compared with that of matched subjects with major depression (non-melancholic, non-psychotic) as well as healthy control subjects.

Patients with CFS demonstrated impaired lymphocyte responses to phytohaemagglutinin (PHA) stimulation, and reduced or absent delayed-type hypersensitivity (DTH) skin responses when compared either with subjects with major depression or with healthy control subjects (P less than 0.05 for each analysis).

Although depression is common in patients with CFS, the disturbances of cell-mediated immunity in this disorder differ in prevalence and magnitude from those associated with major depression. These observations strengthen the likelihood of a direct relationship between abnormal cell-mediated immunity and the etiology of CFS.

 

Source: Lloyd A, Hickie I, Hickie C, Dwyer J, Wakefield D. Cell-mediated immunity in patients with chronic fatigue syndrome, healthy control subjects and patients with major depression. Clin Exp Immunol. 1992 Jan;87(1):76-9. http://www.ncbi.nlm.nih.gov/pubmed/1733640

Note : You can read the full article herehttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1554231/