Tag: subgroups

The case definition of chronic fatigue syndrome

Abstract:

The 1994 case definition of chronic fatigue syndrome is widely used not only for diagnosis but also for clinical and laboratory-based observations of this clinical entity. The criteria for the 1994 case definition are based primarily on symptoms and not on physical signs or chemical or immunological tests. This situation has resulted in conflicting clinical and laboratory observations that in all likelihood is due to different populations of patients being studied in different centers.

Based on some of the recent publications, there appears to be an emerging picture of this disease entity that we propose could be used to subgroup chronic fatigue syndrome into four different subclasses. These subclasses would consist of chronic fatigue with primarily nervous system disorders such as impaired memory or concentration and headache, chronic fatigue with primarily endocrine system disorders such as unrefreshing sleep and postexertional malaise, chronic fatigue with musculoskeletal system disorders such as muscle pain and joint pain, and chronic fatigue with immune system/infectious disorders such as sore throat and tender lymph nodes.

It is suggested that if clinical and laboratory-based studies on chronic fatigue syndrome were conducted on more homogeneous subgroups of patients, the data from one center to the other might not be as conflicting and more insights can be shed on the nature of this clinical condition.

 

Source: Tan EM, Sugiura K, Gupta S. The case definition of chronic fatigue syndrome. J Clin Immunol. 2002 Jan;22(1):8-12. http://www.ncbi.nlm.nih.gov/pubmed/11958593

 

What is chronic fatigue syndrome? Heterogeneity within an international multicentre study

Abstract:

OBJECTIVE: We sought to compare the characteristics of patients presenting with chronic fatigue (CF) and related syndromes in eight international centres and to subclassify these subjects based on symptom profiles. The validity of the subclasses was then tested against clinical data.

METHOD: Subjects with a clinical diagnosis of CF completed a 119-item self-report questionnaire to provide clinical symptom data and other information such as illness course and functional impairment. Subclasses were generated using a principal components-like analysis followed by latent profile analysis (LPA).

RESULTS: 744 subjects returned complete data sets (mean age 40.8 years, mean length of illness 7.9 years, female to male ratio 3:1). Overall, the subjects had a high rate of reporting typical CF symptoms (fatigue, neuropsychological dysfunction, sleep disturbance). Using LPA, two subclasses were generated. Class one (68% sample) was characterized by: younger age, lower female to male ratio; shorter episode duration; less premorbid, current and familial psychiatric morbidity; and, less functional disability. Class two subjects (32%) had features more consistent with a somatoform illness. There was substantial variation in subclass prevalences between the study centres (Class two range 6-48%).

CONCLUSIONS: Criteria-based approaches to the diagnosis of CF and related syndromes do not select a homogeneous patient group. While substratification of patients is essential for further aetiological and treatment research, the basis for allocating such subcategories remains controversial.

 

Source: Wilson A, Hickie I, Hadzi-Pavlovic D, Wakefield D, Parker G, Straus SE, Dale J, McCluskey D, Hinds G, Brickman A, Goldenberg D, Demitrack M, Blakely T,Wessely S, Sharpe M, Lloyd A. What is chronic fatigue syndrome? Heterogeneity within an international multicentre study. Aust N Z J Psychiatry. 2001 Aug;35(4):520-7. http://www.ncbi.nlm.nih.gov/pubmed/11531735

 

Brain MRI abnormalities exist in a subset of patients with chronic fatigue syndrome

Abstract:

Presence of MRI brain abnormalities in patients with Chronic Fatigue Syndrome (CFS) was determined and the profile of MRI abnormalities was compared between 39 CFS patients, 18 with (CFS-Psych) and 21 without (CFS-No Psych) a DSM-III-R Axis I psychiatric diagnosis since illness onset, and 19 healthy, sedentary controls (HC).

Two neuroradiologists, blind to group membership, separately read the MR films using a detailed protocol for rating and categorizing abnormal signal changes. When findings were incongruent, the two neuroradiologists met to try to reach consensus, otherwise a third neuroradiologist evaluated the MR images and served as a tie-breaker.

The CFS-No Psych group showed a significantly larger number of brain abnormalities on T2 weighted images than the CFS-Psych and HC groups. Cerebral changes in the CFS-No Psych group consisted mostly of small, punctate, subcortical white matter hyperintensities, found predominantly in the frontal lobes. No significant difference was found when both CFS groups were combined and compared to the HC group.

The use of stratification techniques is an important strategy in understanding the pathophysiology of CFS. This frontal lobe pathology could explain the more severe cognitive impairment previously reported in this subset of CFS patients.

Comment in: Brain MRI abnormalities exist in chronic fatigue syndrome. [J Neurol Sci. 1999]

 

Source: Lange G, DeLuca J, Maldjian JA, Lee H, Tiersky LA, Natelson BH. Brain MRI abnormalities exist in a subset of patients with chronic fatigue syndrome. J Neurol Sci. 1999 Dec 1;171(1):3-7. http://www.ncbi.nlm.nih.gov/pubmed/10567042

 

Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment

Abstract:

This study aimed to determine symptom patterns in patients with chronic fatigue syndrome (CFS), in summer and winter. Comparison data for patients with seasonal affective disorder (SAD) were used to evaluate seasonal variation in mood and behavior, atypical neurovegetative symptoms characteristic of SAD, and somatic symptoms characteristic of CFS.

Rating scale questionnaires were mailed to patients previously diagnosed with CFS. Instruments included the Personal Inventory for Depression and SAD (PIDS) and the Systematic Assessment for Treatment Emergent Effects (SAFTEE), which catalogs the current severity of a wide range of somatic, behavioral, and affective symptoms. Data sets from 110 CFS patients matched across seasons were entered into the analysis. Symptoms that conform with the Centers for Disease Control and Prevention (CDC) case definition of CFS were rated as moderate to very severe during the winter months by varying proportions of patients (from 43% for lymph node pain or enlargement, to 79% for muscle, joint, or bone pain).

Fatigue was reported by 92%. Prominent affective symptoms included irritability (55%), depressed mood (52%), and anxiety (51%). Retrospective monthly ratings of mood, social activity, energy, sleep duration, amount eaten, and weight change showed a coherent pattern of winter worsening.

Of patients with consistent summer and winter ratings (n = 73), 37% showed high global seasonality scores (GSS) > or = 10. About half this group reported symptoms indicative of major depressive disorder, which was strongly associated with high seasonality.

Hierarchical cluster analysis of wintertime symptoms revealed 2 distinct clinical profiles among CFS patients: (a) those with high seasonality, for whom depressed mood clustered with atypical neurovegetative symptoms of hypersomnia and hyperphagia, as is seen in SAD; and (b) those with low seasonality, who showed a primary clustering of classic CFS symptoms (fatigue, aches, cognitive disturbance), with depressed mood most closely associated with irritability, insomnia, and anxiety.

It appears that a subgroup of patients with CFS shows seasonal variation in symptoms resembling those of SAD, with winter exacerbation. Light therapy may provide patients with CFS an effective treatment alternative or adjunct to antidepressant drugs.

 

Source: Terman M, Levine SM, Terman JS, Doherty S. Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment. Am J Med. 1998 Sep 28;105(3A):115S-124S. http://www.ncbi.nlm.nih.gov/pubmed/9790493

 

Chronic fatigue syndrome: identification of distinct subgroups on the basis of allergy and psychologic variables

Abstract:

BACKGROUND: We investigated a role for allergic inflammation and psychologic parameters in the development of chronic fatigue syndrome (CFS).

METHODS: The design was a comparison between subjects with CFS and age- and sex-matched control cohorts. Studies were performed on CFS subjects (n = 18) and control cohorts consisting of normal subjects (n = 11), allergic subjects (n = 14), and individuals with primary depression (n = 12). We quantified cytokines at baseline as cell-associated immunoreactive peptides and as transcripts evaluated by means of semiquantitative RNA-based polymerase chain reactions. Psychologic evaluations included administration of the Diagnostic Interview Schedule, the Structured Clinical Interview, and the Symptom Checklist 90-Revised.

RESULTS: Increases in tumor necrosis factor (TNF)-alpha were identified in individual subjects with CFS (50.1 +/- 14.4 pg TNF-alpha per 10(7) peripheral blood mononuclear cells [PBMCs]; mean +/- SEM) and allergic subjects (41.6 +/- 7.6) in comparison with normal subjects (13.1 +/- 8.8) (P < .01 and P < .05, respectively). Similar trends were observed for interferon (IFN)-alpha in allergic subjects (3.0 +/- 1.7 pg/10(7) PBMCs) and subjects with CFS (6.4 +/- 3.4) compared with normal subjects (1.9 +/- 1.4). A significant increase (P < .05) in TNF-alpha transcripts was demonstrated between subjects with CFS and depressed subjects. In contrast to these proinflammatory cytokines, both subjects with CFS (2.6 +/- 1.8 pg/10(7) PBMCs) and allergic subjects (3.4 +/- 2.8) were associated with a statistically significant (P < .01) decrease in IL-10 concentrations compared with normal subjects (60.2 +/- 18.2). As shown in other studies, most of our subjects with CFS were allergic (15 of 18) and therefore presumably demonstrated cytokine gene activation on that basis. The seasonal exacerbation of allergy was associated with a further increase in cellular IFN-alpha (from 2.1 +/- 1.2 to 14.2 +/- 4.5 pg/107 PBMCs; P < .05) but no further modulation of TNF-alpha or IL-10. Similarly, self-reported exacerbations of CFS were associated with a further increase in IFN-alpha (from 2.5 +/- 1.0 to 21.9 +/- 7.8; P < .05) and occurred at times of seasonal exposures to allergens. This linkage does not permit making any definitive conclusions regarding a causative influence of either seasonal allergies or the increase in cellular IFN-alpha with the increase in CFS symptoms. The close association between atopy and CFS led us to speculate that CFS may arise from an abnormal psychologic response to the disordered expression of these proinflammatory and antiinflammatory cytokines. Psychologic variables were predictive of immune status within the CFS sample (65.9% of the variance in immune status; F (3,10) = 6.44, P < .05). Specifically, the absence of a personality disorder but greater endorsement of global psychiatric symptoms was predictive of immune activation.

CONCLUSIONS: Most of our subjects with CFS were allergic, and the CFS and allergy cohorts were similar in terms of their immune status. However, the CFS subjects could be discriminated by the distinct psychologic profiles among subjects with and without immune activation. We propose that in at least a large subgroup of subjects with CFS who had allergies, the concomitant influences of immune activation brought on by allergic inflammation in an individual with the appropriate psychologic profile may interact to produce the symptoms of CFS. In a psychologically predisposed individual, symptoms associated with allergic inflammation are recognized as illness.

 

Source: Borish L, Schmaling K, DiClementi JD, Streib J, Negri J, Jones JF. Chronic fatigue syndrome: identification of distinct subgroups on the basis of allergy and psychologic variables. J Allergy Clin Immunol. 1998 Aug;102(2):222-30. http://www.ncbi.nlm.nih.gov/pubmed/9723665

 

Serum neopterin and somatization in women with chemical intolerance, depressives, and normals

Abstract:

The symptom of intolerance to low levels of environmental chemicals (CI, chemical intolerance) is a feature of several controversial polysymptomatic conditions that overlap symptomatically with depression and somatization, i.e., chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity, and Persian Gulf syndrome. These syndromes can involve many somatic symptoms consistent with possible inflammation. Immunological or neurogenic triggering might account for such inflammation.

Serum neopterin, which has an inverse relationship with l-tryptophan availability, may offer a marker of inflammation and macrophage/monocyte activation. This study compared middle-aged women with CI (who had high levels of affective distress; n = 14), depressives without CI (n = 10), and normals (n = 11).

Groups did not differ in 4 p.m. resting levels of serum neopterin. However, the CI alone had strong positive correlations between neopterin and all of the scales measuring somatization. These preliminary findings suggest the need for additional research on biological correlates of ‘unexplained’ multiple somatic symptoms in subtypes of apparent somatizing disorders.

 

Source: Bell IR, Patarca R, Baldwin CM, Klimas NG, Schwartz GE, Hardin EE. Serum neopterin and somatization in women with chemical intolerance, depressives, and normals. Neuropsychobiology. 1998;38(1):13-8. http://www.ncbi.nlm.nih.gov/pubmed/9701717

 

Graded exercise in chronic fatigue syndrome. Chronic fatigue syndrome is heterogeneous condition

Comment on: Randomised controlled trial of graded exercise in patients with the chronic fatigue syndrome. [BMJ. 1997]

 

Editor—The study reported by Kathy Y Fulcher and Peter D White will provide new hope to many patients diagnosed as having the chronic fatigue syndrome.1 Before exercise regimens become the treatment of choice, however, it is worth noting that over two fifths of the patients in the study reported no or little improvement. It is a pity that the researchers did not compare those who were “very much better” with those who were not, in terms of variables such as the onset of illness (acute or gradual, history of infection) 2 and the presence of additional symptoms frequently associated with the syndrome—for example, cognitive difficulties, nausea, and malaise after exercise. This might have shown whether one particular subgroup fared better than another, allowing doctors to tailor their advice and further improve patients’ care.3

The possibility that subgroups may have different prognoses also deserves consideration. For instance, a recent study found that 70% of patients diagnosed as having epidemic neuromyasthenia recovered within two years.4 If two thirds of the subjects studied by Fulcher and White also had disease of acute onset linked to infection, one could argue that the exercise regimen reflected the natural course of the illness while the flexibility training made patients worse.

A final point concerns the 20 subjects taking full dose antidepressants. The authors do not specify why these drugs were being taken by people who did not have clinical depression or sleep disorders. Moreover, since many patients with the chronic fatigue syndrome cannot tolerate therapeutic doses of antidepressants,5 some of the reported fatigue and malaise may have been drug induced.

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127599/pdf/9361552.pdf

 

Source: Goudsmit EM. Graded exercise in chronic fatigue syndrome. Chronic fatigue syndrome is heterogeneous condition. BMJ. 1997 Oct 11;315(7113):948. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127599/

 

Immune responses associated with chronic fatigue syndrome: a case-control study

Abstract:

An exploratory case-control study was conducted to assess whether the many reported differences in the immune function of chronic fatigue syndrome (CFS) patients are detectable in rigorously defined cases of CFS. Although many studies have reported differences between cases and controls in various measures of immune function, none of these differences were found in all studies.

In this study, no differences were found in white blood cell numbers; immune complex, complement, or serum immunoglobulin levels; delayed type hypersensitivity and allergic responses; NK cell function; and proliferative responses to mitogens and antigens. Marginal differences were detected in cytokine responses and in cell surface markers in the total CFS population.

However, when the patients were subgrouped by type of disease onset (gradual or sudden) or by how well they were feeling on the day of testing, more pronounced differences were seen

 

Source: Mawle AC, Nisenbaum R, Dobbins JG, Gary HE Jr, Stewart JA, Reyes M, Steele L, Schmid DS, Reeves WC. Immune responses associated with chronic fatigue syndrome: a case-control study. J Infect Dis. 1997 Jan;175(1):136-41. http://jid.oxfordjournals.org/content/175/1/136.long (Full article)

 

Postinfectious chronic fatigue: a distinct syndrome?

Abstract:

Chronic fatigue syndrome (CFS) is often preceded by a viral illness and has recurrent “flu-like” symptoms. We compared demographic, clinical, and laboratory features (markers of inflammation and viral infection) among 717 patients with chronic fatigue (CF) with and without a self-reported postinfectious onset to identify associated clinical and biologic findings and to examine the subset of patients with CFS. Only subjective fever, chills, sore throat, lymphadenopathy, poorer functional status, and attribution of illness to a physical condition were significantly associated with a postinfectious onset. The features of patients with CFS were virtually identical to those of the broader category of patients with CF. We conclude that a postinfectious onset was not associated with a pattern of abnormalities across multiple psychosocial and biologic parameters.

 

Source: Buchwald D, Umali J, Pearlman T, Kith P, Ashley R, Wener M. Postinfectious chronic fatigue: a distinct syndrome? Clin Infect Dis. 1996 Aug;23(2):385-7. http://cid.oxfordjournals.org/content/23/2/385.long (Full article)

 

‘Seronegative’ Sjögren’s syndrome manifested as a subset of chronic fatigue syndrome

Abstract:

We determined the extent to which chronic fatigue syndrome (CFS) patients with sicca symptoms fulfil the diagnostic criteria for Sjögren’s syndrome (SS). Three sets of diagnostic criteria for SS, formulated by the Japanese, Europeans and Fox, were used. One-third of the CFS patients with sicca symptoms fulfilled the diagnostic criteria for SS. However, they were ‘seronegative’, differing from the ordinary primary SS.

 

Source: Nishikai M1, Akiya K, Tojo T, Onoda N, Tani M, Shimizu K. ‘Seronegative’ Sjögren’s syndrome manifested as a subset of chronic fatigue syndrome. Br J Rheumatol. 1996 May;35(5):471-4. http://rheumatology.oxfordjournals.org/content/35/5/471.long (Full article)