Myalgic encephalomyelitis--a persistent enteroviral infection?

Non-pharmacological approaches to treatment

Chronic fatigue syndrome (CFS) as currently defined overlaps with other syndromes including chronic pain, fibromyalgia, anxiety and depression. It also resembles historical descriptions of neurasthenia. The role of psychological (cognitive) and behavioural therapies in CFS is examined. There are both pragmatic and theoretical arguments for their application to CFS. It is pragmatic to target obvious and treatable factors including inactivity and depression. A theoretical model in which psychological, physiological and social factors interact offers a plausible rationale for such treatment but is not yet empirically proven. While there is evidence for the efficacy of this type of therapy in related syndromes, the evidence in CFS is inconclusive. A randomized controlled trial of combined cognitive and behavioural therapy currently in progress is described. Initial results suggest that most patients receiving cognitive behaviour therapy improve, especially in terms of functional impairment. It remains to be seen whether this therapy will prove to be more effective than standard general practitioner care. In the meantime cognitive behaviour therapy offers a pragmatic and rational therapy for patients with CFS.

Pharmacological approaches to the therapy of chronic fatigue syndrome

Although a variety of pharmacological agents have been used to treat patients with chronic fatigue syndrome none has been shown to effect a complete resolution of symptoms. Data obtained from a retrospective study and from an objective assessment of the aerobic work capacity of patients with this disorder suggest that the underlying pathophysiological abnormality is a disorder of sleep regulation. This results not only in profound fatigue and lethargy but also reduced sensory threshold for pain, disordered temperature regulation, cardiovascular abnormalities, disturbed higher cerebral function and mental depression. Drugs which modulate sleep, such as tricyclic antidepressants, have a limited effect in improving the symptoms that CFS patients experience. We suggest that other agents which affect central nervous system neurotransmitters, particularly serotonin, may have potential in the management of this condition and need to be evaluated in large controlled clinical trials.

Special problems of children with myalgic encephalomyelitis/chronic fatigue syndrome and the enteroviral link

Since 1997, it has been known that myalgic encephalomyelitis/chronic fatigue syndrome constitutes the biggest cause of long-term sickness leading to absence from school, in both staff and pupils. The scale of the problem in children is substantial, and the pattern of illness in schools suggests a prominent role for viral infection--for example, the clustering of cases. The Dowsett-Colby study of 1997, researching long-term sickness, reported on a school roll of 333,024 pupils and 27,327 staff, and found a prevalence of long-term sickness in 70 of 100,000 pupils and 500 of 100,000 staff; 39% of cases were in clusters of three or more. The peak age was 14-16 years. The illness is known to be potentially severe and chronic. In addition, the Tymes Trust has reported that many affected children struggle for recognition of their needs, and are bullied by medical and educational professionals. Children should have time to recover sufficiently before returning to school; sustainable, energy-efficient and often home-based education is important here to fulfil legal obligations. Research is needed on viruses that trigger childhood myalgic encephalomyelitis--for example, enteroviruses--and on the neurocognitive defects caused by myalgic encephalomyelitis. We should recognise the value of previous biological research and records of outbreaks, and I recommend that myalgic encephalomyelitis be made notifiable owing to the encephalitic nature of the effects commonly reported in this illness.

Chronic fatigue syndrome: the need for subtypes

Chronic fatigue syndrome (CFS) is an important condition confronting patients, clinicians, and researchers. This article provides information concerning the need for appropriate diagnosis of CFS subtypes. We first review findings suggesting that CFS is best conceptualized as a separate diagnostic entity rather than as part of a unitary model of functional somatic distress. Next, research involving the case definitions of CFS is reviewed. Findings suggest that whether a broad or more conservative case definition is employed, and whether clinic or community samples are recruited, these decisions will have a major influence in the types of patients selected. Review of further findings suggests that subtyping individuals with CFS on sociodemographic, functional disability, viral, immune, neuroendocrine, neurology, autonomic, and genetic biomarkers can provide clarification for researchers and clinicians who encounter CFS' characteristically confusing heterogeneous symptom profiles. Treatment studies that incorporate subtypes might be particularly helpful in better understanding the pathophysiology of CFS. This review suggests that there is a need for greater diagnostic clarity, and this might be accomplished by subgroups that integrate multiple variables including those in cognitive, emotional, and biological domains.

Chronic Fatigue: A Survey, Outcome Study and Proposals

BACKGROUND

  Sample sizes in studies of childhood chronic fatigue remain small and there is a need to integrate research findings and establish common criteria.

METHOD

  This is a detailed report of 20 children with medically unexplained fatigue, referred to as Chronic Fatigue Syndrome (CFS). It includes an uncontrolled outcome study of treatment based on a pragmatic cognitive-behavioural model adapted for children at Great Ormond Street Hospital for Children.

RESULTS

  The data revealed psychological distress at 30 times the prevalence found in the normal child population, with specific high-ranking symptoms, including headache, social withdrawal and decreased appetite. Onset tended to occur at 11 years of age with some earlier problems at school age, suggesting it might be possible to identify those most at risk. Follow-up demonstrated improvement in 87% of the sample (parental report), a significant increase in school attendance and a significant decrease in symptom severity. Factors associated with good outcome were short duration of fatigue (less than a year) and behaviours that tended to combat the cycle of avoidance, such as carefully planned home-tuition.

CONCLUSIONS

  Recording a comprehensive range of symptoms and factors facilitates comparisons within and between child studies. It is proposed that symptom severity is a particularly relevant measure for Chronic Fatigue Syndrome which is characterised by persisting symptoms.

Baroreceptor reflex and integrative stress responses in chronic fatigue syndrome

OBJECTIVE

Altered cardiovascular responses to mental and postural stressors have been reported in chronic fatigue syndrome (CFS). This study examined whether those findings may involve changes in baroreceptor reflex functioning.

METHODS

Chronotropic baroreceptor reflex (by sequential analysis) and cardiovascular stress responses were recorded during postural (5-minute of active standing) and cognitive (speech task) stress testing in patients with CFS grouped into cases with severe (N = 21) or less severe (N = 22) illness, and in 29 matched control subjects.

RESULTS

Patients with CFS had a greater decline in baroreceptor reflex sensitivity (BRS) during standing, although only those with severe CFS were significantly different from the controls. Systolic blood pressure declined during standing in the control group but was maintained in the CFS patients. In contrast, the patients with less severe CFS had blunted increases in blood pressure during the speech task, which could not, however, be explained by inadequate inhibition of the baroreceptor reflex, with all groups showing an appropriate reduction in BRS during the task.

CONCLUSIONS

These results indicate that in CFS, deficiencies in orthostatic regulation, but not in centrally mediated stress responses, may involve the baroreceptor reflex. This study also suggests that classifying patients with CFS on illness severity may discriminate between patients with abnormalities in peripheral vs. central mechanisms of cardiovascular stress responses.

Atypical depression as a secondary symptom in chronic fatigue syndrome

Chronic fatigue syndrome (CFS) has gained prominence since 1988 and a substantial amount of research has been done in this domain. However, it is still regarded as a controversial condition. Moreover, most of the symptoms of CFS itself are non-specific, occurring in many illnesses; some of the symptoms are also common in depression. Indeed, an area of continued controversy and debate involves the diagnostic overlap between CFS and psychiatric disorders. Through anecdotal evidence, atypical depression appears to be common in CFS. Recent developments in psychobiology underscore the role of the acute phase response and its associated sickness behavior in affective disorders. Thus, we hypothesize that atypical depression is sickness behavior rather than an affective disorder as shown by anecdotal evidence in CFS.

Variability in diagnostic criteria for chronic fatigue syndrome may result in substantial differences in patterns of symptoms and disability

Chronic fatigue syndrome (CFS) is an illness that involves severe, prolonged exhaustion as well as neurologic, immunologic, and endocrine system pathology. Because the pathogenesis of CFS has yet to be determined, case definitions have relied on clinical observation in classifying signs and symptoms for diagnosis. The current investigation examined differences between CFS as defined by Fukuda and colleagues and a set of criteria that has been stipulated for myalgic encephalomyelitis (ME). Dependent measures included psychiatric comorbidity, symptom frequency, symptom severity, and functional impairment. The ME and Fukuda et al. (1994) CFS criteria were compared with a group having chronic fatigue due to psychiatric reasons. Significant differences occurred primarily with neurologic, neuropsychiatric, fatigue/weakness, and rheumatological symptoms. These findings suggest that it might be inappropriate to synthesize results from studies of this illness that use different definitions to select study populations.

Interventions for the treatment and management of chronic fatigue syndrome/myalgic encephalomyelitis



 The research evidence on the effectiveness of interventions for the treatment and management of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) published in a recent issue of Effective Health Care is reviewed.

Specific oxidative alterations in vastus lateralis muscle of patients with the diagnosis of chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a poorly understood disease characterized by mental and physical fatigue, most often observed in young white females. Muscle pain at rest, exacerbated by exercise, is a common symptom. Although a specific defect in muscle metabolism has not been clearly defined, yet several studies report altered oxidative metabolism. In this study, we detected oxidative damage to DNA and lipids in muscle specimens of CFS patients as compared to age-matched controls, as well as increased activity of the antioxidant enzymes catalase, glutathione peroxidase, and transferase, and increases in total glutathione plasma levels. From these results we hypothesize that in CFS there is oxidative stress in muscle, which results in an increase in antioxidant defenses. Furthermore, in muscle membranes, fluidity and fatty acid composition are significantly different in specimens from CFS patients as compared to controls and to patients suffering from fibromyalgia. These data support an organic origin of CFS, in which muscle suffers oxidative damage.

Coping and adaptive outcome in chronic fatigue syndrome: importance of illness cognitions

In this study, the relations between illness representations, coping behavior, and adaptive outcomes in chronic fatigue syndrome (CFS) patients (N=98) were examined. Following Leventhal's self-regulation model, it was hypothesized that illness representations would be directly related to coping and, via coping, to adaptive outcome. The results showed patients who considered their illness to be a serious condition, who believed that they had no control over their illness, who saw little possibility for cure, and who believed their illness to have serious consequences to cope with their illness in a passive way, report higher levels of impairment in physical and social functioning and report greater problems in mental health and vitality. A series of regression analyses showed illness representations to be stronger predictors of adaptive outcome than coping scores. The implications of these findings for the treatment of CFS patients are discussed.

Urinary free cortisol excretion in chronic fatigue syndrome, major depression and in healthy volunteers

Urinary free cortisol excretion (UFC) was compared in 21 patients with chronic fatigue syndrome (CFS), in 10 melancholic depressives and in 15 healthy controls. Patients with depression had UFC values which were significantly higher than healthy comparison subjects, whereas UFC excretion of CFS patients was significantly lower than the comparison group. These findings are in keeping with currently held hypotheses of hyperactivity and hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis in depression and chronic fatigue syndrome respectively. Five of the 21 CFS patients had a co-morbid depressive illness. This sub-group retained the profile of UFC excretion of those with CFS alone, suggesting a different pathophysiological basis for depressive symptoms in CFS.

Fibromyalgia and chronic fatigue syndrome: similarities and differences

CFS and FM are clinical conditions characterized by a variety of nonspecific symptoms including prominent fatigue, myalgia, and sleep disturbances. There are no diagnostic studies or widely accepted, pathogenic, explanatory models for either illness. Despite remarkably different diagnostic criteria, CFS and FM have many demographic and clinical similarities. More specifically, few differences exist in the domains of symptoms, examination findings, laboratory tests, functional status, psychosocial features, and psychiatric disorders. FM appears to represent an additional burden of suffering among those with CFS, however, underscoring the importance of recognizing concurrent CFS and FM. Further clarification of the similarities (and differences) between CFS and FM may be useful in studies of prognosis and help define subsets of patients who may benefit from specific therapeutic interventions.

A comparison of the characteristics of chronic fatigue syndrome in primary and tertiary care

BACKGROUND

To evaluated the characteristics of Chronic Fatigue Syndrome (CFS) in primary and tertiary care.

METHOD

A comparison of subjects fulfilling criteria for CFS, identified as part of a prospective cohort study in primary care, compared to 79 adults fulfilling the same criteria referred for treatment to a specialist CFS clinic.

RESULTS

Hospital cases were more likely to belong to upper socio-economic groups, and to have physical illness attributions. They had higher levels of fatigue and more somatic symptoms, and were more impaired functionally, but had less overt psychological morbidity. Women were over-represented in both primary care and hospital groups. Nearly half of those referred to a specialist clinic did not fulfil operational criteria for CFS.

CONCLUSION

The high rates of psychiatric morbidity and female excess that characterise CFS in specialist settings are not due to selection bias. On the other hand higher social class and physical illness attributions may be the result of selection bias and not intrinsic to CFS.

The epidemiology of fatigue and depression: a French primary-care study

The prevalence of fatigue as a presenting complaint and as a symptom is evaluated in French general practice patients. The data for a sample of 3784 persons 18-64 years-of-age who were seen by 367 general practitioners were examined for fatigue as a presenting complaint, diagnosis, and reported symptoms of persistent fatigue. Gender, age, and socio-professional category were considered as potential risk correlates. At least one of the symptoms of persistent fatigue was reported by 41.2% of the patients, but only 7.6% had presented with fatigue to the doctor. Women reported more symptoms of fatigue than men, but they were only slightly more likely to present with, or be diagnosed with fatigue; women were more frequently diagnosed with depression. There was a strong relationship between the symptoms of depression as measured by the Center for Epidemiologic Studies-Depression Scale (CES-D) and fatigue, but fatigue was neither sensitive nor specific for the diagnosis of depression. Age and fatigue as a presenting complaint and diagnosis were strongly associated for men. After adjusting for sex and age, we found that lower social classes were less likely to be diagnosed as fatigued, though they were more likely to report symptoms of fatigue.

Coping with chronic fatigue syndrome: illness responses and their relationship with fatigue, functional impairment and emotional status

The implications of patients' approaches to managing chronic fatigue syndrome were examined in a cross-sectional study. With severity of fatigue controlled, attempting to maintain activity was associated with less functional impairment, while accommodating to the illness was positively related to impairment; behavioural disengagement was related not only to higher levels of impairment but also to greater emotional disturbance. Fatigue itself was positively associated with focusing on symptoms and with behavioural disengagement; it was associated also with illness accommodation, but only for illness of longer duration. The causal direction of relationships between coping and fatigue severity is ambiguous, and a follow-up study will address the effects of coping on changes in the illness over time.

Chronic fatigue syndrome: a cognitive approach

Observations concerning the characteristics of patients who presented to a medical clinic with a principal complaint of chronic medically unexplained fatigue (Chronic Fatigue Syndrome or CFS) are described, including the cognitions (thoughts and assumptions) elicited from a sample of these patients who were treated using cognitive behavioural therapy. On the basis of these observations a cognitive theory of the aetiology of CFS is proposed. These observations have implications for the treatment of patients with CFS.

Use of dynamic tests of muscle function and histomorphometry of quadriceps muscle biopsies in the investigation of patients with chronic alcohol misuse and chronic fatigue syndrome

Ischaemic lactate/ammonia tests, serum carnosinase and creatine kinase assays and percutaneous needle muscle biopsies were performed on 10 patients with chronic fatigue syndrome (CFS), and 10 with chronic alcohol misuse complaining of muscular symptoms. Basal serum lactate levels were significantly elevated in the alcohol misusers compared to the CFS patients, but all were within the reference range. Lactate profiles after ischaemic forearm exercise did not differ significantly for the two patient groups. In one patient previously diagnosed as having CFS, myoadenylate deaminase deficiency was identified on the basis of a flat ammonia response to ischaemia and absent muscle adenosine monophosphate deaminase activity. In addition, two further patients in the CFS group were subsequently shown to have other disorders: one had polymyositis and one had myopathy with mild type II fibre atrophy of unknown cause. Histomorphometric examination of muscle needle biopsy in the alcohol misusers showed features of chronic alcohol-induced skeletal myopathy in six patients and polymyositis in one patient. Type II fibre atrophy factors were significantly elevated in the alcohol group but were within the reference range in CFS patients. Dynamic tests of muscle function and muscle histology are valuable tools in excluding alternative pathology in CFS, whereas muscle histomorphometry is of the greatest value in the diagnosis of chronic alcoholic myopathy.

Viruses, neurosis and fatigue

The evidence for viral infections as a cause of anxiety, depression and fatigue is reviewed. It is argued that in order to fully understand any proposed relationship the effects of psychosocial factors on immunity, convalescence and illness behaviour must be acknowledged.

Recurrent lymphocytic meningitis associated with hereditary isolated IgG subclass 3 deficiency

We report the case of an otherwise healthy young adult woman who has suffered three episodes of lymphocytic meningitis of possible enteroviral aetiology during a 5 year period. Analysis of immunoglobulin subclasses has revealed a sustained reduction of IgG3 to below the fifth percentile. In addition, the patient's father and brother have a similar degree of IgG3 deficiency. Isolated IgG3 deficiency has previously been described in association with recurrent upper respiratory tract infections, asthma, obstructive lung disease and enteral infections. However, our patient did not have any of these and there was no other identifiable immune defect to account for the recurrent meningitis. Although a mere chance association is possible, the case is interesting as antibody responses involving IgG3 tend to be triggered by protein antigens such as viral envelopes, while humoral immunity is known to be important in the clearance of enteroviral infection.

Treatment of the chronic fatigue syndrome. A review and practical guide

The chronic fatigue syndrome (CFS) was formally defined in 1988 to describe a syndrome of severe and disabling fatigue of uncertain aetiology associated with a variable number of somatic and/or psychological symptoms. CFS has been reported in most industrialised countries and is most prevalent in women aged between 20 and 50 years. Despite occasional claims to the contrary, the aetiology of CFS remains elusive. Although abnormalities in tests of immune function and cerebral imaging have been described in variable numbers of CFS patients, such findings have been inconsistent and cannot be relied upon, either to establish or exclude the diagnosis. Thus, diagnosis rests on fulfillment of the Centers for Disease Control case definition which was revised in 1992. This case definition remains somewhat controversial, largely due to its subjectiveness. The mainstay of treatment is establishing the diagnosis and educating the patient about the illness. An empathetic clinician can stop further consultations elsewhere ('doctor shopping') and subsequent excessive investigations, which frequently occur in such patients. Most patients should undertake a trial of antidepressant therapy, even if major depression is not present. The choice of antidepressant drug should tailor the tolerability profile to relief of particular CFS symptoms, such as insomnia or hypersomnia. Failure to improve within 12 weeks warrants an alternative antidepressant agent of another class. Many other drugs have been reported anecdotally to be beneficial, but no therapy has been demonstrated to be reproducibly useful in double-blind, placebo-controlled clinical trials with an adequate duration of follow-up.

Fatigue, depression, and social adjustment in chronic fatigue syndrome

The aims of this study were to determine the characteristics and perceived levels of fatigue and the prevalence of depression in children with chronic fatigue syndrome and to assess the effects of illness on schooling and social functioning. Twelve children with chronic fatigue syndrome were compared with a matched group of children with cystic fibrosis and matched healthy controls. Levels of fatigue (fatigue questionnaire), depression (children's depression inventory), and social adjustment (semistructured interview with parents) were compared between groups. Children with chronic fatigue syndrome had significantly higher median scores for physical and mental fatigue and depressive symptomatology than either comparison group and five children scored as depressed on the children's depression inventory. Schooling and social functioning were seriously disrupted. Children with chronic fatigue syndrome reported high levels of fatigue affecting both physical and mental functioning, the association with depression found in adult studies was confirmed, and social adjustment was poor.

Follow up of patients presenting with fatigue to an infectious diseases clinic

OBJECTIVES

To determine the symptomatic and functional status during follow up of patients referred to hospital with unexplained fatigue and to identify patient variables associated with persistent functional impairment.

DESIGN

Follow up by postal questionnaire six weeks to four years (median 1 year) after initial clinical assessment of patients referred to hospital during 1984-8.

SETTING

Infectious diseases outpatient clinic in a teaching hospital.

PATIENTS

200 consecutive patients with fatigue of uncertain cause for at least six weeks; 177 fulfilled the inclusion criteria.

MAIN OUTCOME MEASURES

Findings at initial assessment; current symptoms, beliefs about the cause of illness, coping behaviours emotional disorder, social variables including membership of self help organizations, and degrees of recovery and functional impairment from questionnaire responses.

RESULTS

144 (81%) patients returned completed questionnaires. Initial assessment did not indicate the cause of fatigue, other than preceding infection. The proportion of patients with functional impairment was significantly smaller with longer follow up (33% (11/33) at two to four years, 73% (29/40) at six weeks to six months; chi 2 for trend = 12.5, df = 1; p less than 0.05). Functional impairment was significantly associated with belief in a viral cause of the illness (odds ratio = 3.9; 95% confidence interval 1.5 to 9.9), limiting exercise (3.2; 1.5 to 6.6), avoiding alcohol (4.5; 1.8 to 11.3), changing or leaving employment (3.1; 1.4 to 6.9), belonging to a self help organization (7.8; 2.5 to 23.9), and current emotional disorder (4.4; 2.0 to 9.3).

CONCLUSIONS

Short term prognosis for recovery of function was poor but improved with time. Most patients had made a functional recovery by two years after initial clinic attendance. Impaired functioning was more likely with certain patient characteristics. Prospective studies are required to clarify whether these associations are the consequences of a more disabling illness or indicate factors contributing to impaired function.

General practitioners' experience of the chronic fatigue syndrome

In order to examine the prevalence of patients with symptoms fulfilling the criteria for the chronic fatigue syndrome an extensive survey was carried out of general practitioners on 10 local government lists in two health boards (91% response rate). At the same time practitioners' attitudes to the syndrome and their experience in terms of workload and the characteristics of patients affected were documented. The majority of general practitioners (71%) accepted the existence of chronic fatigue syndrome, but 22% were undecided. The doctors reported a prevalence among their patients of 1.3 per 1000 patients (range 0.3-2.7 for the 10 areas) with a peak in the 30-44 years age group. Female patients were more commonly affected than males (sex ratio 1.8:1.0), but the severity of illness and the use of general practitioner's time was the same among male and female patients. Patients in occupations where they were exposed to infection were affected (teachers and students, 22% of sample; hospital workers, 7%), but many patients were unskilled (8%) and skilled workers (9%). Patients suffering from the chronic fatigue syndrome appear to be a real and distinct group for general practitioners and may represent a substantial part of the workload of doctors in particular areas.

Tired, weak, or in need of rest: fatigue among general practice attenders

OBJECTIVES

To determine the prevalence and associations of symptoms of fatigue.

DESIGN

Questionnaire survey.

SETTING

London general practice.

PARTICIPANTS

611 General practice attenders.

MAIN OUTCOME MEASURES

Scores on a fatigue questionnaire and reasons given for fatigue.

RESULTS

10.2% Of men (17/167) and 10.6% of women (47/444) had substantial fatigue for one month or more. Age, occupation, and marital status exerted minor effects. Subjects attributed fatigue equally to physical and non-physical causes. Physical ill health, including viral infection, was associated with more severe fatigue. Women rather than men blamed family responsibilities for their fatigue. The profile of persistent fatigue did not differ from that of short duration. Only one person met criteria for the chronic fatigue syndrome.

CONCLUSIONS

Fatigue is a common complaint among general practice attenders and can be severe. Patients may attribute this to physical, psychological, and social stress.