Epidemic neuromyasthenia; clinical syndrome

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

An evaluation of HHV-6 as an etiologic agent in Hodgkin lymphoma and brain cancer using IARC criteria for oncogenicity

BACKGROUND

Human herpesvirus-6 (HHV-6) is a ubiquitous double-stranded DNA virus that can cause roseola infantum, encephalitis, and seizure disorders. Several studies have shown an association between HHV-6 and cancer but confirmation of an etiologic role is lacking. We reviewed the criteria for viral causation of cancer used by The International Agency for Research on Cancer (IARC) for six oncogenic viruses and applied criteria to published reports of HHV-6 and its association with Hodgkin lymphoma and brain tumors.

METHODS

Our major criteria for oncogenicity were finding evidence of the virus in every tumor cell and prevention of the tumor by an antiviral vaccine. Our six minor criteria included: 1) suggestive serologic correlation, such as higher virus antibody levels in cases compared to controls; 2) evidence of the virus in some but not all tumor cells, and 3) time space clustering. We focused on Epstein-Barr virus (EBV) as the primary virus for comparison as HHV-6 and EBV are both Herpesviridae, ubiquitous infections, and EBV is well-accepted as a human oncovirus. Particular attention was given to Hodgkin lymphoma (HL) and brain cancer as these malignancies have been the most studied.

RESULTS

No studies reported HHV-6 satisfying either of the major criteria for oncogenicity. Of the minor criteria used by IARC, serologic studies have been paramount in supporting EBV as an oncogenic agent in all EBV-associated tumors, but not for HHV-6 in HL or brain cancer. Clustering of cases was suggestive for both HL and brain cancer and medical intervention suggested by longer survival in patients treated with antiviral agents was reported for brain cancer.

CONCLUSION

There is insufficient evidence to indicate HHV-6 is an etiologic agent with respect to HL and brain cancers. We suggest that methods demonstrating EBV oncogenicity be applied to HHV-6. It is important that one study has found HHV-6 in all cancer cells in oral cancer in a region with elevated HHV-6 antibodies and therefore HHV-6 can still be considered a possible human oncogenic virus.

EBV Chronic Infections

The infection from Epstein-Barr virus (EBV) or virus of infectious mononucleosis, together with other herpes viruses' infections, represents a prototype of persistent viral infections characterized by the property of the latency. Although the reactivations of the latent infection are associated with the resumption of the viral replication and eventually with the "shedding", it is still not clear if this virus can determine chronic infectious diseases, more or less evolutive. These diseases could include some pathological conditions actually defined as "idiopathic"and characterized by the "viral persistence" as the more credible pathogenetic factor. Among the so-called idiopathic syndromes, the "chronic fatigue syndrome" (CFS) aroused a great interest around the eighties of the last century when, just for its relationship with EBV, it was called "chronic mononucleosis" or "chronic EBV infection".Today CFS, as defined in 1994 by the CDC of Atlanta (USA), really represents a multifactorial syndrome characterized by a chronic course, where reactivation and remission phases alternate, and by a good prognosis. The etiopathogenetic role of EBV is demonstrated only in a well-examined subgroup of patients, while in most of the remaining cases this role should be played by other infectious agents - able to remain in a latent or persistent way in the host - or even by not infectious agents (toxic, neuroendocrine, methabolic, etc.). However, the pathogenetic substrate of the different etiologic forms seems to be the same, much probably represented by the oxidative damage due to the release of pro-inflammatory cytokines as a response to the triggering event (infectious or not infectious).Anyway, recently the scientists turned their's attention to the genetic predisposition of the subjects affected by the syndrome, so that in the last years the genetic studies, together with those of molecular biology, received a great impulse. Thanks to both these studies it was possibile to confirm the etiologic links between the syndrome and EBV or other herpesviruses or other persistent infectious agents.The mechanisms of EBV latency have been carefully examined both because they represent the virus strategy to elude the response of the immune system of the host, and because they are correlated with those oncologic conditions associated to the viral persistence, particularly lymphomas and lymphoproliferative disorders. Just these malignancies, for which a pathogenetic role of EBV is clearly documented, should represent the main clinical expression of a first group of chronic EBV infections characterized by a natural history where the neoplastic event aroused from the viral persistence in the resting B cells for all the life, from the genetic predisposition of the host and from the oncogenic potentialities of the virus that chronically persists and incurs reactivations.Really, these oncological diseases should be considered more complications than chronic forms of the illness, as well as other malignancies for which a viral - or even infectious - etiology is well recognized. The chronic diseases, in fact, should be linked in a pathogenetic and temporal way to the acute infection, from whom start the natural history of the following disease. So, as for the chronic liver diseases from HBV and HCV, it was conied the acronym of CAEBV (Chronic Active EBV infection), distinguishing within these pathologies the more severe forms (SCAEBV) mostly reported in Far East and among children or adolescents. Probably only these forms have to be considered expressions of a chronic EBV infection "sensu scrictu", together with those forms of CFS where the etiopathogenetic and temporal link with the acute EBV infection is well documented. As for CFS, also for CAEBV the criteria for a case definition were defined, even on the basis of serological and virological findings. However, the lymphoproliferative disorders are excluded from these forms and mantain their nosographic (e.g. T or B cell or NK type lymphomas) and pathogenetic collocation, even when they occur within chronic forms of EBV infection. In the pathogenesis, near to the programs of latency of the virus, the genetic and environmental factors, independent from the real natural history of EBV infection, play a crucial role.Finally, it was realized a review of cases - not much numerous in literature - of chronic EBV infection associated to chronic liver and neurological diseases, where the modern techniques of molecular biology should be useful to obtain a more exact etiologic definition, not always possibile to reach in the past.The wide variety of clinical forms associated to the EBV chronic infection makes difficult the finding of a univocal pathogenetic link. There is no doubt, however, that a careful examination of the different clinical forms described in this review should be useful to open new horizons to the study of the persistent viral infections and the still not well cleared pathologies that they can induce in the human host.

Chronic fatigue in historical perspective

Chronic fatigue as a presenting complaint, in the absence of other evident organic illness, was seldom reported historically before the second half of the 19th century. Its first eruption was the so-called 'bed cases' or 'sofa cases' among middle-class females in the period from 1860 to about 1910. 'Neurasthenia' does not necessarily represent an early forerunner of chronic fatigue. Many patients receiving that diagnosis did not complain of fatigue. Others with functional fatigue did not receive the diagnosis 'neurasthenia'. Both medical-anecdotal and quantitative sources make it clear that by the time of the First World War, chronic fatigue was a common complaint in Europe and North America. Medical concepts of chronic fatigue since the 1930s have run along four separate lines: (1) 'postinfectious neuromyasthenia', going back to an atypical 'poliomyelitis' epidemic in 1934; (2) 'chronic Epstein-Barr virus' infection, an illness attribution that increased in frequency after the discovery in 1968 that this virus caused mononucleosis; (3) 'myalgic encephalomyelitis', dating from an epidemic at the Royal Free Hospital in London in 1955; and (4) 'fibrositis', or 'fibromyalgia', used as a rheumatological description since the turn of the century. Recently, these four separate paths have tended to converge into the diagnosis of 'chronic fatigue syndrome'.

Chronic fatigue syndrome: probable pathogenesis and possible treatments

Chronic fatigue syndrome (CFS) belongs in the medically unexplained illnesses. It affects approximately 0.2-0.7% of the population in Western countries. It is characterised by unexplained fatigue, lasting 6 months or more, impairment of neurocognitive functions and quality of sleep, and of somatic symptoms, such as recurrent sore throat, muscle aches, arthralgias, headache and postexertional malaise. No link between infections and CFS has been clearly established but the immune system is activated, there are aberrations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. No specific treatment has been found. Cognitive behavioural therapy is established to be of value to improve quality of life. More effective treatment should result, as advances in biomedical as well as psychological research continue.

Chronic fatigue syndrome: new insights and old ignorance

Chronic fatigue syndrome (CFS) is a condition characterized by impairment of neurocognitive functions and quality of sleep and of somatic symptoms such as recurrent sore throat, muscle aches, arthralgias, headache, and postexertional malaise. A majority of patients describe an infectious onset but the link between infections and CFS remains uncertain. Findings show an activation of the immune system, abberations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. The origin is bound to be complex and it may well be that the solution will come together with a more generally altered view about mind-body dualism, and the concept of illness and disease.

Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome

OBJECTIVE

To report chronic fatigue syndrome (CFS) associated with both Ehlers-Danlos syndrome (EDS) and orthostatic intolerance.

STUDY DESIGN

Case series of adolescents referred to a tertiary clinic for the evaluation of CFS. All subjects had 2-dimensional echocardiography, tests of orthostatic tolerance, and examinations by both a geneticist and an ophthalmologist.

RESULTS

Twelve patients (11 female), median age 15.5 years, met diagnostic criteria for CFS and EDS, and all had either postural tachycardia or neurally mediated hypotension in response to orthostatic stress. Six had classical-type EDS and 6 had hypermobile-type EDS.

CONCLUSIONS

Among patients with CFS and orthostatic intolerance, a subset also has EDS. We propose that the occurrence of these syndromes together can be attributed to the abnormal connective tissue in dependent blood vessels of those with EDS, which permits veins to distend excessively in response to ordinary hydrostatic pressures. This in turn leads to increased venous pooling and its hemodynamic and symptomatic consequences. These observations suggest that a careful search for hypermobility and connective tissue abnormalities should be part of the evaluation of patients with CFS and orthostatic intolerance syndromes.

The epidemiology of chronic fatigue in San Francisco

Despite considerable research on chronic fatigue syndrome (CFS) and conditions associated with unexplained chronic fatigue (CF), little is known about their prevalence and demographic distribution in the population. The present study describes the epidemiology and characteristics of self-reported CF and related conditions in a diverse urban community. The study used a cross-sectional telephone screening survey of households in San Francisco, followed by interviews with fatigued and nonfatigued residents. Respondents who appeared to meet case definition criteria for CFS, based on self-reported fatigue characteristics, symptoms, and medical history, were classified as CFS-like cases. Subjects who reported idiopathic chronic fatigue (ICF) that did not meet CFS criteria were classified as ICF-like cases. Screening interviews were completed for 8,004 households, providing fatigue and demographic information for 16,970 residents. Unexplained CF was extremely rare among household residents <18 years of age, but was reported by 2% of adult respondents. A total of 33 adults (0.2% of the study population) were classified as CFS-like cases and 259 (1.8%) as ICF-like cases. Neither condition clustered within households. CFS- and ICF-like illnesses were most prevalent among women and persons with annual household incomes below $40,000, and least prevalent among Asians. The prevalence of CFS-like illness was elevated among African Americans, Native Americans, and persons engaged in clerical occupations. Although CFS-like cases were more severely ill than those with ICF-like illness, a similar symptom pattern was observed in both groups. In conclusion, conditions associated with unexplained CF occur in all sociodemographic groups but appear to be most prevalent among women, persons with lower income, and some racial minorities.

Neurally mediated hypotension and chronic fatigue syndrome

A substantial body of clinical evidence now supports an association between various forms of hypotension and both idiopathic chronic fatigue and the chronic fatigue syndrome (CFS). Patients with CFS have a high prevalence of neurally mediated hypotension, and open treatment of this autonomic dysfunction has been associated with improvements in CFS symptoms. Randomized trials are now in progress to evaluate the efficacy of treatments directed at neurally mediated hypotension in those with CFS patients, and the results of these trials should help guide more basic inquiries into the mechanisms of orthostatic intolerance in affected individuals.

Estimating the prevalence of chronic fatigue syndrome among nurses

The present study assessed the prevalence of chronic fatigue syndrome (CFS) in a sample of nurses. There is a paucity of studies on the prevalence of CFS in healthcare professionals. Two samples of nurses were recruited through mailed questionnaires. Data were collected on demographic characteristics and symptoms. In addition from the sample, those nurses with CFS-like symptoms were more comprehensively evaluated using a structured clinical interview and reviewing their medical records. A physician review team estimated the prevalence of CFS to be 1,088 per 100,000. These findings suggest that nurses might represent a high-risk group for this illness, possibly due to occupational stressors such as exposure to viruses in the work setting, stressful shift work that is disruptive to biologic rhythms, or to other possible stressors in the work settings (e.g., accidents).

Cancer and a fatiguing illness in Northern Nevada--a causal hypothesis

PURPOSE

We investigated the possibility that chronic fatigue syndrome (CFS) predisposes to cancer by comparing the cancer pattern in an area in northern Nevada, where an outbreak of a fatiguing illness, which included cases of CFS, was reported, to an area in southern Nevada, where no such illness was reported.

METHODS

Data from the computerized Nevada Cancer Registry were utilized to compare incidence rates of four malignancies--brain cancer, non-Hodgkin lymphoma (NHL), lung cancer, and breast cancer--in Washoe and Lyon Counties, where an unexplained fatiguing illness was reported during 1984-86, with comparably sized Clark County, where no such illness was reported.

RESULTS

Higher incidences of NHL and primary brain tumors were noted in the two northern Nevada counties (Washoe and Lyon) in 1986 and 1987 respectively, compared to the southern Nevada (Clark) county. Similar patterns were not seen for breast or lung cancer.

CONCLUSIONS

This study provides a model for investigating the possible predisposition of CFS patients to develop cancer using other cohorts, but it is currently premature to accept such a link at this time.

Fibromyalgia, chronic fatigue, and other iatrogenic diagnostic algorithms. Do some labels escalate illness in vulnerable patients?

Contemporary medicine has the sophistication to identify the clinical settings in which the hunt for a diagnosis can be harmful to a patient's health. Which patients are best served by a prolonged search for a cause? Why has the disease-illness paradigm backfired for so many patients? Dr Hadler challenges readers to look at the difficult questions linked with diagnostic labels that might teach patients to stay sick.

[Definition of "chronic fatigue syndrome" (CFS)]

The definition of "Chronic Fatigue Syndrome" (CFS) in 1988 was an attempt to establish a uniform basis for the previously heterogeneous approaches to research of this severe and inexplicable state of fatigue. At the same time, researchers wished to narrow down a pathogenetically founded disease entity a priori by specifying precise disease criteria. The empirical data gathered in accordance with the CFS definition, however, have failed to confirm the assumption that the disease entity is pathogenetically uniform. Furthermore, the originally selected criteria have proven to be impracticable ore theoretically questionable. In the period that followed, modifications that permitted a more comprehensive and yet more differentiated classification of fatigue states of unclear etiology were proposed. The new research approach avoids postulation of causal entities and puts CFS back in a category with other descriptive states of fatigue.

The natural history of concurrent sick building syndrome and chronic fatigue syndrome

An outbreak of chronic fatigue syndrome linked with sick building syndrome was recently described as a new association. Whether chronic fatigue syndrome acquired in this setting tends to remit or, as sporadic cases often do, persist, is unknown. To clarify the natural history of chronic fatigue syndrome in association with sick building syndrome the 23 individuals involved in the outbreak were interviewed four years after the onset. In the previous interview one year after the onset of symptoms, 15 (including 5 with chronic fatigue syndrome and 10 with idiopathic chronic fatigue) of the 23 noted fatigue. Three years later 10 of the 15 were "fatigue free" or "much improved". Five were only "some better", "the same", or "worse". Three of the five people previously diagnosed with chronic fatigue syndrome were "much improved" (two) or "fatigue free" (one). The remaining two were seriously impaired, homebound and unable to work. The 10 individuals with substantially improved fatigue (three of the five with chronic fatigue syndrome and seven of the 10 with idiopathic chronic fatigue) were more likely to have noted improvement in nasal and sinus symptoms, sore throats, headaches, and tender cervical lymph nodes when compared to those with a lingering significant fatigue (p < 0.001). Upper respiratory symptoms and headaches improved in those with reduced fatigue but remained problematic in those with persisting significant fatigue. We conclude that the fatigue related to sick building syndrome, including chronic fatigue syndrome, is significantly more likely to improve than fatigue identified in sporadic cases of chronic fatigue syndrome.

Epidemiologic advances in chronic fatigue syndrome

Epidemiologic studies of chronic fatigue syndrome (CFS) have been hampered by the absence of a specific diagnostic test, but with increasing interest in this disorder there has been a greater understanding of the risk factors, illness patterns, and other aspects of this multisystem disorder. Working case definitions have been developed for research purposes but they have continued to change over time and have not always been utilized precisely by various investigators. This has been a major factor in the widely varying estimates of prevalence rates, but two different studies using the same working definition and including a medical work-up have estimated the prevalence to be approximately 200/100,000. Clusters of CFS cases, which appear to be related to earlier reports of "epidemic neuromyasthenia", have attracted considerable attention and appear to be well documented, although investigated with varying methodology and often with dissimilar case definitions. Risk factors for cases occurring in clusters and sporadically appear to be similar, the most consistent ones being female gender and the co-existence of some form of stress, either physical or psychological. The prognosis of CFS is difficult to predict, although cases occurring as part of clusters appear to have a better prognosis as a group than sporadic cases, and those with an acute onset have a better prognosis than those with gradual onset. It is highly unlikely that there is a single agent, infectious or noninfectious, that is responsible for more than a small proportion of CFS cases and, at the present time, the risk factors for developing CFS appear to lie more prominently in the host rather than the environment.

An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome

We surveyed households in four rural Michigan communities to confirm a reported cluster of cases resembling chronic fatigue syndrome (CFS) and to study the epidemiology of fatigue in a rural area. Data were collected from 1698 households. We did not confirm the reported cluster. The prevalence of households containing at least one fatigued person was similar between communities thought to harbor the cluster and communities selected for comparison. Symptoms and features of generic forms of fatigue were very similar to those often attributed to CFS.

The use of transfer factors in chronic fatigue syndrome: prospects and problems

Chronic fatigue syndrome (CFS) is a heterogeneous disorder characterized by severe prolonged unexplained fatigue and a variety of associated symptoms such as arthralgias, myalgias, cognitive dysfunction, and severe sleep disturbances. Many patients initially present with an acute onset of apparent infectious origin with either an upper respiratory or gastrointestinal illness, fever, chills, tender lymphadenopathy, and malaise suggestive of a flu-like illness. In some cases, specific viral infections can be identified at the outset, particularly herpes viruses such as Epstein-Barr virus (EBV), human herpes virus-6 (HHV-6), and cytomegalovirus (CMV). Transfer factors (TF) with specific activity against these herpes viruses has been documented. With some studies suggesting that persistent viral activity may play a role in perpetuation of CFS symptoms, there appears to be a rationale for the use of TF in patients with CFS and recent reports have suggested that transfer factor may play a beneficial role in this disorder. This report focuses on the heterogeneity of CFS, the necessity for randomized coded studies, the importance of patient selection and sub-classification in clinical trials, and the need to utilize specific end-points for determining efficacy of treatment.

Chronic active Epstein-Barr virus infection, an AIDS-Co-Factor or predominant infection?

Chronic Active Epstein-Barr Virus is associated with Epstein-Barr Virus 2B (EBNA2B) and AIDS and possibly a widespread clinical syndrome. Provocative conclusions regarding their association are noted.

Search for retrovirus in the chronic fatigue syndrome

AIM

To examine peripheral blood and skeletal muscle from patients with chronic fatigue syndrome for exogenous retrovirus.

METHODS

Blood samples from 30 patients and muscle biopsy specimens of 15 patients were examined for retroviral sequences by DNA extraction, polymerase chain reaction (PCR), and Southern blotting hybridisation. Sera were examined for human foamy virus by western immunoblotting and indirect immunofluorescence techniques.

RESULTS

No differences between the patient and control populations was found for any of the PCR primer sets used (gag, pol, env, and tax regions of HTLV I/II). An endogenous gag band was observed in both the patient and control groups. All sera were negative for antibody to human foamy virus.

CONCLUSION

The results indicate that there is no evidence of retroviral involvement in the chronic fatigue syndrome.

Psychological aspects of chronic fatigue syndrome

Research on Chronic Fatigue Syndrome has not identified a definitive cause or treatment but psychological aspects have been noted.

Mitochondrial abnormalities in the postviral fatigue syndrome

We have examined the muscle biopsies of 50 patients who had postviral fatigue syndrome (PFS) for from 1 to 17 years. We found mild to severe atrophy of type II fibres in 39 biopsies, with a mild to moderate excess of lipid. On ultrastructural examination, 35 of these specimens showed branching and fusion of mitochondrial cristae. Mitochondrial degeneration was obvious in 40 of the biopsies with swelling, vacuolation, myelin figures and secondary lysosomes. These abnormalities were in obvious contrast to control biopsies, where even mild changes were rarely detected. The findings described here provide the first evidence that PFS may be due to a mitochondrial disorder precipitated by a virus infection.

Enteroviral RNA sequences detected by polymerase chain reaction in muscle of patients with postviral fatigue syndrome

OBJECTIVE

To determine the presence of enteroviral sequences in muscle of patients with the postviral fatigue syndrome.

DESIGN

Detection of sequences with the polymerase chain reaction in a well defined group of patients with the syndrome and controls over the same period.

SETTING

Institute of Neurological Sciences, Glasgow.

SUBJECTS

60 consecutive patients admitted to the institute with the postviral fatigue syndrome who had undergone extensive investigation to exclude other conditions. 41 controls from the same catchment area without evidence of fatigue, all undergoing routine surgery.

MAIN OUTCOME MEASURES

Routine investigations, serological screen for antibodies to a range of viruses, and presence of enteroviral RNA sequences in muscle biopsy specimens.

RESULTS

15 (25%) patients and 10 (24.4%) controls had important serological findings. 12 patients had neutralising antibody titres of greater than or equal to 256 to coxsackieviruses B1-5 (six positive for enteroviral RNA sequences, six negative); three were positive for Epstein-Barr virus specific IgM (two positive, one negative). Six controls had similar neutralising antibody titres to coxsackieviruses (all negative); one was positive for Epstein-Barr virus specific IgM (negative); and three had titres of complement fixing antibody greater than or equal to 256 to cytomegalovirus (all negative). Overall, significantly more patients than controls had enteroviral RNA sequences in muscle (32/60, 53% v 6/41, 15%; odds ratio 6.7, 95% confidence interval 2.4 to 18.2). This was not correlated with duration of disease, patient and age, or to raised titres of antibodies to coxsackieviruses B1-5.

CONCLUSIONS

Persistent enteroviral infection of muscle may occur in some patients with postviral fatigue syndrome and may have an aetiological role.

Antibody to Coxsackie B virus in diagnosing postviral fatigue syndrome

OBJECTIVE

To study the association between coxsackie B virus infection and the postviral fatigue syndrome and to assess the immunological abnormalities associated with the syndrome.

DESIGN

Case-control study of patients with the postviral fatigue syndrome referred by local general practitioners over one year.

SETTING

General practitioner referrals in Dunbartonshire, Scotland.

PATIENTS

254 Patients referred with the postviral fatigue syndrome (exhaustion, myalgia, and other symptoms referable to postviral fatigue syndrome of fairly recent onset--that is, several months) and age and sex matched controls obtained from same general practitioner; 11 patients were rejected because of wrong diagnoses, resolution of symptoms, and refusal to participate, leaving 243 patients and matched controls.

MAIN OUTCOME MEASURES

Detailed questionnaire (patients and controls) and clinical examination (patients) and blind analysis of blood sample at entry and after six months for determination of coxsackie B virus IgM and IgG antibodies and other variables (including lymphocyte protein synthesis, lymphocyte subsets, and immune complexes).

RESULTS

Percentage positive rates for coxsackie B virus IgM at entry were 24.4% for patients and 22.6% for controls and for coxsackie B virus IgG 56.2% and 55.3% respectively; there were no significant differences between different categories of patients according to clinical likelihood of the syndrome nor any predictive value in a fourfold rise or fall in the coxsackie B virus IgG titre in patients between entry and review at six months. The rates of positive antibody test results in patients and controls showed a strong seasonal variation. Of the numerous immunological tests performed, only a few detected significant abnormalities; in particular the mean value for immune complex concentration was much higher in 35 patients and 35 controls compared with the normal range and mean value for total IgM was also raised in 227 patients and 35 controls compared with the normal range.

CONCLUSIONS

Serological tests available for detecting coxsackie B virus antibodies do not help diagnose the postviral fatigue syndrome. Percentage positive rates of the antibodies in patients simply reflect the background in the population as probably do the raised concentrations of total IgM and immune complexes.

Effect of high doses of essential fatty acids on the postviral fatigue syndrome

Sixty-three adults with the diagnosis of the postviral fatigue syndrome were enrolled in a double-blind, placebo-controlled study of essential fatty acid therapy. The patients had been ill for from one to three years after an apparently viral infection, suffering from severe fatigue, myalgia and a variety of psychiatric symptoms. The preparation given contained linoleic, gamma-linolenic, eicosapentaenoic and docosahexaenoic acids and either it, or the placebo, was given as 8 x 500 mg capsules per day over a 3-month period. The trial was parallel in design and patients were evaluated at entry, one month and three months. In consultation with the patient the doctors assessed overall condition, fatigue, myalgia, dizziness, poor concentration and depression on a 3-point scale. The essential fatty acid composition of their red cell membrane phospholipids was analysed at the first and last visits. At 1 month, 74% of patients on active treatment and 23% of those on placebo assessed themselves as improved over the baseline, with the improvement being much greater in the former. At 3 months the corresponding figures were 85% and 17% (p less than 0.0001) since the placebo group had reverted towards the baseline state while those in the active group showed continued improvement. The essential fatty acid levels were abnormal at the baseline and corrected by active treatment. There were no adverse events. We conclude that essential fatty acids provide a rational, safe and effective treatment for patients with the post-viral fatigue syndrome.

Chronic Fatigue Syndrome: Searching for the Cause and Treatment

Chronic fatigue syndrome exploded into the nation's consciousness in 1985 with a pseudoepidemic in a Nevada resort community. Initially and erroneously linked to the Epstein-Barr virus, the cause of this puzzling blend of largely subjective features continues to elude researchers.

Features of Coxsackie B virus (CBV) infection in children with prolonged physical and psychological morbidity

A retrospective study of the clinical features in 39 children who were investigated for evidence of Coxsackie B virus (CBV) infection is reported. Eighteen children were found to have serological evidence of infection. An extensive range of features was elicited in both seropositive and seronegative patients, most children complaining of abnormalities referable to muscle and, in particular, of weakness and easy fatiguability. Children with evidence of CBV infection were significantly more likely to belong to social classes I and II, to have relatives with serological evidence of CBV infection, and to show certain dysphoric features as well as to complain of sore throats. The relationship between CBV infection and 'myalgic encephalomyelitis' or 'post-viral syndrome' is discussed, and it is suggested that these descriptions are inappropriate given our current knowledge, and inadequately describe the clinical features seen in the children under study. An alternative description, 'fatigue-dysphoria syndrome' is proposed.

Chronic fatigue syndromes: relationship to chronic viral infections

Chronic fatigue syndrome (CFS) is a newly-recognized clinical entity characterized by chronic, debilitating fatigue lasting longer than six months. Common associated findings are chronic and recurrent fever, pharyngitis, myalgias, adenopathy, arthralgias, difficulties in cognition and disorders of mood. In the majority of patients, the illness starts suddenly with an acute, 'flu-like' illness. The following abnormalities are seen with some frequency although none are seen in all patients: lymphocytosis, atypical lymphocytosis, monocytosis, elevation of hepatocellular enzymes, low levels of antinuclear antibodies, low levels of immune complexes. Clinical and serologic studies suggest an association of CFS with all of the human herpesviruses, particularly Epstein-Barr virus (EBV) and the recently-discovered human B-lymphotropic virus (HBLV) or human herpesvirus-6; neither EBV nor HBLV has yet been shown to play a causal role in the illness.

Chronic fatigue and myalgia syndrome: mitochondrial and glycolytic studies in skeletal muscle

Clinical and biochemical findings in skeletal muscle in 11 patients with chronic fatigue myalgia syndromes of unknown aetiology are reported. All patients had severe asthenia for from one to 10 years with greatly limited exercise capacity and protracted exhaustion after minor exercise. Diffuse myalgia was prominent and was exacerbated for hours to days after exercise. Assay of skeletal muscle carnitine, phosphorylase, all glycolytic enzymes and the mitochondrial marker enzymes monoamine oxidase, isocitrate dehydrogenase and cytochrome oxidase were normal. These findings lend no support to the presence of a major defect in muscle intermediary energy pathways in this syndrome.

Depression in patients with neuromyasthenia (benign myalgic encephalomyelitis)

Neuromyasthenia (benign myalgic encephalomyelitis) is a term used to describe a protracted and incomplete recovery phase following viral-like illnesses. There are few significant physical findings or abnormal laboratory determinations. Although depressive symptoms have been observed in individuals with neuromyasthenia, systematic psychological investigations based on a standardized interview technique have not been reported. This study was designed to investigate the prevalence of psychiatric disorders and psychiatric symptoms in a group of patients presenting with neuromyasthenia. The study consisted of three parts: a structured psychiatric interview (The National Institute of Mental Health Diagnostic Interview Schedule), a self-report measure (The Beck Depression Inventory) and Dexamethasone Suppression Test. Results indicated that relative to a matched comparison group of non-clinical volunteers, a significant percentage (67%) of neuromyasthenic patients met criteria for major depression. Even more striking was the observation that 50 percent of the sample had a major depressive episode prior to the development of neuromyasthenia. These findings suggest that sporadic neuromyasthenia may be the result of an organic illness in psychologically susceptible individuals.

Current issues concerning management of the fibrositis/fibromyalgia syndrome

The fibrositis/fibromyalgia syndrome is one of the commonest forms of musculoskeletal pain seen in clinical practice. It is diagnosed on the basis of widespread pain accompanied by the physical finding of multiple tender points in remarkably reproducible locations. Accompanying the pain are two symptoms commonly associated with the "systemic" rheumatic disorders, namely morning stiffness and easy fatigability. Unlike the classical rheumatic diseases, however, fibrositis is not responsive to anti-inflammatory medications, including corticosteroids. Current therapeutic strategies, which are only partly successful, are aimed at modifying those factors that seemingly influence the severity and course of the condition; such afferent features include sleep disturbance, overuse syndromes, mechanical stress, psychic stress, and other causes of chronic pain. Major unresolved issues center around the assessment of functional disability in fibrositis and the apparent relationship to trauma in some patients. Until more is known about the underlying pathogenesis of this common condition, significant progress will be thwarted.

The postviral fatigue syndrome--an analysis of the findings in 50 cases

The clinical, pathological, electrophysiological, immunological and virological abnormalities in 50 patients with the postviral fatigue syndrome are recorded. These findings confirm the organic nature of the disease. A metabolic disorder, caused by persistent virus infection and associated with defective immunoregulation, is suggested as the pathogenetic mechanism.

Early outbreaks of 'epidemic neuromyasthenia'

The literature of the outbreaks of 'epidemic neuromyasthenia' (ENM) from 1934 to 1955 has been selected to show that the disease affects other people besides young adult females in hospitals and nursing homes. There have been district epidemics, in which the male: female ratio was almost even and several male outbreaks affecting soldiers in barracks. Some outbreaks appear to have been triggered off by an epidemic of poliomyelitis, and the epidemiology of outbreaks in Iceland in 1948 and 1955 suggests that the normal cytopathological effects of poliomyelitis infection have been suppressed by the new disease. In the Durban epidemic (1955) a toxic metabolite was discovered in the urine of many patients and a markedly increased urinary excretion of creatine was noted in two New York State outbreaks. The results of the transmission of an agent from patients with ENM to monkeys suggest that the neurological disorder might be in the form of mild disseminated lesions scattered throughout the nervous system from the brain to peripheral nerves and associated with perivascular round cell infiltration without significant cellular damage. ENM infection was widespread in the North of England in 1955 and associated with lymphocyte abnormalities, which have persisted in some cases for several years. This suggests a continuous organic process.