Tag: review

Is human herpesvirus-6 a trigger for chronic fatigue syndrome?

Abstract:

Chronic fatigue syndrome (CFS) is an illness currently defined entirely by a combination of non-specific symptoms. Despite this subjective definition, CFS is associated with objective underlying biological abnormalities, particularly involving the nervous system and immune system.

Most studies have found that active infection with human herpesvirus-6 (HHV-6)–a neurotropic, gliotropic and immunotropic virus–is present more often in patients with CFS than in healthy control and disease comparison subjects, yet it is not found in all patients at the time of testing. Moreover, HHV-6 has been associated with many of the neurological and immunological findings in patients with CFS.

Finally, CFS, multiple sclerosis and seizure disorders share some clinical and laboratory features and, like CFS, the latter two disorders also are being associated increasingly with active HHV-6 infection. Therefore, it is plausible that active infection with HHV-6 may trigger and perpetuate CFS in a subset of patients.

 

Source: Komaroff AL. Is human herpesvirus-6 a trigger for chronic fatigue syndrome? J Clin Virol. 2006 Dec;37 Suppl 1:S39-46. https://www.ncbi.nlm.nih.gov/pubmed/17276367

 

Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: new trends and future directions

Abstract:

Fibromyalgia (FM) and chronic fatigue syndrome (CFS) patients often have memory and cognitive complaints. Objective cognitive testing demonstrates long-term and working memory impairments. In addition, CFS patients have slow information-processing, and FM patients have impaired control of attention, perhaps due to chronic pain. Neuroimaging studies demonstrate cerebral abnormalities and a pattern of increased neural recruitment during cognitive tasks. Future work should focus on the specific neurocognitive systems involved in cognitive dysfunction in each syndrome.

 

Source: Glass JM. Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: new trends and future directions. Curr Rheumatol Rep. 2006 Dec;8(6):425-9. https://www.ncbi.nlm.nih.gov/pubmed/17092441

 

Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/myalgic encephalomyelitis: an updated systematic review

Abstract:

OBJECTIVES: To determine whether any particular intervention or combination of interventions is effective in the treatment, management and rehabilitation of adults and children with a diagnosis of chronic fatigue syndrome / myalgic encephalomyelitis (CFS/ME).

DESIGN: Substantive update of a systematic review published in 2002. Randomized (RCTs) and non-randomized controlled trials of any intervention or combination of interventions were eligible for inclusion. Study participants could be adults or children with a diagnosis of CFS/ME based on any criteria. We searched eleven electronic databases, reference lists of articles and reviews, and textbooks on CFS/ME. Additional references were sought by contact with experts.

RESULTS: Seventy studies met the inclusion criteria. Studies on behavioural, immunological, pharmacological and complementary therapies, nutritional supplements and miscellaneous other interventions were identified. Graded exercise therapy and cognitive behaviour therapy appeared to reduce symptoms and improve function based on evidence from RCTs. For most other interventions, evidence of effectiveness was inconclusive and some interventions were associated with significant adverse effects.

CONCLUSIONS: Over the last five years, there has been a marked increase in the size and quality of the evidence base on interventions for CFS/ME. Some behavioural interventions have shown promising results in reducing the symptoms of CFS/ME and improving physical functioning. There is a need for research to define the characteristics of patients who would benefit from specific interventions and to develop clinically relevant objective outcome measures.

Comment in: Chronic fatigue syndrome. [J R Soc Med. 2007]

 

Source: Chambers D, Bagnall AM, Hempel S, Forbes C. Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/myalgic encephalomyelitis: an updated systematic review. J R Soc Med. 2006 Oct;99(10):506-20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1592057/ (Full article)

 

Conceptual issues in undifferentiated somatoform disorder and chronic fatigue syndrome

Abstract:

PURPOSE OF REVIEW: To review the conceptual problems in distinguishing between undifferentiated somatoform disorder and chronic fatigue syndrome, for both may present with fatigue as the main symptom.

RECENT FINDINGS: The differences and/or similarities between undifferentiated somatoform disorder and chronic fatigue syndrome have not been studied, conceptually or empirically. The literature fails to present discriminant validity of chronic fatigue syndrome in relation to undifferentiated somatoform disorder. A critical feature is implied in the definition of undifferentiated somatoform disorder but absent from the definitions of chronic fatigue syndrome: some patients experience their fatigue as being exclusively physical and not as mental, which is prima facie peculiar, for fatigue is necessarily a mental experience. One is not able to experience fatigue without a mind (or a brain). This experience is characterized as a ‘mindless’ fatigue, underpinned by pathological reductionist thinking. By not recognizing this critical feature, diagnostic endeavours may perpetuate the problem as a function of the patient’s difficulty.

SUMMARY: Proponents of chronic fatigue syndrome should distinguish chronic fatigue syndrome from undifferentiated somatoform disorder, if chronic fatigue syndrome is a distinct entity at all. Further, the ‘mindless’ quality is a critical feature that needs consideration in refining the concept of undifferentiated somatoform disorder.

 

Source: van Staden WC. Conceptual issues in undifferentiated somatoform disorder and chronic fatigue syndrome. Curr Opin Psychiatry. 2006 Nov;19(6):613-8. https://www.ncbi.nlm.nih.gov/pubmed/17012941

 

Chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is thought to have a worldwide prevalence of 0.4-1% with approximately 240,000 patients in the UK. Diagnosis is based on clinical criteria and critically depends on exclusion of other physical and psychiatric diseases. Studies of pathogenesis have revealed immune system abnormalities and chronic immune activation, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, brain abnormalities, evidence of emotional stress (comprising host aspects) and evidence of exogenous insults, for example, various microbial infections (Epstein-Barr virus, enteroviruses, parvovirus B19, Coxiella burnetii and Chlamydia pneumoniae), vaccinations and exposure to organophosphate chemicals and other toxins (comprising environmental aspects).

Emotional stress appears to be very important as it reduces the ability of the immune system to clear infections, its presence has been shown to determine whether or not an individual develops symptoms upon virus infection, and it leads to activation of the HPA axis. But, emotional stress is distinct from depression, the presence of which precludes a diagnosis of CFS. There is no specific treatment for CFS other than the much underutilised approach of specific treatment of virus infections. Current priorities are to understand the molecular pathogenesis of disease in terms of human and virus gene expression, to develop a diagnostic test based on protein biomarkers, and to develop specific curative treatments.

 

Source: Devanur LD, Kerr JR. Chronic fatigue syndrome.  J Clin Virol. 2006 Nov;37(3):139-50. Epub 2006 Sep 15. https://www.ncbi.nlm.nih.gov/pubmed/16978917

 

Current research priorities in chronic fatigue syndrome/myalgic encephalomyelitis: disease mechanisms, a diagnostic test and specific treatments

Abstract:

Chronic fatigue syndrome (CFS) is an illness characterised by disabling fatigue of at least 6 months duration, which is accompanied by various rheumatological, infectious and neuropsychiatric symptoms. A collaborative study group has been formed to deal with the current areas for development in CFS research–namely, to develop an understanding of the molecular pathogenesis of CFS, to develop a diagnostic test and to develop specific and curative treatments. Various groups have studied the gene expression in peripheral blood of patients with CFS, and from those studies that have been confirmed using polymerase chain reaction (PCR), clearly, the most predominant functional theme is that of immunity and defence. However, we do not yet know the precise gene signature and metabolic pathways involved. Currently, this is being dealt with using a microarray representing 47,000 human genes and variants, massive parallel signature sequencing and real-time PCR. It will be important to ensure that once a gene signature has been identified, it is specific to CFS and does not occur in other diseases and infections. A diagnostic test is being developed using surface-enhanced, laser-desorption and ionisation-time-of-flight mass spectrometry based on a pilot study in which putative biomarkers were identified. Finally, clinical trials are being planned; novel treatments that we believe are important to trial in patients with CFS are interferon-beta and one of the anti-tumour necrosis factor-alpha drugs.

 

Source: Kerr JR, Christian P, Hodgetts A, Langford PR, Devanur LD, Petty R, Burke B, Sinclair LI, Richards SC, Montgomery J, McDermott CR, Harrison TJ, Kellam P, Nutt DJ, Holgate ST; Collaborative Clinical Study Group. Current research priorities in chronic fatigue syndrome/myalgic encephalomyelitis: disease mechanisms, a diagnostic test and specific treatments. J Clin Pathol. 2007 Feb;60(2):113-6. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860619/ (Full article)

 

Myalgic encephalomyelitis: a review with emphasis on key findings in biomedical research

Abstract:

This review examines research findings in patients with myalgic encephalomyelitis in light of the current debate about this chronic multiple-symptom, multiorgan, multisystem illness and the conflicting views in medicine. These issues cannot be separated from the political opinions and assertions that conflict with science and medicine, and will be part of this review as they have enormous consequences for scientific and medical research, patients, clinicians, carers and policy makers.

 

Source: Hooper M. Myalgic encephalomyelitis: a review with emphasis on key findings in biomedical research. J Clin Pathol. 2007 May;60(5):466-71. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994528/ (Full article)

 

Long-chain polyunsaturated fatty acids and the pathophysiology of myalgic encephalomyelitis (chronic fatigue syndrome)

Abstract:

Evidence is put forward to suggest that myalgic encephalomyelitis, also known as chronic fatigue syndrome, may be associated with persistent viral infection. In turn, such infections are likely to impair the ability of the body to biosynthesise n-3 and n-6 long-chain polyunsaturated fatty acids by inhibiting the delta-6 desaturation of the precursor essential fatty acids–namely, alpha-linolenic acid and linoleic acid.

This would, in turn, impair the proper functioning of cell membranes, including cell signalling, and have an adverse effect on the biosynthesis of eicosanoids from the long-chain polyunsaturated fatty acids dihomo-gamma-linolenic acid, arachidonic acid and eicosapentaenoic acid. These actions might offer an explanation for some of the symptoms and signs of myalgic encephalomyelitis.

A potential therapeutic avenue could be offered by bypassing the inhibition of the enzyme delta-6-desaturase by treatment with virgin cold-pressed non-raffinated evening primrose oil, which would supply gamma-linolenic acid and lipophilic pentacyclic triterpenes, and with eicosapentaenoic acid. The gamma-linolenic acid can readily be converted into dihomo-gamma-linolenic acid and thence arachidonic acid, while triterpenes have important free radical scavenging, cyclo-oxygenase and neutrophil elastase inhibitory activities. Furthermore, both arachidonic acid and eicosapentaenoic acid are, at relatively low concentrations, directly virucidal.

 

Source: Puri BK. Long-chain polyunsaturated fatty acids and the pathophysiology of myalgic encephalomyelitis (chronic fatigue syndrome). J Clin Pathol. 2007 Feb;60(2):122-4. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860620/ (Full article)

 

A new look at chronic fatigue syndrome/myalgic encephalomyelitis

Abstract:

It has been 3 years since the Chief Medical Officer reported on chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and the time has come for a thorough investigation by an All Party Group drawn from the House of Commons and the House of Lords. We have received many written submissions and are engaged in taking oral evidence in 2-h sessions, which we open to the public as well as interested groups. The group has received a fantastic response to its requests for written evidence over the past few months.

Questions that arise for a government response are the lack of provision and support for patients with CFS/ME, the issue of the clinical definition of CFS/ME, the need for a diagnostic test for CFS/ME, effectiveness of the National Institute for Clinical Excellence guidelines, and criteria used to decide which treatments are best for patients with CFS or myalgic encephalomyelitis.

 

Source: Gibson I. A new look at chronic fatigue syndrome/myalgic encephalomyelitis.J Clin Pathol. 2007 Feb;60(2):120-1. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860614/ (Full article)

 

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

Abstract:

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 fulfill 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.

 

Source: Colby J. Special problems of children with myalgic encephalomyelitis/chronic fatigue syndrome and the enteroviral link. J Clin Pathol. 2007 Feb;60(2):125-8. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860612/ (Full article)