Tag: review

Scientific Advances in and Clinical Approaches to Small-Fiber Polyneuropathy: A Review

Abstract:

IMPORTANCE: Small-fiber polyneuropathy involves preferential damage to the thinly myelinated A-delta fibers, unmyelinated C sensory fibers, or autonomic or trophic fibers. Although this condition is common, most patients still remain undiagnosed and untreated because of lagging medical and public awareness of research advances. Chronic bilateral neuropathic pain, fatigue, and nausea are cardinal symptoms that can cause disability and dependence, including pain medication dependence.

OBSERVATIONS: Biomarker confirmation is recommended, given the nonspecificity of symptoms. The standard test involves measuring epidermal neurite density within a 3-mm protein gene product 9.5 (PGP9.5)-immunolabeled lower-leg skin biopsy. Biopsies and autonomic function testing confirm that small-fiber neuropathy not uncommonly affects otherwise healthy children and young adults, in whom it is often associated with inflammation or dysimmunity. A recent meta-analysis concluded that small-fiber neuropathy underlies 49% of illnesses labeled as fibromyalgia. Initially, patients with idiopathic small-fiber disorders should be screened by medical history and blood tests for potentially treatable causes, which are identifiable in one-third to one-half of patients. Then, secondary genetic testing is particularly important for familial and childhood cases. Treatable genetic causes include Fabry disease, transthyretin and primary systemic amyloidosis, hereditary sensory autonomic neuropathy-1, and ion-channel mutations. Immunohistopathologic evidence suggests that small-fiber dysfunction and denervation, especially of blood vessels, contributes to diverse symptoms, including postexertional malaise, postural orthostatic tachycardia, and functional gastrointestinal distress. Preliminary evidence implicates acute or chronic autoreactivity in some cases, particularly in female patients and otherwise healthy children and young adults. Different temporal patterns akin to Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy have been described; here, corticosteroids and immunoglobulins, which are often efficacious for inflammatory neuropathic conditions, are increasingly considered.

CONCLUSIONS AND RELEVANCE: Because small fibers normally grow throughout life, improving contributory conditions may permit regrowth, slow progression, and prevent permanent damage. The prognosis is often hopeful for improving quality of life and sometimes for abatement or resolution, particularly in the young and otherwise healthy individuals. Examples include diabetic, infectious, toxic, genetic, and inflammatory causes. The current standard of care requires prompt diagnosis and treatment, particularly in children and young adults, to restore life trajectory. Consensus diagnostic and tracking metrics should be established to facilitate treatment trials.

Source: Oaklander AL, Nolano M. Scientific Advances in and Clinical Approaches to Small-Fiber Polyneuropathy: A Review. JAMA Neurol. 2019 Sep 9. doi: 10.1001/jamaneurol.2019.2917. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31498378

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown aetiology that is recognized by the World Health Organization (WHO) and the United States Center for Disease Control and Prevention (US CDC) as a disorder of the brain. The disease predominantly affects adults, with a peak age of onset of between 20 and 45 years with a female to male ratio of 3:1. Although the clinical features of the disease have been well established within diagnostic criteria, the diagnosis of ME/CFS is still of exclusion, meaning that other medical conditions must be ruled out.

The pathophysiological mechanisms are unclear but the neuro-immuno-endocrinological pattern of CFS patients gleaned from various studies indicates that these three pillars may be the key point to understand the complexity of the disease. At the moment, there are no specific pharmacological therapies to treat the disease, but several studies’ aims and therapeutic approaches have been described in order to benefit patients’ prognosis, symptomatology relief, and the recovery of pre-existing function.

This review presents a pathophysiological approach to understanding the essential concepts of ME/CFS, with an emphasis on the population, clinical, and genetic concepts associated with ME/CFS.

Source: Cortes Rivera M, Mastronardi C, Silva-Aldana CT, Arcos-Burgos M, Lidbury BA. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review. Diagnostics (Basel). 2019 Aug 7;9(3). pii: E91. doi: 10.3390/diagnostics9030091. https://www.ncbi.nlm.nih.gov/pubmed/31394725

Epstein-Barr virus (EBV) reactivation and therapeutic inhibitors

Abstract:

Epstein-Barr virus (EBV) is a ubiquitous human virus which infects almost all humans during their lifetime and following the acute phase, persists for the remainder of the life of the individual. EBV infects B lymphocytes leading to their immortalisation, with persistence of the EBV genome as an episome. In the latent phase, EBV is prevented from reactivating through efficient cytotoxic cellular immunity.

EBV reactivates (lytic phase) under conditions of psychological stress with consequent weakening of cellular immunity, and EBV reactivation has been shown to occur in a subset of individuals with each of a variety of cancers, autoimmune diseases, the autoimmune-like disease, chronic fatigue syndrome/myalgic encephalitis and under other circumstances such as being an inpatient in an intensive care unit.

Chronic EBV reactivation is an important mechanism in the pathogenesis of many such diseases, yet is rarely tested for in immunocompetent individuals. This review summarises the pathogenesis of EBV infection, EBV reactivation and its role in disease, and methods which may be used to detect it. Known inhibitors of EBV reactivation and replication are discussed, including drugs licensed for treatment of other herpesviruses, licensed or experimental drugs for various other indications, compounds at an early stage of drug development and nutritional constituents such as vitamins and dietary supplements.

Source: Kerr JR. Epstein-Barr virus (EBV) reactivation and therapeutic inhibitors. J Clin Pathol. 2019 Jul 17. pii: jclinpath-2019-205822. doi: 10.1136/jclinpath-2019-205822. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31315893

Pathological Mechanisms Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

The underlying molecular basis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is not well understood. Characterized by chronic, unexplained fatigue, a disabling payback following exertion (“post-exertional malaise”) and variably presenting, multi-system symptoms, ME/CFS is a complex disease which demands concerted biomedical investigation from disparate fields of expertise.

ME/CFS research and patient treatment have been challenged by the lack of diagnostic biomarkers and finding these is a prominent direction of current work. Despite these challenges, modern research demonstrates a tangible biomedical basis for the disorder across many body systems. This evidence is largely comprised of disturbances to immunological and inflammatory pathways, autonomic and neurologic systems, abnormalities in muscle and mitochondrial function, shifts in metabolism, and gut physiology or gut microbiome disturbances. It is possible that these threads are together entangled as parts of an underlying molecular pathology reflecting a far-reaching homeostatic shift affecting each of these systems.

Due to the variability of non-overlapping symptom presentation or precipitating events such as infection or other bodily stresses, the initiation of body-wide pathological cascades with similar outcomes stemming from different causes may be implicated in the condition. Patient stratification to account for this heterogeneity is therefore one important consideration during exploration of potential diagnostic developments.

Source: Missailidis, D.; Annesley, S.; Fisher, P. Pathological Mechanisms Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Preprints 2019, 2019070196 (doi: 10.20944/preprints201907.0196.v1). https://www.preprints.org/manuscript/201907.0196/v1

Myalgic encephalomyelitis or chronic fatigue syndrome

Abstract:

In this review, we discuss the myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), which is characterised by extreme mental and physical fatigue with associated symptoms of pain, disturbed sleep, cognitive and autonomic dysfunction, as well as post-exertional malaise. This condition is often preceded by an infection, severe physiological and/or psychological strain. Over the last decades, research has demonstrated mitochondrial, neuroendocrine, immunological, and metabolic perturbations in patients with ME/CFS, giving hope for the development of new biomarkers and new treatment modalities.

Source: Brinth L, Nielsen H, Varming K, Boonen SE, Ebsen ACG, Fernández-Guerra P, Schou AS, Mehlsen J, Gregersen N, Brandslund I, Olsen RKJ. Myalgic encephalomyelitis or chronic fatigue syndrome. Ugeskr Laeger. 2019 Jun 10;181(24). pii: V08180570. [Article in Danish] https://www.ncbi.nlm.nih.gov/pubmed/31267953

Advances in Understanding the Pathophysiology of Chronic Fatigue Syndrome

Introduction:

The illness now called myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) was first described in the mid-1980s. At that time, nothing was known about its underlying biology. Indeed, because many standard laboratory test results were normal, some clinicians explained to patients that “there is nothing wrong.” There was, of course, an alternative explanation: the standard laboratory tests might not have been the right tests to identify the underlying abnormalities.

Over the past 35 years, thousands of studies from laboratories in many countries have documented underlying biological abnormalities involving many organ systems in patients with ME/CFS, compared with healthy controls: in short, there is something wrong. Moreover, most of the abnormalities are not detected by standard laboratory tests. In 2015, the Institute of Medicine of the National Academy of Sciences concluded that ME/CFS “is a serious, chronic, complex systemic disease that often can profoundly affect the lives of patients,” affects up to an estimated 2.5 million people in the United States, and generates direct and indirect expenses of approximately $17 billion to $24 billion annually.

Read the rest of this article HERE.

Source: Anthony L. Komaroff, MD. Advances in Understanding the Pathophysiology of Chronic Fatigue Syndrome. JAMA. Published online July 5, 2019. doi:10.1001/jama.2019.8312 https://jamanetwork.com/journals/jama/fullarticle/2737854 (Full article)

The clinical value of cytokines in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a heterogeneous disorder with uncertain pathogenesis. Without effective therapy, CFS is characterized by disabling fatigue, depression, memory loss, and somatic discomfort. This comprehensive and impartial review aimed to assess the available evidence and examined the potential clinical value of using cytokines for the monitoring of CFS and as targets for the treatment of CFS.

Inflammatory reactions and immune modulation are considered to contribute to the pathophysiology of CFS, and it is well documented that cytokines present in both blood and cerebrospinal fluid (CSF) are closely associated with the progression and severity of CFS. However, pathophysiological and methodological limitations prevent using circulating cytokines as independent diagnostic indices. Moreover, there is no evidence to support the use of CSF cytokines as independent diagnostic indices.

Nevertheless, a comprehensive evaluation of changes in circulating and CSF cytokines may improve clinical understanding of the pathophysiology of patients with CFS, aiding in the establishment of an appropriate diagnosis. Importantly, the available evidence does not support the value of cytokines as therapeutic targets. We believe that an improved understanding of cytokine-related mechanisms will be helpful to explore new cytokine-related therapeutic targets.

Source: Yang T, Yang Y, Wang D, Li C, Qu Y, Guo J, Shi T, Bo W, Sun Z, Asakawa T. The clinical value of cytokines in chronic fatigue syndrome. J Transl Med. 2019 Jun 28;17(1):213. doi: 10.1186/s12967-019-1948-6 https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-019-1948-6 (Full article)

Understanding Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and the Emerging Osteopathic Approach: A Narrative Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating syndrome of unknown origin, characterized by profound postexertional malaise and fatigue, unrefreshing sleep, cognitive impairments, immune dysfunction, pain, autonomic dysfunction, and neuroendocrine symptoms. Although ME/CFS is well documented within the medical literature, it remains difficult to diagnosis and manage.

Some of the current challenges include an absence of diagnostic markers, differing diagnostic criteria, and an overall lack of awareness within the medical community. As a result, patients are often frustrated by the difficulties in acquiring a diagnosis and from the overall lack of available treatments. In an effort to increase awareness, this review discusses disease pathophysiology, clinical presentation, and treatment options, while also highlighting the benefits of an osteopathic approach.

J Am Osteopath Assoc. 2019 Jul 1;119(7):446-455. doi: 10.7556/jaoa.2019.081.

Source: Larrimore C, Ramnot A, Jaghab A, Sarduy S, Guerrero G, Troccoli P, Hilton K, Bested A. Understanding Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and the Emerging Osteopathic Approach: A Narrative Review. J Am Osteopath Assoc. 2019 Jul 1;119(7):446-455. doi: 10.7556/jaoa.2019.081. https://www.ncbi.nlm.nih.gov/pubmed/31233110

Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, and Chronic Fatigue: Three Distinct Entities Requiring Complete Different Approaches

Abstract:

PURPOSE OF REVIEW: A recent review implicates that myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS), and chronic fatigue are part of the “fatigue spectrum” and recommends “longitudinal studies integrating biopsychosocial approaches to inform early management and targeted rehabilitation strategies.”

RECENT FINDINGS: ME is a neuromuscular disease distinguished by muscle fatigability (prolonged muscle weakness after minor exertion) and specific signs of neurological dysfunction. ME is not equivalent to CFS, as proposed by the authors. CFS is defined as unexplained chronic fatigue accompanied by at least four out of a list of eight specific symptoms. CFS is a distinct clinical entity and not merely a severe variant of CF, as suggested. Proof that CF, CFS, and ME are part of a “fatigue continuum” and that CF can convert to CFS at a later stage is lacking. Biopsychosocial approaches for early management and rehabilitation of CF, as promoted by the authors, are at odds with the current understandings of ME, CFS, and CF. The (bio)psychosocial explanatory models for ME and CFS have proven to be invalid, and the associated interventions, cognitive behavioral therapy and graded exercise therapy, have shown to be ineffective and even potentially harmful. ME, CFS, and CF are three very distinct clinical entities. Interventions justified by (bio)psychosocial models appear to be unsuccessful and potentially noxious. To develop effective treatments, it is crucial to make a clear distinction between ME, CFS, and CF and to leave the (bio)psychosocial explanations and therapies behind us.

Source: Twisk FNM. Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, and Chronic Fatigue: Three Distinct Entities Requiring Complete Different Approaches. Curr Rheumatol Rep. 2019 May 9;21(6):27. doi: 10.1007/s11926-019-0823-z. https://www.ncbi.nlm.nih.gov/pubmed/31073713

Assessment of the scientific rigour of randomized controlled trials on the effectiveness of cognitive behavioural therapy and graded exercise therapy for patients with myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review

Abstract:

Cognitive behavioural therapy and graded exercise therapy have been promoted as effective treatments for patients with myalgic encephalomyelitis/chronic fatigue syndrome. However, criticism on the scientific rigour of these studies has been raised. This review assessed the methodological quality of studies on the effectiveness of cognitive behavioural therapy and graded exercise therapy. The methodological quality of the 18 included studies was found to be relatively low, as bias was prominently found, affecting the main outcome measures of the studies (fatigue, physical functioning and functional impairment/status). Future research should focus on including more objective outcome measures in a well-defined patient population.

Source: Ahmed SA, Mewes JC, Vrijhoef H. Assessment of the scientific rigour of randomized controlled trials on the effectiveness of cognitive behavioural therapy and graded exercise therapy for patients with myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review. J Health Psychol. 2019 May 10:1359105319847261. doi: 10.1177/1359105319847261. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31072121