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Muscle & Nerve Jan 2021Autonomic neuropathies represent a complex group of disorders that preferentially target autonomic fibers and can be classified as either acute/subacute or chronic in... (Review)
Review
Autonomic neuropathies represent a complex group of disorders that preferentially target autonomic fibers and can be classified as either acute/subacute or chronic in onset. Acute-onset autonomic neuropathies manifest with such conditions as paraneoplastic syndromes, Guillain-Barre syndrome, Sjögren syndrome, infection, or toxins/chemotherapy. When the presentation is acute, immune-mediated, and without a secondary cause, autoimmune autonomic ganglionopathy is likely, and should be considered for immunotherapy. Of the chronic-onset forms, diabetes is the most widespread and disabling, with autonomic impairment portending increased mortality and cardiac wall remodeling risk. Acquired light chain (AL) and transthyretin (TTR) amyloidosis represent two other key etiologies, with TTR amyloidosis now amenable to newly-approved gene-modifying therapies. The COMPASS-31 questionnaire is a validated outcome measure that can be used to monitor autonomic severity and track treatment response. Symptomatic treatments targeting orthostatic hypotension, among other symptoms, should be individualized and complement disease-modifying therapy, when possible.
Topics: Amyloid Neuropathies, Familial; Autoimmune Diseases of the Nervous System; Autonomic Nervous System; Autonomic Nervous System Diseases; Humans; Peripheral Nervous System Diseases; Prealbumin
PubMed: 32926436
DOI: 10.1002/mus.27048 -
Neurobiology of Disease Feb 2020Parkinson's disease (PD) is a neurodegenerative disease with a 200 year-long research history. Our understanding about its clinical phenotype and pathogenesis remains... (Review)
Review
Parkinson's disease (PD) is a neurodegenerative disease with a 200 year-long research history. Our understanding about its clinical phenotype and pathogenesis remains limited, although dopaminergic replacement therapy has significantly improved patient outcomes. Autonomic dysfunction is an essential category of non-motor phenotypes that has recently become a cutting edge field that directs frontier research in PD. In this review, we initially describe the epidemiology of dysautonomic symptoms in PD. Then, we perform a meticulous analysis of the pathophysiology of autonomic dysfunction in PD and propose that the peripheral autonomic nervous system may be a key route for α-synuclein pathology propagation from the periphery to the central nervous system. In addition, we recommend that constipation, orthostatic hypotension, urinary dysfunction, erectile dysfunction, and pure autonomic failure should be viewed as prodromal dysautonomic markers in PD prediction and diagnosis. Finally, we summarize the strategies currently available for the treatment of autonomic dysfunction in PD and suggest that high-quality, better-designed, randomized clinical trials should be conducted in the future.
Topics: Animals; Autonomic Nervous System; Autonomic Nervous System Diseases; Humans; Mice; Parkinson Disease
PubMed: 31809788
DOI: 10.1016/j.nbd.2019.104700 -
American Journal of Physiology. Heart... Dec 2022Cardiovascular disease (CVD), the leading cause of death among US adults, is more prevalent in menopausal females compared with age-matched males. Vasomotor symptoms of... (Review)
Review
Cardiovascular disease (CVD), the leading cause of death among US adults, is more prevalent in menopausal females compared with age-matched males. Vasomotor symptoms of menopause (VMS; hot flashes/flushes and night sweats) are common among females undergoing menopausal transition and have been associated with elevated blood pressure (BP) and increased CVD risk. Autonomic dysregulation of BP has been posited as a contributing factor to the elevated CVD risk in menopausal females with VMS. This review includes ) a brief overview of the relationship between VMS and CVD, ) mechanisms of hot flushes and their potential impact on short- and long-term BP regulation, and ) how the disruption of autonomic function associated with VMS might provide a mechanistic pathway to CVD development. Finally, this review will highlight knowledge gaps and future directions toward better understanding of hot flush physiology and VMS contributions to CVD.
Topics: Adult; Female; Humans; Cardiovascular Diseases; Sweating; Menopause; Hot Flashes; Autonomic Nervous System Diseases; Vasomotor System
PubMed: 36367692
DOI: 10.1152/ajpheart.00477.2022 -
Experimental Physiology Jan 2023What is the topic of this review? The emerging condition of long COVID, its epidemiology, pathophysiological impacts on patients of different backgrounds, physiological... (Review)
Review
NEW FINDINGS
What is the topic of this review? The emerging condition of long COVID, its epidemiology, pathophysiological impacts on patients of different backgrounds, physiological mechanisms emerging as explanations of the condition, and treatment strategies being trialled. The review leads from a Physiological Society online conference on this topic. What advances does it highlight? Progress in understanding the pathophysiology and cellular mechanisms underlying Long COVID and potential therapeutic and management strategies.
ABSTRACT
Long COVID, the prolonged illness and fatigue suffered by a small proportion of those infected with SARS-CoV-2, is placing an increasing burden on individuals and society. A Physiological Society virtual meeting in February 2022 brought clinicians and researchers together to discuss the current understanding of long COVID mechanisms, risk factors and recovery. This review highlights the themes arising from that meeting. It considers the nature of long COVID, exploring its links with other post-viral illnesses such as myalgic encephalomyelitis/chronic fatigue syndrome, and highlights how long COVID research can help us better support those suffering from all post-viral syndromes. Long COVID research started particularly swiftly in populations routinely monitoring their physical performance - namely the military and elite athletes. The review highlights how the high degree of diagnosis, intervention and monitoring of success in these active populations can suggest management strategies for the wider population. We then consider how a key component of performance monitoring in active populations, cardiopulmonary exercise training, has revealed long COVID-related changes in physiology - including alterations in peripheral muscle function, ventilatory inefficiency and autonomic dysfunction. The nature and impact of dysautonomia are further discussed in relation to postural orthostatic tachycardia syndrome, fatigue and treatment strategies that aim to combat sympathetic overactivation by stimulating the vagus nerve. We then interrogate the mechanisms that underlie long COVID symptoms, with a focus on impaired oxygen delivery due to micro-clotting and disruption of cellular energy metabolism, before considering treatment strategies that indirectly or directly tackle these mechanisms. These include remote inspiratory muscle training and integrated care pathways that combine rehabilitation and drug interventions with research into long COVID healthcare access across different populations. Overall, this review showcases how physiological research reveals the changes that occur in long COVID and how different therapeutic strategies are being developed and tested to combat this condition.
Topics: Humans; COVID-19; Post-Acute COVID-19 Syndrome; SARS-CoV-2; Risk Factors; Autonomic Nervous System Diseases
PubMed: 36412084
DOI: 10.1113/EP090802 -
Pain Medicine (Malden, Mass.) Jun 2022There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated... (Review)
Review
There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated multifactorial disease remains low (with some notable exceptions; e.g., the recent work on the dorsal root ganglion stimulation). The semi-systematic (though in some cases narrative) approach to review is necessary so that we might treat our patients while waiting for "better research." This semi-systematic review was conducted by experts in the field, (deliberately) some of whom are promising young researchers supplemented by the experience of "elder statesman" researchers, who all mention the system they have used to examine the literature. What we found is generally low- to medium-quality research with small numbers of subjects; however, there are some recent exceptions to this. The primary reason for this paucity of research is the fact that this is a rare disease, and it is very difficult to acquire a sufficient sample size for statistical significance using traditional statistical approaches. Several larger trials have failed, probably due to using the broad general diagnostic criteria (the "Budapest" criteria) in a multifactorial/multi-mechanism disease. Responsive subsets can often be identified in these larger trials, but not sufficient to achieve statistically significant results in the general diagnostic grouping. This being the case the authors have necessarily included data from less compelling protocols, including trials such as case series and even in some instances case reports/empirical information. In the humanitarian spirit of treating our often desperate patients with this rare syndrome, without great evidence, we must take what data we can find (as in this work) and tailor a treatment regime for each patient.
Topics: Aged; Complex Regional Pain Syndromes; Ganglia, Spinal; Humans; Reflex Sympathetic Dystrophy
PubMed: 35687369
DOI: 10.1093/pm/pnac046 -
Progress in Cardiovascular Diseases 2020Although diagnostic criteria have been developed characterizing postural orthostatic tachycardia syndrome (POTS), no single set of criteria is universally accepted.... (Review)
Review
Although diagnostic criteria have been developed characterizing postural orthostatic tachycardia syndrome (POTS), no single set of criteria is universally accepted. Furthermore, there are gaps in the present criteria used to identify individuals who have this condition. The reproducibility of the physiological findings, the relationship of symptoms to physiological findings, the presence of symptoms alone without any physiological findings and the response to various interventions confuse rather than clarify this condition. As many disease entities can be confused with POTS, it becomes critical to identify what this syndrome is. What appears to be POTS may be an underlying condition that requires specific therapy. POTS is not simply orthostatic intolerance and symptoms or intermittent orthostatic tachycardia but the syndrome needs to be characterized over time and with reproducibility. Here we address critical issues regarding the pathophysiology and diagnosis of POTS in an attempt to arrive at a rational approach to categorize the syndrome with the hope that it may help both better identify individuals and better understand approaches to therapy.
Topics: Blood Pressure; Diagnosis, Differential; Heart Rate; Humans; Postural Orthostatic Tachycardia Syndrome; Posture; Predictive Value of Tests; Prognosis; Reproducibility of Results
PubMed: 32222376
DOI: 10.1016/j.pcad.2020.03.010 -
Autonomic Neuroscience : Basic &... Dec 2020Neurogenic orthostatic hypotension (OH) is a disabling disorder caused by impairment of the normal autonomic compensatory mechanisms that maintain upright blood... (Review)
Review
Neurogenic orthostatic hypotension (OH) is a disabling disorder caused by impairment of the normal autonomic compensatory mechanisms that maintain upright blood pressure. Nonpharmacologic treatment is always the first step in the management of this condition, but a considerable number of patients will require pharmacologic therapies. Denervation hypersensitivity and impairment of baroreflex buffering makes these patients sensitive to small doses of pressor agents. Understanding the underlying pathophysiology can help in selecting between treatment options. In general, patients with low "sympathetic reserve", i.e., those with peripheral noradrenergic degeneration (pure autonomic failure, Parkinson's disease) and low plasma norepinephrine, tend to respond better to "norepinephrine replacers" (midodrine and droxidopa). On the other hand, patients with relatively preserved "sympathetic reserve", i.e., those with impaired central autonomic pathways but spared peripheral noradrenergic fibers (multiple system atrophy) and normal or slightly reduced plasma norepinephrine, tend to respond better to "norepinephrine enhancers" (pyridostigmine, atomoxetine, and yohimbine). There is, however, a spectrum of responses within these extremes, and treatment should be individualized. Other nonspecific treatments include fludrocortisone and octreotide. The presence of associated clinical conditions, such as supine hypertension, heart failure, postprandial hypotension, PD, MSA, and diabetes need to be considered in the pharmacologic management of these patients.
Topics: Humans; Hypotension, Orthostatic; Multiple System Atrophy; Parkinson Disease; Pure Autonomic Failure
PubMed: 32979782
DOI: 10.1016/j.autneu.2020.102721 -
Neurotherapeutics : the Journal of the... Oct 2020Recognition of the importance of nonmotor dysfunction as a component of Parkinson's disease has exploded over the past three decades. Autonomic dysfunction is a frequent... (Review)
Review
Recognition of the importance of nonmotor dysfunction as a component of Parkinson's disease has exploded over the past three decades. Autonomic dysfunction is a frequent and particularly important nonmotor feature because of the broad clinical spectrum it covers. Cardiovascular, gastrointestinal, urinary, sexual, and thermoregulatory abnormalities all can appear in the setting of Parkinson's disease. Cardiovascular dysfunction is characterized most prominently by orthostatic hypotension. Gastrointestinal dysfunction can involve virtually all levels of the gastrointestinal tract. Urinary dysfunction can entail either too frequent voiding or difficulty voiding. Sexual dysfunction is frequent and frustrating for both patient and partner. Alterations in sweating and body temperature are not widely recognized but often are present. Autonomic dysfunction can significantly and deleteriously impact quality of life for individuals with Parkinson's disease. Because effective treatment for many aspects of autonomic dysfunction is available, it is vitally important that assessment of autonomic dysfunction be a regular component of the neurologic history and exam and that appropriate treatment be initiated and maintained.
Topics: Autonomic Nervous System Diseases; Cardiovascular Diseases; Gastrointestinal Diseases; Humans; Hypotension, Orthostatic; Parkinson Disease; Sexual Dysfunction, Physiological
PubMed: 32789741
DOI: 10.1007/s13311-020-00897-4 -
Journal of Neurology Nov 2020Disturbances of balance, gait and posture are a hallmark of parkinsonian syndromes. Recognition of these axial features can provide important and often early clues to... (Review)
Review
Disturbances of balance, gait and posture are a hallmark of parkinsonian syndromes. Recognition of these axial features can provide important and often early clues to the nature of the underlying disorder, and, therefore, help to disentangle Parkinson's disease from vascular parkinsonism and various forms of atypical parkinsonism, including multiple system atrophy, progressive supranuclear palsy, and corticobasal syndrome. Careful assessment of axial features is also essential for initiating appropriate treatment strategies and for documenting the outcome of such interventions. In this article, we provide an overview of balance, gait and postural impairment in parkinsonian disorders, focusing on differential diagnostic aspects.
Topics: Gait; Humans; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive
PubMed: 31119450
DOI: 10.1007/s00415-019-09382-1 -
Heart Rhythm Nov 2022Postural orthostatic tachycardia syndrome (POTS) is a complex multisystem disorder characterized by orthostatic intolerance and tachycardia and may be triggered by viral... (Review)
Review
Postural orthostatic tachycardia syndrome (POTS) is a complex multisystem disorder characterized by orthostatic intolerance and tachycardia and may be triggered by viral infection. Recent reports indicate that 2%-14% of coronavirus disease 2019 (COVID-19) survivors develop POTS and 9%-61% experience POTS-like symptoms, such as tachycardia, orthostatic intolerance, fatigue, and cognitive impairment within 6-8 months of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Pathophysiological mechanisms of post-COVID-19 POTS are not well understood. Current hypotheses include autoimmunity related to SARS-CoV-2 infection, autonomic dysfunction, direct toxic injury by SARS-CoV-2 to the autonomic nervous system, and invasion of the central nervous system by SARS-CoV-2. Practitioners should actively assess POTS in patients with post-acute COVID-19 syndrome symptoms. Given that the symptoms of post-COVID-19 POTS are predominantly chronic orthostatic tachycardia, lifestyle modifications in combination with the use of heart rate-lowering medications along with other pharmacotherapies should be considered. For example, ivabradine or β-blockers in combination with compression stockings and increasing salt and fluid intake has shown potential. Treatment teams should be multidisciplinary, including physicians of various specialties, nurses, psychologists, and physiotherapists. Additionally, more resources to adequately care for this patient population are urgently needed given the increased demand for autonomic specialists and clinics since the start of the COVID-19 pandemic. Considering our limited understanding of post-COVID-19 POTS, further research on topics such as its natural history, pathophysiological mechanisms, and ideal treatment is warranted. This review evaluates the current literature available on the associations between COVID-19 and POTS, possible mechanisms, patient assessment, treatments, and future directions to improving our understanding of post-COVID-19 POTS.
Topics: Humans; Postural Orthostatic Tachycardia Syndrome; Orthostatic Intolerance; Pandemics; COVID-19; SARS-CoV-2; Tachycardia
PubMed: 35853576
DOI: 10.1016/j.hrthm.2022.07.014