Antiadrenergic autoimmunity in postural tachycardia syndrome

Joint Hypermobility, Autonomic Dysfunction, Gastrointestinal Dysfunction, and Autoimmune Markers: Clinical Associations and Response to Intravenous Immunoglobulin Therapy

INTRODUCTION

We examined autoimmunity markers (AIM) and autonomic dysfunction in patients with chronic neurogastroenterological symptoms and their relationship to joint hypermobility/hypermobility spectrum disorder (JH/HSD).

METHODS

AIM positivity was defined as a diagnosis of known autoimmune/autoinflammatory disorder with at least 1 positive seromarker of autoimmunity or at least 2 positive seromarkers by themselves. Three cohorts were studied: (i) retrospective (n = 300), (ii) prospective validation cohort (n = 133), and (iii) treatment cohort (n = 40), administered open-label intravenous immunoglobulin (IVIG).

RESULTS

AIM positivity was found in 40% and 29% of the retrospective and prospective cohorts, the majority of whom (71% and 69%, respectively) had autoinflammatory disorder. Significantly more patients with AIM had elevations of C-reactive protein (31% vs 15%, P < 0.001) along with an increased proportion of cardiovascular autonomic dysfunction (48% vs 29%; P < 0.001), small fiber neuropathy (20% vs 9%; P = 0.002), and HLADQ8 positivity (24% vs 13%, P = 0.01). Patients with JH/HSD were more likely to have AIM (43% vs 15%, P = 0.001) along with more severe autonomic and gastrointestinal (GI) symptom scores. IVIG treatment was associated with robust improvement in pain, GI, and autonomic symptoms, but adverse events were experienced by 62% of patients.

DISCUSSION

Autoimmune markers and autonomic dysfunction are common in patients with unexplained GI symptoms, especially in those with JH/HSD. Many patients seem to respond to IVIG treatment, but this needs to be confirmed by controlled trials. These results highlight the need for vigilance for autoimmune and autonomic factors and JH/HSD in patients with neurogastroenterological disorders. Clinicaltrials.gov , NCT04859829.

G protein-coupled receptors related to autoimmunity in postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is characterized by exaggerated orthostatic tachycardia in the absence of orthostatic hypotension. The pathophysiology of POTS may involve hypovolemia, autonomic neuropathy, a hyperadrenergic state, and cardiovascular deconditioning, any of which can co-occur in the same patient. Furthermore, there is growing evidence of the role of autoimmunity in a subset of POTS cases. In recent years, investigators have described an increased rate of autoimmune comorbidities as evidenced by the finding of several types of neural receptor autoantibody and non-specific autoimmune marker in patients with POTS. In particular, the association of the disease with several types of anti-G protein-coupled receptor (GPCR) antibodies and POTS has frequently been noted. A previous study reported that autoantibodies to muscarinic AChRs may play an important role in POTS with persistent, gastrointestinal symptoms. To date, POTS is recognized as one of the sequelae of coronavirus disease 2019 (COVID-19) and its frequency and pathogenesis are still largely unknown. Multiple autoantibody types occur in COVID-related, autonomic disorders, suggesting the presence of autoimmune pathology in these disorders. Herein, we review the association of anti-GPCR autoantibodies with disorders of the autonomic nervous system, in particular POTS, and provide a new perspective for understanding POTS-related autoimmunity.

Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden

Cardiovascular autonomic dysfunction (CVAD) is a malfunction of the cardiovascular system caused by deranged autonomic control of circulatory homeostasis. CVAD is an important component of post-COVID-19 syndrome, also termed long COVID, and might affect one-third of highly symptomatic patients with COVID-19. The effects of CVAD can be seen at both the whole-body level, with impairment of heart rate and blood pressure control, and in specific body regions, typically manifesting as microvascular dysfunction. Many severely affected patients with long COVID meet the diagnostic criteria for two common presentations of CVAD: postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. CVAD can also manifest as disorders associated with hypotension, such as orthostatic or postprandial hypotension, and recurrent reflex syncope. Advances in research, accelerated by the COVID-19 pandemic, have identified new potential pathophysiological mechanisms, diagnostic methods and therapeutic targets in CVAD. For clinicians who daily see patients with CVAD, knowledge of its symptomatology, detection and appropriate management is more important than ever. In this Review, we define CVAD and its major forms that are encountered in post-COVID-19 syndrome, describe possible CVAD aetiologies, and discuss how CVAD, as a component of post-COVID-19 syndrome, can be diagnosed and managed. Moreover, we outline directions for future research to discover more efficient ways to cope with this prevalent and long-lasting condition.

Thrombosis With Thrombocytopenia and Post-COVID-Vaccination Syndrome With Anti-G-Protein-Coupled Receptor (GPCR) Antibodies Treated With Therapeutic Plasma Exchange

We present the case of a female who developed cerebral venous thrombosis with thrombocytopenia after inoculation with the anti-coronavirus disease 2019 (COVID-19) Vaxzevria vaccine, followed by splanchnic thrombosis and diffuse hemorrhages. Despite receiving treatment, the complications increased, and hence therapeutic plasma exchange (TPE) was attempted, leading to laboratory and clinical improvements and discharge after a period of intensive care. Almost two years after the first episode, in the interim of which the patient complained of only minor symptoms such as asthenia and difficulty concentrating, she developed an epileptic syndrome that required neurological treatment. In addition, her fatigue and difficulty concentrating worsened and other serious symptoms of dysautonomia appeared, such as trembling of her right arm, loss of stability, and postural orthostatic tachycardia. As serum analysis revealed a significant number of alterations in autoantibodies against various G-protein-coupled receptors (GPCRs) and RAS-related proteins, two further TPEs were performed, resulting in rapid and sustained clinical improvement. This report highlights the role of the different types of autoantibodies produced in response to anti-COVID-19 vaccination, which can have functional, regulatory, and possibly pathogenic effects on the vascular and nervous systems.

Autoimmunity in Syndromes of Orthostatic Intolerance: An Updated Review

Orthostatic intolerance is a broad term that represents a spectrum of dysautonomic disorders, including postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH), as manifestations of severe autonomic failure. While the etiology of orthostatic intolerance has not yet fully been uncovered, it has been associated with multiple underlying pathological processes, including peripheral neuropathy, altered renin-aldosterone levels, hypovolemia, and autoimmune processes. Studies have implicated adrenergic, cholinergic, and angiotensin II type I autoantibodies in the pathogenesis of orthostatic intolerance. Several case series have demonstrated that immunomodulation therapy resulted in favorable outcomes, improving autonomic symptoms in POTS and OH. In this review, we highlight the contemporary literature detailing the association of autoimmunity with POTS and OH.

Cardiovascular dysautonomia in postacute sequelae of SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) has led to a worldwide pandemic that continues to transform but will not go away. Cardiovascular dysautonomia in postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection has led to persistent symptoms in a large number of patients. Here, we define the condition and its associated symptoms as well as potential mechanisms responsible. We provide a careful and complete overview of the topic addressing novel studies and a generalized approach to the management of individuals with this complex and potentially debilitating problem. We also discuss future research directions and the important knowledge gaps to be addressed in ongoing and planned studies.

Autoimmune Autonomic Neuropathy: From Pathogenesis to Diagnosis

Autoimmune autonomic ganglionopathy (AAG) is a disease of autonomic failure caused by ganglionic acetylcholine receptor (gAChR) autoantibodies. Although the detection of autoantibodies is important for distinguishing the disease from other neuropathies that present with autonomic dysfunction, other factors are important for accurate diagnosis. Here, we provide a comprehensive review of the clinical features of AAG, highlighting differences in clinical course, clinical presentation, and laboratory findings from other neuropathies presenting with autonomic symptoms. The first step in diagnosing AAG is careful history taking, which should reveal whether the mode of onset is acute or chronic, followed by an examination of the time course of disease progression, including the presentation of autonomic and extra-autonomic symptoms. AAG is a neuropathy that should be differentiated from other neuropathies when the patient presents with autonomic dysfunction. Immune-mediated neuropathies, such as acute autonomic sensory neuropathy, are sometimes difficult to differentiate, and therefore, differences in clinical and laboratory findings should be well understood. Other non-neuropathic conditions, such as postural orthostatic tachycardia syndrome, chronic fatigue syndrome, and long COVID, also present with symptoms similar to those of AAG. Although often challenging, efforts should be made to differentiate among the disease candidates.

Noninvasive Vagus Nerve Stimulation in Postural Tachycardia Syndrome: A Randomized Clinical Trial

BACKGROUND

Low-level transcutaneous stimulation of the auricular branch of the vagus nerve at the tragus is antiarrhythmic and anti-inflammatory in animals and humans. Preliminary studies show that transcutaneous vagus nerve stimulation (tVNS) is beneficial in animal models of postural tachycardia syndrome (POTS).

OBJECTIVES

In this study the authors conducted a sham-controlled, double-blind, randomized clinical trial to examine the effect of tVNS on POTS over a 2-month period relative to sham stimulation.

METHODS

tVNS (20 Hz, 1 mA below discomfort threshold) was delivered using an ear clip attached to either the tragus (active; n = 12) or the ear lobe (sham; n = 14) for 1 hour daily over a 2-month period. Postural tachycardia was assessed during the baseline and 2-month visit. Heart rate variability based on 5-minute electrocardiogram, serum cytokines, and antiautonomic autoantibodies were measured at the respective time points.

RESULTS

Mean age was 34 ± 11 years (100% female; 81% Caucasian). Adherence to daily stimulation was 83% in the active arm and 86% in the sham arm (P > 0.05). Postural tachycardia was significantly less in the active arm compared with the sham arm at 2 months (mean postural increase in heart rate 17.6 ± 9.9 beats/min vs 31.7 ± 14.4 beats/min; P = 0.01). Antiadrenergic autoantibodies and inflammatory cytokines were lower in the active arm compared with the sham arm at 2 months (P < 0.05). Heart rate variability was better in the active arm. No device-related side effects were observed.

CONCLUSIONS

Our results support the emerging paradigm of noninvasive neuromodulation to treat POTS. Mechanistically, this effect appears to be related to reduction of antiautonomic autoantibodies and inflammatory cytokines, and improvement in autonomic tone. Further studies are warranted. (Autoimmune Basis for Postural Tachycardia Syndrome; NCT05043051).

Randomized controlled trial of intravenous immunoglobulin for autoimmune postural orthostatic tachycardia syndrome (iSTAND)

OBJECTIVE

This study assesses response to intravenous immunoglobulin (IVIG) in presumed autoimmune postural orthostatic tachycardia syndrome (POTS).

BACKGROUND

POTS may be associated with autoimmune disorders, serum autoantibodies, or recent infection. Uncontrolled case studies suggest that IVIG is beneficial for treating autoimmune POTS. No previous randomized controlled trials have been conducted.

METHODS

This single-site randomized controlled trial compared IVIG with intravenous albumin infusions. Albumin comparator ensured blinding and control for effects of volume expansion. Eligible patients with POTS had COMPASS-31 total weighted score ≥ 40 and met predetermined criteria suggesting autoimmunity. Over 12 weeks, participants received eight infusions (0.4 gm/kg each). Four infusions were given weekly followed by four infusions every other week. Primary outcome measure was improvement in COMPASS-31 2 weeks after final infusion.

RESULTS

A total of 50 participants consented; 30 met inclusion criteria and received study drug (16 IVIG and 14 albumin; 29 female). Group baseline characteristics were well matched; 27 participants completed treatment protocol. Change in COMPASS-31 did not differ between groups (median change [IQR]; IVIG: -5.5 [-23.3, 2.5] versus albumin: -10.6 [-14.1, -4.7]; p-value = 0.629). The IVIG group had a higher response rate (46.7% versus 38.5%), but this was not statistically significant. Adverse events were common but usually mild and did not differ between treatment groups.

CONCLUSIONS

This small randomized controlled trial of IVIG in POTS found no statistical difference in response compared with albumin infusion. Both groups showed improvement possibly related to volume expansion or other effects obscuring group differences. These findings inform development of future immunomodulatory clinical trials in POTS.

Non-invasive Vagus Nerve Simulation in Postural Orthostatic Tachycardia Syndrome

Postural orthostatic tachycardia syndrome (POTS) is a chronic debilitating condition of orthostatic intolerance, predominantly affecting young females. Other than postural tachycardia, symptoms of POTS include a spectrum of non-cardiac, systemic and neuropsychiatric features. Despite the availability of widespread pharmacological and non-pharmacological therapeutic options, the management of POTS remains challenging. Exaggerated parasympathetic withdrawal and sympathetic overdrive during postural stress are principal mechanisms of postural tachycardia in POTS. Non-invasive, transcutaneous, vagus nerve stimulation (tVNS) is known to restore sympathovagal balance and is emerging as a novel therapeutic strategy in cardiovascular conditions including arrhythmias and heart failure. Furthermore, tVNS also exerts immunomodulatory and anti-inflammatory effects. This review explores the effects of tVNS on the pathophysiology of POTS and its potential as an alternative non-pharmacological option in this condition.

Autonomic Manifestations of Long-COVID Syndrome

PURPOSE OF REVIEW

Long-COVID is a novel condition emerging from the COVID-19 pandemic. Long-COVID is characterized by symptoms commonly seen in autonomic disorders including fatigue, brain fog, light-headedness, and palpitations. This article will critically evaluate recent findings and studies on Long-COVID and its physiological autonomic manifestations.

RECENT FINDINGS

Studies have reported on the prevalence of different symptoms and autonomic disorders in Long-COVID cohorts. Autonomic nervous system function, including both the parasympathetic and sympathetic limbs, has been studied using different testing techniques in Long-COVID patients. While numerous mechanisms may contribute to Long-COVID autonomic pathophysiology, it is currently unclear which ones lead to a Long-COVID presentation. To date, studies have not tested treatment options for autonomic disorders in Long-COVID patients. Long-COVID is associated with autonomic abnormalities. There is a high prevalence of clinical autonomic disorders among Long-COVID patients, with limited knowledge of the underlying mechanisms and the effectiveness of treatment options.

Dysregulations in hemostasis, metabolism, immune response, and angiogenesis in post-acute COVID-19 syndrome with and without postural orthostatic tachycardia syndrome: a multi-omic profiling study

Post-acute COVID-19 (PACS) are associated with cardiovascular dysfunction, especially postural orthostatic tachycardia syndrome (POTS). Patients with PACS, both in the absence or presence of POTS, exhibit a wide range of persisting symptoms long after the acute infection. Some of these symptoms may stem from alterations in cardiovascular homeostasis, but the exact mechanisms are poorly understood. The aim of this study was to provide a broad molecular characterization of patients with PACS with (PACS + POTS) and without (PACS-POTS) POTS compared to healthy subjects, including a broad proteomic characterization with a focus on plasma cardiometabolic proteins, quantification of cytokines/chemokines and determination of plasma sphingolipid levels. Twenty-one healthy subjects without a prior COVID-19 infection (mean age 43 years, 95% females), 20 non-hospitalized patients with PACS + POTS (mean age 39 years, 95% females) and 22 non-hospitalized patients with PACS-POTS (mean age 44 years, 100% females) were studied. PACS patients were non-hospitalized and recruited ≈18 months after the acute infection. Cardiometabolic proteomic analyses revealed a dysregulation of ≈200 out of 700 analyzed proteins in both PACS groups vs. healthy subjects with the majority (> 90%) being upregulated. There was a large overlap (> 90%) with no major differences between the PACS groups. Gene ontology enrichment analysis revealed alterations in hemostasis/coagulation, metabolism, immune responses, and angiogenesis in PACS vs. healthy controls. Furthermore, 11 out of 33 cytokines/chemokines were significantly upregulated both in PACS + POTS and PACS-POTS vs. healthy controls and none of the cytokines were downregulated. There were no differences in between the PACS groups in the cytokine levels. Lastly, 16 and 19 out of 88 sphingolipids were significantly dysregulated in PACS + POTS and PACS-POTS, respectively, compared to controls with no differences between the groups. Collectively, these observations suggest a clear and distinct dysregulation in the proteome, cytokines/chemokines, and sphingolipid levels in PACS patients compared to healthy subjects without any clear signature associated with POTS. This enhances our understanding and might pave the way for future experimental and clinical investigations to elucidate and/or target resolution of inflammation and micro-clots and restore the hemostasis and immunity in PACS.

Cardiorespiratory dysautonomia in post-COVID-19 condition: Manifestations, mechanisms and management

A significant proportion of COVID-19 patients experience debilitating symptoms for months after the acute infection. According to recent estimates, approximately 1 out of 10 COVID-19 convalescents reports persistent health issues more than 3 months after initial recovery. This 'post-COVID-19 condition' may include a large variety of symptoms from almost all domains and organs, and for some patients it may mean prolonged sick-leave, homestay and strongly limited activities of daily life. In this narrative review, we focus on the symptoms and signs of post-COVID-19 condition in adults - particularly those associated with cardiovascular and respiratory systems, such as postural orthostatic tachycardia syndrome or airway disorders - and explore the evidence for chronic autonomic dysfunction as a potential underlying mechanism. The most plausible hypotheses regarding cellular and molecular mechanisms behind the wide spectrum of observed symptoms - such as lingering viruses, persistent inflammation, impairment in oxygen sensing systems and circulating antibodies directed to blood pressure regulatory components - are discussed. In addition, an overview of currently available pharmacological and non-pharmacological treatment options is presented.

Postural orthostatic tachycardia syndrome and other related dysautonomic disorders after SARS-CoV-2 infection and after COVID-19 messenger RNA vaccination

The COVID-19 pandemic has caused a challenge for our society due to the post-acute sequelae of the disease. Persistent symptoms and long-term multiorgan complications, known as post-acute COVID-19 syndrome, can occur beyond 4 weeks from the onset of the COVID-19 infection. Postural orthostatic tachycardia syndrome (POTS) is considered a variety of dysautonomia, which is characterized by chronic symptoms that occur with standing and a sustained increase in heart rate, without orthostatic hypotension. POTS can lead to debilitating symptoms, significant disability, and impaired quality of life. In this narrative review, the etiopathogenic basis, epidemiology, clinical manifestations, diagnosis, treatment, prognosis, and socioeconomic impact of POTS, as well as other related dysautonomic disorders, after COVID-19 infection and SARS-CoV-2 postvaccination, were discussed. After a search conducted in March 2023, a total of 89 relevant articles were selected from the PubMed, Google Scholar, and Web of Science databases. The review highlights the importance of recognizing and managing POTS after COVID-19 infection and vaccination, and the approach to autonomic disorders should be known by all specialists in different medical areas. The diagnosis of POTS requires a comprehensive clinical assessment, including a detailed medical history, physical examination, orthostatic vital signs, and autonomic function tests. The treatment of POTS after COVID-19 infection or vaccination is mainly focused on lifestyle modifications, such as increased fluid and salt intake, exercise, and graduated compression stockings. Pharmacotherapy, such as beta-blockers, fludrocortisone, midodrine, and ivabradine, may also be used in selected cases. Further research is needed to understand the underlying mechanisms, risk factors, and optimal treatment strategies for this complication.

Evidence for Impaired Renin Activity in Postural Orthostatic Tachycardia Syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous condition predominantly affecting autonomic control of the cardiovascular system. Its extensive symptom diversity implies multi-organ involvement that interacts in ways still requiring full exploration. Current understanding of POTS pathophysiology suggests alterations in the renin-angiotensin-aldosterone system as a possible contributing factor. Therefore, we investigated the relationship between the activity of the renin-angiotensin-aldosterone system and hemodynamic parameters in a cohort of POTS patients and controls recruited at a tertiary referral center.

METHODS

The case-control study included 46 patients with POTS (27 ± 9 years), and 48 healthy controls (30 ± 9 years) without orthostatic intolerance. Plasma renin activity, expressed as angiotensin I generation, and plasma aldosterone were measured by enzyme-linked immunosorbent assay and were correlated with hemodynamic parameters obtained during active standing tests.

RESULTS

Renin activity was significantly downregulated in POTS patients compared to healthy individuals (median, 3406 ng/mL vs. 9949 ng/mL, p < 0.001), whereas aldosterone concentration did not differ between POTS and healthy controls (median, 218 pmol/L vs. 218 pmol/L, p = 0.26). A significant inverse correlation between renin activity and supine and orthostatic blood pressure levels was observed in healthy individuals (p < 0.05 for all), but not in POTS patients.

CONCLUSIONS

Renin activity, but not aldosterone concentration, is downregulated in patients with POTS. Moreover, renin activity in POTS is dissociated from supine and standing blood pressure levels in contrast to healthy individuals. These findings suggest impaired renin function in POTS, which may direct future therapeutic approaches.

Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

BACKGROUND

Many COVID-19 patients are left with symptoms several months after resolution of the acute illness; this syndrome is known as post-acute sequalae of COVID-19 (PASC). We aimed to determine the prevalence of objective hemodynamic cardiovascular autonomic abnormalities (CAA), explore sex differences, and assess the prevalence of CAA among hospitalized vs nonhospitalized patients with PASC.

METHODS

Patients with PASC (n = 70; female [F] = 56; 42 years of age; 95% confidence interval [CI], 40-48) completed standard autonomic tests, including an active stand test 399 days (338, 455) after their COVID-19 infection. Clinical autonomic abnormalities were evaluated.

RESULTS

Most patients with PASC met the criteria for at least 1 CAA (51; 73%; F = 43). The postural orthostatic tachycardia syndrome hemodynamic (POTSHR) criterion of a heart rate increase of > 30 beats per minute within 5 to 10 minutes of standing was seen in 21 patients (30%; F = 20; P = 0.037 [by sex]). The initial orthostatic hypotension hemodynamic (IOH40) criterion of a transient systolic blood pressure change of > 40 mm Hg in the first 15 seconds of standing was seen in 43 (61%) patients and equally among female and male patients (63% vs 57%; P = 0.7). Only 9 (13%) patients were hospitalized; hospitalized vs nonhospitalized patients had similar frequencies of abnormalities (67% vs 74%; P = 0.7).

CONCLUSIONS

Patients with PASC have evidence of CAA, most commonly IOH40, which will be missed unless an active stand test is used. Female patients have increased frequency of POTSHR, but IOH40 is equally prevalent between sexes. Finally, even nonhospitalized "mild" infections can result in long-term CAAs.

Distinct Hemodynamic Responses That Culminate With Postural Orthostatic Tachycardia Syndrome

It is of paramount importance to characterize the individual hemodynamic response of patients with postural orthostatic tachycardia syndrome (POTS) to select the best therapeutic intervention. Our aim in this study was to describe the hemodynamic changes in 40 patients with POTS during the head-up tilt test and compare them with 48 healthy patients. Hemodynamic parameters were obtained by cardiac bioimpedance. Patients were compared in supine position and after 5, 10, 15, and 20 minutes of orthostatic position. Patients with POTS demonstrated higher heart rate (74 beats per minute [64 to 80] vs 67 [62 to 72], p <0.001) and lower stroke volume (SV) (83.0 ml [72 to 94] vs 90 [79 to 112], p <0.001) at supine position. The response to orthostatic challenge was characterized by a decrease in SV index (SVI) in both groups (ΔSVI in ml/m²: -16 [-25 to -7.] vs -11 [-17 to -6.1], p = NS). Peripheral vascular resistance (PVR) was reduced only in POTS (ΔPVR in dyne.seg/cm⁵:-52 [-279 to 163] vs 326 [58 to 535], p <0.001). According to the best cut-off points obtained using the receiver operating characteristic analysis for the variation of SVI (-15.5%) and PVR index (PVRI) (-5.5%), we observed 4 distinct groups of POTS: 10% presented an increase in both SVI and PVRI after the orthostatic challenge, 35% presented a PVRI decrease with SVI maintenance or increase, 37.5% presented an SVI decrease with PVRI maintenance or elevation, and 17.5% presented a reduction in both variables. Body mass index, ΔSVI, and ΔPVRI were strongly correlated with POTS (area under the curve = 0.86 [95% confidence interval 0.77 to 0.92], p <0.0001). In conclusion, the use of appropriate cut-off points for hemodynamic parameters using bioimpedance cardiography during the head-up tilt test could be a useful strategy to identify the main mechanism involved and to select the best individual therapeutic strategy in POTS.

Long COVID: pathophysiological factors and abnormalities of coagulation

Acute COVID-19 infection is followed by prolonged symptoms in approximately one in ten cases: known as Long COVID. The disease affects ~65 million individuals worldwide. Many pathophysiological processes appear to underlie Long COVID, including viral factors (persistence, reactivation, and bacteriophagic action of SARS CoV-2); host factors (chronic inflammation, metabolic and endocrine dysregulation, immune dysregulation, and autoimmunity); and downstream impacts (tissue damage from the initial infection, tissue hypoxia, host dysbiosis, and autonomic nervous system dysfunction). These mechanisms culminate in the long-term persistence of the disorder characterized by a thrombotic endothelialitis, endothelial inflammation, hyperactivated platelets, and fibrinaloid microclots. These abnormalities of blood vessels and coagulation affect every organ system and represent a unifying pathway for the various symptoms of Long COVID.

A review of cytokine-based pathophysiology of Long COVID symptoms

The Long COVID/Post Acute Sequelae of COVID-19 (PASC) group includes patients with initial mild-to-moderate symptoms during the acute phase of the illness, in whom recovery is prolonged, or new symptoms are developed over months. Here, we propose a description of the pathophysiology of the Long COVID presentation based on inflammatory cytokine cascades and the p38 MAP kinase signaling pathways that regulate cytokine production. In this model, the SARS-CoV-2 viral infection is hypothesized to trigger a dysregulated peripheral immune system activation with subsequent cytokine release. Chronic low-grade inflammation leads to dysregulated brain microglia with an exaggerated release of central cytokines, producing neuroinflammation. Immunothrombosis linked to chronic inflammation with microclot formation leads to decreased tissue perfusion and ischemia. Intermittent fatigue, Post Exertional Malaise (PEM), CNS symptoms with "brain fog," arthralgias, paresthesias, dysautonomia, and GI and ophthalmic problems can consequently arise as result of the elevated peripheral and central cytokines. There are abundant similarities between symptoms in Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). DNA polymorphisms and viral-induced epigenetic changes to cytokine gene expression may lead to chronic inflammation in Long COVID patients, predisposing some to develop autoimmunity, which may be the gateway to ME/CFS.

Autoimmunity in Long Covid and POTS

Orthostatic intolerance and other autonomic dysfunction syndromes are emerging as distinct symptom clusters in Long Covid. Often accompanying these are common, multi-system constitutional features such as fatigue, malaise and skin rashes which can signify generalized immune dysregulation. At the same time, multiple autoantibodies are identified in both Covid-related autonomic disorders and non-Covid autonomic disorders, implying a possible underlying autoimmune pathology. The lack of specificity of these findings precludes direct interpretations of cause and association, but their prevalence with its supporting evidence is compelling.

Transcutaneous vagus nerve stimulation attenuates autoantibody-mediated cardiovagal dysfunction and inflammation in a rabbit model of postural tachycardia syndrome

PURPOSE

Previous studies demonstrated M2 muscarinic acetylcholine receptor-activating autoantibodies (M2R-AAb) were present in some patients with postural tachycardia syndrome (POTS). This study examines how these autoantibodies might contribute to the pathophysiology of POTS, and whether low-level tragus stimulation (LLTS) can ameliorate autoantibody-mediated autonomic dysregulation in the rabbit.

METHODS

Five New Zealand white rabbits were immunized with a M2R second extracellular loop peptide to produce cholinomimetic M2R-AAb. Tilt test and infusion studies were performed on conscious rabbits before immunization, 6 weeks after immunization, and 8 weeks after immunization with 2-week daily LLTS treatment. Each rabbit served as its own control.

RESULTS

Compared to preimmune state, an enhanced heart rate increase and decreased parasympathetic activity upon tilting were observed in immunized rabbits. Furthermore, these rabbits demonstrated an attenuated heart rate-slowing response to infusion of the M2R orthosteric agonist arecaidine propargyl ester (APE), suggesting an inhibitory allosteric effect of M2R-AAb. There was also a significant increase in serum inflammatory cytokines in immunized rabbits. LLTS treatment suppressed the postural tachycardia, improved the sympathovagal balance with increased acetylcholine secretion, reduced the levels of inflammatory cytokines, and reversed the attenuated heart rate response to APE in immunized rabbits. No suppression of M2R-AAb expression by LLTS was found during this short-term study period. Receptor-modulating activity of M2R-AAb produced in immunized rabbits was confirmed with in vitro bioassay.

CONCLUSIONS

Autoantibody inhibition of cholinergic ligand activity may be involved in the development of cardiovagal dysfunction and inflammation associated with POTS, both of which can be improved by vagal stimulation.

The Effect of Cardiac Mass and Venous Return in Children with Postural Orthostatic Tachycardia Syndrome: A Prospective, Observational Study

Low left ventricular mass index (LVMI) is thought to limit exercise tolerance in adult patients with postural orthostatic tachycardia syndrome (POTS). This finding has not been studied in children. We evaluated the effect of LVMI and hemodynamics at baseline and during exercise in POTS versus controls. POTS and control subjects aged 12-18 years were prospectively enrolled. POTS patients underwent autonomic studies. An echocardiogram was performed on all patients at baseline and during exercise. LVMI, venous return from inferior vena cava (IVC-VTI), left ventricular dimension, and cardiac output were assessed at baseline and during exercise. Generalized linear modeling with mixed effects was used to perform repeated measures testing between POTS and controls. Eighteen POTS patients (14 female, aged 15.4 ± 1.4 years) and nine control subjects (six female, aged 15.0 ± 1.3 years; p = 0.44) were enrolled. At baseline, LVMI was similar in both groups. During exercise, IVC-VTI, left ventricular end-diastolic dimension and volume, and stroke volume were lower in POTS patients. Peak heart rate was higher in POTS patients, but cardiac output was similar in both groups. Exercise time was higher in the control group (11.4 ± 2.7 min vs 9.2 ± 2.1, p = 0.024). Lower venous return resulted in smaller cardiac dimension and stroke volume during exercise. Higher heart rate in POTS may compensate to achieve similar cardiac output compared with control subjects. Lower ventricular filling and earlier time to peak heart rate may explain lower exercise capacity in pediatric POTS.

Low-level tragus stimulation improves autoantibody-induced hyperadrenergic postural tachycardia syndrome in rabbits

Background

Recent studies have demonstrated that antiadrenergic autoantibodies are involved in the pathophysiology of postural orthostatic tachycardia syndrome (POTS).

Objective

The purpose of this study was to test the hypothesis that transcutaneous low-level tragus stimulation (LLTS) ameliorates autoantibody-induced autonomic dysfunction and inflammation in a rabbit model of autoimmune POTS.

Methods

Six New Zealand white rabbits were co-immunized with peptides from the α1-adrenergic and β1-adrenergic receptors to produce sympathomimetic antibodies. The tilt test was performed on conscious rabbits before immunization, 6 weeks after immunization, and 10 weeks after immunization with 4-week daily LLTS treatment. Each rabbit served as its own control.

Results

An enhanced postural heart rate increase in the absence of significant change in blood pressure was observed in immunized rabbits, confirming our previous report. Power spectral analysis of heart rate variability during the tilt test showed a predominance of sympathetic over parasympathetic activity in immunized rabbits as reflected by markedly increased low-frequency power, decreased high-frequency power, and increased low-to-high-frequency ratio. Serum inflammatory cytokines were also significantly increased in immunized rabbits. LLTS suppressed the postural tachycardia, improved the sympathovagal balance with increased acetylcholine secretion, and attenuated the inflammatory cytokine expression. Antibody production and activity were confirmed with in vitro assays, and no antibody suppression by LLTS was found in this short-term study.

Conclusion

LLTS improves cardiac autonomic imbalance and inflammation in a rabbit model of autoantibody-induced hyperadrenergic POTS, suggesting that LLTS may be used as a novel neuromodulation therapy for POTS.

Postural orthostatic tachycardia syndrome: New concepts in pathophysiology and management

Postural orthostatic tachycardia syndrome (POTS) is a common and therapeutically challenging condition affecting numerous people worldwide. Recent studies have begun to shed light on the pathophysiology of this disorder. At the same time, both non-pharmacologic and pharmacologic therapies have emerged that offer additional treatment options for those afflicted with this condition. This paper reviews new concepts in both the pathophysiology and management of POTS.

Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants

Chronic fatigue syndrome (CFS), fibromyalgia, silicone breast implants syndrome (SBIs), COVID and post-COVID syndrome (PCS), sick building syndrome (SBS), post-orthostatic tachycardia syndrome (POTS), autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants (ASIA) are frequently accompanied by clinical symptoms characteristic for dysautonomia: severe fatigue, dizziness, fogginess, memory loss, dry mouth and eyes, hearing dysfunction, tachycardia etc. The recent discovery of an imbalance of autoantibodies against G protein-coupled receptors (GPCR) in some autoimmune diseases, post-COVID syndrome, SBIs allowed researchers to assume the novel mechanism in these conditions - autoimmune autonomic nervous system imbalance. In this review, all data published on an imbalance of autoantibodies against GPCR, clinical symptoms and pathogenic mechanisms in CFS, Fibromyalgia, SBIs, COVID and PCS, SBS, POTS, and some autoimmune diseases were analyzed. Possible criteria to diagnose the autoimmune autonomic nervous system imbalance were created.

Immunotherapy with subcutaneous immunoglobulin or plasmapheresis in patients with postural orthostatic tachycardia syndrome (POTS)

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS), one of the most common autonomic disorders, is associated with significant morbidity and functional impairment. Although several possible etiologies have been proposed, autoimmunity has emerged as one of the leading causes with various specific and non-specific antibodies identified in patients with POTS. Treatment with intravenous immunoglobulin has been previously described. We present a case series of patients with severe POTS refractory to the standard pharmacologic and non-pharmacologic therapies treated with immunotherapy consisting of either subcutaneous immunoglobulin (SCIG) therapy or plasmapheresis (PLEX) and report their treatment outcomes.

METHODS

Clinical history of 7 patients with POTS who were treated with SCIG or PLEX was reviewed. Response to treatment was assessed using COMPASS 31 and functional ability scale (FAS), completed by patients retrospectively, pre- and 3-12 months post-treatment with SCIG or PLEX.

RESULTS

All patients improved following SCIG or PLEX with an average 50% reduction in COMPASS 31 score and 217% increase in FAS scores. Six out of seven patients were able to reduce or discontinue oral medications for POTS, and five patients were able to return to work or school. Four patients had skin biopsy or quantitative sudomotor axon reflex test (QSART)-proven small fiber neuropathy, and five had various positive antibodies at low titers.

CONCLUSION

Patients with severe, treatment-refractory POTS experienced significant functional improvement with reduction in the autonomic symptoms following immunotherapy with SCIG or PLEX. Randomized controlled trials of SCIG and/or PLEX are needed to determine the efficacy and safety of these long-term therapies in patients with POTS.

WITHDRAWN: Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.autrev.2022.103230. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Sinus Tachycardia: a Multidisciplinary Expert Focused Review

Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.

Detection of G Protein-Coupled Receptor Autoantibodies in Postural Orthostatic Tachycardia Syndrome Using Standard Methodology

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) is a disorder of orthostatic intolerance that primarily affects women of childbearing age. The underlying pathophysiology of POTS is not fully understood, but it has been suggested that autoimmunity may play a role. The aim of this study was to compare concentrations of autoantibodies to cardiovascular G protein-coupled receptors between patients with POTS and healthy controls.

METHODS

Sera were collected from 116 patients with POTS (91% female; medium age, 29 years) and 81 healthy controls (84% female; medium age, 27 years) from Calgary, Canada, and Malmö, Sweden. Samples were evaluated for autoantibodies to 11 receptors (adrenergic, muscarinic, angiotensin II, and endothelin) using a commercially available enzyme-linked immunosorbent assay.

RESULTS

Autoantibody concentrations against all of the receptors tested were not significantly different between controls and patients with POTS. The majority of patients with POTS (98.3%) and all controls (100%) had α1 adrenergic receptor autoantibody concentrations above the seropositive threshold provided by the manufacturer (7 units/mL). The proportion of patients with POTS versus healthy controls who fell above the diagnostic thresholds was not different for any tested autoantibodies. Receiver operating characteristic curves showed a poor ability to discriminate between patients with POTS and controls.

CONCLUSIONS

Patients with POTS and healthy controls do not differ in their enzyme-linked immunosorbent assay-derived autoantibody concentrations to cardiovascular G protein-coupled receptors. These findings suggest that these tests are not useful for establishing the role of autoimmunity in POTS.

Brain fog in neuropathic postural tachycardia syndrome may be associated with autonomic hyperarousal and improves after water drinking

Background

Brain fog is a common and highly disturbing symptom for patients with neuropathic postural tachycardia syndrome (POTS). Cognitive deficits have been measured exclusively in the upright body position and mainly comprised impairments of higher cognitive functions. The cause of brain fog is still unclear today. This study aimed to investigate whether increased autonomic activation might be an underlying mechanism for the occurrence of brain fog in neuropathic POTS. We therefore investigated cognitive function in patients with neuropathic POTS and a healthy control group depending on body position and in relation to catecholamine release as a sensitive indicator of acute stress. The second aim was to test the effect of water intake on cardiovascular regulation, orthostatic symptoms, cognitive function and catecholamine release.

Methods

Thirteen patients with neuropathic POTS and 15 healthy control subjects were included. All participants completed a total of four rounds of cognitive testing: two before and two after the intake of 500 ml still water, each first in the supine position and then during head-up tilt. At the end of each cognitive test, a blood sample was collected for determination of plasma catecholamines. After each head-up tilt phase participants were asked to rate their current symptoms on a visual analogue scale.

Results

Working memory performance in the upright body position was impaired in patients, which was associated with self-reported symptom severity. Patients had elevated plasma norepinephrine independent of body position and water intake that increased excessively in the upright body position. The excessive increase of plasma norepinephrine was related to heart rate and symptom severity. Water intake in patients decreased norepinephrine concentrations and heart rate, and improved symptoms as well as cognitive performance.

Conclusion

Brain fog and symptom severity in neuropathic POTS are paralleled by an excessive norepinephrine secretion. Bolus water drinking down-regulates norepinephrine secretion and improves general symptom severity including brain fog.

Postural orthostatic tachycardia syndrome explained using a baroreflex response model

Patients with postural orthostatic tachycardia syndrome (POTS) experience an excessive increase in heart rate (HR) and low-frequency (∼0.1 Hz) blood pressure (BP) and HR oscillations upon head-up tilt (HUT). These responses are attributed to increased baroreflex (BR) responses modulating sympathetic and parasympathetic signalling. This study uses a closed-loop cardiovascular compartment model controlled by the BR to predict BP and HR dynamics in response to HUT. The cardiovascular model predicts these quantities in the left ventricle, upper and lower body arteries and veins. HUT is simulated by letting gravity shift blood volume (BV) from the upper to the lower body compartments, and the BR control is modelled using set-point functions modulating peripheral vascular resistance, compliance, and cardiac contractility in response to changes in mean carotid BP. We demonstrate that modulation of parameters characterizing BR sensitivity allows us to predict the persistent increase in HR and the low-frequency BP and HR oscillations observed in POTS patients. Moreover, by increasing BR sensitivity, inhibiting BR control of the lower body vasculature, and decreasing central BV, we demonstrate that it is possible to simulate patients with neuropathic and hyperadrenergic POTS.

Postural orthostatic tachycardia syndrome and post-acute COVID-19

While the acute illness of COVID-19 was the initial focus of concern, there are increasing reports of patients with chronic symptoms, known as long-COVID. Dysautonomia may be a possible post-acute neurological complication explaining the persistent symptoms observed in long COVID. Postural tachycardia syndrome (POTS), a form of dysautonomia characterized by sustained tachycardia and orthostatic intolerance, has been increasingly reported in patients after SARS-CoV-2 infection. In this context, this review aimed to report and discuss the available literature pertaining to post COVID-19 POTS.

Dysautonomia in COVID-19 Patients: A Narrative Review on Clinical Course, Diagnostic and Therapeutic Strategies

Introduction

On March 11, 2020, the World Health Organization sounded the COVID-19 pandemic alarm. While efforts in the first few months focused on reducing the mortality of infected patients, there is increasing data on the effects of long-term infection (Post-COVID-19 condition). Among the different symptoms described after acute infection, those derived from autonomic dysfunction are especially frequent and limiting.

Objective

To conduct a narrative review synthesizing current evidence of the signs and symptoms of dysautonomia in patients diagnosed with COVID-19, together with a compilation of available treatment guidelines.

Results

Autonomic dysfunction associated with SARS-CoV-2 infection occurs at different temporal stages. Some of the proposed pathophysiological mechanisms include direct tissue damage, immune dysregulation, hormonal disturbances, elevated cytokine levels, and persistent low-grade infection. Acute autonomic dysfunction has a direct impact on the mortality risk, given its repercussions on the respiratory, cardiovascular, and neurological systems. Iatrogenic autonomic dysfunction is a side effect caused by the drugs used and/or admission to the intensive care unit. Finally, late dysautonomia occurs in 2.5% of patients with Post-COVID-19 condition. While orthostatic hypotension and neurally-mediated syncope should be considered, postural orthostatic tachycardia syndrome (POTS) appears to be the most common autonomic phenotype among these patients. A review of diagnostic and treatment guidelines focused on each type of dysautonomic condition was done.

Conclusion

Symptoms deriving from autonomic dysfunction involvement are common in those affected by COVID-19. These symptoms have a great impact on the quality of life both in the short and medium to long term. A better understanding of the pathophysiological mechanisms of Post-COVID manifestations that affect the autonomic nervous system, and targeted therapeutic management could help reduce the sequelae of COVID-19, especially if we act in the earliest phases of the disease.

Is post-COVID syndrome an autoimmune disease?

INTRODUCTION

: Coronavirus disease 2019 (COVID-19) causes a long-term and persistent condition with clinical features similar to previous virulent outbreaks and other epidemics. Currently, post-COVID syndrome (PCS) is recognized as a new entity in the context of SARS-CoV-2 infection. Though its pathogenesis is not completely understood, persistent inflammation from acute illness and the development of autoimmunity play a critical role in its development. As the pandemic develops, the increasing latent and overt autoimmunity cases indicate that PCS is at the intersection of autoimmunity.

AREAS COVERED

The mechanisms involved in the emergence of PCS, their similarities with post-viral and post-care syndromes, its inclusion in the spectrum of autoimmunity and possible targets for its treatment.

EXPERT OPINION

An autoimmune phenomenon plays a major role in most causative theories explaining PCS. Due to the wide scope of symptoms and pathophysiology associated with PCS, there is a need for both PCS definition and classification criteria (including severity scores). Longitudinal and controlled studies are necessary to better understand this new entity, and to confirm that PCS is the chronic phase of COVID-19 as well as to find what additional factors participate into its development. With the high prevalence of COVID-19 cases worldwide, together with the current evidence on latent autoimmunity in PCS, we may observe an increase of autoimmune diseases (ADs) in the coming years. Vaccination's effect on the development of PCS and ADs will also receive attention in the future. Health and social care services need to develop a new framework to deal with PCS.

Orthostatic hypotonia as a probably late sequela of SARS-CoV-2 infection in a patient provided with palliative home care: a case report

Background

The SARS-CoV-2 pandemic has become a challenge for the entire healthcare system. Treatment for COVID-19 includes casual and symptomatic management in the acute phase of the disease and focuses on the treating early complications of the disease. Long-term health consequences of the infection have not yet been fully identified. A special group of patients with comorbidities, including neoplastic disease for whom the interpretation and management of symptoms is a major challenge.

Case presentation

In this case report, we present a 73-year-old woman with recently diagnosed gastric adenocarcinoma in whom we diagnosed orthostatic hypotonia in the aftermath of SARS-CoV-2 infection. We administered thiethylperazine maleate 6.5 mg daily. Additionally, we advised the patient to slowly lift from the recumbent position, raise the headboard, take meals in small portions, and increase fluid intake. These pharmacological and nonpharmacological measures resulted in sustained relief of dizziness and nausea.

Conclusions

The occurrence of orthostatic hypotonia seems a possible late sequela of SARS-CoV-2 infection, and simple measures appeared sufficient to achieve sustained symptom control.

Tolerability of COVID-19 mRNA vaccines in patients with postural tachycardia syndrome: a cross-sectional study

Background: Postural tachycardia syndrome (POTS) is a form of autonomic dysregulation. There is increasing evidence that the etiology may be immune-mediated in a subgroup of patients. Patients with POTS often experience an exacerbation of their symptoms associated with (viral) infections and often fear the same symptom aggravation after vaccination. In this report we describe the tolerability of messenger ribonucleic acid (mRNA) vaccines against coronavirus disease 19 (COVID-19) and the consequences of a COVID-19 infection on POTS symptoms in our cohort of patients with neuropathic POTS. Methods: We conducted a standardized, checklist-based interview with 23 patients and recorded the acute side effects of mRNA vaccination, acute symptoms of COVID-19 infection as well as the effects of vaccination and COVID-19 infection on POTS symptoms. Results: Of all included patients, 20 patients received two mRNA vaccines without having had a previous COVID-19 infection, and five patients in total had suffered a COVID-19 infection. Of these, three had COVID-19 without and two after being vaccinated. No increased frequency of side effects after both doses of mRNA vaccines was observed. Six patients reported a mild and short-term aggravation of their POTS symptoms beyond the duration of acute vaccine side effects. All five patients who suffered a COVID-19 infection subsequently reported a pronounced and persistent exacerbation of POTS symptoms. Conclusions: Our observations suggest that mRNA vaccines are not associated with a higher frequency of acute side effects in patients with POTS. Symptom exacerbation as a consequence of mRNA vaccination seems to be less frequent and of shorter duration compared to patients who suffered a COVID-19 infection.

Postural orthostatic tachycardia syndrome in children and adolescents

Background: Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous disorder in children and adolescents. Recently, there have been some data concerning the prevalence of POTS in adults. However, current studies on POTS in children and adolescents are rare. Thus, many young patients with POTS are misdiagnosed with migraine or other diseases.Current Concepts: The diagnosis and treatment of POTS differ between pediatric and adult patients. POTS in children and adolescents is diagnosed with chronic symptoms of orthostatic intolerance, such as a heart rate rise of 40 beat per minute (bpm) or a heart rate exceeding 130 bpm without orthostatic hypotension. There are three major POTS categories: hypovolemic POTS, neuropathic POTS, and hyperadrenergic POTS. These categories are distinguished by their major mechanisms. The different subtypes of POTS in children and adolescents have their own clinical characteristics and laboratory findings.Discussion and Conclusion: Treatment of POTS in children and adolescents should always include lifestyle changes, nutritional adjustments, exercise, and drugs depending on the different subtypes of POTS.

Post-HPV-Vaccination Mast Cell Activation Syndrome: Possible Vaccine-Triggered Escalation of Undiagnosed Pre-Existing Mast Cell Disease?

For nearly a decade, case reports and series have emerged regarding dysautonomias-particularly postural orthostatic tachycardia syndrome (POTS)-presenting soon after vaccination against human papilloma virus (HPV). We too have observed a number of such cases (all following vaccination with the Gardasil product), and have found several to have detectable mast cell activation syndrome (MCAS) as well as histories suggesting that MCAS was likely present long before vaccination. We detail 11 such cases here, posing a hypothesis that HPV vaccination (at least with the Gardasil product) may have triggered or exacerbated MCAS in teenagers previously not recognized to have it. Only recently recognized, MCAS is being increasingly appreciated as a prevalent and chronic multisystem disorder, often emerging early in life and presenting with inflammatory ± allergic phenomena following from known mast cell (MC) mediator effects. There is rising recognition, too, of associations of MCAS with central and peripheral neuropathic disorders, including autonomic disorders such as POTS. Given the recognized potential for many antigens to trigger a major and permanent escalation of baseline MC misbehavior in a given MCAS patient, we hypothesize that in our patients described herein, vaccination with Gardasil may have caused pre-existing (but not yet clinically recognized) MCAS to worsen to a clinically significantly degree, with the emergence of POTS and other issues. The recognition and management of MCAS prior to vaccinations in general may be a strategy worth investigating for reducing adverse events following HPV vaccinations and perhaps even other types of vaccinations.

Association of autoantibodies to muscarinic acetylcholine receptors with gastrointestinal symptoms and disease severity in patients with postural orthostatic tachycardia syndrome

Previous studies have reported a relationship between postural orthostatic tachycardia syndrome (POTS) and positivity for serum autoantibodies against G-protein-coupled receptors (GPCRs). However, the role of these autoantibodies in POTS is unclear. The present retrospective study analyzed the autoimmune etiology of POTS in 24 patients using a head-up tilt test to assess for any correlation between the clinical features of POTS and serum levels of autoantibodies against diverse GPCRs. In total, ten assessment items, including autonomic function tests, were analyzed. Of these, persistent, gastrointestinal symptoms and disease severity showed a significant association with the serum level of anti-muscarinic acetylcholine receptor (mAChRs) antibodies (gastrointestinal symptoms, M1, M2, M5; disease severity, M1, M3, M4, M5) [P <0.05]), while no significant association was found between the clinical features and autoantibodies against adrenergic receptors (α1, α2, β1, β2), angiotensin receptor 1, or endothelin receptor A. The patients were further divided into two groups based on the presence or absence of persistent gastrointestinal symptoms and then were characterized by the ten assessment items and neuropsychological tests, including the Wechsler Adult Intelligence Scale score and Self-Rating Depression Scale score. The results demonstrated a clear difference between the two groups in terms of disease severity, age at onset (older or younger than 20 years), and processing speed index (P <0.05), which were highly consistent with the association between these clinical features and the levels of serum anti-mAChR antibodies, particularly the anti-M5 receptor antibody. These findings suggested that anti-mAChR antibodies may play an important role in a subgroup of POTS patients with persistent gastrointestinal symptoms.

Dysautonomia Following Tetanus, Diphtheria, and Pertussis Vaccine (Tdap): The First Case of Extreme Cachexia Caused by Autoimmune/Inflammatory Syndrome Induced by Adjuvants (ASIA Syndrome) in a Human

Autoimmune/inflammatory Syndrome Induced by Adjuvants (ASIA; Shoenfeld’s syndrome) comprehends a group of autoimmune conditions that flourish in genetically predisposed individuals, following an external stimulus by the so-called adjuvants. Many adjuvants were described, such as vaccines, aluminum and other metals, silicone, tattoos, among others. Those conditions entail defined diseases, such as sarcoidosis and Sjogren’s syndrome, and generalized complex symptoms, for example, fatigue, sleep disturbance, orthostatic intolerance, and other dysautonomic manifestations. Those complaints were previously associated with autoantibodies against nervous system autonomic receptors, especially antibeta 1 adrenergic receptor antibodies, suggesting the autoimmune component of the condition. Here we report on a case of an 18-year-old woman who presented with extreme cachexia due to severe dysautonomia caused by the ASIA syndrome induced by the tetanus, diphtheria, and pertussis vaccine (Tdap).

How COVID-19 can cause autonomic dysfunctions and postural orthostatic syndrome? A Review of mechanisms and evidence

Coronavirus disease 2019 (COVID-19) is a viral disease spread by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Because the recent pandemic has resulted in significant morbidity and mortality, understanding various aspects of this disease has become critical. SARS-CoV-2 can affect a variety of organs and systems in the body. The autonomic nervous system plays an important role in regulating body functions, and its dysfunction can cause a great deal of discomfort for patients. In this study, we focused on the effect of COVID-19 on the autonomic system and syndromes associated with it, such as postural orthostatic syndrome (POTS).

Preparing for the long-haul: Autonomic complications of COVID-19

As global numbers of COVID-19 grow, chronic neurological symptoms, including those of autonomic dysfunction, are being reported with increasing frequency. Mounting evidence suggests that many patients experience chronic and sometimes debilitating symptoms long after their acute infectious period, leading to the new diagnostic category of post-acute COVID syndrome. Many symptoms of post-acute COVID syndrome appear autonomic in nature, suggesting that autonomic impairment may play a central role in the underlying pathophysiology. In this review, we discuss the autonomic symptoms and manifestations of post-acute COVID syndrome, potential mechanisms involved, and future directions for a better understanding of this novel condition.

Cutaneous Pathology of COVID-19 as a Window into Immunologic Mechanisms of Disease

Many skin manifestations of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection reflect activation of cutaneous and systemic immune responses involving effector pathways of both the innate and adaptive arms of the immune system. This article reviews evidence from the recent clinical and scientific literature that informs the current understanding of the consequences of coronavirus disease 2019 (COVID-19)-induced immune cell activation, as relevant to dermatology. Topics include the clinical consequences of autoantibody production in patients with COVID-19, immunologic evidence for chilblains as a manifestation of SARS-CoV-2 infection, and the relationship between type I interferons and COVID-19 disease severity.

[A case of chronic postural tachycardia syndrome with positive anti-ganglionic acetylcholine receptor (gAChR) antibody]

Postural orthostatic tachycardia syndrome (POTS) is a form of orthostatic intolerance characterized by symptoms such as lightheadedness, fainting, and brain fog that occur with a rapid elevation in heart rate when standing up from a reclining position. The etiology of POTS has yet to be established. However, a growing body of evidence suggests that POTS may be an autoimmune disorder such as autoimmune autonomic ganglionopathy, an acquired, immune-mediated form of diffuse autonomic failure. Many patients have serum antibodies that bind to the ganglionic acetylcholine receptors (gAChRs) in the autonomic ganglia. Herein, we describe a 39-year-old female patient with an eight-year history of orthostatic intolerance. POTS was diagnosed based on the findings of a head-up tilt test, in which a rapid increase in the patient's heart rate from 58 bpm in the lying position to 117 bpm in the upright position without orthostatic hypotension was observed. The POTS symptoms were refractory to various medications except for pyridostigmine bromide, which resulted in a partial resolution of her symptoms. Her serum was found to be strongly positive for anti-gAChR (β4 subunit) autoantibody (2.162 A.I., normal range: below 1.0). Based on these findings, a limited form of autoimmune POTS was diagnosed. After obtaining written informed consent, she was treated with intravenous immunoglobulin (IVIg) 400 mg/kg/day for five days, which led to clinical improvement by reducing her heart rate increase in the upright position. She was able to return to work with IVIg treatment at regular intervals. Our case provides further evidence of a potential autoimmune pathogenesis for POTS. Aggressive immunotherapy may be effective for POTS even in chronic cases.