Phenoconversion in pure autonomic failure: a multicentre prospective longitudinal cohort study.

We aimed to describe the clinical features of patients with pure autonomic failure (PAF) preceding phenoconversion that could be useful as predictive markers for advancing α-synuclein-associated neurodegeneration of the brain. Patients diagnosed with PAF were evaluated at eight centres (seven US-based and one European) and enrolled in a longitudinal observational cohort study (NCT01799915). Subjects underwent detailed assessments of motor, sleep, olfactory, cognitive and autonomic function and were followed prospectively to determine whether they developed parkinsonism or dementia for up to 10 years. We identified incident cases of Parkinson's disease (PD), dementia with Lewy bodies (DLB) or multiple system atrophy (MSA) and computed hazard ratios for phenoconversion as functions of clinical features. A total of 209 participants with PAF with a median disease duration of 6 years (IQR: 3-10) were enrolled. Of those, 149 provided follow-up information at an office or telemedicine visit. After a mean follow-up duration of 3 years, 48 (33%) participants phenoconverted (42% to PD, 35% to DLB and 23% to MSA). Faster phenoconversion from study enrolment to any diagnosis was associated with urinary and sexual dysfunction [hazard ratio (HR) 5.9, 95% confidence interval (CI): 1.6-22 and HR: 3.6, 95% CI: 1.1-12] followed by subtle motor signs (HR: 2.7, 95% CI: 1.2-6), trouble swallowing (HR 2.5, 95% CI: 1.4-4.5) and changes in speech (HR:2.4, 95% CI:1.1-4.8) at enrolment. Subjects reporting deterioration of handwriting were more likely to phenoconvert to PD (HR: 2.6, 95% CI: 1.1-5.9) and those reporting difficulty handling utensils were more likely to phenoconvert to DLB (HR: 6.8, 95% CI: 1.2-38). Patients with a younger age of PAF onset (HR: 11, 95% CI: 2.6-46), preserved olfaction (HR: 8.7, 95% CI: 1.7-45), anhidrosis (HR: 1.8, 95% CI: 1-3.1, P = 0.042) and severe urinary problems (HR 1.6, 95% CI: 1-2.5, P = 0.033) were more likely to phenoconvert to MSA. The best autonomic predictor of PD was a blunted heart rate increase during the tilt-table test (HR: 6.1, 95% CI: 1.4-26). Patients with PAF have an estimated 12% (95% CI: 9-15%) per year annual risk following study entry of phenoconverting to a manifest CNS synucleinopathy.

Effect of Lower Extremity Nerve Decompression in Patients With Painful Diabetic Peripheral Neuropathy: The Diabetic Neuropathy Nerve Decompression Randomized, Observation Group and Placebo Surgery-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effect of nerve decompression on pain in patients with lower extremity painful diabetic peripheral neuropathy (DPN). BACKGROUND: Currently, no treatment provides lasting relief for patients with DPN. The benefits of nerve decompression remain inconclusive. METHODS: This double-blinded, observation and same-patient sham surgery-controlled randomized trial enrolled patients aged 18 to 80 years with lower extremity painful DPN who failed 1 year of medical treatment. Patients were randomized to nerve decompression or observation group (2:1). Decompression-group patients were further randomized and blinded to nerve decompression in either the right or left leg and sham surgery in the opposite leg. Pain (11-point Likert score) was compared between decompression and observation groups and between decompressed versus sham legs at 12 and 56 months. RESULTS: Of 2987 screened patients, 78 were randomized. At 12 months, compared with controls (n=37), both the right-decompression group (n=22) and left-decompression group (n=18) reported lower pain (mean difference for both: -4.46; 95% CI: -6.34 to -2.58 and -6.48 to -2.45, respectively; P < 0.0001). Decompressed and sham legs equally improved. At 56 months, compared with controls (n=m 14), pain was lower in both the right-decompression group (n=20; mean difference: -7.65; 95% CI: -9.87 to -5.44; P < 0.0001) and left-decompression group (n=16; mean difference: -7.26; 95% CI: -9.60 to -4.91; P < 0.0001). The mean pain score was lower in decompressed versus sham legs (mean difference: 1.57 95% CI: 0.46 to 2.67; P =0.0002). CONCLUSIONS: Although nerve decompression was associated with reduced pain, the benefit of surgical decompression needs further investigation as a placebo effect may be responsible for part or all of these effects.

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.

Skin Biopsy Detection of Phosphorylated α-Synuclein in Patients With Synucleinopathies.

Importance: Finding a reliable diagnostic biomarker for the disorders collectively known as synucleinopathies (Parkinson disease [PD], dementia with Lewy bodies [DLB], multiple system atrophy [MSA], and pure autonomic failure [PAF]) is an urgent unmet need. Immunohistochemical detection of cutaneous phosphorylated α-synuclein may be a sensitive and specific clinical test for the diagnosis of synucleinopathies. Objective: To evaluate the positivity rate of cutaneous α-synuclein deposition in patients with PD, DLB, MSA, and PAF. Design, Setting, and Participants: This blinded, 30-site, cross-sectional study of academic and community-based neurology practices conducted from February 2021 through March 2023 included patients aged 40 to 99 years with a clinical diagnosis of PD, DLB, MSA, or PAF based on clinical consensus criteria and confirmed by an expert review panel and control participants aged 40 to 99 years with no history of examination findings or symptoms suggestive of a synucleinopathy or neurodegenerative disease. All participants completed detailed neurologic examinations and disease-specific questionnaires and underwent skin biopsy for detection of phosphorylated α-synuclein. An expert review panel blinded to pathologic data determined the final participant diagnosis. Exposure: Skin biopsy for detection of phosphorylated α-synuclein. Main Outcomes: Rates of detection of cutaneous α-synuclein in patients with PD, MSA, DLB, and PAF and controls without synucleinopathy. Results: Of 428 enrolled participants, 343 were included in the primary analysis (mean [SD] age, 69.5 [9.1] years; 175 [51.0%] male); 223 met the consensus criteria for a synucleinopathy and 120 met criteria as controls after expert panel review. The proportions of individuals with cutaneous phosphorylated α-synuclein detected by skin biopsy were 92.7% (89 of 96) with PD, 98.2% (54 of 55) with MSA, 96.0% (48 of 50) with DLB, and 100% (22 of 22) with PAF; 3.3% (4 of 120) of controls had cutaneous phosphorylated α-synuclein detected. Conclusions and Relevance: In this cross-sectional study, a high proportion of individuals meeting clinical consensus criteria for PD, DLB, MSA, and PAF had phosphorylated α-synuclein detected by skin biopsy. Further research is needed in unselected clinical populations to externally validate the findings and fully characterize the potential role of skin biopsy detection of phosphorylated α-synuclein in clinical care.

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.

Responsiveness of UMSARS and other clinical measures in a longitudinal structured care clinic for multiple system atrophy.

PURPOSE: As understanding of multiple system atrophy (MSA) pathophysiology improves, clinical trials of disease-modifying therapies are starting. Outcome measures responsive to disease progression will be critical, but the United MSA Rating Scale (UMSARS) has limitations. The MSA multidisciplinary clinic at the University of Texas Southwestern is a longitudinal clinic with structured assessments performed at fixed time intervals. The objective of this study was to evaluate the performance of clinical measures in assessing MSA progression over time. METHODS: Data from 73 subjects with clinically diagnosed MSA were analyzed using repeated measures correlation models. Observations were made every 4 months, with up to 3 years of data included for each patient. RESULTS: UMSARS-I and UMSARS-II correlated positively with the MSA Quality of Life (QOL) scale. The rate of change was 3.12 points per year (ppy) for UMSARS-I and 5.55 ppy for UMSARS-II. Some individual UMSARS questions contributed more significantly than others to overall UMSARS rate of change. Based on this finding, and using repeated measures correlations between question combinations and QOL, an optimization of UMSARS parts I and II was curated. The amended UMSARS-I included 8 of the 12 subquestions, and the amended UMSARS-II included 10 of the 14 subquestions. CONCLUSIONS: Data from a longitudinal MSA clinic allows better characterization of the performance of UMSARS as a clinical outcome measure. A curated set of UMSARS questions appears more responsive to change and accounts for correlation with QOL, and could be the starting point for an improved MSA outcome measure.

Autoimmune encephalitis: proposed recommendations for symptomatic and long-term management.

The objective of this paper is to evaluate available evidence for each step in autoimmune encephalitis management and provide expert opinion when evidence is lacking. The paper approaches autoimmune encephalitis as a broad category rather than focusing on individual antibody syndromes. Core authors from the Autoimmune Encephalitis Alliance Clinicians Network reviewed literature and developed the first draft. Where evidence was lacking or controversial, an electronic survey was distributed to all members to solicit individual responses. Sixty-eight members from 17 countries answered the survey. The most popular bridging therapy was oral prednisone taper chosen by 38% of responders while rituximab was the most popular maintenance therapy chosen by 46%. Most responders considered maintenance immunosuppression after a second relapse in patients with neuronal surface antibodies (70%) or seronegative autoimmune encephalitis (61%) as opposed to those with onconeuronal antibodies (29%). Most responders opted to cancer screening for 4 years in patients with neuronal surface antibodies (49%) or limbic encephalitis (46%) as opposed to non-limbic seronegative autoimmune encephalitis (36%). Detailed survey results are presented in the manuscript and a summary of the diagnostic and therapeutic recommendations is presented at the conclusion.

Autoimmune encephalitis: proposed best practice recommendations for diagnosis and acute management.

The objective of this paper is to evaluate available evidence for each step in autoimmune encephalitis management and provide expert opinion when evidence is lacking. The paper approaches autoimmune encephalitis as a broad category rather than focusing on individual antibody syndromes. Core authors from the Autoimmune Encephalitis Alliance Clinicians Network reviewed literature and developed the first draft. Where evidence was lacking or controversial, an electronic survey was distributed to all members to solicit individual responses. Sixty-eight members from 17 countries answered the survey. Corticosteroids alone or combined with other agents (intravenous IG or plasmapheresis) were selected as a first-line therapy by 84% of responders for patients with a general presentation, 74% for patients presenting with faciobrachial dystonic seizures, 63% for NMDAR-IgG encephalitis and 48.5% for classical paraneoplastic encephalitis. Half the responders indicated they would add a second-line agent only if there was no response to more than one first-line agent, 32% indicated adding a second-line agent if there was no response to one first-line agent, while only 15% indicated using a second-line agent in all patients. As for the preferred second-line agent, 80% of responders chose rituximab while only 10% chose cyclophosphamide in a clinical scenario with unknown antibodies. Detailed survey results are presented in the manuscript and a summary of the diagnostic and therapeutic recommendations is presented at the conclusion.

A comparison of health-related quality of life in autonomic disorders: postural tachycardia syndrome versus vasovagal syncope.

PURPOSE: Postural tachycardia syndrome (POTS) and vasovagal syncope (VVS) are two disorders of orthostatic intolerance which are often misdiagnosed as the other. In each case, patients experience a reduced health-related quality of life (HRQoL) compared to healthy populations. This study was conducted to test the hypothesis that HRQoL is worse in POTS. METHODS: POTS patients were recruited from the Dysautonomia International Annual Patient and Caregiver Conference. VVS patient data came from those enrolled in the Second Prevention of Syncope Trial. Participants aged ≥ 18 years (177 POTS and 72 VVS) completed the RAND 36-Item Health Survey, a generic and coherent health-related quality of life survey. RESULTS: POTS patients reported reduced HRQoL compared to VVS patients in physical functioning (42.5 ± 1.7 vs. 76.5 ± 2.9, p < 0.001), role limitations due to physical health (11.4 ± 1.9 vs. 33.0 ± 5.0, p < 0.001), energy and fatigue (27.2 ± 1.3 vs. 50.7 ± 2.6, p < 0.001), social functioning (45.2 ± 1.8 vs. 71.2 ± 2.9, p < 0.001), pain (48.8 ± 1.9 vs. 67.7 ± 2.9, p < 0.001), and general health (31.2 ± 1.5 vs. 60.5 ± 2.6, p < 0.001) domains. Scores did not differ significantly in the role limitations due to emotional health (p = 0.052) and emotional well-being (p = 0.271) domains. Physical and general health composite scores were lower in the POTS population, while mental health composite scores were not different. CONCLUSION: Differences in HRQoL exist between these patient populations. POTS patients report lower scores in physical and general health domains than VVS patients, but emotional health domains do not differ significantly. Targeting physical functioning in these patients may help improve quality of life.

Long-COVID postural tachycardia syndrome: an American Autonomic Society statement.

COVID-19 is a global pandemic that has had a devastating effect on the health and economy of much of human civilization. While the acute impacts of COVID-19 were the initial focus of concern, it is becoming clear that in the wake of COVID-19, many patients are developing chronic symptoms that have been called Long-COVID. Some of the symptoms and signs include those of postural tachycardia syndrome (POTS). Understanding and managing long-COVID POTS will require a significant infusion of health care resources and a significant additional research investment. In this document from the American Autonomic Society, we outline the scope of the problem, and the resources and research needed to properly address the impact of Long-COVID POTS.

Autonomic function testing in the COVID-19 pandemic: an American Autonomic Society position statement.

COVID-19 is a global pandemic that is wreaking havoc with the health and economy of much of human civilization. In this document from the American Autonomic Society, we identify the potential risks of exposure to patients, physicians, and allied healthcare staff. We provide guidance for conducting autonomic function testing safely in this environment.

Human papillomavirus (HPV) vaccine and autonomic disorders: a position statement from the American Autonomic Society.

INTRODUCTION: Human papillomavirus (HPV) vaccination has been anecdotally connected to the development of dysautonomia, chronic fatigue, complex regional pain syndrome and postural tachycardia syndrome. OBJECTIVES: To critically evaluate a potential connection between HPV vaccination and the above-noted conditions. METHODS: We reviewed the literature containing the biology of the virus, pathophysiology of infection, epidemiology of associated cancers, indications of HPV vaccination, safety surveillance data and published reports linking HPV vaccination to autonomic disorders. RESULTS: At this time, the American Autonomic Society finds that there are no data to support a causal relationship between HPV vaccination and CRPS, chronic fatigue, and postural tachycardia syndrome to other forms of dysautonomia. CONCLUSION: Certain conditions are prevalent in the same populations that are vaccinated with the HPV vaccine (peri-pubertal males and females). This association, however, is an insufficient proof of causality.

Autoimmune autonomic neuropathies and ganglionopathies: epidemiology, pathophysiology, and therapeutic advances.

Autonomic disorders can be the result of autoimmunity. The classic, well-characterized example is autoimmune autonomic ganglionopathy (AAG), in which antibodies against the ganglionic nicotinic acetylcholine receptor impair autonomic transmission, causing autonomic failure, which responds to immunotherapy. However, a number of other autoimmune disorders cause autonomic failure through a variety of mechanisms. In this article, we review autoimmune disorders causing impairment of the peripheral autonomic nervous system (ganglia and nerves), including AAG, other autoimmune autonomic neuropathies, paraneoplastic autonomic neuropathies, and neuromuscular and rheumatologic diseases with autonomic symptomatology. Awareness of primary autoimmune autonomic disorders and the autonomic manifestations of other autoimmune diseases promotes timely diagnosis and appropriate management, including supportive care for unpleasant or dangerous autonomic dysfunction, a search for underlying malignancy when indicated, and the use of immunotherapy when appropriate. A better understanding of the underlying pathophysiology aids in the judicious use and selection of immunotherapy.

A novel gain-of-function Nav1.7 mutation in a carbamazepine-responsive patient with adult-onset painful peripheral neuropathy.

Voltage-gated sodium channel Nav1.7 is a threshold channel in peripheral dorsal root ganglion (DRG), trigeminal ganglion, and sympathetic ganglion neurons. Gain-of-function mutations in Nav1.7 have been shown to increase excitability in DRG neurons and have been linked to rare Mendelian and more common pain disorders. Discovery of Nav1.7 variants in patients with pain disorders may expand the spectrum of painful peripheral neuropathies associated with a well-defined molecular target, thereby providing a basis for more targeted approaches for treatment. We screened the genome of a patient with adult-onset painful peripheral neuropathy characterized by severe burning pain and report here the new Nav1.7-V810M variant. Voltage-clamp recordings were used to assess the effects of the mutation on biophysical properties of Nav1.7 and the response of the mutant channel to treatment with carbamazepine (CBZ), and multi-electrode array (MEA) recordings were used to assess the effects of the mutation on the excitability of neonatal rat pup DRG neurons. The V810M variant increases current density, shifts activation in a hyperpolarizing direction, and slows kinetics of deactivation, all gain-of-function attributes. We also show that DRG neurons that express the V810M variant become hyperexcitable. The patient responded to treatment with CBZ. Although CBZ did not depolarize activation of the mutant channel, it enhanced use-dependent inhibition. Our results demonstrate the presence of a novel gain-of-function variant of Nav1.7 in a patient with adult-onset painful peripheral neuropathy and the responsiveness of that patient to treatment with CBZ, which is likely due to the classical mechanism of use-dependent inhibition.

Seronegative autoimmune autonomic neuropathy: a distinct clinical entity.

PURPOSE: Autoimmune autonomic ganglionopathy (AAG) is associated with ganglionic acetylcholine receptor (gAChR) antibodies. We describe a similar but distinct series of patients with autoimmune autonomic failure lacking this antibody. METHODS: Retrospective chart review. RESULTS: Six patients presented with subacute autonomic failure, seronegative for gAChR antibodies. Orthostatic hypotension and gastrointestinal complaints were common. Autonomic testing revealed predominant sympathetic failure and no premature pupillary redilation. All patients had sensory symptoms and/or pain, which was severe in three. Immunotherapy with plasma exchange, intravenous immunoglobulin, and rituximab was ineffective. Three patients responded to intravenous steroids. CONCLUSION: In these cases of autoimmune autonomic failure, key differences from seropositive AAG emerge. Testing showed prominent sympathetic (rather than cholinergic) failure, specific pupillary findings of AAG were absent, and sensory symptoms were prominent. AAG responds to antibody-targeted immunotherapy, while these patients responded best to steroids. This seronegative autoimmune autonomic neuropathy is a distinct clinical entity requiring a different treatment approach from AAG.

Autoimmunity-associated autonomic failure with sympathetic denervation.

We report a case of autoimmunity-associated autonomic failure in a young adult woman who developed arthritis followed 3 years later by pandysautonomia. There was early recovery of parasympathetic functions but persistent neurogenic orthostatic hypotension from post-ganglionic sympathetic denervation. Clinical laboratory testing indicated variable amounts of sympathetic neuronal re-sprouting in the heart, kidneys, eyes, and body as a whole upon follow-up evaluation after 1.5 years.

Factors contributing to delay in diagnosis of Guillain-Barré syndrome and impact on clinical outcome.

INTRODUCTION: Heterogeneity of presenting symptoms makes the initial clinical diagnosis of Guillain-Barré syndrome (GBS) challenging. METHODS: Observational retrospective study from 2 teaching hospitals (Parkland Memorial Hospital and University of Texas Southwestern University Hospital) between 2008 and 2013. RESULTS: Sixty-nine GBS patients were identified. GBS was suspected on initial emergency department visit in only 49%. During first hospital encounter, 58% were evaluated by a neurologist. Neuropathic pain and presence of intact deep tendon reflexes were associated with delayed GBS diagnosis (P < 0.05). There was significantly better clinical outcome among patients who were evaluated by a neurologist during the initial visit (P < 0.005). Among these patients there was also significant difference in discharge destination; 71.2% of patients evaluated by a neurologist were discharged home (P < 0.01). Patients in whom GBS was not suspected at the time of initial Neurology evaluation were more likely to require intubation and to have residual weakness at the time of discharge (P < 0.05). CONCLUSIONS: Atypical clinical signs and symptoms may lead to delayed diagnosis of GBS. Early neurological evaluation is associated with improved clinical diagnosis and discharge disposition.

Clinical experience of seropositive ganglionic acetylcholine receptor antibody in a tertiary neurology referral center.

INTRODUCTION: Antibody against the acetylcholine receptor of autonomic ganglia (gAChR-Ab) is implicated in the pathogenesis of autoimmune autonomic ganglionopathy (AAG) and several other disorders. METHODS: This study was a retrospective evaluation of 95 patients positive for gAChR-Ab. RESULTS: Twenty-one (22%) patients had AAG, with a greater median gAChR-Ab level (0.21 nmol/L) and higher percentage (57%) of antibody levels >0.20 nmol/L when compared with the remaining 74 patients without autonomic manifestations (non-AAG group, 0.10 nmol/L and 15%, respectively). Only 2 new cases of malignancy were diagnosed after gAChR-Ab detection. The non-AAG group was associated with high frequencies of neurological and non-neurological autoimmunity, but also included 23 (31%) patients with mostly degenerative disorders. CONCLUSION: Detection of gAChR-Ab, especially at a higher level, is helpful for the diagnosis of AAG in patients with corresponding autonomic symptoms. However, its value is limited for predicting cancer risk and for diagnosis and management of patients without autonomic symptoms.