Recurrent acute-onset of chronic inflammatory demyelinating polyneuropathy after COVID-19 vaccination.

This is the case of 54-year-old male with a past medical history of Chronic Inflammatory Demyelinating Polyneuropathy (CIPD) who was found to have an acute exacerbation of CIPD shortly after receiving his 1st COVID 19 booster (3rd dose of vaccination series) and was successfully treated with intravenous immunoglobulin (IVIG) and then was found to have another acute exacerbation of CIDP 6 months later after receiving his 2nd COVID 19 booster (4th dose of vaccination series) that required intubation and long term tracheostomy. CIPD is an acquired immune-mediated polyneuropathy that mainly affects the peripheral nerve roots nerves. It typically presents with relapsing/remitting, or progressive symmetrical muscle weakness and sensory involvement and can cause decreased respiratory effort. COVID-19 is mainly a respiratory disease, but it has been associated with a wide variety of neurological conditions. Although there have been several findings of acute inflammatory demyelinating polyneuropathy in association with COVID-19, CIDP exacerbation as a result of COVID-19 has rarely been seen in the literature. Furthermore, CIDP exacerbation as a result of COVID-19 vaccination is even less frequently seen.

Autoimmune Peripheral Neuropathies

Autoimmune peripheral neuropathies (APNs) occur when immunological tolerance to peripheral nerve components (myelin, axon, or ganglionic neurons) is lost. The most common APNs are acute inflammatory polyneuropathies, such as Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN), immunoglobulin M (IgM)–anti–myelin-associated glycoprotein (MAG) antibody–mediated paraproteinemic neuropathy, and those caused by vasculitis or viral infections. Both cellular and humoral factors, either independently or in concert with each other, appear to play a role, but the specific immune mechanisms have not been fully elucidated. Infectious agents, such as Campylobacter jejuni and Zika virus via molecular mimicry, and now COVID-19, are implicated in some GBS subtypes, but the factors that break tolerance in the other APNs remain unknown. In some acute or chronic APN, antibodies against peripheral nerve glycolipids or glycoproteins are pathogenic and well characterized. Pathogenic IgG4 antibodies against antigens at the nodes of Ranvier that cause disadhesion of nodal and paranodal proteins and conduction block define distinct CIDP subtypes, which respond only to rituximab. Some newly emerging, not pathogenic, autoantibodies more commonly seen in small fiber sensory neuropathies and neuropathic pains are briefly discussed. The current immunotherapies in all APNs are described based on controlled trials or clinical experience. © 2023 Elsevier Ltd. All rights reserved.

MOTOR CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY IN A CHILD.

Motor chronic inflammatory demyelinating polyneuropathy (M-CIDP) is a form of atypical CIDP. This article presents a clinical observation of M-CIDP in a 15-year-old boy, as well as a description of laboratory and instrumental diagnostic data. The boy had a chronic development (> 2 months) of flaccid tetraparesis, predominantly of the proximal muscles of the limbs, without sensory disorders. According to electroneuromyography, there were signs of demyelinating lesions of the proximal parts of the peripheral nerves. There was an increase in the thickness of the nerves of the upper limbs according to ultrasound. In the liquor protein-cell dissociation, as well as in the blood, IgG antibodies to the surface glycoprotein S of the SARS-CoV-2 coronavirus were found. The clinical and neurophysiological picture corresponded to the reliable criteria for CIDP. The therapy with intravenous immunoglobulins had a significant positive effect in the form of an increase in the strength of the limb muscles.Copyright © Russian Neurological Journal. All rights reserved.

MOTOR CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY IN A CHILD.

Motor chronic inflammatory demyelinating polyneuropathy (M-CIDP) is a form of atypical CIDP. This article presents a clinical observation of M-CIDP in a 15-year-old boy, as well as a description of laboratory and instrumental diagnostic data. The boy had a chronic development (> 2 months) of flaccid tetraparesis, predominantly of the proximal muscles of the limbs, without sensory disorders. According to electroneuromyography, there were signs of demyelinating lesions of the proximal parts of the peripheral nerves. There was an increase in the thickness of the nerves of the upper limbs according to ultrasound. In the liquor protein-cell dissociation, as well as in the blood, IgG antibodies to the surface glycoprotein S of the SARS-CoV-2 coronavirus were found. The clinical and neurophysiological picture corresponded to the reliable criteria for CIDP. The therapy with intravenous immunoglobulins had a significant positive effect in the form of an increase in the strength of the limb muscles.Copyright © Russian Neurological Journal. All rights reserved.

MOTOR CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY IN A CHILD.

Motor chronic inflammatory demyelinating polyneuropathy (M-CIDP) is a form of atypical CIDP. This article presents a clinical observation of M-CIDP in a 15-year-old boy, as well as a description of laboratory and instrumental diagnostic data. The boy had a chronic development (> 2 months) of flaccid tetraparesis, predominantly of the proximal muscles of the limbs, without sensory disorders. According to electroneuromyography, there were signs of demyelinating lesions of the proximal parts of the peripheral nerves. There was an increase in the thickness of the nerves of the upper limbs according to ultrasound. In the liquor protein-cell dissociation, as well as in the blood, IgG antibodies to the surface glycoprotein S of the SARS-CoV-2 coronavirus were found. The clinical and neurophysiological picture corresponded to the reliable criteria for CIDP. The therapy with intravenous immunoglobulins had a significant positive effect in the form of an increase in the strength of the limb muscles.Copyright © Russian Neurological Journal. All rights reserved.

The impact of the SARS-CoV-2-pandemic on patients with chronic inflammatory neuropathies: Results from the German INHIBIT register

Introduction: COVID-19 pandemic is especially compromising for patients with autoimmune diseases and receiving an immunomodulatory treatment. This study aimed to investigate the longitudinal changes in the health care of patients with immunemediated neuropathies during the COVID-19 pandemic. Method(s): We performed a cross-sectional survey using questionnaires in a prospective cohort of patients with immune-mediated neuropathies at two timepoints of the pandemic: May-July 2021 and May-July 2022. The questionnaire examines five subcategories in 13 questions: general health care situation, demand of physiotherapy and ergotherapy, COVID-19 disease, COVID-19 vaccination-offer and vaccine data. Result(s): The cohort consisted of 73 patients (55 male), mean age 61 years. 34 patients with typical CIDP, 23 patients with distal CIDP, 10 patients with multifocal CIDP, one patient with sensory CIDP, four patients with multifocal motor neuropathy and one patient with Paranodopathy. In 2021, 19% of patients reported a reduced number of physician-patient-contacts, while 14% reported this in 2022. Nevertheless, the overall health-care situation worsened from 2021 to 2022: 15% reported reduced overall healthcare in 2021, and 26% in 2022. In 2021, 29% of patients reported absence of physio-/ergotherapy, while 34% reported this in 2022. Due to the absence 70% of the patients reported a worsening of symptoms in 2021, 82% in 2022. Switching immunomodulatory treatment and stretching of intervals occurred more often in 2022 (38%) than in 2021(27%). Due to this changes 50% of the patients reported a worsening of symptoms in 2021. 68% reported this in 2022. 18 COVID-19-infections occurred overall, with typical but only mild symptoms. In May-July 2021 the rate of fully vaccinated patients was 62%, in May-July 2022 99%. Only minor side-effects were reported. Conclusion(s): Despite mitigation of COVID-19 restrictions, the health-care situation of patients worsened from 2021 to 2022 although the physician-patient-contacts increased again in the same timespan. Reasons could be the international shortage of immunoglobulins during the pandemic and reduced physio/ergotherapy due to regulatory restrictions. Thus, there is a need to continue to work on coping strategies for this and future pandemics and to adopt new approaches to provide satisfactory care to patients. Vaccination rate was high in our cohort of patients compared to the general German population. No severe COVID cases were reported in our cohort with patients with immunomodulatory treatment. Disclosures: The authors have nothing to declare related to this .Copyright © 2023

Risk of disease relapse, safety and tolerability of SARS-CoV-2 vaccination in patients with chronic inflammatory neuropathies.

BACKGROUND AND PURPOSE: The aim was to evaluate the risk of relapse after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, and its safety and tolerability, in patients with chronic inflammatory neuropathies. METHODS: In this multicenter, cohort and case-crossover study, the risk of relapse associated with SARS-CoV-2 vaccination was assessed by comparing the frequency of relapse in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN) patients who underwent or did not undergo vaccination. Frequency of relapse in the 3 months prior to and after vaccination, and safety and tolerability of SARS-CoV-2 vaccination, were also assessed. RESULTS: In all, 336 patients were included (278 CIDP, 58 MMN). Three hundred and seven (91%) patients underwent SARS-CoV-2 vaccination. Twenty-nine patients (9%) did not undergo vaccination. Mild and transient relapses were observed in 16 (5%) patients (13 CIDP, 3 MMN) after SARS-CoV-2 vaccination and in none of the patients who did not undergo vaccination (relative risk [RR] 3.21, 95% confidence interval [CI] 0.19-52.25). There was no increase in the specific risk of relapse associated with type of vaccine or diagnosis. Comparison with the 3-month control period preceding vaccination revealed an increased risk of relapse after vaccination (RR 4.00, 95% CI 1.35-11.82), which was restricted to CIDP patients (RR 3.25, 95% CI 1.07-9.84). The safety profile of SARS-CoV-2 vaccination was characterized by short-term, mild-to-moderate local and systemic adverse events. CONCLUSIONS: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in CIDP and MMN patients does not seem to be associated with an increased risk of relapse at the primary end-point, although a slightly increased risk in CIDP patients was found compared to the 3 months before vaccination.

TH-261. A case of GBS-like polyneuropathy with unusual progression (Case Report)

Nodal and paranodal antibody-associated neuropathies have been recently classified as auto-immune nodopathies. Their clinical presentation can be easily mistaken for acute or chronic idiopathic demyelinating polyneuropathy (AIDP/CIDP). We present a case of pan-neurofascin antibody associated paranodal neuropathy with serial electrodiagnostic findings. A 61-year-old man presented with acute onset generalized weakness and tiredness one day after the Covid-19 booster vaccination. He had progressive sensory disturbance and weakness in his upper limbs spreading to the lower limbs. He was treated with IVIg for Guillain-Barre syndrome (GBS) and discharged with some improvement. Five days later, he developed rapidly progressive predominantly motor symptoms becoming quadriplegic and bedbound within 9 days with no cranial or respiratory involvement. He was found to have paranodal antibodies (neurofascin-155), consistent with a pan-neurofascin antibody positive neuropathy. Although the patient responded poorly to conventional immunomodulatory therapies, he showed a rapid remarkable recovery with rituximab. He was able to walk independently again within 3 weeks after the second dose of rituximab. Electrodiagnostic studies showed only subtle proximal demyelinating features with the initial presentation. The repeat study after his relapse showed a significant deterioration with features of a generalized, non-length-dependent, primarily demyelinating, sensorimotor polyneuropathy with conduction block, but the sural nerve biopsy showed axonal neuropathy. Electrodiagnostic findings nearly normalized two months after rituximab treatment with the resolution of the all the demyelinating features. This case presentation highlights the importance of considering nodal/paranodal neuropathy as a differential for AIDP/CIDP in an early stage of the disease, especially in patients with atypical presentation. In addition, it supports the currently available evidence that more targeted treatment such as rituximab can have an excellent outcome. Copyright © 2022

Acute-onset chronic inflammatory demyelinating polyneuropathy complicating SARS-CoV-2 infection and Ad26.COV2.S vaccination: report of two cases.

Background: The spectrum of reported neurological sequelae associated with SARS-CoV-2 is continuously expanding, immune mediated neuropathies like Guillain-Barre syndrome (GBS) and exacerbations of preexisting chronic inflammatory demyelinating polyneuropathy (CIDP) being among them. However, respective cases of acute onset CIDP (A-CIDP) are rare. Case presentation: We hereby report two cases of A-CIDP after COVID-19 infection and Ad26.COV2.S vaccination that presented with flaccid paraparesis and acroparesthesias (Case presentation 1; female, 52) and facial diplegia accompanied by acroparesthesias (Case presentation 2; male, 62), respectively. In both instances clinical, neurophysiological and CSF findings were indicative of acute inflammatory demyelinating polyneuropathy, thus both patients were initially treated with intravenous immunoglobulins resulting in clinical improvement. Nevertheless, the first patient relapsed 5 weeks after the initial episode, thus was diagnosed with GBS with treatment related fluctuations (GBS-TRF) and treated successfully with seven plasma exchange (PLEX) sessions. However, 11 weeks from symptom onset she relapsed again. Taking into account that the second relapse occurred more than 8 weeks after the first episode, the potential diagnosis of A-CIDP was reached and oral dexamethasone 40 mg/d for 4 consecutive days every 4 weeks was administered. With regards to the second patient, he relapsed > 8 weeks after the initial episode, thus was also diagnosed with A-CIDP and treated with 7 PLEX sessions followed by similar to the aforementioned corticosteroid therapy. On 2 month follow-up both patients exhibited remarkable clinical improvement. Conclusions: Close surveillance of patients presenting with immune neuropathies in the context of SARS-CoV-2 infection or immunization is crucial for timely implementation of appropriate treatment. Prompt A-CIDP distinction from GBS-TRF is of paramount importance as treatment approach and prognosis between these two entities differ. Supplementary Information: The online version contains supplementary material available at 10.1186/s41983-022-00515-4.

An Unusual Clinical Evolution in Anticontactin- 1 Positive CIDP

Specific clinical, electrophysiological and serological features are used to recognise a phenotype fitting the atypical chronic inflammatory demyelinating (CIDP) variant spectrum. We report a 28-year-old male patient, without any significant history apart from a recent asymptomatic COVID-19 infection, presenting at first with bilateral facial nerve palsy, subsequently -three months later- developing an subacute onset symmetric sensory ataxia and arefl exia, and thirdly experiencing diffuse rapidly progressive motor deficits. Additional investigations suggested an autoimmune polyneuropathy: Liquor analysis showed cytoalbuminologic dissociation. Cerebrospinal fluid protein elevation was remarkable: 631 mg/dL. Nerve conduction studies showed prominent distal latencies prolongation and dispersion of the potentials, meeting the electrodiagnostic criteria of the European Federation of Neurological Societies/Peripheral Nerve Society for CIDP (2021). Full spine magnetic resonance imaging depicted pathological thickening and enhancement of the roots of the cauda equina as seen in radiculitis. There was no or poor response to conventional treatment, i.e. immunoglobulins (IVIG), corticosteroids and even plasmapheresis. Muscle weakness deteriorated. Presence of serum IgG4 anti- contactin-1 (CNTN1) antibodies was found by ELISA identifi- cation and titration, and the patient improved substantially after rituximab treatment. While contributing to the expanding confidence in nodal and paranodal antibodies as valuable biomarkers in clinical practice, our case entails several peculiarities: 1/ SARS-CoV2 positivity as a possible trigger of this auto-immune polyneuropathy 2/ A considerably younger age of onset than in the patients already described (range 33-76 years). 3/ The clinical course progressed in an atypical manner even for atypical CIDP: Initial presentation with bilateral asymmetric facial palsy, followed by sensory ataxia, which prompted the initial diagnosis of Miller-Fisher syndrome, and later development of severe motor impairment. 4/ Proteinorachy was so pronounced that we considered neuroborreliosis as a potential associated disorder. Borrelia seroconversion occurred after the first IVIG-treatment, and could be false positive. However, the patient was treated with intravenous ceftriaxone, which had no effect on the clinic. 5/ Antibodies against CNTN1 were undetectable after 2 months of rituximab. Emphasising the both diagnostic and therapeutic importance of recognising a phenotype compatible with atypical CIDP, an underrecognized and consequently undertreated disease where early diagnosis and prevention of axonal damage is crucial in.

2022 EAN/PNS GBS Guideline

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. This is the first systematic clinical guideline, developed by an international task force using formal GRADE methodology. The diagnostic criteria remain primarily clinical, based on history and examination findings of acute progressive limb weakness and areflexia. Variants of GBS may include motor GBS, Miller Fisher Syndrome, and regional variants with weakness predominantly in lower limbs, face, or pharynx/neck/ arms. The differential diagnosis is wide. When uncertain, diagnosis may be assisted by nerve conduction tests, raised cerebrospinal fluid protein, and less often by MRI spine with contrast, or serum antibodies to gangliosides (especially for variants) or nodalparanodal antibodies (especially if not improving). Axonal versus demyelinating subtyping does not affect clinical management. A history of recent gastrointestinal or respiratory infection or of surgery may support the diagnosis. The risk of GBS is only very slightly increased after Covid-19 infection and after the adenovirus-vector vaccines to SARS-CoV2 (AstraZeneca or Johnson & Johnson) but not mRNA vaccines. Immune treatment is recommended with intravenous immunoglobulin or plasma exchange, for most patients except those mildly affected or after four weeks from onset. A repeat course is reasonable after a treatment-related fluctuation. Corticosteroids are not recommended. There is no evidence of benefi t from any other disease-modifying treatment. Respiratory function should be monitored by forced vital capacity and single breath count to assess the risk of needing mechanical ventilation, guided by the mEGRIS scale. Pain is very common. It may be musculoskeletal or neuropathic, and treated with gabapentin, tricyclic antidepressants or carbamazepine. Patients who fail to improve should be reassessed for the correct diagnosis and for axonal degeneration. Around 5% of patients with GBS may later develop CIDP but no test can reliably indicate this within the first eight weeks. Nodal-paranodal antibodies should be tested if CIDP is suspected or if the patient is not recovering well. The long-term outcome is less good in patients of older age, with preceding diarrhoea, or more severe weakness, as quantified by the mEGOS scale, and also in patients with smaller motor potential amplitudes or raised serum neurofilament light chain level.

IVIg Treatment in Chronic Inflammatory Neuropathies During the COIVD19 Pandemic

During the COVID19 pandemic, there were changes in the organization of healthcare together with immunoglobulins shortage, which had influence on cybetween clic treatment regimens in some patients. In Poland, intravenous immunoglobulin (IVIg) treatment is used only as inpatient treatment, which was challenging during the COVID19 pandemic. The aim of the study was to assess how the COVID19 pandemic influenced the therapy regimen and the course of the disease in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) treated with cyclic IVIg. Materials and methods: 15 patients were cyclically treated with IVIg our center: 8 with MMN (5F and 3M) mean age 54.6 years and 7 with CIDP (3F and 4M) mean age 51 years. Three periods were compared: Before the pandemic (Jan.2019-Feb.2020) and two periods during the pandemic: I (Mar- Dec.2020), II (Jan-Dec.2021). The following parameters were assessed: Mean doses (g / kg bw / week), mean intervals between drug administrations (weeks) and treatment efficacy assessed using functional scales: For MMN-INCAT, MMN-RODS, for CIDP-INCAT. Results: During the pandemic, lengthening of the intervals between administrations or reduction of the doses per treatment were observed in the majority of patients. A reduction in mean doses was demonstrated in 4/8 patients with MMN and CIDP in 1/7 compared to period I pandemic and in 3/7 compared to period II pandemic. Due to disease progression, the mean dose was increased in 3/8 patients with MMN. Prolongation of intervals was observed in 3/8 patients with MMN and 3/7 with CIDP. Most patients had a point in time when symptoms worsened (worsening of INCAT by at least 1) due to lack of treatment in MMN in 6/8 and in CIDP in 5/7, reversible with increased dose. The extension of the intervals resulted not only from the pandemic restrictions, but from the limited availability of IVIg as well. No statistically significant differences were found between the mean periods, between consecutive IVIg administrations and the mean IVIg doses in the periods before the pandemic and during the pandemic (I, II) and functional assessments at the end of analyzed period. Conclusion: The limited availability of IVIg and epidemiological restrictions during the COVID19 pandemic required modification of treatment regimens. Drug dose reduction and prolongation of the intervals between drug administrations, lead in the majority of CIDP patients to temporary deterioration in functional status, reversible by increased dosage of IVIg.

Overview of COVID-19 Infection and NM Disease Associated with COVID-19 Infection (e.g., GBS/neuritis, Myositis)

The COVID-19 pandemic caused by infection by SARS-CoV-2 has been associated with several neuromuscular disorders including various inflammatory neuropathies (e.g., Guillain-Barre syndrome) and myopathies (e.g., rhabdomyolysis, myositis). Temporal associations however do not imply causality. In this lecture, Dr. Amato will review the literature regarding to neuromuscular complications associated with SARS-CoV-2 infection. There are conflicting studies but if SARS-CoV-2 infection indeed causes GBS it is likely quite rare (probably < 1 case per 100000 infection). Less is known about other infl ammatory neuropathies (mononeuritis, plexitis, or CIDP). Larger epidemiological studies are needed to better define the causality. Elevated serum creatine kinase and myalgias are common in hospitalized patients with COVID-19 and in some myositis has been demonstrated on muscle biopsy. Furthermore, autopsy series have shown myositis and neuritis in patients who died from COVID-19 though virus has not been demonstrated in muscle or peripheral nerve. The inflammation is primarily felt to be due to cytokine release and not direct viral invasion of muscle or nerve. Finally, many affected patients have lingering symptoms (Long COVID) or Post-Acute Sequelae of COVID-19 (PASC) that often include neuromuscular symptoms (fatigue, weakness, lightheadedness, sensory loss and pain) that are of unclear nature.

Access to immunoglobulin treatment for CIDP patients during the COVID-19 pandemic

Background: Immunoglobulin supplies are limited;we aimed to determine if the COVID-19 pandemic was associated with difficulty accessing immunoglobulin treatment for patients diagnosed with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Methods: A retrospective cross-sectional study was conducted with CIDP patients (n=16, 68.75% female, mean age 60.38 ± 11.32) recruited from three Montreal tertiary care institutions. Patients completed a questionnaire inquiring about changes in their immunoglobulin treatment during the pandemic and about their quality of life. We used weighted chi-squared statistical tests and Cramer's V correlation ratios to measure associations with treatment change. Results: Eighteen months after the pandemic started, 25% of our population were receiving immunoglobulin treatment at a different frequency, 6.3% were receiving a different dose, 12.5% were receiving a different dose and frequency, and 6.3% were receiving a different treatment. Reasons associated with treatment change were worsening of neurological condition (18.8%;Cramer's V=0.480;p-value=0.055), improvement of neurological condition (25%;Cramer's V=0.577;p-value=0.021) and reduced availability of treatment (6.3%;Cramer's V=0.258;p-value=0.302). There were no significant correlations between lower quality of life (p-value=0.323) or lower Rasch-built Overall Disability Scale score (p-value=0.574) and treatment change. Conclusions: Difficulty accessing immunoglobulin treatment was not significantly associated with treatment change for CIDP patients during the COVID-19 pandemic.

Super Slow Conduction Velocitiesin Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

Objective: NA Background: Chronic inflammatory demyelinating polyneuropathy (CIDP) is characterized on nerve conduction study (NCS) by prolonged distal latencies, slowed conduction velocities, prolonged late responses, conduction blocks, and temporal dispersion. Unmyelinated fibers typically conduct action potentials at speeds of 0.5-10 m/s;myelinated fibers conduct an order of magnitude faster, e.g. 50-70 m/s. While very slow conduction velocities < 25 m/s are typically associated with the genetic neuropathies as in the Charcot-Marie Tooth neuropathies, CIDP can manifest with slow conduction velocities. Prompt recognition of CIDP is crucial for the timely initiation of immunotherapy. Design/Methods: NA Results: This case series of three CIDP patients demonstrates very slow conduction velocities and prolonged distal latencies. An 81-year-old woman with history of multiple sclerosis and chronic myelogenous leukemia presented with inability to walk over a few months with diffuse sensory loss. NCS showed absent motor responses in the leg, partial conduction blocks in the arm, prolonged ulnar motor distal latency 7.9 ms (normal ≤3.4ms), and very slow conduction velocities < 15 m/s. A 50-year-old woman with prior history of COVID-19 presented with diffuse weakness. NCS showed ulnar motor distal latency of 23.2 ms, slowed motor conduction velocities < 30 m/s. After treatment initiation with intravenous immunoglobulin, sensory responses improved, and conduction velocities increased to > 30 m/s. A 49-year-old woman presented with 3 months of bilateral weakness and sensory symptoms two weeks after a COVID-19 vaccination. NCS showed ulnar motor distal latency of 14 ms and slowed motor conduction velocities < 30 m/s. Conclusions: Very slow conduction velocities are a feature not just of the genetic neuropathies but also of acquired demyelination as seen in CIDP, and the latter is distinguished by abnormal temporal dispersion and conduction blocks. Astute electrophysiologists should modify sweep speed and gain to increase sensitivity for delayed or dispersed responses.

Safety and Tolerability of SARS-Cov-2 Vaccination in Patients with Neuromuscular Disorders: A Single Center Experience

Objective: To describe side effects from SARS-Cov-2 vaccination and its effect on underlying neuromuscular disease amongst patients followed at the University of California, Irvine Neuromuscular Center. Background: Extensive data on safety and tolerability of SARS-Cov-2 vaccines exists for healthy individuals. However, patients with neuromuscular conditions and especially those on immune modulatory therapy were not included in the pivotal vaccine trials. It is primarily through expert consensus that vaccination is recommended for this patient population. Design/Methods: Patients were advised to inform the study team about their vaccination status. We collected data during in-person clinic visits or via telehealth encounters using a standardized questionnaire between December 2020 and August 2021. When information was provided about upcoming vaccination dates, patients were contacted within 2 weeks for follow up. Results: Information on 363 administered vaccine doses in 214 patients was recorded, including 199 Pfizer-BioNT, 155 Moderna and 9 Johnson & Johnson doses. Our cohort included 84 patients with myasthenia gravis (MG) and 34 with motor neuron disease (Amyotrophic Lateral Sclerosis, Primary Lateral Sclerosis). The remainder (96 patients) included other immunemediated disorders (idiopathic inflammatory myopathies, Chronic Inflammatory Demyelinating Neuropathy, Guillain-Barre Syndrome and other immune neuropathies) as well as acquired and inherited neuromuscular disorders (Inclusion Body Myositis, muscular dystrophy, inherited and acquired neuropathies). One patient with generalized MG had MG exacerbation, and another experienced impending crisis within one week of vaccine administration;both recovered with appropriate therapy. Detailed analyses of the dataset are being performed and will be presented at the meeting. Conclusions: SARS-Cov-2 vaccinations were well tolerated for the majority of our neuromuscular cohort, similar to what has been reported in healthy individuals. Vaccination did not result in disease exacerbation in the majority of patients with immune-mediated neuromuscular disorders.