Interlaboratory comparison of a multiplex immunoassay that measures human serum IgG antibodies against six-group B streptococcus polysaccharides

Measurement of IgG antibodies against group B streptococcus (GBS) capsular polysaccharide (CPS) by use of a standardized and internationally accepted multiplex immunoassay is important for the evaluation of candidate maternal GBS vaccines in order to compare results across studies. A standardized assay is also required if serocorrelates of protection against invasive GBS disease are to be established in infant sera for the six predominant GBS serotypes since it would permit the comparison of results across the six serotypes. We undertook an interlaboratory study across five laboratories that used standardized assay reagents and protocols with a panel of 44 human sera to measure IgG antibodies against GBS CPS serotypes Ia, Ib, II, III, IV, and V. The within-laboratory intermediate precision, which included factors like the lot of coated beads, laboratory analyst, and day, was generally below 20% relative standard deviation (RSD) for all six serotypes, across all five laboratories. The cross-laboratory reproducibility was < 25% RSD for all six serotypes, which demonstrated the consistency of results across the different laboratories. Additionally, anti-CPS IgG concentrations for the 44-member human serum panel were established. The results of this study showed assay robustness and that the resultant anti-CPS IgG concentrations were reproducible across laboratories for the six GBS CPS serotypes when the standardized assay was used.

Efficacy of Teleconsultation-Based Rehabilitation in Children with Landry-Guillain-Barré Syndrome: An Open Label Randomized Controlled Trial (Tele Rehab-LGBS Trial)

OBJECTIVES

To evaluate the feasibility and efficacy of teleconsultation-based rehabilitation in children with Landry-Guillain-Barré syndrome (LGBS), measured with Medical Research Council (MRC) sum score and Hughes score.

METHODS

A pragmatic, prospective, parallel open label randomized controlled trial was conducted among a total of 50 children with LGBS. The children were randomized using computer generated block randomization into 2 groups (25 in each group): Standard of care (Group A) and teleconsultation-based rehabilitation (Group B). Primary and secondary outcomes were measured with MRC sum score and Hughes score at 12- and 24-wk follow-up.

RESULTS

The mean age was 6.4 ± 3.3 y; 29 (58%) were boys. Baseline MRC sum score (median, IQR), and Hughes score (median, IQR) in group A was 24 (7-31) and 5 (4-5) respectively; and in group B was 18 (9-24) and 4 (4-5) respectively. At discharge, median (IQR) MRC sum score in group A and B was 34 (28-41), and 30 (25-43) (p value = 0.31) respectively. Tele-rehabilitation was provided to group B for 24 wk with 96% compliance. At 12 wk, median MRC sum score in group A and group B were similar [48 (IQR 44-54) vs. 52 (IQR 46-60), p value = 0.08]. At 12 wk and 24 wk, median Hughes score in group A and B were similar. At 24 wk, 15 out of 23 subjects of group A and 18 out of 25 subjects of group B were ambulatory (p value = 0.61).

CONCLUSIONS

Teleconsultation-based rehabilitation was feasible with a high compliance rate. The functional outcomes measured with MRC sum score and Hughes score were similar in both the groups at 12 and 24 wk follow-up. Teleconsultation-based rehabilitation has similar efficacy as physical rehabilitation.

Recurrent Guillain-Barré Syndrome: Clinical Profile and Outcome

OBJECTIVES

To compare clinical, neurological, treatment and outcome of recurrent Guillian-Barré Syndrome (GBS) with non-recurrent GBS. Also, to compare different episodes of recurrent GBS.

METHODS

The patient's case records were retrieved retrospectively from the electronic database and case record files. Clinical profile, nerve conduction study, treatment, and outcome details of children with a diagnosis of GBS admitted in Pediatric Intensive Care Unit (PICU) from 2010 to March 2022 were screened. Recurrent GBS cases, as defined by the National Institute of Neurological and Communicative Diseases and Strokes (NINCDS) criteria, were analysed separately. The comparison was made between the first episode of recurrent GBS with non-recurrent GBS, and predictors of recurrence were identified. A comparison of course and outcome was also done between different episodes of GBS in recurrent cases.

RESULTS

Recurrent GBS was observed in 11 (4.7%) out of 234 cases during the study period. The presence of respiratory (p 0.015) and gastrointestinal illness (p 0.007) as preceding illnesses were associated with recurrence. No difference was noted between the first episode of recurrent GBS and non-recurrent GBS. The first and second episodes of GBS in 11 recurrent cases were similar in course and outcome.

CONCLUSIONS

Recurrent GBS is underreported but a known entity. No difference was seen between the two episodes of recurrent GBS. However, more data is required to find the features of recurrent GBS so that limited PICU resources can be used judiciously and intervention planned accordingly.

The sural-sparing pattern in clinical variants and electrophysiological subtypes of Guillain-Barré syndrome

BACKGROUND

 Guillain-Barré syndrome (GBS) is the most common cause of acute flaccid paralysis worldwide and can be classified into electrophysiological subtypes and clinical variants.

OBJECTIVE

 This study aimed to compare the frequency of the sural-sparing pattern (SSP) in subtypes and variants of GBS.

METHODS

 This retrospective cohort study analyzed clinical and electrophysiological data of 171 patients with GBS hospitalized in public and private hospitals of Natal, Rio Grande do Norte, Brazil, between 1994 and 2018; all cases were followed up by the same neurologist in a reference neurology center. Patients were classified according to electrophysiological subtypes and clinical variants, and the SSP frequency was compared in both categories. The exact Fisher test and Bonferroni correction were used for statistical analysis.

RESULTS

 The SSP was present in 53% (57 of 107) of the patients with acute inflammatory demyelinating polyradiculoneuropathy (AIDP), 8% (4 of 48) of the patients with axonal subtypes, and 31% (5 of 16) of the equivocal cases. The SSP frequency in the AIDP was significantly higher than in the axonal subtypes (p < 0.0001); the value was kept high after serial electrophysiological examinations. Only the paraparetic subtype did not present SSP.

CONCLUSION

 The SSP may be present in AIDP and axonal subtypes, including acute motor axonal neuropathy, but it is significantly more present in AIDP. Moreover, the clinical variants reflect a specific pathological process and are correlated to its typical electrophysiological subtype, affecting the SSP frequency.

Autoantibodies Against Dihydrolipoamide S-Acetyltransferase in Immune-Mediated Neuropathies

BACKGROUND AND OBJECTIVES

This study aimed to identify disease-related autoantibodies in the serum of patients with immune-mediated neuropathies including chronic inflammatory demyelinating polyneuropathy (CIDP) and to investigate the clinical characteristics of patients with these antibodies.

METHODS

Proteins extracted from mouse brain tissue were used to react with sera from patients with CIDP by western blotting (WB) to determine the presence of common bands. Positive bands were then identified by mass spectrometry and confirmed for reactivity with patient sera using enzyme-linked immunosorbent assay (ELISA) and WB. Reactivity was further confirmed by cell-based and tissue-based indirect immunofluorescence assays. The clinical characteristics of patients with candidate autoantibody-positive CIDP were analyzed, and their association with other neurologic diseases was also investigated.

RESULTS

Screening of 78 CIDP patient sera by WB revealed a positive band around 60-70 kDa identified as dihydrolipoamide S-acetyltransferase (DLAT) by immunoprecipitation and mass spectrometry. Serum immunoglobulin G (IgG) and IgM antibodies' reactivity to recombinant DLAT was confirmed using ELISA and WB. A relatively high reactivity was observed in 29 of 160 (18%) patients with CIDP, followed by patients with sensory neuropathy (6/58, 10%) and patients with MS (2/47, 4%), but not in patients with Guillain-Barré syndrome (0/27), patients with hereditary neuropathy (0/40), and healthy controls (0/26). Both the cell-based and tissue-based assays confirmed reactivity in 26 of 33 patients with CIDP. Comparing the clinical characteristics of patients with CIDP with anti-DLAT antibodies (n = 29) with those of negative cases (n = 131), a higher percentage of patients had comorbid sensory ataxia (69% vs 37%), cranial nerve disorders (24% vs 9%), and malignancy (20% vs 5%). A high DLAT expression was observed in human autopsy dorsal root ganglia, confirming the reactivity of patient serum with mouse dorsal root ganglion cells.

DISCUSSION

Reactivity to DLAT was confirmed in patient sera, mainly in patients with CIDP. DLAT is highly expressed in the dorsal root ganglion cells, and anti-DLAT antibody may serve as a biomarker for sensory-dominant neuropathies.

Electrodiagnostic methods to verify Guillain-Barré syndrome subtypes in Istanbul: A prospective multicenter study

BACKGROUND AND AIMS

This study aimed to identify the clinical characteristics and electrodiagnostic subtypes of Guillain-Barré syndrome (GBS) in Istanbul.

METHODS

Patients with GBS were prospectively recruited between April 2019 and March 2022 and two electrodiagnostic examinations were performed on each patient. The criteria of Ho et al., Hadden et al., Rajabally et al., and Uncini et al. were compared for the differentiation of demyelinating and axonal subtypes, and their relations with anti-ganglioside antibodies were analyzed.

RESULTS

One hundred seventy-seven patients were included, 69 before the coronavirus disease 2019 pandemic (April 2019-February 2020) and 108 during the pandemic (March 2020-March 2022), without substantial changes in monthly frequencies. As compared with the criteria of Uncini et al., demyelinating GBS subtype diagnosis was more frequent according to the Ho et al. and Hadden et al. criteria (95/162, 58.6% vs. 110/174, 63.2% and 121/174, 69.5%, respectively), and less frequent according to Rajabally et al.'s criteria (76/174, 43.7%). Fourteen patients' diagnoses made using Rajabally et al.'s criteria were shifted to the other subtype with the second electrodiagnostic examination. Of the 106 analyzed patients, 22 had immunoglobulin G anti-ganglioside antibodies (14 with the axonal subtype). They had less frequent sensory symptoms (54.5% vs. 83.1%, p = 0.009), a more frequent history of previous gastroenteritis (54.5% vs. 22.9%, p = 0.007), and a more severe disease as compared with those without antibodies.

INTERPRETATION

Serial electrodiagnostic examinations are more helpful for accurate subtype diagnosis of GBS because of the dynamic pathophysiology of the disease. We observed no significant increase in GBS frequency during the pandemic in this metropolis.

[Guillain-Barré syndrome caused by intravesical instillation of Bacillus Calmette-Guérin]

Introduction - Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating polyneuropathy. In the vast majority of patients, 1-4 weeks before the onset of GBS-related symptoms, an event such as upper respiratory tract or gastrointestinal tract infection, surgical intervention or vaccination is present. To the best of our knowledge, this is the first case of GBS that occurred after intravesical Bacillus Calmette-Guérin (BCG) therapy in the absence of tuberculosis or any other infection in the English literature.
Case report – A 65-year-old male patient, who had no systemic disorders except hypertension and coronary artery disease, underwent transurethral resection of a bladder tumour further to imaging studies investigating macroscopic haematuria. A pathologic examination revealed a non-muscle-invasive high-grade (pT1HG) transitional cell carcinoma. Immediately after the fourth cycle of intravesical BCG, which was administered 2 months after surgery, the patient experienced numbness and weakness in his lower and upper extremities, respectively. There were no signs or symptoms related to an acute cranial pathology or infectious disease. Nerve conduction studies, which were carried out on the 7th day after the onset of the neurologic symptoms, revealed a demyelinating sensorimotor polyneuropathy with mild secondary axonal damage in upper and lower limbs with a sural sparing pattern.
Conclusion - Without tuberculosis infection, GBS can occur secondary to increased immune response and antibodies triggered by intravesical BCG therapy. However, considering the worldwide use of BCG vaccination and thousands of intravesical BCG therapies, this is a very rare adverse effect. 

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Cardiovascular, Neurological, and Immunological Adverse Events and the 23-Valent Pneumococcal Polysaccharide Vaccine

Importance

Despite widespread immunization with the 23-valent pneumococcal polysaccharide vaccine (PPSV23), safety concerns remain owing to a lack of statistical power and largely outdated evidence.

Objective

To evaluate the association between cardiovascular, neurological, and immunological adverse events and PPSV23 vaccination in older adults.

Design, Setting, and Participants

This population-based cohort study using a self-controlled risk interval design used a large linked database created by linking the Korea Immunization Registry Information System and the National Health Information Database (2018 to 2021). Participants included patients aged 65 years or older with a history of PPSV23 vaccination and incident cardiovascular, neurological, or immunological events during the risk and control intervals. Data were analyzed from November 2022 to April 2023.

Exposure

23-valent pneumococcal polysaccharide vaccine.

Main Outcomes and Measures

The occurrence of 1 among 6 cardiovascular events (myocardial infarction, atrial fibrillation, cardiomyopathy, heart failure, hypotension, and myocarditis or pericarditis), 2 neurological events (Bell palsy and Guillain-Barré syndrome), and 3 immunological events (sepsis, thrombocytopenia, and anaphylaxis) during the risk and control periods. The risk and control intervals were defined as 1 to 28 and 57 to 112 days after PPSV23 vaccination, respectively. Conditional Poisson regression was used to estimate the incidence rate ratio (IRR) with a 95% CI.

Results

Altogether, 4355 of the 1 802 739 individuals who received PPSV23 vaccination and experienced at least 1 outcome event were included (mean [SD] age, 72.4 [8.2] years; 2272 male participants [52.1%]). For cardiovascular events, there were no significant associations for myocardial infarction (IRR, 0.96; 95% CI, 0.81-1.15), heart failure (IRR, 0.85; 95% CI, 0.70-1.04), and stroke (IRR, 0.92; 95% CI, 0.84-1.02). Similarly, no increased risks were observed for neurological and immunological outcomes: Bell palsy (IRR, 0.95; 95% CI, 0.72-1.26), Guillain-Barré syndrome (IRR, 0.27; 95% CI, 0.06-1.17), sepsis (IRR, 0.99; 95% CI, 0.74-1.32), and thrombocytopenia (IRR, 1.18; 95% CI, 0.60-2.35).

Conclusions and Relevance

In this self-controlled risk interval study, there was no appreciable increase in risk for most cardiovascular, neurological, or immunological adverse events following PPSV23. The updated safety profile of PPSV23 provides supportive evidence for the establishment of immunization strategies for older adults.

Chronic inflammatory demyelinating polyneuropathy after SARS-CoV2 vaccination: update of the literature and patient characterization

Since the beginning of worldwide vaccination against COVID-19 disease, some reports have revealed a possible relationship between SARS CoV2 vaccination and chronic inflammatory demyelinating polyneuropathy (CIDP). We reviewed the available evidences regarding this topic, adding three new cases to those reported so far, with the purpose to outline the characteristics of these post-vaccinal CIDP. Seventeen subjects were studied. A total of 70.6% of CIDP cases were related to viral vector vaccines, most occurring after the administration of the first dose. CIDPs that occurred after the second dose (17%) were temporally associated with mRNA vaccines. The clinical course and electrophysiology of all patients met the criteria for acute-subacute CIDP (A-CIDP). Administration of the viral vector vaccine was significantly correlated with a higher probability of having cranial nerve impairment (p = 0.004). The electrophysiological phenotype, laboratory and imaging data, and first-line therapies were substantially similar to those of the classical CIDP. The take-home message of the present paper is that the SARS CoV2 vaccine, especially the AstraZeneca vaccine, may be associated with inflammatory neuropathies with acute onset, often indistinguishable from Guillain-Barré syndrome (GBS). Hence, the importance of tracked prospectively patients with GBS occurred post-SARS-CoV2 vaccine. Distinguishing GBS from A-CIDP is crucial because treatment strategies and long-term prognosis are different.

Outcome of Neuromuscular Electrodiagnostic Testing in Children

This study aimed to describe the spectrum of the results of neuromuscular electrodiagnostic investigations performed by age and pathology in paediatric patients. This retrospective observational study took place from January 2019 to December 2021. Electrodiagnostic records of paediatric patients (birth to 15 years) were referred to the electromyography (EMG) laboratory for EMG and nerve conduction study (NCS). Electrodiagnostic and demographic data were collected. Among these, 151 (56%) were males and 118 (44%) were females. Forty-four percent tests came out to be normal and 151(56%) tests revealed electrophysiological abnormality. Peripheral nerve neuropathy (n = 39, 14.5%), polyneuropathy (n = 35, 13%) and myopathy (n = 28, 10%) were the most common electrophysiological diagnoses. The electrodiagnostic test helps in differentiating the aetiologies, thus guiding the subsequent work-up logically in the paediatric population. Key Words: Brachial plexus neuropathies, Electromyography, Duchene muscular dystrophy, Neuromuscular junction disorders, Nerve conduction studies, Acute inflammatory demyelinating polyneuropathy, Rehabilitation, Electromyography, Hereditary sensory motor polyneuropathy.

Complement-membrane regulatory proteins are absent from the nodes of Ranvier in the peripheral nervous system

BACKGROUND

Homozygous CD59-deficient patients manifest with recurrent peripheral neuropathy resembling Guillain-Barré syndrome (GBS), hemolytic anemia and recurrent strokes. Variable mutations in CD59 leading to loss of function have been described and, overall, 17/18 of patients with any mutation presented with recurrent GBS. Here we determine the localization and possible role of membrane-bound complement regulators, including CD59, in the peripheral nervous systems (PNS) of mice and humans.

METHODS

We examined the localization of membrane-bound complement regulators in the peripheral nerves of healthy humans and a CD59-deficient patient, as well as in wild-type (WT) and CD59a-deficient mice. Cross sections of teased sciatic nerves and myelinating dorsal root ganglia (DRG) neuron/Schwann cell cultures were examined by confocal and electron microscopy.

RESULTS

We demonstrate that CD59a-deficient mice display normal peripheral nerve morphology but develop myelin abnormalities in older age. They normally express myelin protein zero (P0), ankyrin G (AnkG), Caspr, dystroglycan, and neurofascin. Immunolabeling of WT nerves using antibodies to CD59 and myelin basic protein (MBP), P0, and AnkG revealed that CD59 was localized along the internode but was absent from the nodes of Ranvier. CD59 was also detected in blood vessels within the nerve. Finally, we show that the nodes of Ranvier lack other complement-membrane regulatory proteins, including CD46, CD55, CD35, and CR1-related gene-y (Crry), rendering this area highly exposed to complement attack.

CONCLUSION

The Nodes of Ranvier lack CD59 and are hence not protected from complement terminal attack. The myelin unit in human PNS is protected by CD59 and CD55, but not by CD46 or CD35. This renders the nodes and myelin in the PNS vulnerable to complement attack and demyelination in autoinflammatory Guillain-Barré syndrome, as seen in CD59 deficiency.

CANVAS-related RFC1 mutations in patients with immune-mediated neuropathy

Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) has recently been attributed to biallelic repeat expansions in RFC1. More recently, the disease entity has expanded to atypical phenotypes, including chronic neuropathy without cerebellar ataxia or vestibular areflexia. Very recently, RFC1 expansions were found in patients with Sjögren syndrome who had neuropathy that did not respond to immunotherapy. In this study RFC1 was examined in 240 patients with acute or chronic neuropathies, including 105 with Guillain-Barré syndrome or Miller Fisher syndrome, 76 with chronic inflammatory demyelinating polyneuropathy, and 59 with other types of chronic neuropathy. Biallelic RFC1 mutations were found in three patients with immune-mediated neuropathies, including Guillain-Barré syndrome, idiopathic sensory ataxic neuropathy, or anti-myelin-associated glycoprotein (MAG) neuropathy, who responded to immunotherapies. In addition, a patient with chronic sensory autonomic neuropathy had biallelic mutations, and subclinical changes in Schwann cells on nerve biopsy. In summary, we found CANVAS-related RFC1 mutations in patients with treatable immune-mediated neuropathy or demyelinating neuropathy.

Neurological disorders associated with COVID-19 in Sri Lanka

BACKGROUND

Neurological manifestations of SARS-CoV-2 infection have been reported from many countries around the world, including the South Asian region. This surveillance study aimed to describe the spectrum of neurological disorders associated with COVID-19 in Sri Lanka.

METHODS

COVID-19 patients manifesting neurological disorders one week prior and up to six weeks after infection were recruited from all the neurology centres of the government hospitals in Sri Lanka from May 2021 - May 2022. Data was collected using a structured data form that was electronically transmitted to a central repository. All patients were evaluated and managed by a neurologist. Data were analysed using simple descriptive analysis to characterise demographic and disease related variables, and simple comparisons and logistic regression were performed to analyse outcomes and their associations.

RESULTS

One hundred and eighty-four patients with neurological manifestations associated with COVID-19 were recruited from all nine provinces in Sri Lanka. Ischaemic stroke (31%) was the commonest neurological manifestation followed by encephalopathy (13.6%), Guillain-Barre syndrome (GBS) (9.2%) and encephalitis (7.6%). Ischaemic stroke, encephalitis and encephalopathy presented within 6 days of onset of COVID-19 symptoms, whereas GBS and myelitis presented up to 10 days post onset while epilepsy and Bell palsy presented up to 20 - 40 days post onset. Haemorrhagic stroke presented either just prior to or at onset, or 10 - 25 days post onset of COVID-19 symptomatic infection. An increased frequency of children presenting with encephalitis and encephalopathy was observed during the Omicron variant predominant period. A poor outcome (no recovery or death) was associated with supplemental oxygen requirement during admission (Odds Ratio: 12.94; p = 0.046).

CONCLUSIONS

The spectrum and frequencies of COVID-19 associated neurological disorders in Sri Lanka were similar to that reported from other countries, with strokes and encephalopathy being the commonest. Requiring supplemental oxygen during hospitalisation was associated with a poor outcome.

Pan-Neurofascin autoimmune nodopathy - a life-threatening, but reversible neuropathy

PURPOSE OF REVIEW

Autoimmune nodopathies are immune-mediated neuropathies associated with antibodies targeting the peripheral node of Ranvier. Recently, antibodies against all neurofascin-isoforms (pan-neurofascin) have been linked to a clinical phenotype distinct from previously described autoimmune nodopathies. Here, we aim at highlighting the molecular background and the red flags for diagnostic assessment and provide treatment and surveillance approaches for this new disease.

RECENT FINDINGS

Neurofascin-isoforms are located at different compartments of the node of Ranvier: Neurofascin-186 at the axonal nodal gap, and Neurofascin-155 at the terminal Schwann cell loops at the paranode. Pan-neurofascin antibodies recognize a common epitope on both isoforms and can access the node of Ranvier directly. Depending on their subclass profile, antibodies can induce direct structural disorganization and complement activation. Affected patients present with acute and immobilizing sensorimotor neuropathy, with cranial nerve involvement and long-term respiratory insufficiency. Early antibody-depleting therapy is crucial to avoid axonal damage, and remission is possible despite extended disease and high mortality. The antibody titer and serum neurofilament light chain levels can serve as biomarkers for diagnosis and therapy monitoring.

SUMMARY

Pan-neurofascin-associated autoimmune nodopathies has unique molecular and clinical features. Testing should be considered in severe and prolonged Guillain-Barré-like phenotype.

Updated consensus statement: Intravenous immunoglobulin in the treatment of neuromuscular disorders report of the AANEM ad hoc committee

Intravenous immune globulin (IVIG) is an immune-modulating biologic therapy that is increasingly being used in neuromuscular disorders despite the paucity of high-quality evidence for various specific diseases. To address this, the AANEM created the 2009 consensus statement to provide guidance on the use of IVIG in neuromuscular disorders. Since then, there have been several randomized controlled trials for IVIG, a new FDA-approved indication for dermatomyositis and a revised classification system for myositis, prompting the AANEM to convene an ad hoc panel to update the existing guidelines.New recommendations based on an updated systemic review of the literature were categorized as Class I-IV. Based on Class I evidence, IVIG is recommended in the treatment of chronic inflammatory demyelinating polyneuropathy, Guillain-Barré Syndrome (GBS) in adults, multifocal motor neuropathy, dermatomyositis, stiff-person syndrome and myasthenia gravis exacerbations but not stable disease. Based on Class II evidence, IVIG is also recommended for Lambert-Eaton myasthenic syndrome and pediatric GBS. In contrast, based on Class I evidence, IVIG is not recommended for inclusion body myositis, post-polio syndrome, IgM paraproteinemic neuropathy and small fiber neuropathy that is idiopathic or associated with tri-sulfated heparin disaccharide or fibroblast growth factor receptor-3 autoantibodies. Although only Class IV evidence exists for IVIG use in necrotizing autoimmune myopathy, it should be considered for anti-hydroxy-3-methyl-glutaryl-coenzyme A reductase myositis given the risk of long-term disability. Insufficient evidence exists for the use of IVIG in Miller-Fisher syndrome, IgG and IgA paraproteinemic neuropathy, autonomic neuropathy, chronic autoimmune neuropathy, polymyositis, idiopathic brachial plexopathy and diabetic lumbosacral radiculoplexopathy.

Post-authorization safety surveillance of Ad.26.COV2.S vaccine: Reports to the Vaccine Adverse Event Reporting System and v-safe, February 2021-February 2022

BACKGROUND

On 2/27/2021, FDA authorized Janssen COVID-19 Vaccine (Ad.26.COV2.S) for use in individuals 18 years of age and older. Vaccine safety was monitored using the Vaccine Adverse Event Reporting System (VAERS), a national passive surveillance system, and v-safe, a smartphone-based surveillance system.

METHODS

VAERS and v-safe data from 2/27/2021 to 2/28/2022 were analyzed. Descriptive analyses included sex, age, race/ethnicity, seriousness, AEs of special interest (AESIs), and cause of death. For prespecified AESIs, reporting rates were calculated using the total number of doses of Ad26.COV2.S administered. For myopericarditis, observed-to-expected (O/E) analysis was performed based on the number verified cases, vaccine administration data, and published background rates. Proportions of v-safe participants reporting local and systemic reactions, as well as health impacts, were calculated.

RESULTS

During the analytic period, 17,018,042 doses of Ad26.COV2.S were administered in the United States, and VAERS received 67,995 reports of AEs after Ad26.COV2.S vaccination. Most AEs (59,750; 87.9 %) were non-serious and were similar to those observed during clinical trials. Serious AEs included COVID-19 disease, coagulopathy (including thrombosis with thrombocytopenia syndrome; TTS), myocardial infarction, Bell's Palsy, and Guillain-Barré syndrome (GBS). Among AESIs, reporting rates per million doses of Ad26.COV2.S administered ranged from 0.06 for multisystem inflammatory syndrome in children to 263.43 for COVID-19 disease. O/E analysis revealed elevated reporting rate ratios (RRs) for myopericarditis; among adults ages 18-64 years, the RR was 3.19 (95 % CI 2.00, 4.83) within 7 days and 1.79 (95 % CI 1.26, 2.46) within 21 days of vaccination. Of 416,384 Ad26.COV2.S recipients enrolled into v-safe, 60.9 % reported local symptoms (e.g. injection site pain) and 75.9 % reported systemic symptoms (e.g., fatigue, headache). One-third of participants (141,334; 33.9 %) reported a health impact, but only 1.4 % sought medical care.

CONCLUSION

Our review confirmed previously established safety risks for TTS and GBS and identified a potential safety concern for myocarditis.

Immune-Mediated Neuropathies: Pathophysiology and Management

Dysfunction of the immune system can result in damage of the peripheral nervous system. The immunological mechanisms, which include macrophage infiltration, inflammation and proliferation of Schwann cells, result in variable degrees of demyelination and axonal degeneration. Aetiology is diverse and, in some cases, may be precipitated by infection. Various animal models have contributed and helped to elucidate the pathophysiological mechanisms in acute and chronic inflammatory polyradiculoneuropathies (Guillain-Barre Syndrome and chronic inflammatory demyelinating polyradiculoneuropathy, respectively). The presence of specific anti-glycoconjugate antibodies indicates an underlying process of molecular mimicry and sometimes assists in the classification of these disorders, which often merely supports the clinical diagnosis. Now, the electrophysiological presence of conduction blocks is another important factor in characterizing another subgroup of treatable motor neuropathies (multifocal motor neuropathy with conduction block), which is distinct from Lewis-Sumner syndrome (multifocal acquired demyelinating sensory and motor neuropathy) in its response to treatment modalities as well as electrophysiological features. Furthermore, paraneoplastic neuropathies are also immune-mediated and are the result of an immune reaction to tumour cells that express onconeural antigens and mimic molecules expressed on the surface of neurons. The detection of specific paraneoplastic antibodies often assists the clinician in the investigation of an underlying, sometimes specific, malignancy. This review aims to discuss the immunological and pathophysiological mechanisms that are thought to be crucial in the aetiology of dysimmune neuropathies as well as their individual electrophysiological characteristics, their laboratory features and existing treatment options. Here, we aim to present a balance of discussion from these diverse angles that may be helpful in categorizing disease and establishing prognosis.

Reliability and validity of prognostic indicators for Guillain-Barré syndrome in children

AIM

To explore the clinical characteristics and prognostic predictors of Guillain-Barré syndrome (GBS) in Chinese paediatric patients.

METHOD

The clinical features of children with GBS hospitalized in the Children's Hospital of Chongqing Medical University were summarized retrospectively. The correlation between the Erasmus GBS Outcome Score (EGOS)/modified Erasmus GBS Outcome Score (mEGOS), GBS disability score (GDS)/modified Rankin Scale (MRS), Erasmus GBS Respiratory Insufficiency Score (EGRIS), and mechanical ventilation were evaluated.

RESULTS

One hundred forty-two patients (86 males, 56 females; median 62.50 months [interquartile range 41.00-97.50]) with classic GBS were enrolled in the study. In the present GBS cohort, 134 (94.37%) patients could walk independently (GDS ≤2) and 121 (85.21%) could manage without assistance (MRS ≤2) at 6 months. Eighteen (12.68%) patients with GBS required mechanical ventilation. The performance of mEGOS on admission, mEGOS on day 7, and EGOS-predicted GDS outcome at 4 weeks, 3 months, and 6 months in the paediatric patients with GBS admitted within 2 weeks of disease onset and that of the MRS outcome were evaluated. The EGRIS in individuals who required mechanical ventilation was significantly higher than in patients without mechanical ventilation (median = 6 vs median = 3, p < 0.001).

INTERPRETATION

In Chinese paediatric patients with GBS who were admitted 2 weeks after disease onset, the mEGOS and EGOS are validated indicators for the prediction of clinical outcomes 6 months after onset. EGRIS is helpful in predicting the implementation of mechanical ventilation in the acute phase.

WHAT THIS PAPER ADDS

The Erasmus Guillain-Barré syndrome (GBS) Outcome Score (EGOS) and modified EGOS are reliable prognostic predictors in paediatric patients with GBS. The Erasmus GBS Respiratory Insufficiency Score (EGRIS) is an effective predictor of mechanical ventilation in paediatric patients with GBS. An EGRIS of ≥5 indicates a high risk of mechanical ventilation in the acute phase.

Long-Term Neurological, Behavioral, Functional, Quality of Life, and School Performance Outcomes in Children With Guillain-Barré Syndrome Admitted to PICU

BACKGROUND

Most children with Guillain-Barré syndrome (GBS) recover but may suffer from long-term sequelae, interfering with development and quality of life. Owing to the lack of published data, we aimed to assess the long-term neurological, behavioral, functional, quality of life, and school performance outcomes them.

METHODS

Design: Cross-sectional observational.

SETTING

Pediatric intensive care unit.

PATIENTS

Children, aged one to 12 years, with GBS admitted over five years (July 2012 to June 2017) were enrolled during one year (July 2017 to June 2018). These children were assessed for the following outcomes: neurological (Hughes disability score, Pediatric Cerebral Performance Category [PCPC], Pediatric Overall Performance Category [POPC], and Glasgow Outcome Scale-Extended Pediatric version [GOS-E Peds] scales), behavioral (Childhood Psychopathology Measurement Schedule [CPMS]), functional (Vineland Social Maturity Scale [VSMS]-Indian Adaptation), quality of life (Pediatric Quality of Life [PedsQL]), and school performance (Parent-Directed Questionnaire).

RESULTS

Eighty children were enrolled after a median of 3.0 (1.3-4.2) years from discharge. The majority (95%) had favorable neurological recovery (Hughes disability score 0 to 1). Favorable outcome was noted in 95% of children on PCPC, 87.5% on POPC, 60% on GOS-E Peds, 86.2% on CPMS, 92.5% on VSMS, and 98% on PedsQL. The majority (97.5%) of childre were attending schools, and 57.7% had satisfactory school performance. The presence of quadriparesis at admission, mechanical ventilation, tracheostomy requirement, poor ambulatory status at discharge, and longer pediatric intensive care unit and hospital stay predicted unfavorable neurological outcome on different tools. Absence of quadriparesis at admission and no requirement of mechanical ventilation predicted a favorable result on all outcome measures.

CONCLUSIONS

On long-term follow-up, most children with severe GBS showed favorable neurological, behavioral, functional, and quality of life outcomes. Severe clinical presentation and prolonged intensive care unit stay predict poor long-term outcome.

Serum anti-GM2 and anti-GalNAc-GD1a ganglioside IgG antibodies are biomarkers for immune-mediated polyneuropathies in cats

Recent work identified anti-GM2 and anti-GalNAc-GD1a IgG ganglioside antibodies as biomarkers in dogs clinically diagnosed with acute canine polyradiculoneuritis, in turn considered a canine equivalent of Guillain-Barré syndrome. This study aims to investigate the serum prevalence of similar antibodies in cats clinically diagnosed with immune-mediated polyneuropathies. The sera from 41 cats clinically diagnosed with immune-mediated polyneuropathies (IPN), 9 cats with other neurological or neuromuscular disorders (ONM) and 46 neurologically normal cats (CTRL) were examined for the presence of IgG antibodies against glycolipids GM1, GM2, GD1a, GD1b, GalNAc-GD1a, GA1, SGPG, LM1, galactocerebroside and sulphatide. A total of 29/41 IPN-cats had either anti-GM2 or anti-GalNAc-GD1a IgG antibodies, with 24/29 cats having both. Direct comparison of anti-GM2 (sensitivity: 70.7%; specificity: 78.2%) and anti-GalNAc-GD1a (sensitivity: 70.7%; specificity: 70.9%) antibodies narrowly showed anti-GM2 IgG antibodies to be the better marker for identifying IPN-cats when compared to the combined ONM and CTRL groups (P = .049). Anti-GA1 and/or anti-sulphatide IgG antibodies were ubiquitously present across all sample groups, whereas antibodies against GM1, GD1a, GD1b, SGPG, LM1 and galactocerebroside were overall only rarely observed. Anti-GM2 and anti-GalNAc-GD1a IgG antibodies may serve as serum biomarkers for immune-mediated polyneuropathies in cats, as previously observed in dogs and humans.

Guillain-Barré syndrome AMSAN variant in a 90-year-old woman after COVID-19: a case report

BACKGROUND

Guillain-Barré syndrome (GBS) is an inflammatory disease of the peripheral nervous system characterized by rapidly evolving polyneuropathy caused by autoimmune demyelination and/or axonal degeneration. Since SARS-CoV-2 outbreak, several GBS cases following exposure to coronavirus disease-2019 (COVID-19) have been reported in literature, raising the concern of the latter being a potential trigger event for GBS.

CASE PRESENTATION

We report the case of a 90-year-old Caucasian woman who was admitted to our hospital because of fatigue, worsening gait and leg strength, dysphonia, dysarthria and dysphagia, started 3 weeks after being exposed to COVID-19. Based on clinical presentation GBS was suspected, so she performed a lumbar puncture and electromyography, which confirmed the diagnosis of acute motor and sensory axonal neuropathy (AMSAN) variant. We administered high dose of intravenous immunoglobulin with slight neurological improvement. However, after 2 weeks of hospitalization with maximization of care, her physical condition worsen, manifesting severe frailty. The patient was discharged with home support services for managing parenteral nutrition and intense scheduled physiotherapy. A few days later, the patient experienced a further decline in her clinical condition and died at home.

CONCLUSIONS

To the best of our knowledge, we report the oldest woman with GBS AMSAN variant after COVID-19 described in the existing literature. Our case supports further research aimed at improving recognition, characterization and prompt management of neurological diseases related to COVID-19 in older patients.

Axolemmal nanoruptures arising from paranodal membrane injury induce secondary axon degeneration in murine Guillain-Barré syndrome

The major determinant of poor outcome in Guillain-Barré syndrome (GBS) is axonal degeneration. Pathways leading to primary axonal injury in the motor axonal variant are well established, whereas mechanisms of secondary axonal injury in acute inflammatory demyelinating polyneuropathy (AIDP) are unknown. We recently developed an autoantibody-and complement-mediated model of murine AIDP, in which prominent injury to glial membranes at the node of Ranvier results in severe disruption to paranodal components. Acutely, axonal integrity was maintained, but over time secondary axonal degeneration occurred. Herein, we describe the differential mechanisms underlying acute glial membrane injury and secondary axonal injury in this model. Ex vivo nerve-muscle explants were injured for either acute or extended periods with an autoantibody-and complement-mediated injury to glial paranodal membranes. This model was used to test several possible mechanisms of axon degeneration including calpain activation, and to monitor live axonal calcium signalling. Glial calpains induced acute disruption of paranodal membrane proteins in the absence of discernible axonal injury. Over time, we observed progressive axonal degeneration which was markedly attenuated by axon-specific calpain inhibition. Injury was unaffected by all other tested methods of protection. Trans-axolemmal diffusion of fluorescent proteins  and live calcium imaging studies indirectly demonstrated the presence of nanoruptures in the axon membrane. This study outlines one mechanism by which secondary axonal degeneration arises in the AIDP variant of GBS where acute paranodal loop injury is prominent. The data also support the development of calpain inhibitors to attenuate both primary and secondary axonal degeneration in GBS.

The endogenous calpain inhibitor calpastatin attenuates axon degeneration in murine Guillain-Barré syndrome

Axon degeneration accounts for the poor clinical outcome in Guillain-Barré syndrome (GBS), yet no treatments target this key pathogenic stage. Animal models demonstrate anti-ganglioside antibodies (AGAb) induce axolemmal complement pore formation through which calcium flux activates the intra-axonal calcium-dependent proteases, calpains. We previously showed protection of axonal components using soluble calpain inhibitors in ex vivo GBS mouse models, and herein, we assess the potential of axonally-restricted calpain inhibition as a neuroprotective therapy operating in vivo. Using transgenic mice that over-express the endogenous human calpain inhibitor calpastatin (hCAST) neuronally, we assessed distal motor nerve integrity in our established GBS models. We induced immune-mediated injury with monoclonal AGAb plus a source of human complement. The calpain substrates neurofilament and AnkyrinG, nerve structural proteins, were assessed by immunolabelling and in the case of neurofilament, by single-molecule arrays (Simoa). As the distal intramuscular portion of the phrenic nerve is prominently targeted in our in vivo model, respiratory function was assessed by whole-body plethysmography as the functional output in the acute and extended models. hCAST expression protects distal nerve structural integrity both ex and in vivo, as shown by attenuation of neurofilament breakdown by immunolabelling and Simoa. In an extended in vivo model, while mice still initially undergo respiratory distress owing to acute conduction failure, the recovery phase was accelerated by hCAST expression. Axonal calpain inhibition can protect the axonal integrity of the nerve in an in vivo GBS paradigm and hasten recovery. These studies reinforce the strong justification for developing further animal and human clinical studies using exogenous calpain inhibitors.

What Is Guillain-Barré Syndrome?

This JAMA Patient Page describes the autoimmune disease Guillain-Barré syndrome and its risk factors, diagnosis, treatment, and prognosis.

Advanced thallium toxicity

Thallium is a highly toxic tasteless, odourless and water-soluble metal that can be absorbed through the skin, inhaled or ingested. Due to the rarity of thallium toxicity, it is frequently misdiagnosed or the diagnosis is delayed. We report a 41-year-old male landscaper admitted for acute polyneuropathy and abdominal pain. He was treated for suspected Guillain-Barré syndrome and later autoimmune encephalopathy. However, over the next 42 days, he developed worsening muscle weakness, delirium and alopecia, and was diagnosed with thallium toxicity. After combining Prussian blue, activated charcoal and continuous venovenous haemofiltration, he improved though with neuropsychiatric and neuromuscular sequelae. We highlight the need to manage information disclosure properly and to preserve evidence, when the source of a toxin is unclear.

Paralytic ileus as first symptom of Miller Fisher syndrome: A case report

INTRODUCTION

Miller Fisher syndrome (MFS), regarded by many scholars as a variant of Guillain Barre syndrome (GBS), accounts for approximately 5% to 10% of GBS cases. The typical clinical manifestations of MFS are extraocular muscle paralysis, ataxia, and tendon reflex loss or disappearance. To date, intestinal obstruction has rarely been reported as the initial symptom.

PATIENT CONCERNS

A 48-year-old woman presenting with abdominal pain and distention was diagnosed with paralytic ileus. There was no significant improvement in symptoms after symptomatic treatment. After that, the patient developed visual rotation, with limited binocular abduction and adduction, and ataxia. Anti-ganglioside testing revealed positive anti-ganglioside antibodies.

DIAGNOSIS

The patient was diagnosed as MFS.

INTERVENTIONS

The early stage is mainly symptomatic treatment of paralytic ileus. After MFS was diagnosed, the patient was given large amounts of immunoglobulin and hormone shock therapy.

OUTCOMES

After 1 week, the symptoms of intestinal obstruction and MFS gradually improved. The patient was later discharged automatically for financial reasons. Six months after discharge, the patient was interviewed by telephone, and she had recovered.

CONCLUSION

To date, intestinal obstruction has rarely been reported as the initial symptom. In case of inconsistencies between the imaging examinations and clinical symptoms, neuroelectrophysiology and cerebrospinal fluid puncture should be performed, striving for timely detection and treatment.

Acute cerebellitis, transverse myelitis and polyradiculoneuritis related to post-COVID-19 infection

CONTEXT

Guillain-Barré syndrome (GBS), acute cerebellitis and transverse myelitis are rare complications of COVID-19 infection separately. The combination of these three, however, has not yet been reported.

FINDINGS

We present an atypical case (42-year-old man) that developed acute ascending flaccid paraparesis, ataxia and urinary retention two weeks after COVID-19 infection. Neurological examination revealed distal and proximal weakness (4/5) on lower extremities, decreased tendon reflexes, sixth cranial nerve palsy and dysmetria without sensory disturbance. His cranial MRI showed cerebellitis whereas the spinal MRI showed transverse myelitis at the T11/12 level. Albuminocytologic dissociation was present in the cerebrospinal fluid. The nerve conduction study was concordant with early findings of GBS. He recovered well after corticosteroid treatment without needing any immunotherapy. On day seven of hospitalization, the modified Rankin Scale score was 0.

CONCLUSION

COVID-19 infection may present with a combination of neurological manifestations such as cerebellitis, transverse myelitis and GBS. This patient presented significant functional recovery after treatment with corticosteroid without immunotherapy.

Real time imaging of intra-axonal calcium flux in an explant mouse model of axonal Guillain-Barré syndrome

The acute motor axonal variant of Guillain-Barré syndrome is associated with the attack of motor axons by anti-ganglioside antibodies which activate complement on the axonal plasma membrane. Animal models have indirectly implicated complement pore-mediated calcium influx as a trigger of axonal damage, through the activation of the protease calpain. However, this calcium influx has never been imaged directly. Herein we describe a method to detect changes in intra-axonal calcium in an ex vivo mouse model of axonal Guillain-Barré syndrome and describe the influence of calcium on axonal injury and the effects of calpain inhibition on axonal outcome. Using ex vivo nerve-muscle explants from Thy1-TNXXL mice which axonally express a genetically encoded calcium indicator, we studied the effect of the binding and activation of complement by an anti-GD1b ganglioside antibody which targets the motor axon. Using live multiphoton imaging, we found that a wave of calcium influx extends retrogradely from the motor nerve terminal as far back as the large bundles within the muscle explant. Despite terminal complement pores being detectable only at the motor nerve terminal and, to a lesser degree, the most distal node of Ranvier, disruption of axonal proteins occurred at more proximal sites implicating the intra-axonal calcium wave. Morphological analysis indicated two different types of calcium-induced changes: acutely, distal axons showed swelling and breakdown at sites where complement pores were present. Distally, in areas of raised calcium which lacked detectable complement pores, axons developed a spindly, vacuolated appearance suggestive of early signs of degeneration. All morphological changes were prevented with treatment with a calpain inhibitor. This is the first investigation of axonal calcium dynamics in a mouse model of Guillain-Barré syndrome and demonstrates the proximal reach of calcium influx following an injury which is confined to the most distal parts of the motor axon. We also demonstrate that calpain inhibition remains a promising candidate for both acute and sub-acute consequences of calcium-induced calpain activation.

Axonal pathology in early stages of Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome (GBS) is an acute-onset, immune-mediated disease of the peripheral nervous system. It may be classified into 2 main subtypes: demyelinating (AIDP) and axonal (AMAN). This study aims to analyse the mechanisms of axonal damage in the early stages of GBS (within 10days of onset).

DEVELOPMENT

We analysed histological, electrophysiological, and imaging findings from patients with AIDP and AMAN, and compared them to those of an animal model of myelin P2 protein-induced experimental allergic neuritis. Inflammatory oedema of the spinal nerve roots and spinal nerves is the initial lesion in GBS. The spinal nerves of patients with fatal AIDP may show ischaemic lesions in the endoneurium, which suggests that endoneurial inflammation may increase endoneurial fluid pressure, reducing transperineurial blood flow, potentially leading to conduction failure and eventually to axonal degeneration. In patients with AMAN associated with anti-ganglioside antibodies, nerve conduction block secondary to nodal sodium channel dysfunction may affect the proximal, intermediate, and distal nerve trunks. In addition to the mechanisms involved in AIDP, active axonal degeneration in AMAN may be associated with nodal axolemma disruption caused by anti-ganglioside antibodies.

CONCLUSION

Inflammatory oedema of the proximal nerve trunks can be observed in early stages of GBS, and it may cause nerve conduction failure and active axonal degeneration.

Th1/Th17-mediated Immunity and Protection from Peripheral Neuropathy in Wildtype and IL10-/- BALB/c Mice Infected with a Guillain-Barré Syndrome-associated Campylobacter jejuni Strain

Campylobacter jejuni is an important cause of bacterial gastroenteritis worldwide and is linked to Guillain-Barré syndrome (GBS), a debilitating postinfectious polyneuropathy. The immunopathogenesis of GBS involves the generation of antibodies that are cross reactive to C. jejuni lipooligosaccharide and structurally similar peripheral nerve gangliosides. Both the C. jejuni infecting strain and host factors contribute to GBS development. GBS pathogenesis is associated with Th2-mediated responses in patients. Moreover, induction of IgG1 antiganglioside antibodies in association with colonic Th2-mediated immune responses has been reported in C. jejuni-infected C57BL/6 IL10-/- mice at 4 to 6 wk after infection. We hypothesized that, due to their Th2 immunologic bias, BALB/c mice would develop autoantibodies and signs of peripheral neuropathy after infection with a GBS patient-derived strain of C. jejuni (strain 260.94). WT and IL10-/- BALB/c mice were orally inoculated with C. jejuni 260.94, phenotyped weekly for neurologic deficits, and euthanized after 5 wk. Immune responses were assessed as C. jejuni-specific and antiganglioside antibodies in plasma and cytokine production and histologic lesions in the proximal colon. Peripheral nerve lesions were assessed in dorsal root ganglia and their afferent nerve fibers by scoring immunohistochemically labeled macrophages through morphometry. C. jejuni 260.94 stably colonized both WT and IL10-/- mice and induced systemic Th1/Th17-mediated immune responses with significant increases in C. jejuni-specific IgG2a, IgG2b, and IgG3 plasma antibodies. However, C. jejuni 260.94 did not induce IgG1 antiganglioside antibodies, colitis, or neurologic deficits or peripheral nerve lesions in WT or IL10-/- mice. Both WT and IL10-/- BALB/c mice showed relative protection from development of Th2-mediated immunity and antiganglioside antibodies as compared with C57BL/6 IL10-/- mice. Therefore, BALB/c mice infected with C. jejuni 260.94 are not an effective disease model but provide the opportunity to study the role of immune mechanisms and host genetic background in the susceptibility to post infectious GBS.

Louis Duménil (1823-1890), surgeon and pioneer in neurology

Louis-Stanislas Duménil (1823-1890) was a surgeon from Normandy who was a contemporary of Jean-Martin Charcot (1825-1893). Throughout his career, Duménil published annotated observations of neurological pathologies. One year before Guillaume Duchenne de Boulogne (1806-1875), he reported a case of "progressive muscular paralysis of the tongue, soft palate, and lips". He added five other cases of progressive muscular atrophy in 1867, together with histological examinations which showed atrophy in the anterior horns of the spinal cord. Charcot, who described amyotrophic lateral sclerosis, did not fail to pay homage to Duménil for his contribution. In 1862, Duménil added clinical observations of progressive locomotor ataxia, one of the first to do so. This included anatomopathological examinations, thus significantly completing the clinical picture presented by Duchenne in 1858. He confirmed the damage to the roots and posterior tracts of the spinal cord. Finally, by providing multiple observations of the syndrome described by Octave Landry (1826-1865) in 1859, he contributed to the clinical picture of "acute ascending paralysis" which has come down to us as Guillain-Barré syndrome, with no mention of the perspicacious physicians of the previous century who had already perfectly recognised this disease. Finally, Augusta Dejerine-Klumpke (1859-1927) paid a warm tribute to Duménil in her 1889 thesis, calling him one of the pioneers in understanding "the individuality and autonomy of the peripheral nervous system." He was indeed a pioneer, although he has been often overlooked.

Case Report: Guillain-Barré Syndrome Characterized by Severe Headache Associated With Metabotropic Glutamate Receptor 5 Antibody

Autoantibodies to metabotropic glutamate receptor 5 (mGluR5) are known to be the cause of autoimmune encephalitis, particularly limbic encephalitis, closely related to Hodgkin’s lymphoma (HL). The involvement of peripheral neuropathy is rarely reported. In our case, mGluR5 antibody was found in a Guillain-Barré syndrome (GBS) patient accompanied by severe headache but without neuropsychiatric manifestations or HL. Presenting with severe headache, the patient developed progressive bilateral limb weakness, areflexia, and cranial nerve involvement consisting of eye movement disorder, restricted mouth opening and chewing, bilateral facial paralysis and bulbar palsy. Cerebrospinal fluid (CSF) revealed elevated CSF protein level and normal cell count, known as “albumino-cytological dissociation”. Oligoclonal IgG bands were found in both the CSF and serum. Electrophysiological studies revealed symmetrical sensory and motor neuropathy with a mixture of axonal and demyelinating features. Brain and spinal cord magnetic resonance imaging (MRI), as well as the electroencephalogram, were normal. The mGluR5 antibody was positive in both serum and CSF with a Cell-Based Assay (CBA). The patient responded well to intravenous gammaglobulin therapy, correlated with a reduction of mGluR5 antibody titer from 1:30 to 1:10 in the serum. After 6 months, the patient recovered completely without any sign of recurrence or neoplasm. This first case of mGluR5 antibody-associated GBS accompanied by severe headache shows that mGluR5-associated disorders are not limited to manifestations of limbic encephalitis and HL.

Motor neuron, peripheral nerve, and neuromuscular junction disorders

In amyotrophic lateral sclerosis (ALS), Guillain-Barré syndrome (GBS), and neuromuscular junction disorders, three mechanisms may lead, singly or together, to respiratory emergencies and increase the disease burden and mortality: (i) reduced strength of diaphragm and accessory muscles; (ii) oropharyngeal dysfunction with possible aspiration of saliva/bronchial secretions/drink/food; and (iii) inefficient cough due to weakness of abdominal muscles. Breathing deficits may occur at onset or more often along the chronic course of the disease. Symptoms and signs are dyspnea on minor exertion, orthopnea, nocturnal awakenings, excessive daytime sleepiness, fatigue, morning headache, poor concentration, and difficulty in clearing bronchial secretions. The "20/30/40 rule" has been proposed to early identify GBS patients at risk for respiratory failure. The mechanical in-exsufflator is a device that assists ALS patients in clearing bronchial secretions. Noninvasive ventilation is a safe and helpful support, especially in ALS, but has some contraindications. Myasthenic crisis is a clinical challenge and is associated with substantial morbidity including prolonged mechanical ventilation and 5%-12% mortality. Emergency room physicians and consultant pulmonologists and neurologists must know such respiratory risks, be able to recognize early signs, and treat properly.

[RAPIDLY PROGRESSING PARAPARESIS AND LOSS OF SENSATION BELOW T10 DURING NEOADJUVANT CHEMOTHERAPY FOR BREAST CANCER]

A 35 years old woman was diagnosed with clinical stage 2, grade 3, hormone receptor positive, human epidermal growth factor receptor 2 (HER2) negative invasive ductal carcinoma, with ki-67 of 60%. She was treated with neoadjuvant chemotherapy with dose dense adriamycin and cyclophosphamide followed by paclitaxel. Six days following the third cycle of paclitaxel the patient presented with rapidly progressive weakness, proximal paresthesia and decreased sensation in both legs. Physical examination revealed hypoesthesia below level, proximal and distal weakness in both lower limbs and absence of reflexes. MRI of the spine demonstrated diffuse leptomeningeal enhancement from T11 to S1 including the cauda equina roots. The rapidly progressive neurological symptoms and the MRI findings were initially interpreted as leptomeningeal spread. High dose dexamethasone was promptly initiated and the patient was urgently planned for radiotherapy and received the first fraction of 3 Gy to level T11-S1. Further workup included lumbar puncture which showed elevated protein level (350 mg/dL), negative cytology for malignancy and EMG which demonstrated demyelinating injury compatible with Guillain-Barre syndrome (GBS). A diagnosis of GBS was made and treatment with intravenous immunoglobulins (IVIG) was initiated, followed by a gradual clinical improvement. Two months after the initial diagnosis, she had a near complete resolution of her neurological deficits. This case illustrates both the tendency to ascribe new symptoms and clinical findings in cancer patients to progressive disease, and the importance of keeping a wide differential diagnosis for non-cancer etiologies when treating our patients.