Neural Antibody Testing for Autoimmune Encephalitis: A Canadian Single-Centre Experience.

Neural antibodies have emerged as useful biomarkers in suspected autoimmune encephalitis. We reviewed results of neural antibody testing (anti-N-methyl D-aspartate receptor (NMDAR), leucine-rich glioma-inactivated protein (LGI1), contactin-associated protein-like 2 (CASPR2), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), γ-aminobutyric acid type B receptor (GABA(B)R), dipeptidyl-peptidase-like protein-6 (DPPX), IgLON family member 5 (IgLON5) and glutamic acid decarboxylase-65 (GAD65)) using cell-based assays (CBAs) and tissue indirect immunofluorescence (TIIF) at our centre. Our findings suggest increased clinical sensitivity of CBA compared to TIIF. However, this may come at some expense to clinical specificity, as evidenced by possible false-positive results when weak serum positivity by CBA was observed for certain antibodies (i.e. anti-NMDAR, CASPR2). In such cases, correlation with serum TIIF, as well as CSF CBA and TIIF, aids in identifying true-positive results.

Provincial Differences in the Diagnosis and Care of Amyotrophic Lateral Sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease resulting in muscle weakness, dysarthria and dysphagia, and ultimately respiratory failure leading to death. Half of the ALS patients survive less than 3 years, and 80% of the patients survive less than 5 years. Riluzole is the only approved medication in Canada with randomized controlled clinical trial evidence to slow the progression of ALS, albeit only to a modest degree. The Canadian Neuromuscular Disease Registry (CNDR) collects data on over 140 different neuromuscular diseases including ALS across ten academic institutions and 28 clinics including ten multidisciplinary ALS clinics. METHODS: In this study, CNDR registry data were analyzed to examine potential differences in ALS care among provinces in time to diagnosis, riluzole and feeding tube use. RESULTS: Significant differences were found among provinces, in time to diagnosis from symptom onset, in the use of riluzole and in feeding tube use. CONCLUSIONS: Future investigations should be undertaken to identify factors contributing to such differences, and to propose potential interventions to address the provincial differences reported.

Use of Geospatial Modeling to Evaluate the Impact of Telestroke on Access to Stroke Thrombolysis in Ontario.

BACKGROUND: The treatment of acute ischemic stroke in Ontario is coordinated through a network of stroke centers, supplemented by emergency telemedicine consultations to nonstroke centers through the Ontario Telemedicine Network's province-wide Telestroke program. Using geoinformatics, we sought to evaluate the overall impact of Telestroke on access to stroke thrombolysis in Ontario. METHODS: Ontario population data (census) were used to overlay polygons created by Service Area Analysis using ArcGIS 10.1. Service areas were divided into predefined driving times toward the nearest stroke center. Centers were compared after they were categorized as being able to administer stroke thrombolysis either independently or through the Telestroke program. RESULTS: Of the 12,857,821 people living in Ontario in 2011, 99.83% had timely access to stroke thrombolysis, leaving 21,829 people, exclusively within Northern Ontario, without access. Of the population, 71.86% was within a 30-minute drive of a regional or district stroke center, increasing to 91.28% when the Telestroke program was included, for an additional 2,501,121 people. Of the population, 1.85% had access to stroke thrombolysis only through the extended time window (between 3 and 4.5 hours), increasing to 3.86% with Telestroke, for an additional 258,618 people. CONCLUSION: The vast majority of people in Ontario have access to stroke thrombolysis. The provincial Telestroke program improves timeliness of access for those living in Southern Ontario, although some remote rural and Northern communities remain without access. Geoinformatics may likewise prove useful in coordinating provincial access to endovascular thrombectomy.

Meningo-cortical manifestations of myelin oligodendrocyte glycoprotein antibody-associated disease: Review of a novel clinico-radiographic spectrum.

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an inflammatory demyelinating disease that is distinct from multiple sclerosis. Initial manifestations of MOGAD that were reported in the literature included optic neuritis, myelitis, brainstem demyelination and encephalitis, with emphasis placed on acute disseminated encephalomyelitis (ADEM) as the primary encephalitic presentation. In 2017, however, Ogawa et al. described four patients with seizures, unilateral cortical hyperintensities on brain magnetic resonance imaging T2-fluid-attenuated inversion recovery sequences, and anti-MOG positivity, indicating a potentially novel form of encephalitis in MOGAD. In 2019, we systematically reviewed the literature to better characterize this unique syndrome, which we referred to as unilateral cortical FLAIR-hyperintense Lesions in Anti-MOG-associated Encephalitis with Seizures (FLAMES). Subsequently, anti-MOG positivity in patients with a variety of cortical and meningeal disease presentations has been reported, indicating a broader spectrum of meningo-cortical manifestations in MOGAD that we review herein.

Comparison of fixed cell-based assay to radioimmunoprecipitation assay for acetylcholine receptor antibody detection in myasthenia gravis.

OBJECTIVE: To compare specificity and sensitivity of a commercially available fixed cell-based assay (F-CBA) to radioimmunoprecipitation assay (RIPA) for acetylcholine receptor antibody (anti-AChR) detection in myasthenia gravis (MG). METHODS: In this retrospective diagnostic cohort study we reviewed the clinical information of suspected MG patients evaluated at the London Health Sciences Centre MG clinic who had anti-AChR RIPA and then F-CBA performed, in order to classify them as MG or non-MG. Classification of each patient as anti-AChR F-CBA-negative/positive, RIPA-negative/positive, and MG/non-MG permitted specificity and sensitivity calculations for each assay. RESULTS: Six-hundred-eighteen patients were included in study analysis. The median patient age at time of sample collection was 45.8 years (range: 7.5-87.5 years) and 312/618 (50.5%) were female. Of 618 patients, 395 (63.9%) were classified as MG. Specificity of both F-CBA and RIPA was excellent (99.6% vs. 100%, P > 0.99). One F-CBA-positive patient was classified as non-MG, although in retrospect ocular MG with functional overlay was challenging to exclude. Sensitivity of F-CBA was significantly higher than RIPA (76.7% vs. 72.7%, P = 0.002). Overall, 20/97 (21%) otherwise seronegative MG (SNMG) patients after RIPA evaluation had anti-AChR detected by F-CBA. CONCLUSIONS: In our study anti-AChR F-CBA and RIPA both had excellent specificity, while F-CBA had 4% higher sensitivity for MG and detected anti-AChR in 21% of SNMG patients. Our findings indicate that F-CBA is a viable alternative to RIPA for anti-AChR detection. Prospective studies comparing F-CBA, RIPA and L-CBA are needed to determine optimal anti-AChR testing algorithms in MG.

Breached Barriers: A Scoping Review of Blood-Central Nervous System Barrier Pathology in Amyotrophic Lateral Sclerosis.

Introduction: Recent studies have implicated changes in the blood-central nervous system barriers (BCNSB) in amyotrophic lateral sclerosis (ALS). The objective of this scoping review is to synthesize the current evidence for BCNSB structure and functional abnormalities in ALS studies and propose how BCNSB pathology may impact therapeutic development. Methods: A literature search was conducted using Ovid Medline, EMBASE, and Web of Science, from inception to November 2021 and limited to entries in English language. Simplified search strategy included the terms ALS/motor neuron disease and [BCNSB or blood-brain barrier (BBB) or blood-spinal cord barrier (BSCB)]. Henceforth, BCNSB is used as a term that is inclusive of the BBB and BSCB. Four independent reviewers conducted a title and abstract screening, hand-searched the reference lists of review papers, and performed a full text review of eligible studies. Included studies were original peer-reviewed full text publications, evaluating the structure and function of the BCNSB in preclinical models of ALS, clinical ALS, or postmortem human ALS tissue. There was no restriction on study design. The four reviewers independently extracted the data. Results: The search retrieved 2,221 non-duplicated articles and 48 original studies were included in the synthesis. There was evidence that the integrity of the BCNSB is disrupted throughout the course of the disease in rodent models, beginning prior to symptom onset and detectable neurodegeneration. Increased permeability, pharmacoresistance with upregulated efflux transporters, and morphological changes in the supporting cells of the BCNSB, including pericytes, astrocytes, and endothelial cells were observed in animal models. BCNSB abnormalities were also demonstrated in postmortem studies of ALS patients. Therapeutic interventions targeting BCNSB dysfunction were associated with improved motor neuron survival in animal models of ALS. Conclusion: BCNSB structural and functional abnormalities are likely implicated in ALS pathophysiology and may occur upstream to neurodegeneration. Promising therapeutic strategies targeting BCNSB dysfunction have been tested in animals and can be translated into ALS clinical trials.

Taking pause: Drawing from the history of neurology during COVID-19.

This narrative account uses a moment of patient care to connect multiple influences on my training as a resident during the COVID-19 pandemic. Seemingly unrelated, my newly found interest in the history of neurology, my patient, and the new dynamics of hospital care have made me become a better physician through this reflective piece.

Classically Described, Paradoxically Underrecognized: A Case of Proximal Weakness, Hyporeflexia/Areflexia, and Dysautonomia.

ABSTRACT: We present a case of chronic, progressive proximal weakness with dysautonomia and hyporeflexia/areflexia ultimately diagnosed with Lambert-Eaton myasthenic syndrome. An approach to neuroanatomical localization is discussed leading to the appropriate selection of electrodiagnostic studies. The electrophysiologic triad of Lambert-Eaton myasthenic syndrome is demonstrated with diffusely reduced motor amplitudes, decrement with low-frequency repetitive nerve stimulation, and increment of motor amplitudes after maximum voluntary contraction. Subsequent serologic testing for P/Q-type voltage-gated calcium channel antibodies are markedly elevated. We highlight the clinical features and pitfalls of examining a patient with Lambert-Eaton myasthenic syndrome when suspecting this challenging diagnosis. The neurophysiological underpinning of the electrodiagnostic results is explained, and the diagnostic utility of single-fiber electromyography is briefly discussed.

The Utility of the Laboratory Work Up at the Time of Diagnosis of Amyotrophic Lateral Sclerosis.

BACKGROUND: Serological testing is routinely performed in the work up for a diagnosis of Amyotrophic Lateral Sclerosis (ALS) to exclude pathologies with similar clinical phenotypes. OBJECTIVE: To determine the proportion of serological workup that changes the primary diagnosis and/or clinical management for patients presenting with signs of ALS. METHODS: A retrospective chart review was conducted on patients from the Calgary Neuromuscular Intake Clinic in which the neurologist working diagnosis post-assessment is ALS. Charts from 2012 to 2016 with completed standard serological workup were reviewed. The proportion of abnormal results per investigation was determined and whether it resulted in a change in diagnosis and/or clinical management. RESULTS: A total of 276 charts were reviewed and 85 met full inclusion criteria. Serum creatine kinase (35%), vitamin B12 (18%), complete blood count with differential (11%), and parathyroid hormone (10%) were the among the investigations that had a proportion of abnormal results greater than 5%. Only 6% of patients had an abnormal result that qualified for a change in their clinical management none of which changed the primary diagnosis of ALS. CONCLUSIONS: Standard serological investigations in the work-up for a patient with ALS may have low utility from a diagnostic and management perspective.