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Hereditary transthyretin-mediated (hATTR) amyloidosis is a progressive disease caused by mutations in the TTR gene leading to multisystem organ dysfunction. Pathogenic TTR aggregation, misfolding, and fibrillization lead to deposition of amyloid in multiple body organs and frequently involve the peripheral nerve system and the heart. Common neurologic manifestations include: sensorimotor polyneuropathy (PN), autonomic neuropathy, small-fiber PN, and carpal tunnel syndrome. Many patients have significant progression due to diagnostic delays as hATTR PN is not considered within the differential diagnosis. Recently, two effective novel disease-modifying therapies, inotersen and patisiran, were approved by Health Canada for the treatment of hATTR PN. Early diagnosis is crucial for the timely introduction of these disease-modifying treatments that reduce impairments, improve quality of life, and extend survival. In this guideline, we aim to improve awareness and outcomes of hATTR PN by making recommendations directed to the diagnosis, monitoring, and treatment in Canada.Lignes directrices sur la prise en charge de l’amylose héréditaire à transthyrétine, accompagnée de polyneuropathie, au Canada.L’amylose héréditaire à transthyrétine (ATTRh) est une maladie évolutive, causée par des mutations du gène de la transthyrétine (TTR), qui entraînent un dysfonctionnement plurisystémique. L’agrégation, le mauvais repliement et la fibrillisation pathogènes de la TTR aboutissent au dépôt de protéines amyloïdes dans plusieurs organes, et affectent souvent le système nerveux périphérique et le cœur. Les troubles neurologiques fréquents comprennent une polyneuropathie sensorimotrice (PN), une neuropathie autonome, une polyneuropathie des petites fibres et le syndrome du canal carpien. Chez bon nombre de patients, la maladie a connu une évolution importante en raison de la pose tardive du diagnostic, la PN-ATTRh ne faisant pas l’objet d’un diagnostic différentiel. Santé Canada a approuvé, depuis peu, deux nouveaux médicaments modificateurs de la PN-ATTRh et efficaces contre l’affection, soit l’inotersen et le patisiran. La pose précoce du diagnostic revêt une importance cruciale dans l’instauration, en temps opportun, de ces tout nouveaux traitements qui atténuent les troubles, améliorent la qualité de vie et prolongent la survie. Les auteurs, par l’élaboration de la nouvelle ligne directrice, espèrent sensibiliser la communauté médicale à la PN-ATTRh, et améliorer les résultats cliniques qui y sont associés, en formulant des recommandations sur le diagnostic et le traitement de la maladie au Canada ainsi que sur la surveillance de son évolution.

Background: Myasthenia gravis (MG) is an autoimmune disorder that frequently affects young women of reproductive age. The multidirectional interplay between MG, pregnancy, and fetal health poses a complex scenario for pregnant women with MG and the healthcare team. Here, we reviewed our local experience with MG, pregnancy, and outcomes. Methods: We performed a retrospective chart review of patients with MG attending the Prosserman Family Neuromuscular Clinic from 2001 to 2019 and who were referred to a high-risk pregnancy clinic. MG status was defined as stable, better, or worse. Information was collected on the delivery route, pregnancy, and neonatal complications. Results: We identified 20 women with MG for a total of 28 pregnancies. Worsening was observed in 50% of pregnancies: 18% during pregnancy, 25% following delivery, and 7% during both. 66.7% of patients with MG duration of 2 years or less had worsening during pregnancy. Three patients who stopped immunosuppressive treatment during pregnancy worsened and one had a crisis. C-section was done in 29% of pregnancies. The rate of delivery complications was 7% and of neonatal MG was 7%. Conclusion: A high proportion of MG patients worsened during pregnancy, particularly those with disease duration less than 2 years, and those who discontinued immunosuppression during pregnancy. However, pregnancy was largely unaffected, rate of neonatal MG was low, frequencies of C-section, delivery complications, and premature births were similar to the general population. While the study has limitations due to the retrospective nature, these insights provide some guidance when counseling young myasthenic women about family planning.

There is an urgent need for new therapeutic options to treat muscle cramps; however, no patient-reported measures exist that capture the entire cramp experience. We conducted a qualitative study to assess the experience of patients suffering muscle cramps, aiming to understand what factors determine the impact cramps have in patients' lives to guide the development of a patient-centered outcome measure of cramp severity and impact.We enrolled patients with cramps due to several etiologies, including motor neuron disease, pregnancy-induced cramps, cirrhosis and hemodialysis, and idiopathic and exercise-induced cramps. Patients participated in semistructured interviews about their experiences with muscle cramps and their responses were recorded and transcribed. Data were analyzed with content analysis using data saturation to determine the sample size. We subsequently developed a conceptual framework of cramp severity and overall cramp impact.Ten patients were interviewed when data saturation was reached. The cramp experience was similar across disease and physiological states known to cause muscle cramps. The main themes that compose the overall cramp impact are cramp characteristics, sleep interference, daytime activities interference, and the effect on mental health.This framework will be used to develop a patient-reported outcome of cramp severity and impact.Évaluer qualitativement l’impact et la gravité des crampes musculaires tout en étant axé sur les patients qui en souffrent. Contexte : Il existe un besoin urgent de mettre en œuvre de nouvelles options thérapeutiquespour le soulagementdes crampes musculaires. Cela dit, aucun patient qui en souffre ne semble avoir fait état d’optionstenant compte de la totalité de leurexpérience. À cet égard, nous avons effectué une étude qualitative afin justement de mieux cerner l’expérience de ces patients et de comprendreles facteurs qui déterminentl’impact que les crampes peuvent avoir dans leur vie. Nous voulons du coup orienter l’élaboration d’indicateursaxés sur les patients eux-mêmes, indicateurs visant à mesurer l’impact et la gravité de leurs crampes musculaires. Méthodes : Nous avons recruté des patients atteints de crampes musculaires en raison de plusieurs étiologies, par exemple des pathologies du motoneurone, des crampes liées à une grossesse, des cas de cirrhosenécessitant une hémodialyse, des crampes idiopathiquesou déclenchées par l’exercice, etc. Les patients recrutés ont participé à des entrevues semi-structurées portant sur leur expérience en lien avec des crampes musculaires, leurs réponses étant enregistrées et par la suite transcrites. En plus déterminer la taille de notre échantillon à l’aide de la saturation de données, nous avons ensuite analysé ces dernières au moyen de la méthode d’analyse de contenu. Enfin, nous avons élaboré un cadre conceptuel de la gravité des crampes musculaires et de leur impact général. Résultats : Une fois nos données saturées, dix patients ont été interviewés. Les expériences liées à leurs crampes se sont révélées comparables peu importe les maladies et les états physiologiques. Parmi les principaux aspects caractérisant l’impact général des crampes, mentionnons les suivants : les caractéristiques des crampes, les perturbations du sommeil qu’elles entraînent, leur interférence dans des activités de jour et leurs effets sur la santé mentale. Conclusions : Ce cadre de référence sera utilisé pour élaborer un outil mesurant la gravité et l’impact des crampes musculaires, et ce, en fonction de l’apport des patients eux-mêmes.

To explore whether higher degrees of electrophysiological abnormalities are associated with a more frequent exposure to a more aggressive treatment regimen, we performed a retrospective chart review of patients attending the neuromuscular clinic from June 2012 to December 2015 and included 87 patients. We compared treatment regimens during the follow-up period between patients with high and low jitter and decrement. Myasthenia gravis patients with high jitter or decrement at baseline were more frequently treated with intravenous immunoglobulins (IVIG) and/or plasma exchange (PLEX) during the follow-up period. In patients with mild disease, IVIG or PLEX treatment was associated with high decrement.La diminution initiale du potentiel moteur de patients atteints de myasthénie grave peut permettre de prédire le type d’immuno-modulation thérapeutique prodiguée. Afin d’explorer dans quelle mesure des niveaux plus élevés d’anomalies électro-physiologiques peuvent être associés à une exposition davantage fréquente à des régimes de traitement plus vigoureux, nous avons effectué un examen rétrospectif des dossiers de patients, 87 au total, s’étant présentés à une clinique neuromusculaire de juin 2012 à décembre 2015. Nous avons alors comparé les régimes de traitement des patients montrant de basses mesures de gigue (jitter) et une faible diminution d’amplitude du potentiel d’action au cours de leur période de suivi avec les régimes de traitement d’autres patients pour qui ces mesures étaient élevées. Les patients atteints de myasthénie grave (MG) dont les mesures de gigue et la diminution d’amplitude du potentiel d’action étaient initialement élevées ont été plus fréquemment traités, lors d’un suivi, avec des immunoglobulines intraveineuses et/ou des échanges plasmatiques. Chez les patients atteints de la forme bénigne de cette maladie, ces deux traitements ont été associés à une diminution d’amplitude du potentiel d’action plus élevée.

Background: High levels of uric acid (UA) are associated with various peripheral neuropathies. Furthermore, uric acid levels have been found to correlate with both the clinical and electrophysiological severity of diabetic sensorimotor polyneuropathy, mainly with sensory functions. Objectives: To determine whether higher UA levels are associated negatively with nerve function in healthy subjects. Methods: A total of 126 healthy subjects recruited prospectively for another study were included. We extracted demographic data, body mass index (BMI), blood pressure, Toronto Clinical Neuropathy Score (TCNS), electrophysiological findings, vibration perception thresholds (VPT), and laboratory test results including UA, hemoglobin A1c (HbA1c), estimated glomerular filtration rate (eGFR), and lipid levels. Results: The mean age of the cohort was 56 ± 17 years with 56% females. Males had higher UA values compared with females. Univariate beta regression coefficient analysis between UA levels and demographic, clinical, electrophysiological, and laboratory findings showed significant positive correlations with male gender, components of the metabolic syndrome, and with VPT, while an inverse correlation was found with electrophysiological sensory parameters. A multivariate regression model showed positive correlations only with BMI, finger VPT, and triglycerides. Conclusion: Higher UA levels correlate with lower sensory nerve function in healthy subjects, expanding the evidence of possible negative influence of UA on peripheral nerves, although a causative role has not yet established.

Background: Neurofibromatosis type 1 (NF1) is a common single-gene disorder. A multidisciplinary approach to the management of NF1 patients is necessitated by the heterogeneity of clinical manifestations. Although multidisciplinary paediatric clinics have been well established, there is a dearth of such resources for adults with NF1. Herein we report our one-year institutional experience with a multidisciplinary adult NF1 clinic. Methods: A multidisciplinary team was assembled, and an NF Patient Registry Initiative questionnaire was adapted to collect patient-reported data during clinics. Multiple databases were searched to identify publications pertaining to the experience of other multidisciplinary NF1 clinics focusing on adult patients. Data on patient epidemiology and clinical staff were compared to our data. Results: A total of 77 patients were scheduled, and 68 attended the clinic, of whom 66 completed the intake questionnaire. The demographic and clinical data from this Canadian population are mostly consistent with previous reports, with some exceptions. Clinical data related to immune system involvement such as asthma, airway/breathing-related difficulties or allergies were striking in our NF1 population. Six relevant published reports of other NF1 clinics were identified. Reports from these studies pertained to periods ranging from 10 to 38 months, and the number of adults assessed ranged from 19 to 177 patients. Conclusions: The structure of our clinic and the patient volume are comparable to those of other established centres found in the literature. Our data offer valuable cross-sectional prevalence statistics in the Canadian population. The patient-reported data concerning involvement of the immune system contribute to an emerging recognized medical concern within the NF1 population and warrant further clinical and basic investigation.

Background:Survivors of acute respiratory distress syndrome (ARDS) report generalized weakness and reduced exercise tolerance up to two years following discharge from the intensive care unit (ICU). Persistent neuromuscular complications of ARDS may contribute to the functional disability observed in these patients.Methods:Sixteen ARDS survivors underwent comprehensive neurological evaluation and standardized electrodiagnostic testing 6 to 24 months after ICU discharge. Four of these patients agreed to open muscle biopsy.Results:Seven of sixteen patients had clinically significant focal compressive mononeuropathies. Electrodiagnostic testing failed to reveal any changes attributable to critical illness polyneuropathy or myopathy. All four muscle biopsies were abnormal, and although the pathological features were structurally non-specific, the presence of an acquired myopathy remains possible. Four patients had persistent mixed sensory complaints but had normal electrodiagnostic evaluation.Conclusions:The high frequency of mononeuropathies highlights the need for vigilance in daily ICU care. The findings also suggest that complaints of weakness and reduced exercise capacity in ARDS survivors may be related to combined effects of compressive neuropathies and generalized longstanding structural changes in muscle and may support an organic basis for longterm functional disability.

Introduction: A cost-minimization analysis (CMA) was performed comparing IVIg and PLEX in the management of patients with exacerbation of myasthenia gravis (MG). Methods: This study combines Ontario-based health costing data with clinical data from a randomized clinical trial where patients with moderate/severe MG received either IVIg or PLEX. The CMA was undertaken under the perspective of a public health care insurer and under the perspective of a tertiary hospital payer. Results: The IVIg group (n=32) was comparable with the PLEX group (n=38) regarding demographics, disease characteristics and severity. PLEX was less costly than IVIg among patients with body mass index (BMI) ≤15.7 Kg/m2, under the perspective of a public health care insurer (CAN$6,271.18 versus CAN$8,309.72, pConclusions: PLEX may be a short-term cost-minimizing therapy when compared with IVIg for treatment of MG exacerbation among patients with BMI ≤15.7 Kg/m2, under the perspective of a public health care insurer. However, when the costs of blood products are absorbed by a third party, the hospital administration may see IVIg as a more attractive therapeutic alternative.