International Consensus Guidance for Management of Myasthenia Gravis: 2020 Update

Current Treatment of Myasthenia Gravis

Myasthenia gravis (MG) is the most extensively studied antibody-mediated disease in humans. Substantial progress has been made in the treatment of MG in the last century, resulting in a change of its natural course from a disease with poor prognosis with a high mortality rate in the early 20th century to a treatable condition with a large proportion of patients attaining very good disease control. This review summarizes the current treatment options for MG, including non-immunosuppressive and immunosuppressive treatments, as well as thymectomy and targeted immunomodulatory drugs.

Socio-Economic Burden of Myasthenia Gravis: A Cost-of-Illness Study in Bulgaria

Background

Myasthenia gravis (MG) is a chronic autoimmune disorder, which is characterized by fatigable muscle weakness with frequent ocular signs and/or generalized muscle fatigue, and occasionally associated with thymoma. MG patients and their families face a significant socio-economic burden. This population is often experiencing unemployment, unwilling job transfers and decreased income.

Objective

This study aimed to estimate the annual costs from a societal perspective in a triple dimension of direct health care costs, direct non-health care costs (formal and informal care) and labor productivity losses in MG patients from Bulgaria, as well as to identify the main clinical and demographical cost drivers.

Methods

A bottom-up, cross-sectional, cost-of-illness analysis of 54 adult MG patients was carried out in 2020. To collect data on demographic characteristics, health resource utilization, informal care and productivity losses, questionnaires were administered to and completed by patients.

Results and Conclusion

Median annual costs of MG in Bulgaria were 4,047 EUR per patient. Direct costs slightly outweighed indirect costs, with drugs cost item having the biggest monetary impact. Despite the zero-inflated median, hospitalizations also influenced the direct costs by an estimated amount of 1,512 EUR in the 3rd quartile. Social services and professional caregiver costs were found to be almost missing, with the vast majority of patients reporting reliance on informal caregivers. Severe generalized disease, disease crises, and recurrent infections were confirmed as statistically significant cost driving factors. There were no severe generalized MG patients in the bottom quartile of the total costs distribution. It should be noted that in both cases of crises or infections, the overall increase in the total costs was mainly due to higher indirect costs observed. Reliance on family members as informal caregivers is routine among Bulgarian MG patients. This phenomenon is likely due to the lack of access to appropriate social services. Moreover, it is directly related with higher disease burden and significant inequalities. There is a need for further research on MG in Bulgaria in order to design targeted health policies that meet the needs and expectations of these patients.

Autoantibody profile in myasthenia gravis patients with a refractory phase

INTRODUCTION

A subgroup of myasthenia gravis (MG) patients fails to respond adequately to recommended treatments, a condition referred to as refractory MG. During the refractory phase patients experience persistent debilitating symptoms with potential life-threatening events or inability to reduce immunosuppressant dosages and minimize long-term toxicities.

METHODS

We conducted a retrospective single-centre study of 113 MG patients to investigate the autoantibody profile and clinical characteristics of refractory MG patients, compared to non-refractory patients, based on predefined criteria.

RESULTS

Fifteen patients (13.3%) were classified as refractory. Double seronegative MG (DSNMG), without detectable nicotinic acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies, was identified in 6 refractory patients, significantly higher than those with non-refractory MG (40% vs 16.3%, p=0.031). None of the refractory patients had MuSK antibodies. Patients in the refractory group more frequently had an earlier disease onset, thymic pathology and thymectomy (all p-values ≤0.03).

DISCUSSION

In this study, patients with refractory MG were more likely than those with non-refractory MG to be DSN; and refractory DSNMG patients had worse MGFA classes in their recent visit compared to anti-AChR positive refractory patients. Refractory DSNMG patients may represent a distinct group that requires more individualized and targeted treatment approaches. This article is protected by copyright. All rights reserved.

Association of immunosuppression treatment with generalization among patients with ocular myasthenia gravis: a propensity score analysis

BACKGROUND

To analyze disease generalization in patients with ocular myasthenia gravis (OMG) treated with immunosuppression compared with patients without immunosuppression treatment.

METHODS

In this retrospective cohort study, we analyzed data from patients with OMG at seven medical centers in China from January 1, 2015 to May 1, 2019 and compared disease generalization in patients (treated with immunosuppression vs. not treated) within 2 years of disease onset using raw and inverse probability of treatment weighting (IPTW) analyses.

RESULTS

In the study population of 813 patients with OMG, 425 (52.3%) with immunosuppression had a mean (SD) onset age of 50.0 (15.1) years, and 188 (44.2%) were women. The remaining 388 (47.7%) patients were not immunosuppressed (mean age, 48.4 [15.0] years; 185 [47.7%] women). Disease generalization developed in 122 (31.4%) and 37 (8.7%) patients in the non-immunosuppression and immunosuppression groups, respectively. Relative to non-immunosuppression, immunosuppression was associated with a lower risk of generalization in a multivariable-adjusted Cox model (hazard ratio [HR], 0.27; 95% confidence interval [CI], 0.18-0.40; P<0.001) and IPTW-weighted Cox model (HR, 0.28; 95% CI, 0.19-0.42; P<0.001). In sensitivity analyses, longer duration of immunosuppression was associated with a lower risk of generalization (HR, 0.90 for every one-month increase; 95% CI, 0.87-0.92; P<0.001; IPTW-adjusted). Combination therapy with steroids and non-steroidal immunosuppressants showed superior efficacy in reducing the risk of generalization (HR, 0.14; 95% CI, 0.07-0.26; P<0.001).

CONCLUSIONS

Immunosuppression significantly reduced the 2-year risk of generalization in patients with OMG.

Risk factors for pregnancy-related clinical outcome in myasthenia gravis: a systemic review and meta-analysis

OBJECTIVE

Myasthenia gravis (MG) is an autoimmune disorder that frequently affects females at reproductive age. Herein, we aimed to assess the associations of clinical factors with pregnancy-related outcome in MG.

METHODS

We searched PubMed and EMBASE for case-control and cohort studies that reported the MG status during or after pregnancy and relevant clinical variables. The data was extracted in proportions and odds ratios (ORs) with 95% confidence intervals (CIs) in subsequent meta-analysis.

RESULTS

Fifteen eligible articles reporting on 734 pregnancies with 193 worsening and 51 improved episodes were included out of 1765 records. The estimated worsening proportions in total, antepartum and postpartum periods were 0.36 (95% CI 0.25-0.40), 0.23 (95% CI 0.14-0.34) and 0.11 (95% CI 0.04-0.22) respectively. The proportion of pregnancy-related improvement in enrolled patients was 0.28 (95% CI 0.17-0.40), with 0.07 (95% CI 0.00-0.28) during pregnancy and 0.14 (95% CI 0.02-0.34) after pregnancy. No significant associations were disclosed between the clinical factors and MG worsening. Thymectomy before delivery is a strong predictor for MG improvement in postpartum period (OR 4.85, 95% CI 1.88-12.50, p = 0.001).

CONCLUSION

The total proportion of pregnancy-related MG worsening and improvement in MG was 0.36 (95% CI 0.25-0.40) and 0.28 (95% CI 0.17-0.40), respectively. Thymectomy before the delivery may aid in clinical improvements associated with pregnancy. Future prospective cohort studies are required to determine more relevant factors.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex^® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex^® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

Ocular myasthenia gravis: a review and practical guide for clinicians

Myasthenia gravis is a rare autoimmune disease characterised by autoantibodies preventing normal function of acetylcholine receptors at the post-synaptic membrane of the neuromuscular junction. This causes weakness of skeletal muscles that can be variable and fatigable, and often manifests as ptosis and/or diplopia, with 60% of patients demonstrating ocular features at onset, and thus may present initially to eye care practitioners. Approximately 15% of patients have ocular myasthenia gravis, where symptoms remain restricted to this distribution. The majority of patients have blocking antibodies against the acetylcholine receptor, but antibodies directed against other related targets account for a smaller proportion and are associated with specific phenotypes. Associations with both thymoma and with other autoimmune phenomena (particularly thyroid disease) can occur. Clinical examination can identify characteristic findings including fatigable ptosis and Cogan's lid twitch sign. Investigations to confirm the diagnosis include simple office-based procedures such as the ice test, and testing for serum autoantibodies, as well as electrophysiological testing such as repetitive nerve stimulation and single-fibre electromyography. The management of ocular myasthenia gravis is discussed, including non-pharmacological options, pyridostigmine, corticosteroids, other immunosuppressive agents, and thymectomy. The goals of management are to alleviate symptoms, and where possible prevent chronic disability or progression to generalised myasthenia gravis.

Preoperative Management of Medications for Neurologic Diseases: Society for Perioperative Assessment and Quality Improvement Consensus Statement

Neurologic diseases are prevalent in patients undergoing invasive procedures; yet, no societal guidelines exist as to best practice in management of perioperative medications prescribed to treat these disorders. The Society for Perioperative Assessment and Quality Improvement tasked experts in internal medicine, anesthesiology, perioperative medicine, and neurology to provide evidence-based recommendations for preoperative management of these medications. The aim of this review is not only to provide consensus recommendations for preoperative management of patients on medications for neurologic disorders, but also to serve as an educational guide to perioperative clinicians. While, in general, medications for neurologic disorders should be continued preoperatively, an individualized approach may be needed in certain situations (eg, holding anticonvulsants on day of surgery if electroencephalographic mapping is planned during epilepsy surgery). Pertinent interactions with commonly used drugs in anesthesia practice, as well as considerations for targeted laboratory testing or perioperative drug substitutions, are addressed as well.

Different Monoclonal Antibodies in Myasthenia Gravis: A Bayesian Network Meta-Analysis

Background: Myasthenia gravis (MG) is a common autoimmune disease with acquired neuromuscular transmission disorders. Recently, monoclonal antibodies have been shown to successfully treat a variety of diseases.

Methods: In this meta-analysis, an appropriate search strategy was used to search eligible randomized controlled trials (RCTs) on different monoclonal antibodies to treat patients with MG published up to September 2021 from the embase, PubMed, and Cochrane Library. We assessed the average difference or odds ratio between each drug and placebo and summarized them as the average and 95% confidence interval (CI), respectively.

Results: In indicators of efficacy, patients receiving eculizumab (MD, −1.9; 95% CI, −3.2–0.76) had decreases in MG-ADL scores compared to placebo. In addition, only eculizumab (MD, −3.1; 95% CI, −4.7–1.5) and efgartigimod (MD, −1.4; 95% CI, −2.1–0.68) showed a significant difference from placebo in the amount of reduction in QMG scores, while neither of the other two monoclonal antibodies was statistically significant. With regard to the safety of monoclonal antibody therapy, there was no significant difference in the probability of AE in subjects treated with any of the four monoclonal antibodies compared to placebo.

Conclusions: eculizumab was effective in reducing MG-ADL scores and QMG scores in myasthenia gravis. Meanwhile, eculizumab also caused fewer AE. As an emerging therapy, monoclonal antibodies are prospective in the treatment of MG. However, more researches are required to be invested in the future as the results obtained from small sample sizes are not reliable enough.

Eculizumab treatment for myasthenia gravis subgroups: 2021 update

Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.

Rheumatoid arthritis and myasthenia gravis: a case-based review of the therapeutic options

Introduction

Myasthenia gravis is an autoimmune disease affecting the neuromuscular junction, often associated with other autoimmune diseases, including rheumatoid arthritis. Patients with rheumatoid arthritis present an increased prevalence of myasthenia gravis compared to the general population. While these two diseases share some therapeutic options, such as glucocorticoids, methotrexate, and rituximab, there are no guidelines for treating concomitant disease. We aim to review the available evidence and to discuss the efficacy and safety of the therapeutic options in patients with rheumatoid arthritis associated with myasthenia gravis.

Method

We described three patients with rheumatoid arthritis associated with myasthenia gravis and we performed a systematic review of the associated literature.

Results

A 48-year-old man and two women (48 and 55 years old) with concomitant diagnoses of active rheumatoid arthritis and well-controlled myasthenia gravis are described. They were treated with methotrexate, leflunomide, upadacitinib, and adalimumab. None of them experienced changes in their myasthenic symptoms. We found 9 additional cases from our literature review. Methotrexate, rituximab, upadacitinib, diphenyl sulfone, auranofin, and loxoprofen sodium did not show an impact on the seven patients with previously well-controlled myasthenia. Glucocorticoids, methotrexate, and rituximab proved effective in active myasthenia gravis and arthritis. Conflicting data emerged for Tumor-necrosis factor inhibitors.

Conclusions

Although the available evidence remains scarce, we consider glucocorticoids, methotrexate, and rituximab as safe and effective options. The role of tumor-necrosis factor inhibitors remains uncertain. Eventually, Janus Kinase inhibitors are a novel interesting option for these patients.

Key Points • To date, the only evidence on the treatment of patients with rheumatoid arthritis and concomitant myasthenia gravis derives from case reports. • Based on the review of the available case reports and on the cases we described, we consider glucocorticoids, methotrexate, and rituximab as safe and effective options, while the role of Tumor-necrosis factor inhibitors remains uncertain. • Based on the cases we described, Janus Kinase inhibitors are a novel interesting option for patients with concomitant rheumatoid arthritis and myasthenia gravis.

Utilization of Decision Tree Algorithms for Supporting the Prediction of Intensive Care Unit Admission of Myasthenia Gravis: A Machine Learning-Based Approach

Myasthenia gravis (MG), an acquired autoimmune-related neuromuscular disorder that causes muscle weakness, presents with varying severity, including myasthenic crisis (MC). Although MC can cause significant morbidity and mortality, specialized neuro-intensive care can produce a good long-term prognosis. Considering the outcomes of MG during hospitalization, it is critical to conduct risk assessments to predict the need for intensive care. Evidence and valid tools for the screening of critical patients with MG are lacking. We used three machine learning-based decision tree algorithms, including a classification and regression tree, C4.5, and C5.0, for predicting intensive care unit (ICU) admission of patients with MG. We included 228 MG patients admitted between 2015 and 2018. Among them, 88.2% were anti-acetylcholine receptors antibody positive and 4.7% were anti-muscle-specific kinase antibody positive. Twenty clinical variables were used as predictive variables. The C5.0 decision tree outperformed the other two decision tree and logistic regression models. The decision rules constructed by the best C5.0 model showed that the Myasthenia Gravis Foundation of America clinical classification at admission, thymoma history, azathioprine treatment history, disease duration, sex, and onset age were significant risk factors for the development of decision rules for ICU admission prediction. The developed machine learning-based decision tree can be a supportive tool for alerting clinicians regarding patients with MG who require intensive care, thereby improving the quality of care.

Ectopic germinal centers in the thymus accurately predict prognosis of myasthenia gravis after thymectomy

The ability of thymic histopathology to predict the long-term impact of thymectomy in non-thymomatous myasthenia gravis (NTMG) is mainly uncharted. We applied digital pathology to quantitatively characterize differences of thymic histology between early-onset (EOMG) and late-onset MG (LOMG) and to investigate the role of thymic changes for thymectomy outcomes in MG. We analyzed 83 thymic H&E slides from thymectomized NTMG patients, of which 69 had EOMG and 14 LOMG, using digital pathology open-access software QuPath. We compared the results to the retrospectively assessed clinical outcome at two years after thymectomy and at the last follow-up visit where complete stable remission and minimal use of medication were primary outcomes. The automated annotation pipeline was an effective and reliable way to analyze thymic H&E samples compared to manual annotation with mean intraclass correlation of 0.80. The ratio of thymic tissue to stroma and fat was increased in EOMG compared to LOMG (p = 8.7e-07), whereas no difference was observed in the ratio of medulla to cortex between these subtypes. AChRAb seropositivity correlated with the number of ectopic germinal centers (eGC; p = 0.00067) but not with other histological areas. Patients with an increased number of eGCs had better post-thymectomy outcomes at two years after thymectomy (p = 0.0035) and at the last follow-up (p = 0.0267). ROC analysis showed that eGC area predicts thymectomy outcome in EOMG with an AUC of 0.79. Digital pathology can thus help in providing a predictive tool to the clinician, the eGC number, to guide the post-thymectomy treatment decisions in EOMG patients.

Vaccination in pediatric acquired inflammatory immune-mediated neuromuscular disorders

AIM

To analyse literature data on vaccine related induction, worsening of the disease and disease reccurrences as well as vaccine safety and efficacy among pediatric patients with acquired inflammatory immune-mediated neuromuscular disorders (NMD).

METHODS

Medline, Pub Med and Scopus database search from 1975 to 2020 focused on pediatric age was conducted including peer reviews, meta analyses and epidemiological studies on vaccination and Guillain-Barré syndrome (GBS), Bell's palsy, optic neuritis (ON), myasthenia gravis (MG), chronic inflammatory demyelinating polyneuropathy (CIDP) and immune-mediated inflammatory myopathy (IM).

RESULTS AND CONCLUSION

s: There are no strong evidence supporting relationship between vaccination with different pediatric vaccines and development of first episodes or reccurrences of GBS, Bell's palsy, optic neuritis (ON), juvenile MG, CIDP, and IM. The vaccination and revaccination with inactivated vaccines is considered safe in children with medical history of GBS, Bell's palsy, ON, MG and IM. Caution when immunization against influenza, quadrivalent conjugated meningococcal vaccine (MCV4) and pneumococcal disease and avoiding tetanus toxoid immunization in CIDP patients is suggested. Patients with immune mediated acquired NMD should be vaccinated with live vaccines before the initiation of immunosupressive treatment. Immunosuppressed patients with low protective antibody titers should be considered for revaccination.

The association between anti-acetylcholine receptor antibody level and clinical improvement in myasthenia gravis

BACKGROUND

Anti-AChR-antibodies in the serum are detected in most patients with generalized myasthenia gravis (MG) and used as a diagnostic tool. The aim of this study was to analyse a possible association between anti-AChR-antibody serum levels and clinical improvement of MG.

METHODS

The Maastricht University Medical Center is a centre of expertise for the treatment of MG. Between 1997 till 2020, more than 4.000 anti-AChR-antibodies were measured for clinical care using quantitative radioimmunoassay (RIA) technique. These results, in combination with the clinical status obtained from the patients' electronic patient files, were retrospectively analysed by a single blinded clinician. Symptoms of MG were classified by the Myasthenia Gravis Foundation of America (MGFA).

RESULTS

In total, 90 anti-AChR-antibody positive MG-patients with 837 blood samples were included. Median follow-up time was 72 months. The majority of the included patients were female (61.1%), on immunosuppressive drug therapy (88.9%), and did undergo a thymectomy (54.4%). Multilevel logistic regression analysis showed a significantly inverse association between change in anti-AChR-antibody level and the odds of MGFA improvement (per 10 percent decrease of anti-AChR-antibody level OR: 1.21, CI: 1.12-1.31, p <0.001).

CONCLUSIONS

A change in anti-AChR-antibody serum level is associated with the clinical status in patients with MG. Analyses of anti-AChR-antibody are not only useful for diagnostics but also in follow-up of adult symptomatic patients with MG. The use of repetitive anti-AChR-antibody serum levels might be valuable as a long-term monitor for clinical improvement in patients with MG, however, further research is required for specific recommendations.

The effectiveness and value of eculizumab and efgartigimod for generalized myasthenia gravis

DISCLOSURES: Funding for this summary was contributed by Arnold Ventures, The Donaghue Foundation, Harvard Pilgrim Health Care, and Kaiser Foundation Health Plan to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from AbbVie, America's Health Insurance Plans, Anthem, Alnylam, AstraZeneca, Biogen, Blue Shield of CA, Boehringer-Ingelheim, Cambia Health Services, CVS, Editas, Evolve Pharmacy, Express Scripts, Genentech/Roche, GlaxoSmithKline, Harvard Pilgrim, Health Care Service Corporation, HealthFirst, Health Partners, Humana, Johnson & Johnson (Janssen), Kaiser Permanente, LEO Pharma, Mallinckrodt, Merck, Novartis, National Pharmaceutical Council, Pfizer, Premera, Prime Therapeutics, Regeneron, Sanofi, Sun Life Financial, uniQure, and United Healthcare. Agboola, Nikitin, and Pearson are employed by ICER. Through their affiliated institutions, Tice, Touchette, and Lien received funding from ICER for the work described in this summary.

Quantitative evaluation of drug efficacy in the treatment of myasthenia gravis

OBJECTIVES

This study aimed to quantitatively evaluate placebo effect and drug efficacy characteristics and identify associated factors that affect quantitative myasthenia gravis (MG) score (QMGs) and MG activities of daily living score (MG-ADLs) in patients with MG.

METHODS

Randomized placebo-controlled clinical trials were comprehensively searched in public databases (PubMed, EMBASE, and Cochrane Library databases).A model-based meta-analysis was developed to describe time-course about drug efficacy and placebo effect.

RESULTS

Twelve articles including 13 trials (673 participants) that were eligible for this study evaluated four immunosuppressants (tacrolimus, cyclosporine, prednisone, and mycophenolate mofetil) and five targeted therapy drugs (eculizumab, belimumab, zilucoplan, efgartigimod, and iscalimab). The pharmacodynamic model showed that eculizumab had the highest efficacy in reducing QMGs scores (3.66 points), and efgartigimod had the highest efficacy in reducing MG-ADLs scores (1.97 points). The placebo effect of QMGs and MG-ADLs increased apparently with time and reached 52% and 90% of their maximum effect in 12 weeks, respectively. In addition, this study found that the activities of daily living ability increased with the increase of the proportion of patients undergoing thymectomy.

CONCLUSION

This study analyzed the efficacy characteristics of nine drugs. The present findings provide necessary quantitative information for drug development of MG.

Bridging the Gap between Ophthalmology and Emergency Medicine in Community-Based Emergency Departments (EDs): A Neuro-Ophthalmology Guide for ED Practitioners

Coordination of care for patients with neuro-ophthalmic disorders can be very challenging in the community emergency department (ED) setting. Unlike university- or tertiary hospital-based EDs, the general ophthalmologist is often not as familiar with neuro-ophthalmology and the examination of neuro-ophthalmology patients in the acute ED setting. Embracing image capturing of the fundus, using a non-mydriatic camera, may be a game-changer for communication between ED physicians, ophthalmologists, and tele-neurologists. Patient care decisions can now be made with photographic documentation that is then conveyed through HIPAA-compliant messaging with accurate and useful information with both ease and convenience. Likewise, external photos of the anterior segment and motility are also helpful. Finally, establishing clinical and imaging guidelines for common neuro-ophthalmic disorders can help facilitate complete and appropriate evaluation and treatment.

Current and Upcoming Treatment Modalities in Myasthenia Gravis

ABSTRACT

Myasthenia gravis (MG) is one of the extensively studied autoimmune disorder. There has been a dramatic increase in research to further understand molecular pathogenesis of MG and clinical trials for new drugs in MG treatment in the past decade. This review article is to consolidate the available information in simple terms with students, residents, and fellows as target audience for easy learning and help application of this knowledge to clinical practice.

Fetal Surveillance in Pregnancies with Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune condition, that commonly impacts adult women of reproductive age. Myasthenia gravis in pregnancy is rare, but the incidence is higher in different geographical areas. Pregnancies in mothers with MG can have an unfortunate outcome. Acetylcholine receptor antibodies may pass into the fetal circulation and can affect the fetal neuromuscular junction, generating transient MG or even fetal arthrogryposis. The 2016 and 2021 International Consensus Guidance for Management of Myasthenia Gravis issued by Myasthenia Gravis Foundation of America is lacking in recommendation for fetal surveillance for pregnancies in women with MG. The aim of this paper is to highlight fetal and neonatal complications in mothers with MG and to offer antenatal care insights. Close maternal and pregnancy monitoring can improve pregnancy outcome. Patients with MG should be encouraged to conceive, to avoid triggers for exacerbations of the disease during pregnancy and a multidisciplinary team should be established to ensure the optimal support and therapy.

Comparative Analysis of BIOCHIP Mosaic-Based Indirect Immunofluorescence with Enzyme-Linked Immunosorbent Assay for Diagnosing Myasthenia Gravis

BACKGROUND

The detection of anti-acetylcholine receptor (AChR) and anti-muscle-specific tyrosine kinase (MuSK) antibodies is useful in myasthenia gravis (MG) diagnosis and management. BIOCHIP mosaic-based indirect immunofluorescence is a novel analytical method, which employs the simultaneous detection of anti-AChR and anti-MuSK antibodies in a single miniature incubation field. In this study, we compare, for the first time, the BIOCHIP MG mosaic with conventional enzyme-linked immunosorbent assay (ELISA) in the diagnosis of MG.

METHODS

A total of 71 patients with MG diagnosis were included in the study. Anti-AChR and anti-MuSK antibodies were measured separately by two different ELISA and simultaneously by BIOCHIP. The results were then compared.

RESULTS

The overall concordance between ELISA and BIOCHIP for anti-AChR reactivity was 74%. Cohen's kappa was 0.51 (95% CI 0.32-0.71), which corresponds to 90% of the maximum possible kappa (0.57), given the observed marginal frequencies. The overall concordance for anti-MuSK reactivity was 84%. Cohen's kappa was 0.11 (95% CI 0.00-0.36), which corresponds to 41% of the maximum possible kappa (0.27).

CONCLUSION

The overall concordance among assays is not optimal.

Neuromuscular Complications of Targeted Anticancer Agents: Can Tyrosine Kinase Inhibitors Induce Myasthenia Gravis? Getting Answers From a Case Report up to a Systematic Review

More than 40 tyrosine kinase inhibitors (TKIs) have received hematological or oncological indications over the past 20 years, following the approval of imatinib, and many others are currently being tested in clinical and preclinical level. Beyond their common toxicities, no certain agent from this large class of molecularly targeted therapies was strongly associated with “off-target” impairment of neuromuscular transmission, and although myasthenia gravis (MG) is a well-characterized autoimmune disorder, only few sporadic events proven by serologically detected causative autoantibodies and/or by positive electrophysiological tests are reported in the literature. Herein, we present the first case of anti-MUSK (+) MG in a woman with metastatic BRAF-mutant melanoma after long-term treatment with dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor). Triggered by this report, a systematic literature review was conducted, summarizing all other cancer cases that developed MG, after exposure to any type of targeted agent and regardless of the underlying malignancy. All available data on the clinical diagnosis, the potential of administered TKIs to induce a seropositive myasthenic syndrome, the immune and non-immune-mediated pathogenesis of postsynaptic damage, and the challenging management of this neuromuscular toxicity were collected and discussed. In the presented case, MG was confirmed by both autoantibodies and nerve-conduction tests, while its reactivation after TKIs rechallenge supports a more than coincidental association. The following review identified 12 cancer cases with TKI-related MG in six case reports and one case series. In most of them, the myasthenia diagnosis was challenging, since the clinical symptomatology of fatigable weakness was not corroborating with consistent laboratory and electrophysiological findings. In fact, anti-AchR titers were positive in five and anti-MuSK only in the abovementioned individual. The symptomatology corresponded to TKI discontinuation and standard treatment with pyridostigmine and prednisolone; intravenous immunoglobulin was added only in three, and two required mechanical ventilation. In an era where TKIs will be prescribed more frequently for various malignancies, even in combinations with immune-checkpoint inhibitors, this report synthesizes their risk for neuromuscular complications and increases the clinicians’ awareness in order to extend the on-treatment and overall survival of TKI-treated cancer patients.

The Role of Plasma Exchange in the Treatment of Refractory Autoimmune Neurological Diseases: a Narrative Review

Autoimmune neurological disorders are commonly treated with immunosuppressive therapy. In patients with refractory conditions, standard immunosuppression is often insufficient for complete recovery or to prevent relapses. These patients rely on other treatments to manage their disease. While treatment of refractory cases differs between diseases, intravenous immunoglobulin, plasma exchange (PLEX), and immune-modulating treatments are commonly used. In this review, we focus on five autoimmune neurological disorders that were the themes of the 2018 Midlands Neurological Society meeting on PLEX in refractory neurology: Autoimmune Encephalitis (AE), Multiple Sclerosis (MS), Neuromyelitis Optica Spectrum disorders (NMOSD), Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Myasthenia Gravis (MG). The diagnosis of inflammatory neuropathies is often challenging, and while PLEX can be very effective in refractory autoimmune diseases, its ineffectiveness can be confounded by misdiagnosis. One example is POEMS syndrome (characterized by Polyneuropathy Organomegaly, Endocrinopathy, Myeloma protein, Skin changes), which is often wrongly diagnosed as CIDP; and while CIDP responds well to PLEX, POEMS does not. Accurate diagnosis is therefore essential. Success rates can also differ within 'one' disease: e.g. response rates to PLEX are considerably higher in refractory relapsing remitting MS compared to primary or secondary progressive MS. When sufficient efforts are made to correctly pinpoint the diagnosis along with the type and subtype of refractory autoimmune disease, PLEX and other immunotherapies can play a valuable role in the patient management.

Thymectomy and Risk of Generalization in Patients with Ocular Myasthenia Gravis: A Multicenter Retrospective Cohort Study

This study aims to investigate the association between thymectomy and the risk of generalization in patients with ocular myasthenia gravis (MG). Data on patients with ocular MG from seven neurological centers in China were retrospectively reviewed. Ocular MG naïve to immunotherapy was categorized according to whether thymectomy was performed (thymectomized group vs. nonsurgical group). Patients in the thymectomized group all underwent surgery within 2 years since ocular symptom onset. The main outcome measure was the generalization. The follow-up period was defined from the date of ocular symptom onset to the date of generalization confirmation, immunotherapy initiation, or last follow-up (defined as 60 months). Of 519 eligible patients (mean [SD] age, 48.7 [15.2] years, 46.6% women), 31 (23.7%) of 131 generalized in the thymectomized group and 122 (31.4%) of 388 did in the nonsurgical group during a median follow-up of 19 months (IQR 8.0-50.0). Thymectomy was independently associated with reduced generalization risk (adjusted HR 0.41, 95% CI 0.25-0.66, P < 0.001). Multivariable stratified analysis also verified this association across the subgroups. Kaplan-Meier curves showed that the 5-year cumulative rate was significantly lower in the thymectomized group than in the nonsurgical group. To conclude, thymectomy may be considered effective in modifying the progression from ocular to generalized MG irrespective of thymoma.

Eculizumab in refractory generalized myasthenia gravis previously treated with rituximab: subgroup analysis of REGAIN and its extension study

INTRODUCTION/AIMS

Individuals with refractory generalized myasthenia gravis (gMG) who have a history of rituximab use and experience persistent symptoms represent a population with unmet treatment needs. The aim of this analysis was to evaluate the efficacy and safety of eculizumab in patients with refractory anti-acetylcholine receptor antibody-positive (AChR⁺ ) gMG previously treated with rituximab.

METHODS

This post hoc subgroup analysis of the phase 3 REGAIN study (NCT01997229) and its open-label extension (OLE; NCT02301624) compared baseline characteristics, safety, and response to eculizumab in participants who had previously received rituximab with those who had not. Rituximab use was not permitted within the 6 months before screening or during REGAIN/OLE.

RESULTS

Of 125 REGAIN participants, 14 had received rituximab previously (7 received placebo and 7 received eculizumab). In the previous-rituximab group, 57% had used at least four other immunosuppressants compared with 16% in the no-previous-rituximab group. Myasthenia Gravis Activities of Daily Living total scores from eculizumab baseline to week 130 of eculizumab treatment improved in both the previous-rituximab and no-previous-rituximab groups (least-squares mean -4.4, standard error of the mean [SEM] 1.0 [n = 9] and least-squares mean -4.6, SEM 0.3 [n = 67], respectively; difference = 0.2, 95% confidence interval -1.88 to 2.22). In addition, in both groups, most patients who were treated with eculizumab for 130 weeks achieved a Myasthenia Gravis Foundation of America post-intervention status of minimal manifestations (66.7% and 65.0%, respectively). The eculizumab safety profile was similar between groups and consistent with its established profile.

DISCUSSION

Eculizumab is an effective therapy for patients with refractory AChR⁺ gMG, irrespective of whether they had received rituximab treatment previously.

Clinical Predictors of Prolonged Hospital Stay in Patients with Myasthenia Gravis: A Study Using Machine Learning Algorithms

Myasthenia gravis (MG) is an autoimmune disorder that causes muscle weakness. Although the management is well established, some patients are refractory and require prolonged hospitalization. Our study is aimed to identify the important factors that predict the duration of hospitalization in patients with MG by using machine learning methods. A total of 21 factors were chosen for machine learning analyses. We retrospectively reviewed the data of patients with MG who were admitted to hospital. Five machine learning methods, including stochastic gradient boosting (SGB), least absolute shrinkage and selection operator (Lasso), ridge regression (Ridge), eXtreme gradient boosting (XGboost), and gradient boosting with categorical features support (Catboost), were used to construct models for identify the important factors affecting the duration of hospital stay. A total of 232 data points of 204 hospitalized MG patients admitted were enrolled into the study. The MGFA classification, treatment of high-dose intravenous corticosteroid, age at admission, treatment with intravenous immunoglobulins, and thymoma were the top five significant variables affecting prolonged hospitalization. Our findings from machine learning will provide physicians with information to evaluate the potential risk of MG patients having prolonged hospital stay. The use of high-dose corticosteroids is associated with prolonged hospital stay and to be used cautiously in MG patients.

Single-cell RNA-Seq reveals transcriptional heterogeneity and immune subtypes associated with disease activity in human myasthenia gravis

Myasthenia gravis (MG) is a rare autoimmune disease. Although the impact of immune cell disorder in MG has been extensively studied, little is known about the transcriptomes of individual cells. Here, we assessed the transcriptional profiles of 39,243 cells by single-cell sequencing and identified 13 major cell clusters, along with 39 subgroups of cells derived from patients with new-onset myasthenia gravis and healthy controls. We found that B cells, CD4⁺ T cells, and monocytes exhibited more heterogeneity in MG patients. CD4⁺ T cells were expanded in MG patients. We reclustered B cells and CD4⁺ T cells, and predict their essential regulators. Further analyses demonstrated that B cells in MG exhibited higher transcriptional activity towards plasma cell differentiation, CD4⁺ T cell subsets were unbalanced, and inflammatory pathways of monocytes were highly activated. Notably, we discovered a disease-relevant subgroup, CD180⁻ B cells. Increased CD180⁻ B cells in MG are indicative of a high IgG composition and were associated with disease activity and the anti-AChR antibody. Together, our data further the understanding of the cellular heterogeneity involved in the pathogenesis of MG and provide large cell-type-specific markers for subsequent research.

Ocular Immune-Related Adverse Events Associated With Immune Checkpoint Inhibitors in Lung Cancer

Immune checkpoint inhibitors (ICIs) are novel immunotherapy-based drugs that have become increasingly popular in the treatment of lung cancer. Researchers have recognized ocular immune-related adverse events (irAEs) secondary to ICIs because of their vision-threatening characteristics. However, they are incompletely characterized and no studies have reported the ICI-related ocular irAEs in lung cancer. Therefore, we aimed to comprehensively illustrate the clinical characteristics, contributory factors, diagnosis, and management of ICI-related ocular irAEs in lung cancer, based on previously reported 79 patients. Ophthalmoplegia (40.51%), uveitis (20.25%), and dry eye (17.72%) were the most common ICI-related ocular irAEs in lung cancer. Ptosis was the most common (36.71%) and the highest mortality (23.33%) of ophthalmoplegia. Patients in Asia and patients who underwent combination therapy with programmed cell death-1 and cytotoxic T-lymphocyte-associated antigen 4 inhibitors demonstrated significantly higher frequency of ophthalmoplegia than other ocular irAEs. Most ICI-related ophthalmoplegia and uveitis in lung cancer were observed in the first 10 weeks following the initiation of ICIs. Furthermore, the onset time of dry eye and other ocular irAEs was much longer. In addition, 92.31% of the patients with ocular irAEs other than ophthalmoplegia could be remised. In conclusion, ocular irAEs secondary to ICIs in lung cancer are non-negligible, particularly ophthalmoplegia. Ethnicity and the type of ICIs play important roles in the distribution of ocular irAEs. ICI-related ophthalmoplegia in lung cancer presented with early onset and worse prognosis features, thus necessitating further attention.

Calprotectin as potential novel biomarker in myasthenia gravis

Myasthenia gravis (MG) is the most common autoimmune disease affecting the neuromuscular junction by specific autoantibodies. The etiology of MG and its heterogeneity in clinical courses are poorly understood, although it was recently shown that gut microbial dysbiosis plays a critical role. Since levels of Calprotectin (CLP) seem to correlate with level of dysbiosis, we hypothesize that CLP may serve as potential disease activity biomarker in MG. Sera from 251 patients with MG and 90 controls were analyzed in an explorative, cross-sectional design. Prospectively, we tested CLP levels in MG patients up to 3 years. Association of CLP levels with socio-demographics, disease activity (quantitative myasthenia gravis (QMG) score, myasthenia gravis-specific Activities of Daily Living scale (MG-ADL)), antibody (Abs) status, history of myasthenic crisis, treatment regime, and history of thymectomy were investigated using univariate analysis. Mean baseline serum levels of CLP were significantly higher in MG patients compared to controls (4.3 μg/ml vs. 2.1 μg/ml; p < 0.0001). Higher levels of CLP were associated with a higher clinical disease severity measured by MGFA classification and QMG score. Nevertheless, the only weak correlation of CLP with clinical outcome parameters needs confirmation in future studies. Currently, there are no validated blood biomarkers for MG. The significantly elevated CLP and mild correlation with parameters of disease activity suggests that CLP holds promise as a biomarker for measurement of individual disease severity.

Myasthenia gravis and telemedicine: a lesson from COVID-19 pandemic

COVID-19 pandemic has induced an urgent reorganization of the healthcare system to ensure continuity of care for patients affected by chronic neurological diseases including myasthenia gravis (MG). Due to the fluctuating nature of the disease, early detection of disease worsening, adverse events, and possibly life-threatening complications is mandatory. This work analyzes the main unresolved issues in the management of the myasthenic patient, the possibilities offered so far by digital technologies, and proposes an online evaluation protocol based on 4 simple tests to improve MG management. Telemedicine and Digital Technology might help neurologists in the clinical decision-making process of MG management, avoiding unnecessary in presence consultations and allowing a rational use of the time and space reduced by the pandemic.

Retrospective analysis of safety and outcomes of rituximab for myasthenia gravis in patients ≥65 years old

INTRODUCTION/AIMS

Optimal management of myasthenia gravis (MG) in individuals ≥65 y old is unknown and patient factors may limit therapeutic choices. Safety and efficacy of rituximab in older patients with MG has not been well-studied.

METHODS

This retrospective study examined 40 patients (14 patients ≥65 y old) treated with rituximab for MG. The primary efficacy outcome was the proportion of patients reaching "Improved" or better on Myasthenia Gravis Foundation of America (MGFA) Post-Intervention Status (PIS) at 12 mo, compared between younger and older patients.

RESULTS

Ninety-two percent of patients ≥65 y old achieved MGFA PIS Improved or better at 12 mo compared to 69% of those <65 y old (P = .11). Median prednisone dose for the cohort decreased in the year following rituximab initiation (20 mg [interquartile range, 10-35] to 10 mg [0-13], P = .01). Non-refractory MG was predictive of favorable outcome, whereas age was not. Serious adverse events (SAEs) were similar between older and younger patients (21.4% vs. 30.8%, P = .715). No patients ≥65 y old required discontinuation of rituximab due to SAE. One death occurred in a patient <65 y old due to systemic inflammatory response syndrome.

DISCUSSION

At 12 mo following initiation of rituximab for MG, patients ≥65 y old experienced similarly high rates of improvement in their myasthenic symptoms as younger patients, without an increased risk of experiencing SAEs. Rituximab should be considered in the treatment paradigm in older patients and in non-refractory MG patients of any age.

Association of NLRP3 rs35829419 and rs10754558 Polymorphisms With Risks of Autoimmune Diseases: A Systematic Review and Meta-Analysis

The existing knowledge about the association between NLRP3 rs35829419/rs10754558 polymorphisms and susceptibility to autoimmune diseases (AIDs) remains controversial. Herein, a meta-analysis was performed to evaluate such association. We searched databases for relevant studies published in English up to February 2021. Stata14 was used to assess the odds ratio (OR). As for NLRP3 rs35829419, no significant association to overall AIDs was found in three genetic models [A vs. C: OR (95%CI) = 0.89 (0.69-1.14); AC vs. CC: 1.00 (0.77-1.30); AA/AC vs. CC: 0.93 (0.71-1.20)]. However, subgroup analysis by disease type showed that NLRP3 rs35829419 A allele may have a significant protective effect on rheumatoid arthritis (RA) susceptibility [A vs. C: 0.74 (0.57-0.96)]. NLRP3 rs10754558 polymorphism contributes to significantly reduce the risk of AIDs in the allelic model [G vs. C: 0.78 (0.71-0.87)], homozygote co-dominant model [GG vs. CC: 0.63 (0.51-0.77)], heterozygote co-dominant model [GC vs. CC: 0.78 (0.66-0.91)], dominant model [GG/GC vs. CC: 0.73 (0.63-0.84)], and recessive model [GG vs. GC/CC: 0.73 (0.62-0.88)]. In the subgroup analysis by ethnicity, association was observed between the NLRP3 rs10754558 G allele and AIDs in Latin Americans, but not in European, Arabian, or Asian populations. Stratification by disease type showed a significant association of the NLRP3 rs10754558 G allele with type 1 diabetes (T1D), RA, and systemic lupus erythematosus (SLE), but not with celiac disease (CD), multiple sclerosis (MS), or myasthenia gravis (MG). This meta-analysis suggests that the NLRP3 rs10754558, but not rs35829419, polymorphism is associated with susceptibility to AIDs, especially in Latin American individuals.

Emerging drugs for the treatment of myasthenia gravis

Introduction: Advances in understanding the immune pathomechanisms in myasthenia gravis (MG) allow for the development of novel targeted immune therapies. By working at specific points in the immunopathogenesis, these agents have the potential to provide rapid and efficacious responses compared to conventional immunosuppressive therapy (IST), addressing unmet needs and consequently are a research priority.Areas covered: This paper reviews the advances in MG treatment modalities with their scientific rationale. A search of clinicaltrials.gov and a literature search of PubMed from January 2015 to the end of June 2021 was done using the search terms: MG, treatment, immune targets to obtain information on recent developments of complement inhibitors, FcRn receptor inhibitors, direct and indirect B cell inhibitors, CAR and CAAR- T cell therapy, and hematopoietic stem cell transplantation. Specific agents in various phases of clinical development, evidence from ongoing trials and potential roadblocks are examined.Expert opinion: Despite several promising novel agents, existing data as to the timing of initiation and duration of treatment, long-term safety profile and utility in certain patient subsets are limited and require further research. Despite these considerations, the future of MG treatment is transitioning from broad-spectrum IST toward precise, target-driven and personalized immunotherapy.

The risk of worsening of myasthenia by cardiovascular medication as reflected by reporting frequency

BACKGROUND AND PURPOSE

Some groups of cardiovascular drugs (beta-blocking drugs, Ca antagonists, antiarrhythmics) are listed as potentially worsening myasthenia. An empirical basis for alternative recommendations for antihypertensive and antiarrhythmic therapy in myasthenia patients has not yet been provided.

METHODS

From the World Health Organization pharmacovigilance database, we retrieved total and myasthenia-related counts of adverse drug reactions for various groups of drugs used in cardiovascular disease and drugs with related mechanism of action used in other indications. We calculated the reporting odds ratio as a measure of a disproportional fraction of myasthenia-related events among all events. A 95% confidence interval of reporting odds ratio (ROR) >1 was taken as an indication for a higher risk. Because our approach involves a considerable number of tests, this situation is referred to as a signal that requires additional confirmation.

RESULTS

A signal for an increased risk was noted for tizanidine, for alpha-blocking drugs, for beta-blocking drugs, and for Ca antagonists. ROR indicated a lower-than-average risk for salbutamol, angiotensin receptor antagonists, oral anticoagulants, thrombocytic function inhibitors, and heparins.

CONCLUSIONS

Angiotensin receptor antagonists, angiotensin-converting enzyme inhibitors, and diuretics seem to be safe in antihypertensive therapy. Surprisingly, and yet requiring confirmation by case reports, alpha receptor-blocking drugs seem to carry a risk of myasthenia worsening. Amiodarone seems to be a safe alternative in antiarrhythmic therapy in patients with myasthenia.

Heterogeneity in myasthenia gravis: considerations for disease management

Introduction: Myasthenia gravis is a rare disease of the neuromuscular junction and a prototype of B cell-driven immunopathology. Pathogenic antibodies target post-synaptic transmembrane proteins, most commonly the nicotinic acetylcholine receptor and the muscle-specific tyrosine kinase, inducing end-plate alterations and neuromuscular transmission impairment. Several clinical subtypes are distinct on the basis of associated antibodies, age at symptom onset, thymus pathology, genetic factors, and weakness distribution. These subtypes have distinct pathogenesis that can account for different responses to treatment. Conventional therapy is based on the use of symptomatic agents, steroids, immunosuppressants and thymectomy. Of late, biologics have emerged as effective therapeutic options.Areas covered: In this review, we will discuss the management of myasthenia gravis in relation to its phenotypic and biological heterogeneity, in the light of recent advances in the disease immunopathology, new diagnostic tools, and results of clinical trialsExpert opinion: Clinical management is shaped on serological subtype, and patient age at onset, lifestyle and comorbidities, balancing therapeutic needs and safety. Although reliable biomarkers predictive of clinical and biologic outcome are still lacking, recent developments promise a more effective and safe treatment. Disease subtyping according to serological testing and immunopathology is crucial to the appropriateness of clinical management.

Clinical Utility of Striational Antibodies in Paraneoplastic and Myasthenia Gravis Paraneoplastic Panels

OBJECTIVE

To critically assess the clinical utility of striational antibodies (StrAbs) within paraneoplastic and myasthenia gravis (MG) serologic evaluations.

METHODS

All Mayo Clinic patients tested for StrAbs from January 1, 2012, to December 31, 2018, utilizing Mayo's Unified Data Platform (UDP) were reviewed for neurologic diagnosis and cancer.

RESULTS

A total of 38,502 unique paraneoplastic evaluations and 1,899 patients with MG were tested. In paraneoplastic evaluations, the StrAbs positivity rate was higher in cancer vs without cancer (5% [321/6,775] vs 4% [1,154/31,727]; p < 0.0001; odds ratio [OR] 1.35; confidence interval [CI] 1.19-1.53), but receiver operating characteristic (ROC) analysis indicated no diagnostic accuracy in cancer (area under the ROC curve [AUC] 0.505). No neurologic phenotype was significantly associated with StrAbs in the paraneoplastic group. Positivity was more common in all MG cancers compared to paraneoplastic cancers (p < 0.0001). In MG evaluations, the StrAbs positivity rate was higher in those with cancer vs without (46% [217/474] vs 26% [372/1,425]; p < 0.0001; OR 2.39, CI 1.9-2.96), with ROC analysis indicating poor diagnostic accuracy for thymic cancer (AUC 0.634, recommended cutoff = 1:60, sensitivity = 56%, specificity = 71%), with worse accuracy for extrathymic cancers (AUC 0.543). In paraneoplastic or MG evaluations, the value of antibody positivity did not improve cancer predictions. Paraneoplastic evaluated patients with positive StrAbs were more likely to obtain CT (p = 0.0001), with cancer found in 3% (12/468).

CONCLUSION

Despite a statistically significant association with cancer, an expansive review of performance in clinical service demonstrates that StrAbs are neither specific nor sensitive in predicting malignancy or neurologic phenotypes. CT imaging is overutilized with positive StrAbs results. Removal of StrAbs from paraneoplastic or MG evaluations will improve the diagnostic characteristics of the current MG test.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that the presence of StrAbs does not accurately identify patients with malignancy or neurologic phenotypes.

Neuromuscular complications of cancer therapy

PURPOSE OF THE REVIEW

The neuromuscular complications of cancer therapy include chemotherapy-induced peripheral neurotoxicity (CIPN), immune-related neuromuscular complications to immune checkpoint inhibitors and radiation-induced neuropathy/plexopathy. With a wider focus on CIPN, we will discuss new pathogenetic insights, recent predictive biomarkers and emerging therapies for neuromuscular complications of cancer therapy.

RECENT FINDINGS

Findings from recent preclinical studies have improved our knowledge on new CIPN pathogenetic pathways, including the activation of senescence-like processes in neurons, axonal degeneration and neuroinflammation. Metabolomics and serum neurofilament light chain levels appear the most promising biomarkers to predict CIPN development and severity. There is some recent evidence of promising pharmacological compounds to prevent or treat CIPN, and new drugs are in early development and testing.

SUMMARY

A multimodal assessment, with neurophysiological, imaging and patient-reported outcome measures, coupled with the use of reliable blood or genetic biomarkers, may offer pathogenetic grounds for future preventive and symptomatic strategies for the multidisciplinary treatment of neuromuscular complications of cancer therapy.

Erectile dysfunction and reduced libido in a myasthenia gravis patient treated with methotrexate

Patients with myasthenia gravis treated with methotrexate are usually young and sexually active. Therefore, sexual dysfunction associated with MTX treatment should be considered and specifically searched in them as it can be an under-recognized cause of treatment failure or poor compliance.

Myasthenia Gravis: Epidemiology, Pathophysiology and Clinical Manifestations

Myasthenia gravis (MG) is an autoimmune neurological disorder characterized by defective transmission at the neuromuscular junction. The incidence of the disease is 4.1 to 30 cases per million person-years, and the prevalence rate ranges from 150 to 200 cases per million. MG is considered a classic example of antibody-mediated autoimmune disease. Most patients with MG have autoantibodies against the acetylcholine receptors (AChRs). Less commonly identified autoantibodies include those targeted to muscle-specific kinase (MuSK), low-density lipoprotein receptor-related protein 4 (Lrp4), and agrin. These autoantibodies disrupt cholinergic transmission between nerve terminals and muscle fibers by causing downregulation, destruction, functional blocking of AChRs, or disrupting the clustering of AChRs in the postsynaptic membrane. The core clinical manifestation of MG is fatigable muscle weakness, which may affect ocular, bulbar, respiratory and limb muscles. Clinical manifestations vary according to the type of autoantibody, and whether a thymoma is present.

Effects of thymectomy on late-onset non-thymomatous myasthenia gravis: systematic review and meta-analysis

BACKGROUND

The effects of thymectomy on late-onset non-thymomatous myasthenia gravis (NTMG) remain controversial. The objective of this study was to conduct a systematic review in order to answer two questions pertinent to late-onset NTMG: (1) do patients with late-onset NTMG experience the same effects from thymectomy as their early-onset counterparts? (2) Compared with conservative treatment, does thymectomy have any benefits for late-onset NTMG patients?

METHODS

We searched the PubMed, EMBASE, and Cochrane Library databases for studies published from January 1, 1950 to March 10, 2021. Outcomes were measured via clinical stable remission/pharmacological remission (CSR/PR) and improvement rates. We used Stata software to analyze the data.

RESULTS

We ultimately included a total of 12 observational articles representing the best evidence answering the questions of our study objective. Of these, nine studies, which included 896 patients overall (766 early-onset and 230 late-onset), compared postoperative outcomes between early- and late-onset NTMG. The remaining three articles, which included 216 patients (75 in the thymectomy group and 141 in the conservative-treatment group), compared thymectomy with conservative treatment for late-onset NTMG. The early- versus late-onset NTMG studies demonstrated that patients in the former category were 1.95× likelier than their late-onset counterparts to achieve clinical remission (odds ratio [OR] 1.95; 95% confidence interval [CI] 1.39-2.73; I2 = 0%). No difference was seen in improvement or remission + improvement rates between these two groups. When comparing thymectomy with conservative treatments in late-onset NTMG patients, neither did we observe any difference in CSR/PR.

CONCLUSION

We found that late-onset NTMG patients had a lower chance of achieving CSR after thymectomy than early-onset patients. Thymectomy in late-onset NTMG also yielded no benefit to CSR or PR compared with conservative treatments. In late-onset NTMG patients, thymectomy should therefore be performed with caution, and the appropriate cutoff between early- and late-onset MG should be further explored in order to tailor and execute the proper therapeutic strategies.

Application Prospect of Artificial Intelligence in Rehabilitation and Management of Myasthenia Gravis

Myasthenia gravis (MG) is a chronic autoimmune disease of the nervous system, which is still incurable. In recent years, with the progress of immunosuppressive and supportive treatment, the therapeutic effect of MG in the acute stage is satisfactory, and the mortality rate has been greatly reduced. However, there is still no consensus on how to conduct long-term management of stable MG, such as guiding patients to identify relapses, practice exercise, return to work and school, etc. In the international consensus guidance for management of myasthenia gravis published by the Myasthenia Gravis Foundation of America (MGFA) in 2020, for the first time, "the role of physical training/exercise in MG" was identified as the topic of discussion. Finally, due to a lack of high-quality evidence on physical training/exercise in patients with MG, the topic was excluded after the literature review. Therefore, this paper reviewed the current status of MG rehabilitation research and the difficulties faced by stable MG patients in self-management. It is suggested that we should take advantage of artificial intelligence (AI) and leverage it to develop the data-driven decision support platforms for MG management which can be used for adverse event monitoring, disease education, chronic management, and a wide variety of data collection and analysis.

A practical approach to the evaluation and management of gastrointestinal symptoms in patients with systemic sclerosis

The gastrointestinal (GI) tract is the most commonly affected internal organ system in systemic sclerosis (SSc). SSc may lead to impaired function in any region of the GI tract, from the esophagus to the anorectum, which causes significant morbidity as well as mortality in patient subsets. Given the low prevalence of SSc in the community, many rheumatologists may not have a systematic framework for diagnosing or treating the GI complaints in this disease. These practice recommendations aim to summarize and consolidate the current guidelines from the fields of gastroenterology and rheumatology and establish a symptom-based framework for diagnosis and management based on available evidence in the literature. Subject areas that are in need of additional research are also identified.