Myasthenic crisis

Respiratory Paralysis in a Patient with Myasthenia Gravis after Ingestion of Marine Carnivorous Gastropods

The salivary glands of marine carnivorous gastropods contain tetramines, which usually cause mild symptoms of poisoning. However, these symptoms may be fatal in rare cases. A 58-year-old woman with a history of myasthenia gravis complained of dyspnea after consuming marine carnivorous gastropods with intact salivary glands. Upon arrival at the hospital, her blood gas analysis revealed type II respiratory failure with a pCO2 of 154 mmHg. Tracheal intubation was immediately performed. Her respiratory condition improved the following day, and she therefore could be weaned off the ventilator. Tetramine poisoning can be fatal for patients with certain underlying medical conditions.

Predictive modeling and interpretative analysis of risks of instability in patients with Myasthenia Gravis requiring intensive care unit admission

Objective

Myasthenia gravis (MG), a low-prevalence autoimmune disorder characterized by clinical heterogeneity and unpredictable disease fluctuations, presents significant risks of acute exacerbations requiring intensive care. These crises contribute substantially to patient morbidity and mortality. This study aimed to develop and validate machine-learning models for predicting intensive care unit (ICU) admission risk among patients with MG-related disease instability.

Methods

In this retrospective analysis of 314 MG patients hospitalized between 2015 and 2018, we implemented four machine learning algorithms, including logistic regression, support vector machine, extreme gradient boosting (XGBoost), and random forest, to predict ICU admission risk. The models incorporated fourteen clinical parameters as predictive features. The SHapley Additive exPlanations method was utilized to assess the importance of factors associated with ICU admission.

Results

Through 10-fold cross-validation, the XGBoost model demonstrated superior predictive performance (area under the receiver operating characteristic curve: 0.8943, accuracy: 0.8603, sensitivity: 0.7222, and specificity: 0.9125). Among the analyzed features, MG severity, as classified by the Myasthenia Gravis Foundation of America clinical classification, was identified as the most significant factor influencing ICU admission. Additionally, disease duration, a key continuous variable, was inversely correlated with the risk of ICU admission.

Conclusion

MG severity is the primary determinant of ICU admission, with shorter disease duration increasing the risk, possibly due to greater susceptibility to exacerbations. The XGBoost model exhibited excellent performance and accuracy, effectively identifying critical clinical factors for predicting ICU admission risk in MG patients. This novel, personalized approach to risk stratification elucidates crucial risk factors and has the potential to enhance clinical decision-making, optimize resource allocation, and ultimately improve patient outcomes.

First line treatment with subcutaneous efgartigimod in impending myasthenic crisis: a case report

In acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG), neonatal Fc-receptor (FcRn) inhibition has broadened the therapeutic spectrum. Myasthenic crisis (MC), heralded by an impending myasthenic crisis (iMC), is a critical condition requiring treatments with rapid onset and sustained efficacy. Currently treatments used for iMC, including intravenous immunoglobulins and plasma exchange/immunoadsorption, have limitations, such as delayed onset of action and potential side effects. So far, there is limited data on the use of FcRn inhibitors in the management of impending or manifest MC (mMC). Here, we present a case of AChR antibody-positive gMG with iMC, where subcutaneous administration of the FcRn inhibitor efgartigimod resulted in rapid clinical remission. Within 24 h of administration, the patient exhibited significant improvement in respiratory and bulbar muscle function, preventing progression to manifest MC and the need for mechanical ventilation. This rapid response was accompanied by a marked reduction in AChR antibody level by 89.8% within 4 weeks. This case supports the potential of efgartigimod as a fast-acting and effective treatment option for managing iMC, offering an alternative to existing therapies.

Myasthenic Crisis and Concomitant Takotsubo Syndrome Complicated by Shock

A man in his 80s with myasthenia gravis (MG) developed dysmobility and chest discomfort. An electrocardiogram revealed ST-segment elevation, and coronary angiography revealed Takotsubo syndrome (TTS). He experienced myasthenic crisis that required ventilation and shock that was refractory to vasopressors and required intra-aortic balloon pump (IABP) insertion. He was managed conservatively without MG-specific treatment until his hemodynamics improved. On hospital day 6, he was weaned from IABP. MG is a high-risk condition for TTS, and TTS with myasthenic crisis (MC) is associated with high mortality. We successfully managed this case of TTS with MC with intubation and IABP, without MG-specific treatment.

Therapeutic development towards T follicular helper cells as a molecular target in myasthenia gravis disease

This review intends to gather literature to provide a comprehensive understanding of the molecular mechanisms and role of T follicular helper cells (Tfh) in the interaction with germinal centers (GCs) in Myasthenia Gravis (MG) disease regarding new developments focusing on Tfh as a therapeutic target and its key regulator B cell lymphoma 6 (Bcl6). Tfh cells are CD4+ T cells specialized in providing signals for the activation and maturation of B cells plus the formation and maintenance of GCs; the role of Bcl6 stands as the key transcriptional factor for the survival of GCs and promotion of Tfh generation. Previous studies have demonstrated gene therapy to be beneficial by achieving re-establishment of "immune homeostasis" and amelioration of the proinflammatory process.

Design of and Early Insights From a Generalized Myasthenia Gravis Patient Engagement Research Council

Background and Aims

An exploratory focus group study was conducted to better understand the needs of patients living with generalized myasthenia gravis (gMG).

Methods

US-based adults with gMG and caregivers of patients with gMG participated in a Patient Engagement Research Council between August 2022 and January 2023. The study consisted of a 15-min prework survey, followed by virtual focus groups facilitated using a semi-structured interview guide. Data concepts were identified using conversational analysis and by direct observation. All transcripts were coded based on concepts using a qualitative research analysis program (MaxQDA).

Results

16 participants (13 patients, three caregivers) were recruited. Participants reported impact on daily activities, fatigue, and psychosocial problems. Many participants experienced delayed diagnosis and difficulty accessing specialist care. Participants described multiple barriers related to their gMG, including barriers to treatment, access-related issues, and communication disconnect between patients and healthcare professionals. Achieving stable disease was the most important goal. There was a preference for the autonomy of self-administered medications at home versus infusions. Study insights led to recommendations to guide patient and healthcare professional education.

Conclusion

The study illustrates the need to improve access to specialist care, achieve earlier diagnosis, prioritize patients' preferences in disease management, and develop treatments that improve outcomes without additional burden.

Patient or Public Contribution

The data collected in this study was provided by the focus group participants, which included patients and caregivers of those with myasthenia gravis.

Intensive care due to myasthenia gravis: Risk factors and prognosis

BACKGROUND AND PURPOSE

Exacerbation of myasthenia gravis (MG) with respiratory failure requires intensive care. We aimed to study the risk factors for intensive care unit admission for MG exacerbation and myasthenic crisis (MC) and the prognosis of people with MG (pwMG) thereafter.

METHODS

This retrospective study investigated patients in the Helsinki and Uusimaa hospital district during the years 2008-2021. PwMG (International Classification of Diseases, 10th revision code G70.0) were identified through a data repository search, followed by a chart review of patient records. Risk factors for intensive care due to MG exacerbation were evaluated as compared with the patients only treated in the outpatient clinic and those treated in the neurological ward for MG exacerbation. The outcomes of patients in intensive care for any reason were also compared with those of patients in intensive care for exacerbation of bronchial asthma.

RESULTS

Of 577 pwMG, 35 (6.1%) needed intensive care for MG within a median of 5.3 months from diagnosis. The mean (±SD) age at MG diagnosis was higher in the intensive care group (60.5 [±16.1] years) compared to the outpatient (48.3 [±20.9] years; p < 0.001) and neurological ward groups (53.4 [±20.8] years; p = 0.044). Thymoma (odds ratio [OR] 4.8, 95% confidence interval [CI] 1.19-19.43; p = 0.028) and female sex (OR 2.1, 95% CI 1.02-4.48; p = 0.045) were independent risk factors for intensive care. In-hospital mortality was 4% for MC patients. Six-month mortality after intensive care for MG exacerbation (14.3%) was twice that for asthma exacerbation (7.7%).

CONCLUSION

Our study shows an increased risk of intensive care treatment for patients with late-onset MG, female sex or thymoma, occurring usually within 6 months from diagnosis, which emphasises the importance of early treatment choices.

Therapeutic challenges and unmet needs in the management of myasthenia gravis: an Italian expert opinion

Myasthenia gravis (MG) is a rare, autoimmune, neurological disorder. Most MG patients have autoantibodies against acetylcholine receptors (AChRs). Some have autoantibodies against muscle-specific tyrosine kinase (MuSK) or lipoprotein-receptor-related protein 4 (LRP4), and some are seronegative. Standard of care, which includes anti-cholinesterase drugs, thymectomy, corticosteroids (CS), and off-label use of non-steroidal immunosuppressive drugs (NSISTs), is bounded by potential side effects and limited efficacy in refractory generalized MG (gMG) patients. This highlights the need for new therapeutic approaches for MG. Eculizumab, a monoclonal antibody that inhibits the complement system, has been recently approved in Italy for refractory gMG. A panel of 11 experts met to discuss unmet therapeutic needs in the acute and chronic phases of the disease, as well as the standard of care for refractory patients. Survival was emphasized as an acute phase outcome. In the chronic phase, persistent remission and early recognition of exacerbations to prevent myasthenic crisis and respiratory failure were considered crucial. Refractory patients require treatments with fast onset of action, improved tolerability, and the ability to slow disease progression and increase life expectancy. The Panel agreed that eculizumab would presumably meet the therapeutic needs of many refractory gMG patients. The panel concluded that the unmet needs of current standard of care treatments for gMG are significant. Evaluating new therapeutic options accurately is essential to find the best balance between efficacy and tolerability for each patient. Collecting real-world data on novel molecules in routine clinical practice is necessary to address unmet needs.

Risk-Benefit Analysis of Novel Treatments for Patients with Generalized Myasthenia Gravis

INTRODUCTION

This study used network meta-analysis (NMA) to inform and compare the number needed to treat (NNT), number needed to harm (NNH), and cost per improved outcome (CPIO) associated with more recently approved treatments for anti-acetylcholine receptor antibody-positive (anti-AChR Ab+) generalized myasthenia gravis (gMG).

METHODS

Clinical trials of neonatal Fc receptor (FcRn) inhibitors, efgartigimod intravenous (IV) and rozanolixizumab, and complement inhibitors, ravulizumab and zilucoplan, versus placebo (with background conventional treatment) were included in the primary NMA to compare efficacy and safety outcomes. The outputs from the NMAs were used to estimate NNT and NNH of each treatment versus placebo. CPIO (2024 USD) was estimated for a ≥ 3- or ≥ 5-point reduction from baseline in Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis-Activities of Daily Living (MG-ADL) scores. Sensitivity analyses were performed adding efgartigimod PH20 subcutaneous (SC) and eculizumab to the NMA.

RESULTS

Efgartigimod IV had the lowest NNT versus placebo for achieving a ≥ 3- and ≥ 5-point reduction in QMG, as well as a ≥ 5-point reduction in MG-ADL, whereas rozanolixizumab had the lowest NNT for a ≥ 3-point reduction in MG-ADL. The NNH versus placebo was similar across comparator treatments. Efgartigimod IV had the lowest CPIO among all treatments for all assessed efficacy outcomes. Sensitivity analyses yielded results consistent with primary analysis and indicated that efgartigimod PH20 SC had comparable NNT and CPIO values to efgartigimod IV, whereas eculizumab had comparable NNT and higher CPIO values compared to other complement inhibitors.

CONCLUSIONS

FcRn inhibitors and complement inhibitors assessed in this study all demonstrated clinical benefit in terms of NNT as well as an acceptable safety profile in terms of NNH. Within the limitations of this meta-analysis, efgartigimod was associated with a favorable benefit-risk profile as well as a better economic value compared to ravulizumab, rozanolixizumab, and zilucoplan as treatments for anti-AChR Ab+ gMG.

Efgartigimod treatment in patients with anti-MuSK-positive myasthenia gravis in exacerbation

Background

The prevalence of patients positive for muscle-specific kinase antibody (hereafter, MuSK-Ab) accounts for 5-8% of all myasthenia gravis (MG) cases. Currently, efgartigimod has shown good therapeutic effects in MUSK-Ab-positive MG patients in a phase III clinical trial. However, phase III clinical trials tend to exclude MG patients in exacerbation, and there are only few real-world studies on the efficacy of efgartigimod in MuSK-Ab-positive myasthenic crisis (MC) patients. This retrospective, real-world study aimed to explore the efficacy of efgartigimod in MuSK-Ab-positive MG with exacerbation.

Methods

We reviewed the clinical data of four MuSK-Ab-positive patients with exacerbation of MG who received efgartigimod at the First Affiliated Hospital of Sun Yat-sen University, including two patients with MC. All patients were admitted between September 2023 and May 2024. Most patients are simultaneously undergoing rituximab treatment.

Results

Each patient completed one cycle of efgartigimod. After the first administration, four patients showed a clinically meaningful decrease in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score (a reduction of more than 4 points compared to baseline), and all patients showed a decrease in IgG levels after one cycle of efgartigimod. Regarding safety, none of the patients experienced any obvious adverse effects. At the final follow-up, all patients achieved the minimal symptom expression status (an MG-ADL score of 0 or 1) following the first administration of efgartigimod for 8.75 ± 5.56 weeks. This article presents a case involving a patient who exhibited prompt alleviation of symptoms following the administration of a high dose of efgartigimod (20 mg/kg, given on days 1 and 5), without the use of any other fast-acting treatment.

Conclusion

This retrospective real-world study demonstrates the effectiveness and safety of efgartigimod in these four MuSK-Ab-positive, female Asian patients with exacerbation of MG, as well as in patients experiencing MC. It is important to note that efgartigimod should not be viewed as a substitute for foundational immunotherapy; rather, it is intended as a rescue treatment during exacerbations and as an adjunctive therapy in the context of long-term immunotherapy. This non-invasive approach has the potential to become another treatment option for MuSK-Ab-positive MG patients.

Targeted Treatments for Myasthenia Gravis in Children and Adolescents

Myasthenia gravis (MG) is an antibody-mediated disorder of the neuromuscular junction affecting children and adults. MG is a treatable condition with most patients requiring immunosuppression for disease control and/or remission. Juvenile myasthenia gravis (JMG) is rare in comparison with adult-onset MG but given the same underlying pathophysiology, treatment strategies are similar to those in adults. Until recently, there were only a few randomised controlled trials (RCTs) for MG treatments in adults and none in children, and management strategies were primarily based on expert consensus. In addition, treatment options for refractory MG cases have been severely limited, resulting in poor long-term quality of life in such patients due to the significant disease burden. Recently, there have been several RCTs focussing on novel therapeutic strategies with potentially promising outcomes, suggesting a change in MG management over the coming years and access to more effective and faster-acting drugs for MG patients. This paper will review current and new MG treatments including efgartigimod, eculizumab, rozanolixizumab, ravulizumab, and zilucoplan, with a focus on juvenile myasthenia gravis.

New treatment strategies in Myasthenia gravis

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder characterized by muscle weakness and fatigue. The disease is primarily caused by antibodies targeting acetylcholine receptors (AChR) and muscle-specific kinase (MuSK) proteins at the neuromuscular junction. Traditional treatments for MG, such as acetylcholinesterase inhibitors, corticosteroids, and immunosuppressants, have shown efficacy but are often associated with significant long-term side effects and variable patient response rates. Notably, approximately 15% of patients exhibit inadequate responses to these standard therapies. Recent advancements in molecular therapies, including monoclonal antibodies, B cell-depleting agents, complement inhibitors, Fc receptor antagonists, and chimeric antigen receptor (CAR) T cell-based therapies, have introduced promising alternatives for MG treatment. These novel therapeutic approaches offer potential improvements in targeting specific immune pathways involved in MG pathogenesis. This review highlights the progress and challenges in developing and implementing these molecular therapies. It discusses their mechanisms, efficacy, and the potential for personalized medicine in managing MG. The integration of new molecular therapies into clinical practice could significantly transform the treatment landscape of MG, offering more effective and tailored therapeutic options for patients who do not respond adequately to traditional treatments. These innovations underscore the importance of ongoing research and clinical trials to optimize therapeutic strategies and improve the quality of life for individuals with MG.

The Impact of COVID-19 Vaccination and Infection on the Exacerbation of Myasthenia Gravis

OBJECTIVES

Myasthenia Gravis (MG) is an autoimmune disorder that can exacerbate for various reasons, including vaccination and infection. This study aimed to investigate the safety of COVID-19 vaccines for MG patients, factors influencing MG exacerbation after COVID-19 infection (MECI), the course and prognosis of MECI, and the impact of COVID-19 vaccine on infected MG patients.

METHODS

Patients were enrolled from the MG database in the Department of Neurology, Xuanwu Hospital, Capital Medical University. Two questionnaires were administered to collect data concerning COVID-19 vaccination (questionnaire 1, Q1) and infection (questionnaire 2, Q2) during two distinct periods. MG exacerbation was defined as an increase of at least two points in the MG activity of daily living (MG-ADL) score. COVID-19 severity was categorized as "hospitalization" or "home management"; Results: During the first data-collecting period, our database registered 1013 adult patients: 273 (26.9%) had received COVID-19 vaccinations and completed Q1, and 8 (2.9%) experienced MG exacerbation after vaccination. During the second data-collecting period, among the newly registered patients, 366 patients completed Q2. Of these, 244 were infected, with 39 (16.0%) experiencing MECI and 21 (8.6%) requiring hospitalization. Multivariate analysis showed that generalized myasthenia gravis was associated with MECI (OR 3.354, 95% CI: 1.423-7.908, p = 0.006). Among the 244 infected patients, 143 had received COVID-19 vaccinations, including 14 who received their booster dose within 6 months before COVID-19 and 129 who were vaccinated more than 6 months before COVID-19. The remaining 101 were unvaccinated. No significant associations were found between COVID-19 vaccination and COVID-19 severity (p = 0.292) or MECI incidence (p = 0.478); Conclusions: COVID-19 vaccines were found to be safe for MG patients in stable condition. Patients with gMG were more susceptible to experiencing MECI. No significant impact of the vaccine on COVID-19 severity or MECI incidence was observed.

Efgartigimod as a fast-acting add-on therapy in manifest and impending myasthenic crisis: A single-center case series

Efgartigimod was the first-in-class neonatal Fc receptor antagonist approved for the treatment of acetylcholine receptor antibody positive (AChR+), Myasthenia Gravis Foundation of America (MGFA) Class II-IV generalized myasthenia gravis (gMG) patients. As a novel therapy, the clinical experiences are still lacking, especially for the use of efgartigimod in manifest and impending myasthenic crisis (IMC). We reported three AChR+, gMG patients, two with myasthenic crisis (MC) and one with IMC, treated with efgartigimod. MGFA class, MG-Activity of Daily Living score (MG-ADL), Quantitative MG score (QMG), and Muscle Research Council sum score (MRC), concentration of anti-AChR antibody, IgG, globulin, and albumin, subsets of T and B lymphocyte were evaluated or measured before, during and after efgartigimod treatment. All patients showed fast and robust response to efgartigimod with marked improvement in MGFA, MG-ADL, QMG, and MRC scores. Patient 1 did not respond effectively to IVIg but was successfully rescued by add-on efgartigimod. She extubated at 7 days after the first infusion and got rid of NIV after 14-days treatment. Patient 2 and patient 3 directly used efgartigimod when symptoms were not ameliorated by adjusting of oral drugs. Patient 2 wean from BiPAP at seven days after the first infusion. Patient 3 in IMC status, overcame the severe dysphagia at three days after the first infusion. Clinical symptoms continued to improve 1-2 weeks after discharge. Concentration of anti-AChR antibody, IgG and globulin were remarkably reduced by efgartigimod treatment. Our study supported that efgartigimod could act as a fast-acting rescue therapy for patients with MC or IMC. Larger studies from multicenter are required to provide further evidence.

Ectopic Thymoma in the Thorax With Associated Myasthenia Gravis

A 52-year-old man presented with a one-year history of episodic unilateral facial numbness, jaw weakness, ptosis, and hoarseness. Brain imaging was unremarkable and an 11.5cm right lower thoracic mass was discovered on chest x-ray, which was further evaluated by CT and MRI radiology. The lesion was biopsied, and histopathological examination revealed a thymoma. A diagnosis of ectopic thymoma with paraneoplastic myasthenia gravis was supported by positive anti-acetylcholine receptor and anti-titin serum antibodies. Paraneoplastic syndromes are rarely reported in association with ectopic thymoma, making this case unusual. We discuss the nuances of diagnosis, classification, and staging of this rare case, as well as the patient's subsequent management by cardiothoracic surgery and neurology specialists.

Pitfalls in the Evaluation of Respiratory Failure in Myasthenia Gravis Patients: A Case Series

Objectives

To highlight the importance of recognizing different presentations of respiratory failure due to myasthenic and non-myasthenic etiologies in myasthenia gravis (MG) patients.

Methods

We describe 3 patients with different presentations of respiratory failure in MG.

Cases

Patient 1 is a 49-year-old female with longstanding MG who presented with lethargy and neck weakness without notable respiratory distress. She was found to be in hypercarbic respiratory failure, which improved with plasmapheresis treatment. Patient 2 is a 58-year-old female who presented with ptosis, dysphagia, and dyspnea requiring intubation. Her hypophonia and dyspnea persisted despite escalation in MG treatment, and further workup revealed glottal stenosis secondary to granulomatosis with polyangiitis. Patient 3 is an 85-year-old female with MG presenting with refractory hypoxia, which was secondary to a large patent foramen ovale resulting in right-to-left shunting.

Discussion

All 3 cases emphasize the role of clinical reasoning and careful analysis based on thorough history taking, detailed neurologic exam and comprehensive laboratory findings to determine the etiologies for respiratory dysfunction in MG and provide appropriate treatment.

Conclusion

A lack of overt signs of respiratory distress in MG does not rule out the presence of respiratory failure due to the sedating effect of hypercapnia. There is a need to consider alternative etiologies of hypoxia in MG patients if typical symptoms or signs of MG exacerbations are absent.

Dihydroartemisinin ameliorates experimental autoimmune myasthenia gravis by regulating CD4+ T cells and modulating gut microbiota

BACKGROUND

Dihydroartemisinin (DHA), a derivative and active metabolite of artemisinin, possesses various immunomodulatory properties. However, its role in myasthenia gravis (MG) has not been clearly explored. Here, we investigated the role of DHA in experimental autoimmune myasthenia gravis (EAMG) and its potential mechanisms.

METHODS

The AChR97-116 peptide-induced EAMG model was established in Lewis rats and treated with DHA. Flow cytometry was used to assess the release of Th cell subsets and Treg cells, and 16S rRNA gene amplicon sequence analysis was applied to explore the relationship between the changes in the intestinal flora after DHA treatment. In addition, network pharmacology and molecular docking were utilized to explore the potential mechanism of DHA against EAMG, which was further validated in the rat model by immunohistochemical and RT-qPCR for further validation.

RESULTS

In this study, we demonstrate that oral administration of DHA ameliorated clinical symptoms in rat models of EAMG, decreased the expression level of Th1 and Th17 cells, and increased the expression level of Treg cells. In addition, 16S rRNA gene amplicon sequence analysis showed that DHA restored gut microbiota dysbiosis in EAMG rats by decreasing Ruminococcus abundance and increasing the abundance of Clostridium, Bifidobacterium, and Allobaculum. Using network pharmacology, 103 potential targets of DHA related to MG were identified, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that PI3K-AKT signaling pathway was related to the treatment of DHA on EAMG. Meanwhile, molecular docking verified that DHA has good binding affinity to AKT1, CASP3, EGFR, and IGF1. Immunohistochemical staining showed that DHA treatment significantly inhibited the phosphorylated expression of AKT and PI3K in the spleen tissues of EAMG rats. In EAMG rats, RT-qPCR results also showed that DHA reduced the mRNA expression levels of PI3K and AKT1.

CONCLUSIONS

DHA ameliorated EAMG by inhibiting the PI3K-AKT signaling pathway, regulating CD4+ T cells and modulating gut microbiota, providing a novel therapeutic approach for the treatment of MG.

Efgartigimod as Rescue Medication in a Patient with Therapy-Refractory Myasthenic Crisis

Myasthenic crises (MC) are potentially life-threatening acute exacerbations of myasthenia gravis (MG) characterized by profound muscle weakness, bulbar symptoms, and potential for respiratory failure. Intravenous immunoglobulins (IVIG) and plasma exchange (PLEX) are conventional treatments for myasthenic exacerbations. Recently, new therapeutic options for generalized acetylcholine-receptor antibody positive (AchR+) MG were approved as an add-on therapy. They mainly consist of complement C5 inhibitors such as eculizumab and ravulizumab and neonatal Fc receptor antagonists such as efgartigimod with the approval of more options pending, e.g., zilucoplan and rozanolixizumab. More therapeutic options are in the pipeline. Although the data show a quick and reliable treatment response, these medications have not been studied for the therapy of myasthenic crisis. We present the case of a 57-year-old male with his first episode of generalized myasthenia gravis (MG) and positive acetylcholine-receptor antibodies (AchR+) who was transferred to our neurological intensive care unit with worsening generalized weakness, dysphagia, and respiratory distress. The crisis was triggered by pneumonia due to dysphagia. He was diagnosed with myasthenic crisis and treated with intravenous pyridostigmine, plasmapheresis (PLEX), and continued prednisone. Initial improvement was followed by deterioration, requiring readmission and additional PLEX. After a further decline, efgartigimod was administered, leading to significant improvement within 48 hours, as evidenced by reduced MG-ADL and QMG scores. The patient continued to improve and was stable enough for transfer to a rehabilitation facility. This case illustrates the potential of efgartigimod as a novel treatment for refractory myasthenic crises.

Epidemiology, Patient Characteristics, and Treatment Patterns of Myasthenia Gravis in Taiwan: A Population-Based Study

INTRODUCTION

Myasthenia gravis (MG) is a chronic neuromuscular disease leading to significant disease burden. This study aimed to investigate the epidemiology of MG in Taiwan.

METHODS

A retrospective study was conducted using the Taiwan National Health Insurance Research Database. Prevalent patients with MG diagnosis (either ocular or generalized MG) from 2013 to 2019 were identified, and 2813 patients with initial MG diagnosis from 2014 to 2019 were further defined as the incident cohort. Patient characteristics, treatment patterns, and the occurrence of MG-related events were analyzed.

RESULTS

The number of prevalent patients with MG increased from 4476 in 2013 to 5752 in 2019, with the prevalence rate increasing from 19 to 24 per 100,000 population. The incidence rate also slightly increased from 1.9 to 2.3 per 100,000 population during the study period. Almost all incident patients (99%, n = 2791) received MG-related treatment during the follow-up period. Among 1876 patients who received monotherapy as their initial treatment in the outpatient setting, the mean time from the index date to initial treatment was 48.8 (standard deviation 164.3) days, and most patients received acetylcholinesterase inhibitors (88.5%, n = 1661) as their initial treatment. During the first year after the index date, 133 (4.7%) incident patients experienced their first myasthenic crisis, and 96.2% of these events occurred within 3 months.

CONCLUSION

The prevalence of MG increased steadily in Taiwan, and the treatment of patients with MG was consistent with guidelines. Despite a high treatment rate, patients still experienced MG-related events, highlighting the limitation of current treatments and emphasizing the need for early intervention and novel treatment approaches.

Rescue treatment with add-on efgartigimod in a patient with impending myasthenic crisis: a case report

Myasthenia gravis (MG) is an autoimmune disorder characterized by fluctuating muscle weakness. Severe patients may develop life-threatening respiratory failure and experience crisis. Plasma exchange or intravenous immunoglobulin (IVIg) is the first-line treatment option for myasthenia crisis, but some patients still poorly respond to them. Here, we first reported a generalized MG patient from China who was in a state of impending myasthenic crisis and did not respond effectively to IVIg but was successfully rescued by add-on efgartigimod. Especially, we also detected meaningful changes in T-cell and B-cell subsets after efgartigimod, promoting a potential role of efgartigimod in re-establishing immune homeostasis.

Generalized myasthenia gravis with acetylcholine receptor antibodies: A guidance for treatment

BACKGROUND

Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research.

METHODS

MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings.

RESULTS

Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended.

CONCLUSIONS

Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

Serum amyloid A facilitates expansion of CD4+ T cell and CD19+ B cell subsets implicated in the severity of myasthenia gravis patients

Serum amyloid A (SAA) is a clinically useful inflammatory marker involved in the pathogenesis of autoimmune diseases. This study aimed to explore the SAA levels in a cohort of patients with myasthenia gravis (MG) in relation to disease-related clinical parameters and myasthenic crisis (MC) and elucidate the effects of SAA on immune response. A total of 82 MG patients including 50 new-onset MG patients and 32 MC patients were enrolled in this study. Baseline data and laboratory parameters of all enrolled MG patients were routinely recorded through electronic medical systems. SAA levels were measured by enzyme-linked immunosorbent assay (ELISA) kit. CD4+ T and CD19+ B cell subsets were analyzed by flow cytometry. In vitro, human recombinant SAA (Apo-SAA) was applied to stimulate peripheral blood mononuclear cells (PBMCs) from MG patients to observe the effect on T and B cell differentiation. Our results indicated that SAA levels in new-onset MG patients were higher than those in controls and were positively correlated with QMG score, MGFA classification, plasmablast cells, IL-6, and IL-17 levels. Subgroup analysis revealed that SAA levels were increased in generalized MG (GMG) patients than in ocular MG (OMG), as well as elevated in late-onset MG (LOMG) than in early-onset MG (EOMG) and higher in MGFA III/IV compared with MGFA I/II. The ROC curve demonstrated that SAA showed good diagnostic value for MC, especially when combined with NLR. In vitro, Apo-SAA promoted the Th1 cells, Th17 cells, plasmablast cells, and plasma cells differentiation in MG PBMCs. The present findings suggested that SAA was increased in MG patients and promoted expansion of CD4+ T cell and CD19+ B cell subsets, which implicated in the severity of MG patients.

Myasthenic crisis-induced Takotsubo cardiomyopathy: a case report

Introduction and importance

Myasthenic crisis (MC) is characterized by severe weakness in the bulbar and respiratory muscles. Takotsubo cardiomyopathy (TC) is a rare clinical entity mainly associated with postmenopausal women. We report a case of both these conditions in a premenopausal woman.

Case presentation

A 31-year-old woman with hypothyroidism presented with dyspnea. Bedside echocardiography in the ICU revealed an apical ballooning with an ejection fraction of 25%, and she was treated with losartan, furosemide, and spironolactone. She was intubated after 2 days as she developed respiratory distress and type II respiratory failure. Upon investigation, the patient tested positive for anti-acetylcholine receptor antibody. Treatment with five doses of IVIG (intravenous immunoglobulin) was given, and she made a remarkable recovery. Repeat echocardiography revealed her ejection fraction is normal and cardiac function is resolved.

Clinical discussion

The association between TC and MC is unusual and not commonly observed. MC can be a natural progression of myasthenia gravis or due to stressors, such as infection, medicine, pregnancy, and surgery. Stressful events can lead to TC. This leads to the possibility of TC, along with other cardiac complications, in patients with MC.

Conclusion

Patients with MC may be at potential risk of developing TC, thus careful cardiac monitoring is necessary while treating them for a better prognosis.

Myasthenia gravis: the changing treatment landscape in the era of molecular therapies

Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junction, leading to muscle weakness and fatigue. MG is caused by antibodies against the acetylcholine receptor (AChR), the muscle-specific kinase (MuSK) or other AChR-related proteins that are expressed in the postsynaptic muscle membrane. The standard therapeutic approach for MG has relied on acetylcholinesterase inhibitors, corticosteroids and immunosuppressants, which have shown good efficacy in improving MG-related symptoms in most people with the disease; however, these therapies can carry a considerable burden of long-term adverse effects. Moreover, up to 15% of individuals with MG exhibit limited or no response to these standard therapies. The emergence of molecular therapies, including monoclonal antibodies, B cell-depleting agents and chimeric antigen receptor T cell-based therapies, has the potential to revolutionize the MG treatment landscape. This Review provides a comprehensive overview of the progress achieved in molecular therapies for MG associated with AChR antibodies and MuSK antibodies, elucidating both the challenges and the opportunities these therapies present to the field. The latest developments in MG treatment are described, exploring the potential for personalized medicine approaches.

Hospitalizations and Mortality From Myasthenia Gravis: Trends From 2 US National Datasets

BACKGROUND AND OBJECTIVES

Myasthenia gravis (MG) is a rare neuromuscular disorder where IgG antibodies damage the communication between nerves and muscles, leading to muscle weakness that can be severe and have a significant impact on patients' lives. MG exacerbations include myasthenic crisis with respiratory failure, the most serious manifestation of MG. Recent studies have found MG prevalence increasing, especially in older patients. This study examined trends in hospital admissions and in-hospital mortality for adult patients with MG and readmissions and postdischarge mortality in older (65 years or older) adults with MG.

METHODS

Data from the Nationwide Inpatient Sample (NIS), an all-payer national database of hospital discharges, were used to characterize trends in hospitalizations and in-hospital mortality related to MG exacerbations and MG crisis among adult patients aged 18 years or older. The Medicare Limited Data Set, a deidentified, longitudinal research database with demographic, enrollment, and claims data was used to assess hospitalizations, length of stay (LOS), readmissions, and 30-day postdischarge mortality among fee-for-service Medicare beneficiaries aged 65 years or older. The study period was 2010-2019. Multinomial logit models and Poisson regression were used to test for significance of trends.

RESULTS

Hospitalization rates for 19,715 unique adult patients and 56,822 admissions increased from 2010 to 2019 at an average annualized rate of 4.9% (MG noncrisis: 4.4%; MG crisis: 6.8%; all p < 0.001). Readmission rates were approximately 20% in each study year for both crisis and noncrisis hospitalizations; the in-hospital mortality rate averaged 1.8%. Among patients aged 65 years or older, annualized increases in hospitalizations were estimated at 5.2%, 4.2%, and 7.7% for all, noncrisis, and crisis hospitalizations, respectively (all p < 0.001). The average LOS was stable over the study period, ranging from 11.3 to 13.1 days, but was consistently longer for MG crisis admissions. Mortality among patients aged 65 years or older was higher compared with that in all patients, averaging 5.0% across each of the study years.

DISCUSSION

Increasing hospitalization rates suggest a growing burden associated with MG, especially among older adults. While readmission and mortality rates have remained stable, the increasing hospitalization rates indicate that the raw numbers of readmissions-and deaths-are also increasing. Mortality rates are considerably higher in older patients hospitalized with MG.

Case report: Recovery from refractory myasthenic crisis to minimal symptom expression after add-on treatment with efgartigimod

Myasthenic crisis, a life-threatening exacerbation of myasthenia gravis, is a significant clinical challenge, particularly when refractory to standard therapies. Here, we described a case of myasthenic crisis in which the patient transitioned from refractory myasthenic crisis to minimal symptom expression after receiving add-on treatment with efgartigimod, a novel neonatal Fc receptor antagonist. A 54 years-old woman who was diagnosed with anti-acetylcholine receptor antibody-positive myasthenia gravis experienced respiratory failure necessitating mechanical ventilation. Despite aggressive treatment with plasmapheresis, intravenous immunoglobulins, and high-dose corticosteroids, her condition continued to deteriorate, culminating in persistent myasthenic crisis. Efgartigimod was administered as salvage therapy. Remarkable improvement in neuromuscular function was observed within days, allowing for successful weaning from mechanical ventilation. Over the subsequent weeks, the patient's symptoms continued to ameliorate, ultimately reaching a state of minimal symptom expression. Serial assessments of her serum anti-acetylcholine receptor antibody titer showed a consistent decline in parallel with this clinical improvement. This case highlights efgartigimod's potential as an effective therapeutic option for refractory myasthenic crisis, offering new hope for patients facing this life-threatening condition.

Depression: A Contributing Factor to the Clinical Course in Myasthenia Gravis Patients

Background and Objectives: The association between myasthenia gravis (MG) and depression is intricate and characterized by bidirectional causality. In this regard, MG can be a contributing factor to depression and, conversely, depression may worsen the symptoms of MG. This study aimed to identify any differences in the progression of the disease among patients with MG who were also diagnosed with depression as compared to those without depression. Our hypothesis focused on the theory that patients with more severe MG symptoms may have a higher likelihood of suffering depression at the same time. Materials and Methods: One hundred twenty-two male and female patients (N = 122) aged over 18 with a confirmed diagnosis of autoimmune MG who were admitted to the Neurology II department of Myasthenia Gravis, Clinical Institute Fundeni in Bucharest between January 2019 and December 2020, were included in the study. Patients were assessed at baseline and after six months. The psychiatric assessment of the patients included the Hamilton Depression Rating Scale-17 items (HAM-D), and neurological status was determined with two outcome measures: Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Activities of Daily Life (MG-ADL). The patients were divided into two distinct groups as follows: group MG w/dep, which comprised 49 MG patients diagnosed with depressive disorder who were also currently receiving antidepressant medication, and group MG w/o dep, which consisted of 73 patients who did not have depression. Results: In our study, 40.16% of the myasthenia gravis (MG) patients exhibited a comorbid diagnosis of depression. Among the MG patients receiving antidepressant treatment, baseline assessments revealed a mean MG-ADL score of 7.73 (SD = 5.05), an average QMG score of 18.40 (SD = 8.61), and a mean Ham-D score of 21.53 (SD = 7.49). After a six-month period, a statistically significant decrease was observed in the MG-ADL (2.92, SD = 1.82), QMG (7.15, SD = 4.46), and Ham-D scores (11.16, SD = 7.49) (p < 0.0001). These results suggest a significant correlation between MG severity and elevated HAM-D depression scores. Regarding the MG treatment in the group with depression, at baseline, the mean dose of oral corticosteroids was 45.10 mg (SD = 16.60). Regarding the treatment with pyridostigmine, patients with depression and undergoing antidepressant treatment remained with an increased need for pyridostigmine, 144.49 mg (SD = 51.84), compared to those in the group without depression, 107.67 mg (SD = 55.64, p < 0.001). Conclusions: Our investigation confirms that the occurrence of depressive symptoms is significantly widespread among individuals diagnosed with MG. Disease severity, along with younger age and higher doses of cortisone, is a significant factor associated with depression in patients with MG. Substantial reductions in MG-ADL and QMG scores were observed within each group after six months, highlighting the effectiveness of MG management. The findings suggest that addressing depressive symptoms in MG patients, in addition to standard MG management, can lead to improved clinical outcomes.

Ravulizumab in Myasthenia Gravis: A Review of the Current Evidence

The terminal complement C5 inhibitor ravulizumab was engineered from the humanized monoclonal antibody eculizumab to have an extended half-life and duration of action. It binds to human terminal complement protein C5, inhibiting its cleavage into C5a and C5b, thus preventing the cascade of events that lead to architectural destruction of the postsynaptic neuromuscular junction membrane by the membrane attack complex, and consequent muscle weakness in patients with anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG). The 26-week randomized, placebo-controlled period (RCP) of the phase 3 CHAMPION MG study demonstrated the rapid efficacy of ravulizumab in reducing MG symptoms. Weight-based dosing of ravulizumab every 8 weeks provided sustained efficacy, in terms of patient-reported (Myasthenia Gravis-Activities of Daily Living) and clinician-reported (Quantitative Myasthenia Gravis) endpoints in patients with anti-AChR antibody-positive gMG. Pharmacokinetic and pharmacodynamic analyses showed therapeutic serum ravulizumab concentrations (>175 µg/mL) were achieved immediately after the first dose and were maintained throughout 26 weeks, irrespective of patient body weight; inhibition of serum free C5 was immediate, complete (<0.5 μg/mL), and sustained in all patients. Interim results from the open-label extension (OLE) showed that after 60 weeks, efficacy was maintained in patients continuing on ravulizumab. Rapid and sustained improvements in efficacy, similar to those seen in patients initiating ravulizumab in the RCP, were observed after initiation of ravulizumab treatment in patients who switched from placebo in the RCP to ravulizumab in the OLE. The findings from the RCP and OLE support ravulizumab's favorable safety profile. In conclusion, ravulizumab has a simple weight-based administration and long dosing interval. Its targeted mechanism of action without generalized immunosuppression is reflected in its rapid onset of symptom improvement, sustained efficacy and good safety profile in the treatment of patients with anti-AChR antibody-positive gMG.

Peripheral immune landscape for hypercytokinemia in myasthenic crisis utilizing single-cell transcriptomics

BACKGROUND

Myasthenia gravis (MG) is the most prevalent autoimmune disorder affecting the neuromuscular junction. A rapid deterioration in respiratory muscle can lead to a myasthenic crisis (MC), which represents a life-threatening condition with high mortality in MG. Multiple CD4+ T subsets and hypercytokinemia have been identified in the peripheral pro-inflammatory milieu during the crisis. However, the pathogenesis is complicated due to the many types of cells involved, leaving the underlying mechanism largely unexplored.

METHODS

We conducted single-cell transcriptomic and immune repertoire sequencing on 33,577 peripheral blood mononuclear cells (PBMCs) from two acetylcholine receptor antibody-positive (AChR +) MG patients during MC and again three months post-MC. We followed the Scanpy workflow for quality control, dimension reduction, and clustering of the single-cell data. Subsequently, we annotated high-resolution cell types utilizing transfer-learning models derived from publicly available single-cell immune datasets. RNA velocity calculations from unspliced and spliced mRNAs were applied to infer cellular state progression. We analyzed cell communication and MG-relevant cytokines and chemokines to identify potential inflammation initiators.

RESULTS

We identified a unique subset of monocytes, termed monocytes 3 (FCGR3B+ monocytes), which exhibited significant differential expression of pro-inflammatory signaling pathways during and after the crisis. In line with the activated innate immune state indicated by MC, a high neutrophil-lymphocyte ratio (NLR) was confirmed in an additional 22 AChR + MC patients in subsequent hemogram analysis and was associated with MG-relevant clinical scores. Furthermore, oligoclonal expansions were identified in age-associated B cells exhibiting high autoimmune activity, and in CD4+ and CD8+ T cells demonstrating persistent T exhaustion.

CONCLUSIONS

In summary, our integrated analysis of single-cell transcriptomics and TCR/BCR sequencing has underscored the role of innate immune activation which is associated with hypercytokinemia in MC. The identification of a specific monocyte cluster that dominates the peripheral immune profile may provide some hints into the etiology and pathology of MC. However, future functional studies are required to explore causality.