Myasthenia Gravis: Epidemiology, Pathophysiology and Clinical Manifestations

Insights from CD71 presentation and serum lipid peroxidation in myasthenia gravis - A small cohort study

Myasthenia gravis (MG) is a multifaceted autoimmune disorder affecting the postsynaptic neuromuscular junction. In this study, we examined CD4+ and CD8+ T lymphocyte levels and ratios within peripheral blood mononuclear cells (PBMCs) in MG patients. Additionally, we assessed lymphocytes for the expression of CD71, which functions as a transferrin receptor mediating the uptake of iron into the cells. Building on recent discussions regarding CD20 depletion treatments in MG, we also scrutinized lymphocytes for CD20 expression. Comparative analyses were conducted among healthy controls, newly diagnosed MG patients, those undergoing pyridostigmine treatment alone, and MG patients receiving combination therapies. In the patients, the ratio of CD3+CD4+ T lymphocytes to CD3+ T lymphocytes was found to be decreased compared to the healthy controls, while the ratio of CD3+CD8+ cells to CD3+CD4+ cells increased. An increase in the percentage of CD71-expressing lymphocytes was observed in MG patients compared to the healthy control group, while CD20+ lymphocytes exhibited no statistical changes. Moreover, heightened serum lipid peroxidation levels were found in MG patients. These results suggest a possible relationship between iron metabolism, levels of CD71-expressing cells, and lipid peroxidation in MG. Conversely, pyridostigmine treatment reduced the levels of CD71-expressing cells and lipid peroxidation, suggesting potential immunomodulatory and antioxidant impacts of pyridostigmine in MG, either directly or indirectly.

Treatment of myasthenia gravis in france: A retrospective claims database study (STAMINA)

BACKGROUND

This study aimed to describe treatment patterns in patients with myasthenia gravis (MG) in France.

METHODS

A retrospective cohort analysis was performed using the French National Health Data System (SNDS) database between 2008 and 2019. MG patients were identified using ICD-10 codes during hospitalization and/or long-term disease. We defined two adult subpopulations: a prevalent MG population of patients alive on 31/12/2019 and an incident population of newly identified patients with MG in 2012 and 2013.

RESULTS

Among the 22,079 prevalent patients, 53.1% (n = 11,498) received at least one chronic MG treatment in 2019. Among these treated patients, 52.5% received Acetylcholinesterase inhibitors (AChEIs) only, 10.2% were treated with corticosteroids (CS) ± AChEIs, 7.3% with non-steroidal immunosuppressive treatments (NSIST) and CS, 24.2% with NSIST w/o CS, and 5.8% received immunoglobulin and/or plasma exchange. Among the 2,661 incident patients, 84.6% received at least one chronic MG treatment over the 6-year follow-up period, and among them, 79.0% had at least one treatment category change. During the first semester of follow-up, 28.1% of patients were treated with an immunomodulator (CS, NSIST). Among patients starting treatment with immunomodulator, the proportion of those treated with CS decreased from 35.3% at initiation to 10.9% at 6 years.

CONCLUSION

This study illustrates the complexity of MG management. Significant CS sparing was observed over time. The frequent treatment changes especially in patients with an immunomodulator treatment reflect the high variability of the disease severity. The need for personalised treatment approaches in the management of MG to reduce the burden of disease remains.

New insights into the effects of organometallic ruthenium complexes on nicotinic acetylcholine receptors

Nicotinic acetylcholine receptors (nAChRs) are expressed in excitable and non-excitable cells of the organism. Extensive studies suggest that nAChR ligands have therapeutic potential, notably for neurological and psychiatric disorders. Organometallic ruthenium complexes are known to inhibit several medically important enzymes such as cholinesterases. In addition, they can also interact with muscle- and neuronal-subtype nAChRs. The present study aimed to investigate the direct effects of three organometallic ruthenium complexes, [(η6-p-cymene)Ru(II)(5-nitro-1,10-phenanthroline)Cl]Cl (C1-Cl), [(η6-p-cymene)Ru(II)(1-hydroxypyridine-2(1H)-thionato)Cl] (C1a) and [(η6-p-cymene)Ru(II)(1-hydroxy-3-methoxypyridine-2(1H)-thionato)pta]PF6 (C1), on muscle-subtype (Torpedo) nAChRs and on the two most abundant human neuronal-subtype nAChRs in the CNS (α4β2 and α7) expressed in Xenopus laevis oocytes, using the two-electrode voltage-clamp. The results show that none of the three compounds had agonistic activity on any of the nAChR subtypes studied. In contrast, C1-Cl reversibly blocked Torpedo nAChR (half-reduction of ACh-evoked peak current amplitude by 332 nM of compound). When tested at 10 μM, C1-Cl was statistically more potent to inhibit TorpedonAChR than α4β2 and α7 nAChRs. Similar results of C1 effects were obtained on Torpedo and α4β2 nAChRs, while no action of the compound was detected on α7 nAChRs. Finally, the effects of C1a were statistically similar on the three nAChR subtypes but, in contrast to C1-Cl and C1, the inhibition was hardly reversible. These results, together with our previous studies on isolated mouse neuromuscular preparations, strongly suggest that C1-Cl is, among the three compounds studied, the only molecule that could be used as a potential myorelaxant drug.

Possible sex and racial disparities in myasthenia gravis care

INTRODUCTION/AIMS

Given the importance of early diagnosis and treatment of myasthenia gravis (MG), it is critical to understand disparities in MG care. We aimed to determine if there are any differences in testing, treatment, and/or access to neurologists for patients of varying sex and race/ethnicity with MG.

METHODS

We used a nationally representative healthcare claims database of privately insured individuals (2001-2018) to identify incident cases of MG using a validated definition. Diagnostic testing, steroid-sparing agents, intravenous immunoglobulin (IVIG), plasma exchange (PLEX), and thymectomy were defined using drug names or CPT codes. Steroid use was defined using AHFS class codes. We also determined whether an individual had a visit to a neurologist and the time between primary care and neurologist visits. Logistic regression determined associations between sex and race/ethnicity and testing, treatments, and access to neurologists.

RESULTS

Female patients were less likely to get a computed tomography (CT) chest (odds ratio (OR) 0.73, 95% confidence interval (CI): 0.64-0.83), receive steroids (OR: 0.85, 95% CI: 0.75-0.97), steroid-sparing agents (OR: 0.84, 95% CI: 0.72-0.97), and IVIG or PLEX (OR: 0.80, 95% CI: 0.67-0.95). Black patients were less likely to receive steroids (OR: 0.78, 95% CI: 0.63-0.96). No significant disparities were seen in access to neurologists.

DISCUSSION

We found healthcare disparities in MG treatment with female and Black patients receiving less treatment than men and those of other races/ethnicities. Further research and detailed assessments accounting for individual patient factors are needed to confirm these apparent disparities.

The changing landscape of autoantibody testing in myasthenia gravis in the setting of novel drug treatments

Acquired myasthenia gravis (MG) is an autoimmune disease targeting the specific proteins in the postsynaptic muscle membrane. 50% of ocular and 80% of generalized MG have acetylcholine receptor antibodies (AChR Abs). 1-10% of MG patients have antibodies against muscle-specific kinase (MuSK), and 2-50 % of seronegative MG cases have antibodies against lipoprotein-receptor-related protein4 antibodies (LRP4 Abs). Serological testing is crucial for diagnosing and determining the appropriate therapeutic approach for MG patients. The radioimmunoprecipitation assay (RIPA) method is a historical standard test for detecting the AChR Abs and MuSK Abs. While it has nearly 100% specificity in the AChR Abs detection, its sensitivity is between 50--92%. The sensitivity and specificity of RIPA for detecting MuSK Abs is much lower. The fixed and live Cell-Based assays (f-CBA and L- CBA) have higher sensitivity than RIPA. With advancements in the serological diagnosis and management of MG, we now recommend a complete reflex testing algorithm on the first pretreatment sample of a suspected MG patient, starting with the binding and blocking assays for AChR Abs by RIPA and/ or f-CBA. If AChR Ab is negative, then reflex to MuSK Abs by RIPA and/ or CBAs. If AChR and MuSK Abs are negative, then use clustered L-CBA by request.

AI-Powered Telemedicine for Automatic Scoring of Neuromuscular Examinations

Telemedicine is now being used more frequently to evaluate patients with myasthenia gravis (MG). Assessing this condition involves clinical outcome measures, such as the standardized MG-ADL scale or the more complex MG-CE score obtained during clinical exams. However, human subjectivity limits the reliability of these examinations. We propose a set of AI-powered digital tools to improve scoring efficiency and quality using computer vision, deep learning, and natural language processing. This paper focuses on automating a standard telemedicine video by segmenting it into clips corresponding to the MG-CE assessment. This AI-powered solution offers a quantitative assessment of neurological deficits, improving upon subjective evaluations prone to examiner variability. It has the potential to enhance efficiency, patient participation in MG clinical trials, and broader applicability to various neurological diseases.

Refractory Myasthenia Gravis and Concurrent Alopecia Areata Postthymectomy With Improvements After Cortisone Taper: A Case Report

This case report presents a unique clinical scenario of a 58-year-old male suffering from severe refractory myasthenia gravis and concurrent alopecia areata postthymectomy. Myasthenia gravis, a common autoimmune disorder, is characterized by muscle weakness due to autoantibodies targeting neuromuscular junction proteins. Alopecia areata, another autoimmune disease, is often seen in individuals with myasthenia gravis, suggesting a shared immunological basis. The patient's condition was resistant to conventional treatment, and he developed alopecia areata following thymectomy. Despite the challenges in managing refractory myasthenia gravis and the associated alopecia areata, significant improvements were observed following a cortisone taper. This case highlights the potential therapeutic role of cortisone tapering in managing refractory myasthenia gravis and associated alopecia areata. This case also prompts further exploration into the immunological shifts following thymectomy, particularly its potential role in triggering alopecia areata.

Epidemiology of myasthenia gravis in Denmark, Finland and Sweden: a population-based observational study

BACKGROUND

Incidence and prevalence rates of myasthenia gravis (MG) vary considerably across studies, and mortality risk is rarely addressed. We examined the prevalence and incidence rates, mortality and factors associated with mortality with MG.

METHOD

This was a registry linkage study based on nationwide health and administrative registries of Denmark, Finland and Sweden (populations of 5.9, 5.6 and 10.5 million, respectively). Patients with MG were identified based on International Classification of Diseases codes from inpatient and outpatient specialised care registries. Yearly prevalence, incidence and mortality rates in relation to the total background population were calculated from 2000 to 2020 (study period). The causes of death and factors associated with mortality were addressed separately.

RESULTS

The overall incidence of MG was 1.34 (95% CI 1.27 to 1.41), 1.68 (95% CI 1.60 to 1.75) and 1.62 (95% CI 1.56 to 1.68) per 100 000, and the overall prevalence per 100 000 was 18.56 (95% CI 18.31 to 18.81), 20.89 (95% CI 20.62 to 21.16) and 23.42 (95% CI 23.21 to 23.64) in Denmark, Finland and Sweden, respectively. The overall standardised mortality ratio (SMR) was 1.32 (95% CI 1.23 to 1.42) among patients with MG in Denmark, 1.23 (95% CI 1.15 to 1.33) in Finland, and 1.20 (95% CI 1.14 to 1.26) in Sweden, with higher SMR observed in women than men. Annual incidence and prevalence increased over time, whereas the SMR remained stable. The most common causes of death were MG, chronic ischaemic heart disease and acute myocardial infarction.

CONCLUSIONS

This population-based study from three Nordic countries highlights the need for improved care of patients with MG, especially young women.

Cardiac implications in myasthenia gravis

This editorial aimed to consolidate the current evidence in literature on the association between myasthenia gravis (MG) and cardiac involvement, focusing on the impact of thymoma, antistriational antibodies, and late-onset MG. Additionally, the study aimed to explore the influence of genetic differences among populations on the association with cardiac disease. We conducted a review of existing literature in PubMed and Google Scholar to find relevant studies on cardiac involvement in MG. We created search criteria using a combination of free text words, including MG, antistriational antibodies, thymectomy, cardiomyopathy, myocarditis, arrhythmias, autonomic dysfunction. Relevant articles published in English language were analyzed and incorporated. The findings indicate a strong association between thymoma, myasthenic crisis, antistriational antibodies, and late-onset MG with cardiac involvement. The study also revealed that genetic differences among populations influence the risk of cardiac disease and electrocardiography (ECG) abnormalities in MG patients. Autonomic dysfunctions altered cardiac autonomic response and increased susceptibility to arrhythmias and sudden cardiac death in MG patients. The study supports the significance of thymoma, antistriational antibodies, and late-onset MG as key factors associated with cardiac involvement in MG patients. It emphasizes the importance of ECG as the initial test in managing MG patients, particularly in the perioperative period, to identify and genetic testing if needed to address their cardiac risk effectively.

Association between baseline lipid profile and risk of worsening in patients with myasthenia gravis: A retrospective cohort study

Background

Dyslipidemia has been implicated in autoimmunity; however, its association with myasthenia gravis (MG) prognosis is unclear. We aimed to investigate the correlation between baseline lipid profiles and risk of MG worsening.

Methods

This 7-year retrospective cohort study conducted at a Chinese hospital included 264 adult patients with MG. Data on baseline lipids, 1-year worsening, and covariates, including demographics, MG characteristics, comorbidities, and treatments were extracted.

Results

Univariate and multivariate logistic regression analyses failed to show a significant association between the risk of 1-year MG worsening and any of the seven blood lipid-related indicators. However, the subsequent non-linear analysis revealed an inflection point in the risk curve of ln[lipoprotein(a)], at 4.06 (58 nmol/L). The lipoprotein(a) levels on the left side of the inflection point presented a positive significant correlation with the risk of MG worsening (relative risk [RR]: 6.06, 95 % confidence interval [CI]: 1.00-38.57), whereas those on the right side of the inflection point demonstrated no significant correlation (RR: 0.86, 95 % CI: 0.55-1.34).

Conclusions

Except for lipoprotein(a) levels being associated with worsening of myasthenia gravis, most lipid parameters were not associated with changes in the clinical course and severity of myasthenia gravis.we observed that lower levels of lipoprotein(a) were associated with a better prognosis in the interval 7-58 nml/L, whereas beyond this interval this was not observed, suggesting dyslipidemia may impact MG prognosis. Further studies are required to validate these findings.

Predictors of High Healthcare Cost Among Patients with Generalized Myasthenia Gravis: A Combined Machine Learning and Regression Approach from a US Payer Perspective

BACKGROUND

High healthcare costs could arise from unmet needs. This study used random forest (RF) and regression methods to identify predictors of high costs from a US payer perspective in patients newly diagnosed with generalized myasthenia gravis (gMG).

METHODS

Adults with gMG (first diagnosis = index) were selected from the IQVIA PharMetrics® Plus database (2017-2021). Predictors of high healthcare costs were measured 12 months pre-index (main cohort) and during both the 12 months pre- and post-index (subgroup). Top 50 predictors of high costs [≥ $9404 (main cohort) and ≥ $9159 (subgroup) per-patient-per-month] were identified with RF models; the magnitude and direction of association were estimated with multivariable modified Poisson regression models.

RESULTS

The main cohort and subgroup included 2739 and 1638 patients, respectively. In RF analysis, the most important predictors of high costs before/on the index date were index MG exacerbation, all-cause inpatient admission, and number of days with corticosteroids. After the index date, these were immunoglobulin and monoclonal antibody use and number of all-cause outpatient visits and MG-related encounters. Adjusting for the top 50 predictors, post-index immunoglobulin use increased the risk of high costs by 261%, monoclonal antibody use by 135%, index MG exacerbation by 78%, and pre-index all-cause inpatient admission by 27% (all p < 0.05).

CONCLUSIONS

This analysis links patient characteristics both before the formal MG diagnosis and in the first year to high future healthcare costs. Findings may help inform payers on cost-saving strategies, and providers can potentially shift to targeted treatment approaches to reduce the clinical and economic burden of gMG.

United States clinical practice experience with eculizumab in myasthenia gravis: symptoms, function, and immunosuppressant therapy use

BACKGROUND/OBJECTIVES

The phase 3 REGAIN study and its open-label extension demonstrated the efficacy of the complement C5 inhibitor eculizumab in patients with treatment-refractory, acetylcholine receptor antibody-positive generalized myasthenia gravis (gMG). The aim of the ELEVATE study was to assess the effectiveness of eculizumab in clinical practice in adults with MG in the United States.

METHODS

A retrospective chart review was conducted in adults with MG who initiated eculizumab treatment between October 23, 2017 and December 31, 2019. Outcomes assessed before and during eculizumab treatment using a pre- versus post-treatment study design included Myasthenia Gravis-Activities of Daily Living (MG-ADL) total scores; minimal symptom expression (MSE); physician impression of clinical change; minimal manifestation status (MMS); and concomitant medication use.

RESULTS

In total, 119 patients were included in the study. A significant reduction was observed in mean MG-ADL total score, from 8.0 before eculizumab initiation to 5.4 at 3 months and to 4.7 at 24 months after eculizumab initiation (both p < 0.001). At 24 months after eculizumab initiation, MSE was achieved by 19% of patients. MMS or better was achieved by 30% of patients at 24 months. Additionally, 64% of patients receiving prednisone at eculizumab initiation had their prednisone dosage reduced during eculizumab treatment and 13% discontinued prednisone; 32% were able to discontinue nonsteroidal immunosuppressant therapy.

DISCUSSION

Eculizumab treatment was associated with sustained improvements in MG-ADL total scores through 24 months in adults with MG. Prednisone dosage was reduced in approximately two-thirds of patients, suggesting a steroid-sparing effect for eculizumab.

Lipoprotein Receptor-Related Protein 4 Antibody Positivity in the Youngest Patient in the Caucasus Region: A Case Report

Juvenile myasthenia gravis is a rare disorder where antibodies targeting the acetylcholine receptor or, less frequently, muscle-specific kinase can be detected in the serum while about half of the patients can be seronegative. A pediatric patient with ocular myasthenia is presented whose serum was negative for acetylcholine receptor and muscle-specific kinase antibodies but tested positive for low-density lipoprotein receptor-related protein 4 antibodies. A favourable clinical response was observed to medical treatment with pyridostigmine and prednisolone, as expected in isolated ocular juvenile myasthenia gravis. This case exemplifies the very rare association of juvenile myasthenia gravis with low-density lipoprotein receptor-related protein 4 positivity, reported in only a few cases so far. The specificity of the antibody and the efficiency of medical treatment emphasize the importance of clinical suspicion and appropriate serological testing in juvenile myasthenia gravis in the absence of acetylcholine receptor and muscle-specific kinase antibodies.

Sero-Positive Isolated Ocular Myasthenia Gravis

Ocular myasthenia gravis (OMG) is a neuromuscular disease characterized by the production of autoantibodies against post-synaptic proteins at the neuromuscular junction (NMJ). An 18-year-old male who had symptoms of drooping eyelids and double vision was diagnosed with ocular myasthenia gravis on investigations and examinations. Treatment was initiated with a tablet of pyridostigmine 60 mg twice daily per oral for two weeks, followed by three times daily for four weeks. The patient demonstrated significant improvement in ptosis and diplopia. There are still a considerable number of challenges in the diagnosis and treatment of ocular myasthenia gravis, with the typical treatment involving acetylcholinesterase inhibitors and immunosuppressants.

Thymoma With Myasthenia Gravis: A Study of Two Cases

Thymoma is a rare, primary neoplasm of the thymus gland, commonly presenting in adults and associated with autoimmune diseases, most commonly myasthenia gravis (MG). Despite its generally indolent behavior, the variability in clinical presentation and potential for malignancy necessitates detailed evaluation and management. In this report, we present two cases: a 41-year-old male and a 39-year-old female, both of whom presented with a mediastinal mass with symptoms of myasthenia. Further investigation, including imaging and histopathological examination, confirmed the diagnosis of a type B2 thymoma and type B1 thymoma for the male and female patients, respectively. The patients underwent successful complete surgical resection of the masses, with the postoperative recovery being uneventful. They were monitored for signs of disease recurrence and associated autoimmune conditions during follow-up visits. This report underscores the importance of early detection and thorough clinical evaluation of thymoma, particularly in patients with associated paraneoplastic syndromes. Complete surgical resection remains the cornerstone of treatment, with adjuvant therapy tailored based on individual risk factors. Ongoing surveillance is crucial for identifying potential recurrences and associated conditions.

Risk of fracture in patients with myasthenia gravis: a nationwide cohort study in Korea

Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junctions, resulting in muscle weakness and fatigue. Muscle weakness, restricted mobility, and frequent use of corticosteroids in patients with MG may predispose them to a higher risk of fractures. However, studies on the impact of MG on bone health and the associated fracture risk are scarce. Utilizing claim database of the Korean National Health Insurance Service collected between 2002 and 2020, we compared the risk of major osteoporotic fracture between 23 118 patients with MG and 115 590 individuals as an age- and sex-matched control group using multivariable Cox proportional hazard models. Over a median follow-up duration of 5.58 years, the MG group (mean age 53.7 years; 55% women) had higher risk of major osteoporotic fracture compared with controls (incidence rate 13.59 versus 9.74 per 10 000 person-years), which remained independent of age, sex, comorbidities, drug use including anti-osteoporotic agents, and previous fracture history (adjusted hazard ratio [aHR] 1.19, P < 0.001; subdistributed HR 1.14, P < 0.001 adjusted for mortality as competing risk). Subgroup analyses showed a greater association between MG and major osteoporotic fracture risk in younger (age 50 or younger) than older individuals (aHR 1.34 vs. 1.17) and in men compared with women (aHR 1.32 vs. 1.15; P for interaction < 0.05 for all). An imminent divergence of the fracture risk curve between MG and controls was observed for vertebral fracture, while there was time delay for non-vertebral sites, showing site-specific association. Factors associated with higher fracture risk in patients with MG were older age, female gender, high dose glucocorticoid use (>7.5 mg/day), immunosuppressant use, and previous history of fracture. In summary, patients with MG had higher risk of major osteoporotic fracture compared with controls, which calls further preventive actions in this patient group.

Frequency and severity of autonomic dysfunction assessed by objective hemodynamic responses and patient-reported symptoms in individuals with myasthenia gravis

Introduction

Myasthenia gravis (MG), a rare autoimmune disorder, poses diagnostic and management challenges, with increasing incidence in Europe and significant impact on patient quality of life. Despite prevalent autonomic symptoms, comprehensive assessments integrating subjective and objective measures are lacking. We aimed to investigate the prevalence and severity of autonomic dysfunction in patients with MG and healthy controls (HCs).

Materials and methods

We used beat-to-beat hemodynamic responses during standardized autonomic function tests (AFTs) and the Composite Autonomic Symptom Score 31 (COMPASS-31) questionnaire. Study participants including, 53 patients with MG and 30 age- and sex matched HCs underwent standardized cardiovascular AFTs and completed the COMPASS-31 questionnaire. Patients were categorized into Non-CAN and CAN groups based on their Cardiovascular Autonomic Neuropathy (CAN) status, as evaluated using the Composite Autonomic Scoring Scale (CASS). During the AFTs, cardiovascular parameters including heart rate, systolic blood pressure (BP), diastolic BP, mean BP, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured.

Results

Twenty patients with MG (38%) exhibited mild CAN (CASS ≥2) with a median total CASS score of 1.00 and CASS 0.00 in HCs. Adrenergic impairment was observed in 27 patients (52%), with 13 patients (24.5%) exhibiting longer pressure recovery time after Valsalva maneuver (VM). Cardiovagal impairment was evident in 71% of patients, with abnormal results observed in 39.6% for the deep breathing test and 56.6% for the VM. CAN MG showed worse scores than HCs for the total COMPASS-31 (p < 0.001), orthostatic (OI) (p < 0.001), secretomotor (p = 0.004), and pupillomotor domains (p = 0.004). Total COMPASS-31 and OI scores were correlated with worse disease outcomes (disease duration, severity), hemodynamic parameter changes (SV, CO, TPR) during phase II late of VM, and with changes (Δtilt-supine) in Δsystolic BP, Δdiastolic BP, Δmean BP, ΔTPR during head-up-tilt test, but not with CASS score.

Conclusion

Our findings demonstrate mild cardiovascular autonomic impairment in adrenergic and cardiovagal domains in patients with MG. Additionally, patient-reported autonomic symptoms correlated with hemodynamic changes during AFTs and worse disease outcomes and not with the grade of autonomic abnormalities. Incorporating beat-to-beat hemodynamics during AFTs may offer further insights for characterizing orthostatic intolerance symptoms in MG group.

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.

Induction cyclophosphamide with maintenance immunosuppression in high-risk myasthenia gravis: long-term follow-up and safety profile

BACKGROUND

Patients with refractory or high-risk myasthenia gravis (MG) respond poorly to conventional immunosuppressive therapy, requiring rescue therapies and often experiencing treatment toxicity. Rescue and injectable therapies do not induce remission and require repetitive administration leading to significant constraints on patients and the healthcare system. This long-term follow-up study demonstrates cyclophosphamide as a rapidly effective and safe treatment in patients with refractory or high-risk MG.

METHODS

Retrospective cohort study of MG patients treated with cyclophosphamide between January 2000 and June 2022 conducted at a quaternary neuroimmunology clinic in New South Wales, Australia.

RESULTS

31 patients were treated: mean age of 64 years; median follow-up 3.6 years (5 months to 11 years); 94% seropositive to acetylcholine receptor (AChR) antibodies and 45% had thymoma. A reduced intensity cyclophosphamide induction protocol followed by oral antiproliferative maintenance is described.Median myasthenia gravis composite scores reduced by >50% after the third cycle of cyclophosphamide. Complete cessation of prednisolone was possible in 11 patients while 20 remained on prednisolone with a median daily dose of 5 mg. Plasma exchange was ceased in 62% of patients and intravenous immunoglobulin ceased in 55%. Cyclophosphamide was generally well tolerated with mild cytopenias. There were no malignancies or cases of haemorrhagic cystitis.

CONCLUSION

We describe a large cohort of high-risk MG patients treated with cyclophosphamide in a retrospective single-clinic cohort. We suggest cyclophosphamide should be considered for rapid remission induction, corticosteroid reduction and long-term freedom from recurrent injectable therapies in selected patients, typically those with AChR antibodies.

Defective autophagy and autophagy activators in myasthenia gravis: a rare entity and unusual scenario

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ) that results from autoantibodies against nicotinic acetylcholine receptors (nAchRs) at NMJs. These autoantibodies are mainly originated from autoreactive B cells that bind and destroy nAchRs at NMJs preventing nerve impulses from activating the end-plates of skeletal muscle. Indeed, immune dysregulation plays a crucial role in the pathogenesis of MG. Autoreactive B cells are increased in MG due to the defect in the central and peripheral tolerance mechanisms. As well, autoreactive T cells are augmented in MG due to the diversion of regulatory T (Treg) cells or a defect in thymic anergy leading to T cell-mediated autoimmunity. Furthermore, macroautophagy/autophagy, which is a conserved cellular catabolic process, plays a critical role in autoimmune diseases by regulating antigen presentation, survival of immune cells and cytokine-mediated inflammation. Abnormal autophagic flux is associated with different autoimmune disorders. Autophagy regulates the connection between innate and adaptive immune responses by controlling the production of cytokines and survival of Tregs. As autophagy is involved in autoimmune disorders, it may play a major role in the pathogenesis of MG. Therefore, this mini-review demonstrates the potential role of autophagy and autophagy activators in MG.Abbreviations: Ach, acetylcholine; Breg, regulatory B; IgG, immunoglobulin G; MG, myasthenia gravis; NMJ, neuromuscular junction; ROS, reactive oxygen species; Treg, regulatory T; Ubl, ubiquitin-like.

Economic burden of generalized myasthenia gravis (MG) in the United States and the impact of common comorbidities and acute MG-events

BACKGROUND

This study assessed the incremental healthcare costs and resource utilization (HRU) associated with generalized myasthenia gravis (gMG), as well as variability in these outcomes among patients with gMG and common comorbidities and acute MG-related events.

METHODS

Adults with gMG and without MG were identified from a large US database (2017-2021). The index date was the first MG diagnosis (gMG cohort) or random date (non-MG cohort). Cohorts were propensity score matched 1:1. The gMG cohort included subgroups of patients with a 12-month pre-index (baseline) cardiometabolic or psychiatric comorbidity, or a post-index MG exacerbation/crisis. Monthly healthcare costs (2021 USD) and HRU were compared post-index between gMG and non-MG cohorts.

RESULTS

The gMG and matched non-MG cohorts each contained 2,739 patients. Mean incremental healthcare costs associated with MG were $4,155 (gMG: $5,567; non-MG: $1,411), with differences driven by incremental inpatient costs of $2,166 (gMG: $2,617; non-MG: $452); all p < 0.001. The gMG versus non-MG cohort had 4.36 times more inpatient admissions and 2.26 times more outpatient visits; all p < 0.001. Among patients with gMG in cardiometabolic (n = 1,859), psychiatric (n = 1,308), and exacerbation/crisis (n = 419) subgroups, mean monthly healthcare costs were $6,660, $7,443, and $17,330, respectively.

CONCLUSIONS

gMG is associated with substantial incremental costs and HRU, with inpatient costs driving the total incremental costs. Costs increased by 20% and 34% among patients with cardiometabolic and psychiatric conditions, respectively, and over three times among those with acute MG-related events. gMG is a complex disease requiring management of comorbidities and treatment options that can prevent acute symptomatic events.

Heterogeneous Presentations and Serologies in Myasthenia Gravis Patients Presenting with Dysphagia

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease that affects the neuromuscular junction. MG patients may present de novo with primary otolaryngology complaints, including swallowing dysfunction. This study describes a range of unique presentations and rare diagnostic serologies, which have not previously been fully described.

METHODS

A retrospective review was performed of all patients presenting with primary symptom of dysphagia and subsequently diagnosed with MG. Data collected included demographics, clinical presentation, swallow studies, serology, imaging, treatment, and response.

RESULTS

Five patients met the inclusion criteria. Four endorsed dysphagia as primary complaint and one endorsed dysphagia and dysphonia. All patients underwent in-office swallow evaluations that showed vallecular or pyriform sinus residue. Three patients completed modified barium swallow studies that showed pharyngeal weakness and epiglottic dysfunction in all, and upper esophageal sphincter dysfunction in two. One patient with additional symptom of dyspnea was admitted and found to be in myasthenic crisis. Upon serologic evaluation, three patients were positive for acetylcholine receptor (AChR) antibodies only, one for muscle-specific-kinase (MuSK) antibodies only, and one for low density lipoprotein receptor-related protein 4 (LRP4) antibodies only. All patients received neurology evaluation and were treated with steroids, pyridostigmine, plasma exchange, or rituximab. In three patients with over 1 year follow-up, symptoms were significantly improved or resolved.

CONCLUSION

MG is an important differential diagnosis in patients with unexplained pharyngeal dysphagia. While workup can include AChR antibody screening, in seronegative patients with persistent symptoms, additional testing for MuSK and LRP4 may lead to diagnosis and effective treatment.

LEVEL OF EVIDENCE

Level 4 Laryngoscope, 2024.

Characterizing Myasthenia Gravis Symptoms, Exacerbations, and Crises From Neurologist's Clinical Notes Using Natural Language Processing

Background Myasthenia gravis (MG) is a rare, autoantibody neuromuscular disorder characterized by fatigable weakness. Real-world evidence based on administrative and structured datasets regarding MG may miss important details related to the clinical encounter. Examination of free-text clinical progress notes has the potential to illuminate aspects of MG care. Objective The primary objective was to examine and characterize neurologist progress notes in the care of individuals with MG regarding the prevalence of documentation of clinical subtypes, antibody status, symptomatology, and MG deteriorations, including exacerbations and crises. The secondary objectives were to categorize MG deteriorations into practical, objective states as well as examine potential sources of clinical inertia in MG care. Methods We performed a retrospective, cross-sectional analysis of de-identified neurologist clinical notes from 2017 to 2022. A qualitative analysis of physician descriptions of MG deteriorations and a discussion of risks in MG care (risk for adverse effects, risk for clinical decompensation, etc.) was performed. Results Of the 3,085 individuals with MG, clinical subtypes and antibody status identified included gMG (n = 400; 13.0%), ocular MG (n = 253; 8.2%), MG unspecified (2,432; 78.8%), seropositivity for acetylcholine receptor antibody (n = 441; 14.3%), and MuSK antibody (n = 29; 0.9%). The most common gMG manifestations were dysphagia (n = 712; 23.0%), dyspnea (n = 626; 20.3%), and dysarthria (n = 514; 16.7%). In MG crisis patients, documentation of difficulties with MG standard therapies was common (n = 62; 45.2%). The qualitative analysis of MG deterioration types includes symptom fluctuation, symptom worsening with treatment intensification, MG deterioration with rescue therapy, and MG crisis. Qualitative analysis of MG-related risks included the toxicity of new therapies and concern for worsening MG because of changing therapies. Conclusions This study of neurologist progress notes demonstrates the potential for real-world evidence generation in the care of individuals with MG. MG patients suffer fluctuating symptomatology and a spectrum of clinical deteriorations. Adverse effects of MG therapies are common, highlighting the need for effective, less toxic treatments.

An unusual initiation of an ocular form of MuSK-positive myasthenia gravis after magnesium administration: a rare case report

Introduction and importance

The primary clinical symptom in people with myasthenia gravis (MG) is muscle weakness that gets worse with activity and gets better with rest; often, the first symptoms are ocular ones, such as ptosis and double vision. On the other hand, individuals with anti-muscle-specific tyrosine kinase may present with unusual symptoms. Nonetheless, it is hypothesized that muscle-specific tyrosine kinase antibodies may be present when no antibodies are present, along with bulbar and respiratory symptoms.

Case presentation

A 26-year-old pregnant patient was referred to the Neurology Department after experiencing tongue enlargement. A neuro-ophthalmic assessment revealed ptosis with lateral diplopia in the right eye, bulbar palsy, facial weakness, weakness in the palate and pharyngeal reflex, dizziness, and hearing loss in her right ear. The patient was given magnesium sulfate for 2 days since pre-eclampsia was suspected; however, this treatment exacerbated the development of symptoms and was discontinued. Her MG symptoms gradually improved after starting medication. Nonetheless, bilateral weakness in the neck and limb flexion persisted. Following a few days of therapy, there were no indications of diplopia, swallowing was normal, and the muscular weakness was somewhat improved.

Clinical discussion

The patient was put on drug treatment for MG (predlon 60 mg daily, amioran 50 mg twice daily, and mistenon).

Conclusion

Treating severe MG patients with a customized approach aims to manage their symptoms and improve their quality of life. Reduce muscle weakness, eradicate circulating antibodies, and suppress the abnormal immunological response. Minimizing side effects while attaining ideal symptom control is the ultimate objective.

Immune Checkpoints and Graves' Disease, Thyroid Eye Disease, and Orbital Myopathy: A Comprehensive Review

Immune checkpoints (ICPs) are essential regulators of the immune system, ensuring a delicate balance between self-tolerance and autoimmune responses. ICP therapy is a rapidly growing cancer treatment strategy that inhibits the interaction between ICPs and their ligands. This biological interaction increases the ability of the immune system in combating cancer. However, in some cases, the use of these agents may lead to immune hyperactivity and, subsequently, autoimmune diseases. Graves' disease (GD), thyroid eye disease (TED), and orbital myopathy are complex autoimmune disorders characterized by the production of autoantibodies. The emergence of these treatment-related adverse events underscore the critical need for a deeper understanding of the immune-checkpoint axis in autoimmune diseases. In this review article, we provide a comprehensive survey of the biological mechanisms of ICPs that are most frequently targeted in cancer therapy, including CTLA-4, PD-1, PDL-1, and LAG3. Furthermore, we investigate the latest scientific findings on the adverse events associated with the inhibition of these ICPs. This paper will particularly focus on the potential risks these complications pose to ocular and orbital tissues, which are a concern in the context of cancer treatment.

Myasthenia gravis: the future is here

Myasthenia gravis (MG) stands as a prototypical antibody-mediated autoimmune disease: it is dependent on T cells and characterized by the presence of autoantibodies targeting proteins located on the postsynaptic surface of skeletal muscle, known as the neuromuscular junction. Patients with MG exhibit a spectrum of weakness, ranging from limited ocular muscle involvement to life-threatening respiratory failure. Recent decades have witnessed substantial progress in understanding the underlying pathophysiology, leading to the delineation of distinct subcategories within MG, including MG linked to AChR or MuSK antibodies as well as age-based distinction, thymoma-associated, and immune checkpoint inhibitor-induced MG. This heightened understanding has paved the way for the development of more precise and targeted therapeutic interventions. Notably, the FDA has recently approved therapeutic inhibitors of complement and the IgG receptor FcRn, a testament to our improved comprehension of autoantibody effector mechanisms in MG. In this Review, we delve into the various subgroups of MG, stratified by age, autoantibody type, and histology of the thymus with neoplasms. Furthermore, we explore both current and potential emerging therapeutic strategies, shedding light on the evolving landscape of MG treatment.

JAK inhibition decreases the autoimmune burden in Down syndrome

Individuals with Down syndrome (DS), the genetic condition caused by trisomy 21 (T21), display clear signs of immune dysregulation, including high rates of autoimmune disorders and severe complications from infections. Although it is well established that T21 causes increased interferon responses and JAK/STAT signaling, elevated autoantibodies, global immune remodeling, and hypercytokinemia, the interplay between these processes, the clinical manifestations of DS, and potential therapeutic interventions remain ill defined. Here, we report a comprehensive analysis of immune dysregulation at the clinical, cellular, and molecular level in hundreds of individuals with DS. We demonstrate multi-organ autoimmunity of pediatric onset concurrent with unexpected autoantibody-phenotype associations. Importantly, constitutive immune remodeling and hypercytokinemia occur from an early age prior to autoimmune diagnoses or autoantibody production. We then report the interim analysis of a Phase II clinical trial investigating the safety and efficacy of the JAK inhibitor tofacitinib through multiple clinical and molecular endpoints. Analysis of the first 10 participants to complete the 16-week study shows a good safety profile and no serious adverse events. Treatment reduced skin pathology in alopecia areata, psoriasis, and atopic dermatitis, while decreasing interferon scores, cytokine scores, and levels of pathogenic autoantibodies without overt immune suppression. Additional research is needed to define the effects of JAK inhibition on the broader developmental and clinical hallmarks of DS. ClinicalTrials.gov identifier: NCT04246372.

Drug Use Patterns in Myasthenia Gravis: A Real-World Population-Based Cohort Study in Italy

Background: In the context of a comparative study of efficacy and safety of drugs used in rare neuromuscular and neurodegenerative diseases (CAESAR-call AIFA_FV_2012-13-14), we assessed the use patterns of drugs indicated for myasthenia gravis (MG). Methods: A retrospective cohort study was conducted based on administrative healthcare data. For a cohort of MG patients, prevalent and incident use of pyridostigmine (Py) and other indicated drugs in the first year after case identification was evaluated. Prevalent combined use of major therapies (azathioprine (Az), prednisone (Pr), vitamin D (Vd)) stratified by Py use was assessed, and a comparison between therapies at the time of MG identification and during the first year of follow-up was performed. Results: We included 2369 MG patients between 2013 and 2019. Among them, prevalent and incident Py users were 38.4% and 22.0%, respectively. In the first year of follow-up, the use of Pr was observed in 74.5% of Py prevalent users and in 82.0% of Py incident users, respectively; the use of Az was observed in 24.9% and 23.0%, respectively; and the use of Vd was observed in 53.3% and 48.2%, respectively. Among 910 Py prevalent users, 13.1% also used Az, Pr, and Vd, while 15.3% used none of these. Among 938 non-Py users, 2.7% used Az, Pr, and Vd, while 53.8% used none of these. During the first year, an increase in combined therapies was evident in incident Py users. Conclusions: Our results suggest that, for some MG patients, there may be a need for treatments that combine a rapid onset of benefit with long-term and consistent disease control. These issues may be addressed by the new treatments currently being developed. To date, more studies are needed to address the heterogeneity, quality, and generalizability of the existing data and to evaluate patterns of use, efficacy, and safety of new or emerging therapies for MG.

Refocusing generalized myasthenia gravis: Patient burden, disease profiles, and the role of evolving therapy

BACKGROUND AND PURPOSE

Generalized myasthenia gravis (gMG) continues to present significant challenges for clinical management due to an unpredictable disease course, frequent disease fluctuations, and varying response to therapy. The recent availability of new pharmacologic therapies presents a valuable opportunity to reevaluate how this disease is classified, assessed, and managed and identify new ways to improve the clinical care of patients with gMG.

METHODS

Narrative review was made of publications identified via searches of PubMed and selected congresses (January 2000-September 2022).

RESULTS

New consensus definitions are required to ensure consistency, to better characterize patients, and to identify patients who will benefit from specific drugs and earlier use of these agents. There is a need for more frequent, standardized patient assessment to identify the cause of motor function deficits, provide a clearer picture of the disease burden and its impact on daily living and quality of life (QoL), and better support treatment decision-making. Novel approaches that target different components of the immune system will play a role in more precise treatment of patients with gMG, alongside the development of new algorithms to guide individualized patient management.

CONCLUSIONS

gMG has a physical, mental, and social impact, resulting in a considerable burden of disease and substantially decreased QoL, despite standard treatments. The availability of novel, targeted treatments that influence key pathological mediators of gMG, together with new biomarkers, offers the potential to optimize patient management and ultimately enables a greater number of patients to achieve minimal manifestation status and a reduced burden of disease.

Real-World experience with efgartigimod in patients with myasthenia gravis

Recommendations for the treatment of myasthenia gravis (MG) have been difficult to develop because of limited evidence from large randomized controlled trials. New drugs and treatment approaches have recently been shown to be effective in phase 3 studies in seropositive generalized (g) MG. One such drug is efgartigimod, a human-Fc-fragment of IgG1, with a high affinity for the endosomal FcRn. We conducted a multicenter study to evaluate the real-world clinical and safety effects of efgartigimod in 22 gMG patients. We evaluated the strategies for the timing of re-treatment with it. The participants received a total of 59 efgartigimod -treatment cycles. The median number of cycles was 2 (range 1-6). Twenty patients (86.3%) improved by at least 2 MG-ADL points after the first treatment cycle. The median MG-ADL score at baseline was 6.5 (range: 3-17) and 2.5 (range: 0-9) post-treatment (p < 0.001). A consistent improvement of at least 2 points in the MG-ADL score after each cycle occurs in 18 patients. The effect duration of the treatment was usually between 4 and 12 weeks. Two major clinical patterns of treatment response were found. Treatment with efgartigimod was also associated with significant reductions of prednisone doses Overall, the treatment was safe and associated with only minor adverse events. The single fatality was apparently due tosevere respiratory failure. We found that efgartigimod is clinically effective, may be used as a steroid sparing agent and is generally safe for gMG patients. We recommend a personalized preventive treatment approach until clinical stabilization, followed by discontinuation and periodic evaluations.

Efficacy and safety of tocilizumab in patients with refractory generalized myasthenia gravis

BACKGROUND

We aimed to compare the efficacy of tocilizumab with conventional immunotherapy in refractory patients with acetylcholine receptor antibody-positive (AChR-Ab+) generalized myasthenia gravis (gMG).

METHODS

This single-center prospective cohort study was based on patients from an MG registry study in China and conducted from February 10, 2021 to March 31, 2022. Adult refractory patients with AChR-Ab+ gMG were assigned to tocilizumab or conventional immunotherapy groups. The primary efficacy outcome was the mean difference of MG activities of daily living (MG-ADL) change at weeks 4, 8, 12, 16, 20, 24 corresponding to that at the baseline between the two groups. A generalized estimating equation model was used for the primary outcome analysis. Safety was assessed based on adverse events.

RESULTS

Of 34 eligible patients, 20 (mean [standard deviation] age, 53.8 [21.9] years; 12 [60.0%] female) received tocilizumab and 14 received conventional immunotherapy (45.8 [18.0] years; 8 [57.1%] female). The tocilizumab group had greater reduction in MG-ADL score at week 4 (adjusted mean difference, -3.4; 95% CI, -4.7 to -2.0; p < 0.001) than the conventional immunotherapy group, with significant differences sustained through week 24 (adjusted mean difference, -4.5; 95% CI, -6.4 to -2.6; p < 0.001). At week 24, the proportion of patients achieving higher levels of MG-ADL (up to 7-point reduction) and QMG (up to 11-point reduction) scores improvement was significantly greater with tocilizumab. Tocilizumab had acceptable safety profiles without severe or unexpected safety issues.

CONCLUSION

Tocilizumab is safe and effective in improving the MG-ADL score and reducing prednisone dose in refractory AChR-Ab+ gMG, suggesting tocilizumab has the potential to be a valuable therapeutic option for such patients.

Unlocking Glioblastoma Vulnerabilities with CRISPR-Based Genetic Screening

Glioblastoma (GBM) is the most common malignant brain tumor in adults. Despite advancements in treatment, the prognosis for patients with GBM remains poor due to its aggressive nature and resistance to therapy. CRISPR-based genetic screening has emerged as a powerful tool for identifying genes crucial for tumor progression and treatment resistance, offering promising targets for tumor therapy. In this review, we provide an overview of the recent advancements in CRISPR-based genetic screening approaches and their applications in GBM. We highlight how these approaches have been used to uncover the genetic determinants of GBM progression and responsiveness to various therapies. Furthermore, we discuss the ongoing challenges and future directions of CRISPR-based screening methods in advancing GBM research.

Nanodrug Delivery Systems for Myasthenia Gravis: Advances and Perspectives

Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by the production of autoantibodies against the postsynaptic membrane receptors present at the neuromuscular junction. This condition is characterized by fatigue and muscle weakness, including diplopia, ptosis, and systemic impairment. Emerging evidence suggests that in addition to immune dysregulation, the pathogenesis of MG may involve mitochondrial damage and ferroptosis. Mitochondria are the primary site of energy production, and the reactive oxygen species (ROS) generated due to mitochondrial dysfunction can induce ferroptosis. Nanomedicines have been extensively employed to treat various disorders due to their modifiability and good biocompatibility, but their application in MG management has been rather limited. Nevertheless, nanodrug delivery systems that carry immunomodulatory agents, anti-oxidants, or ferroptosis inhibitors could be effective for the treatment of MG. Therefore, this review focuses on various nanoplatforms aimed at attenuating immune dysregulation, restoring mitochondrial function, and inhibiting ferroptosis that could potentially serve as promising agents for targeted MG therapy.

Acupuncture and moxibustion treatment for myasthenia gravis: A systematic review and meta-analysis

BACKGROUND

Myasthenia gravis (MG) is a common autoimmune disease that often involves the skeletal muscle of the whole body and seriously affects patients' quality of life. Acupuncture and moxibustion treatment of MG has unique advantages, the aim is to evaluate the clinical effect of acupuncture and moxibustion on MG.

METHODS

The literature on acupuncture and moxibustion treating MG in PubMed, CochraneLibrary, EMBASE, SCI, China Academic Journals full-text database, China Biology Medicine disc, VIP and Wanfang database were searched through computers from the establishment of the database to December 2022.

RESULTS

A total of 11 studies were included, involving 658 patients, where 330 in the treatment group and 328 in the control group. The results of the meta-analysis showed that the treatment group performed better than the control group in improving the total clinical response rate (OR = 3.26, 95%[2.04,5.21], P < .01). Additionally, the treatment group outperformed the control group in raising the absolute clinical score (MD = -3.48, 95%CI[-5.17, -1.78], P < .01). However, there was no significant difference between the treatment group and the control group in improving the level of serum interleukin-6 receptor (MD = -1.45,95%CI[-6.85,3.95], P > .05) and OMG quantitative score (MD = -2.16,95%CI[-4.85,0.52], P > .05). The total clinical effective rate was tested for publication bias, which showed that the 2 sides of the funnel plot were asymmetrical, suggesting the possible existence of publication bias.

CONCLUSION

Acupuncture and moxibustion has a good effect on MG, which is better than conventional Western medicine in improving the total clinical effective rate and absolute clinical score.

Current state of research on exercise for the treatment of myasthenia gravis: A scoping review

OBJECTIVE

To provide a comprehensive overview of existing evidence, research gaps, and future research priorities concerning the treatment of myasthenia gravis (MG) using exercise therapies.

METHOD

Clinical studies on exercise treatment for MG were searched in nine databases to conduct a scoping review. Two independent researchers screened the literature and comprehensively analyzed the characteristics and limitations of the included articles.

RESULTS

A total of 5725 studies were retrieved, of which 24 were included. The included studies were conducted in 16 different countries/regions and 456 patients were enrolled. Study designs included both interventional and observational studies. Exercise interventions included aerobic exercise, resistance exercise, balance training, and stretch training, and are typically administered in conjunction with medication, usual care, or some other interventions. The intensity, frequency, and duration of exercise interventions varied hugely among studies. Six-minute walk test, adverse events, muscle strength, MG quality of life-15 scale, forced vital capacity, quantitative MG scale, and MG activities of daily living scale were the most frequently used outcomes. All studies reported results in favor of the efficacy and safety of exercise in MG, and exercise-related adverse events were reported in two studies.

CONCLUSION

This scoping review provides an overview of the evidence concerning exercise treatment for MG. Key gaps in evidence include a limited number of participants, complex interventions, variability in outcome selection, and insufficient reporting in publications. The promotion of exercise treatment for MG still encounters several obstacles. A larger population, rigorous study design and conduction, standardized interventions and outcomes, and standardized reporting are essential.

Lady With the Blue Hair: An Atypical Cause of Myasthenic Crisis

A myasthenic crisis denotes a severe exacerbation of myasthenia gravis, leading a patient to enter a life-threatening state due to progressing muscle weakness that ultimately results in respiratory failure. A crisis can require intubation, mechanical ventilation, and additional critical care to prevent further decompensation and potentially death. Numerous well-documented precipitating factors exist, such as infections, surgery, stress, and various medications. We present the case of a 43-year-old woman recently diagnosed with myasthenia gravis who has experienced two myasthenic crises since diagnosis without evident triggers such as surgery, changes in medication, or infection. Following an unremarkable initial diagnostic test and continued treatment for the crisis, we sought additional information from the patient's family member at the bedside. We were informed that two weeks prior to both times of crisis with intubation, the patient had dyed her hair blue. The common chemical component in the two different hair dyes used was methylisothiazolinone, which is suspected to have contributed to the exacerbation of the patient's myasthenia gravis. As more evidence for new precipitating factors of myasthenic crises develops, it is crucial for physicians to quickly identify signs and symptoms of a crisis so appropriate intervention can occur in a time-sensitive manner. In addition, myasthenia gravis patients should be made aware to be cautious of precipitating factors of a crisis, including but not limited to new beauty products.

The epidemiology and societal costs of myasthenia gravis in Norway: A non-interventional study using national registry data

BACKGROUND AND PURPOSE

With the emergence of new treatment options for myasthenia gravis (MG), there is a need for information regarding epidemiology, healthcare utilization, and societal costs to support economic evaluation and identify eligible patients. We aimed to enhance the understanding of these factors using nationwide systematic registry data in Norway.

METHODS

We received comprehensive national registry data from five Norwegian health- and work-related registries. The annual incidence and prevalence were estimated for the period 2013-2021 using nationwide hospital and prescription data. The direct, indirect (productivity losses) and intangible costs (value of lost life-years [LLY] and health-related quality of life [HRQoL]) related to MG were estimated over a period of 1 year.

RESULTS

In 2021, the incidence of MG ranged from 15 to 16 cases per year per million population depending on the registry used, while the prevalence varied between 208.9 and 210.3 per million population. The total annual societal costs of MG amounted to EUR 24,743 per patient, of which EUR 3592 (14.5%) were direct costs, EUR 8666 (35.0%) were productivity loss, and EUR 12,485 (50.5%) were lost value from LLY and reduced HRQoL.

CONCLUSION

The incidence and prevalence of MG are higher than previously estimated, and the total societal costs of MG are substantial. Our findings demonstrate that productivity losses, and the value of LLY and HRQoL constitute a considerable proportion of the total societal costs.

Efficacy of ravulizumab in patients with generalized myasthenia gravis by time from diagnosis: A post hoc subgroup analysis of the CHAMPION MG study

INTRODUCTION/AIMS

The CHAMPION MG study demonstrated that ravulizumab significantly improved Myasthenia Gravis-Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) total scores versus placebo in adults with acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ gMG). This post hoc analysis aimed to assess these outcomes by time from MG diagnosis.

METHODS

Changes from baseline to week 26 in MG-ADL and QMG total scores were analyzed by time from MG diagnosis to study entry (≤2 vs. >2 years). Within each subgroup, least-squares (LS) mean changes for ravulizumab and placebo were compared using mixed models for repeated measures.

RESULTS

In ravulizumab-treated patients, differences in LS mean (standard error of the mean) changes from baseline to week 26 were not statistically significant in the ≤2-years subgroup versus the >2-years subgroup for MG-ADL (-4.3 [0.70] vs. -2.9 [0.37]; p = .0511) or QMG (-4.3 [0.94] vs. -2.5 [0.50]; p = .0822) scores. No clear trends were observed in the placebo group. LS mean changes from baseline were significantly greater for ravulizumab versus placebo in both the ≤2 and >2 years from diagnosis subgroups for MG-ADL and QMG scores (all p < .05). The difference in treatment effect between the ≤2-years and >2-years subgroups was not statistically significant. No clinically meaningful between-subgroup differences in treatment-emergent adverse events were observed in ravulizumab-treated patients.

DISCUSSION

Ravulizumab treatment improved clinical outcomes for patients with AChR+ gMG regardless of time from diagnosis. A numerical trend was observed favoring greater treatment effect with earlier versus later treatment after diagnosis. Further studies are required for confirmation.

Myasthenia Gravis Triggered by a COVID-19 Infection: A Case Report and Literature Review

Myasthenia gravis (MG) is an autoimmune disease that induces skeletal muscle weakness, affecting different muscle groups. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), became both a diagnostic and a therapeutic challenge during the pandemic. The effects of COVID-19 are not only limited to the acute symptoms but also to the post-infectious sequelae. We present the case of a 30-year-old Caucasian woman, with no significant medical history, who presented to the emergency room with acute respiratory failure. The patient tested positive for SARS-CoV-2 with a rapid antigen test and during hospitalization developed a myasthenic crisis, ultimately being diagnosed with seropositive MG.

Prevalences of Other Non-Thyroid Autoimmune Diseases and Factor Associated with Their Presence in Ocular Myasthenia Gravis

Purpose

To report the prevalences of other non-thyroid autoimmune diseases and identify factors associated with their presence in ocular myasthenia gravis (OMG) subjects.

Subjects and Methods

A total of 208 subjects with OMG diagnosis were included. Demographic data, clinical characteristics, the ice-pack test, the acetylcholine receptor (AChR) antibody test, electrophysiology tests (single-fiber electromyography and repetitive nerve stimulation), the presence of thymoma, generalized myasthenia gravis conversion, and the presence of other non-thyroid autoimmune diseases (defined as the presence of at least one other non-thyroid autoimmune disease) were retrospectively reviewed. Factors associated with the presence of other non-thyroid autoimmune diseases were analyzed by univariate and multivariate logistic regression.

Results

Of the total 208 subjects, 21 (10.10%) exhibited the presence of other non-thyroid autoimmune diseases (19 subjects (9.14%) and 2 subjects (0.96%) had one and two other non-thyroid autoimmune diseases, respectively), and systemic lupus erythematosus (SLE) was diagnosed in 9 subjects, followed by Sjogren's syndrome (7 subjects), rheumatoid arthritis (6 subjects), and ankylosing spondylitis (1 subject). Therefore, the prevalences of SLE, Sjogren's syndrome, rheumatoid arthritis, and ankylosing spondylitis in OMG subjects were estimated to be 4.33% (95% confidence interval (CI): 2.29-8.02%), 3.37% (95% CI: 1.64-6.79%), 2.88% (95% CI: 1.33-6.14%), and 0.48% (95% CI: 0.08-2.67%), respectively. Positivity of the AChR antibody was the only significant factor associated with the presence of other non-thyroid autoimmune diseases (odds ratio 4.10, 95% CI: 1.11-15.21, p = 0.035).

Conclusions

The presence of other non-thyroid autoimmune diseases was found in approximately 10% of OMG patients, with SLE displaying the highest prevalence. We recommend screening and monitoring for other non-thyroid autoimmune diseases in OMG patients, particularly those with positivity of the AChR antibody.

Long-Term Healthcare Resource Utilization and Costs among Patients with Myasthenia Gravis: A Swedish Nationwide Population-Based Study

INTRODUCTION

Healthcare costs and societal impact of myasthenia gravis (MG), a potentially life-threatening rare, chronic neuromuscular disease, are sparsely studied. We assessed healthcare resource utilization (HCRU) and associated costs among patients with newly diagnosed (ND) and preexisting (PE) MG in Sweden.

METHODS

This observational, retrospective cohort study used data from four linkable Swedish nationwide population-based registries. Adult MG patients receiving pharmacological treatment for MG and having ≥24-month follow-up during the period January 1, 2010, to December 31, 2017, were included.

RESULTS

A total of 1,275 patients were included in the analysis, of which 554 patients were categorized into the ND MG group and 721 into the PE MG group. Mean (±SD) age was 61.3 (±17.4) years, and 52.3% were female. In the first year post-diagnosis, ND patients had significantly higher utilization of acetylcholinesterase inhibitors (96.0% vs. 83.9%), corticosteroids (59.6% vs. 45.8%), thymectomy (12.1% vs. 0.7%), and plasma exchange (3.8% vs. 0.6%); had higher all-cause (70.9% vs. 35.8%) and MG-related (62.5% vs. 18.4%) hospitalization rates with 11 more hospitalization days (all p < 0.01) and an increased risk of hospitalization (odds ratio [95% CI] = 4.4 [3.43, 5.64]) than PE MG. In year 1 post-diagnosis, ND MG patients incurred EUR 7,302 (p < 0.01) higher total all-cause costs than PE MG, of which 84% were estimated to be MG-related and the majority (86%) were related to inpatient care. These results remained significant also after controlling for baseline demographics and comorbidities (p < 0.01). In year 2 post-diagnosis, the all-cause medical costs decreased by ∼55% for ND MG from year 1 and were comparable with PE MG.

CONCLUSION

In this population-based study, MG patients required significantly more healthcare resources in year 1 post-diagnosis than PE MG primarily due to more pharmacological treatments, thymectomies, and associated hospitalizations. These findings highlight the need to better understand potential factors including disease characteristics associated with increased health resource use and costs and need for more efficacious treatments early in the disease course.

Autoimmune and Non-Autoimmune Comorbidities in Myasthenic Patients of East-European Descent: A Case-Control Study

Background: As the life expectancy of patients with myasthenia gravis (MG) is improving, so the number of comorbidities continues to rise, with a potentially significant impact on the overall morbidity and mortality. The main aim of the study was to assess comorbidities of MG in a group of patients of East-European descent. Methods: We retrospectively compared 185 adult myasthenic patients with 895 sex- and age-matched controls, admitted from January 2013 to December 2021. Results: Of these patients, 60% had late-onset MG (LOMG), with a clear predominance of women in both the LOMG and early-onset (EOMG) types; and 23.8% of the patients had a radiological description consistent with thymoma. All myasthenic patients had at least one comorbidity; 20 (10.8%) of the patients associated at least one autoimmune comorbidity. Obesity (p < 0.01), type 2 diabetes (p < 0.0001), cerebrovascular diseases (p < 0.0001), essential hypertension (p < 0.01), and cardiac arrythmias (p < 0.0001) were more frequent in patients than in the control group. The granulocyte-to-lymphocyte ratio was higher in the myasthenic patients compared to the controls (p < 0.01 for LOMG). Discussion: We, thus, suggest a common chronic low-grade inflammatory background as a possible connection between MG subtypes and some of these apparently unconnected comorbidities. Conclusions: The East-European origin of the patients offered a different social and cultural angle of a disease studied mainly on populations of West-European and Asian descent.

Perspectives of people with myasthenia gravis on physical activity and experience of physical activity advice from health professionals in the Australian context: a qualitative study

PURPOSE

Physical activity is an important modifiable determinant of health. There has been a historical aversion to movement in people with myasthenia gravis (MG) due to the pathophysiology of the disease, however, research suggests engagement in physical activity is safe and does not exacerbate symptoms. There are currently no studies investigating the qualitative perspectives of people with MG on physical activity. The aim of this study was to explore perceptions of physical activity, barriers, enablers, and participants' experiences of physical activity advice from health professionals.

MATERIALS AND METHODS

Semi-structured interviews were used, with verbatim transcripts analysed using content analysis.

RESULTS

Ten adults (median age 64.5 years) living in Australia with generalised MG were interviewed. Key findings were identified: (1) Physical activity is perceived to be important for general health and for MG; (2) Medical management and social support are key enablers; (3) Fatigue and pain are potential barriers; and (4) Experiences with healthcare professionals were considered insufficient and failed to provide disease specific advice regarding MG and physical activity.

CONCLUSION

People with MG have unique barriers and enablers to physical activity engagement that clinicians should consider when providing physical activity behaviour change support to this population.

How should newer therapeutic agents be incorporated into the treatment of patients with myasthenia gravis?

Generalized myasthenia gravis (gMG) is a postsynaptic neuromuscular junction disorder that results in fatigable muscle weakness. The traditional treatment approach includes the use of acetylcholinesterase inhibitors, corticosteroids, and steroid-sparing immunosuppressant therapies (ISTs) for chronic management, whereas exacerbations and crises are managed with intravenous immunoglobulin (IVIg) and plasma exchange (PLEX). Over the past 6 years, four new therapeutic agents with novel immunological mechanisms of action-complement and neonatal Fc receptor (FcRn) inhibition-were approved as a result of clinically significant improvement in gMG symptoms of those treated with these newer agents in Phase 3 clinical trials. At present, it is unclear when and in whom to initiate these therapeutic agents and how to integrate them into the current treatment paradigm. When selecting a newer therapeutic agent, we use a simple equation: Value = Clinical Improvement/(Cost + Side Effects + Treatment Burden), which guides our decision-making. We consider using these novel therapeutic agents in two specific clinical situations. Firstly, the newer agents are fast-acting, suggesting they can be used in clinically unstable patients as "bridge therapy," and secondly, they provide additional options for those patients considered treatment-refractory. There are downsides, however, including treatment cost, unique side effect profiles, and intravenous and subcutaneous drug administration (though for some, this may be an advantage). As additional drugs enter the marketplace with unique mechanisms of action, routes of administration, and dosing schedules, the placement of the novel therapeutic agents in the gMG treatment algorithm will likely evolve.

The intricate dance of non-coding RNAs in myasthenia gravis pathogenesis and treatment

Myasthenia gravis (MG) stands as a perplexing autoimmune disorder affecting the neuromuscular junction, driven by a multitude of antibodies targeting postsynaptic elements. However, the mystery of MG pathogenesis has yet to be completely uncovered, and its heterogeneity also challenges diagnosis and treatment. Growing evidence shows the differential expression of non-coding RNAs (ncRNAs) in MG has played an essential role in the development of MG in recent years. Remarkably, these aberrantly expressed ncRNAs exhibit distinct profiles within diverse clinical subgroups and among patients harboring various antibody types. Furthermore, they have been implicated in orchestrating the production of inflammatory cytokines, perturbing the equilibrium of T helper 1 cells (Th1), T helper 17 cells (Th17), and regulatory T cells (Tregs), and inciting B cells to generate antibodies. Studies have elucidated that certain ncRNAs mirror the clinical severity of MG, while others may hold therapeutic significance, showcasing a propensity to return to normal levels following appropriate treatments or potentially foretelling the responsiveness to immunosuppressive therapies. Notably, the intricate interplay among these ncRNAs does not follow a linear trajectory but rather assembles into a complex network, with competing endogenous RNA (ceRNA) emerging as a prominent hub in some cases. This comprehensive review consolidates the landscape of dysregulated ncRNAs in MG, briefly delineating their pivotal role in MG pathogenesis. Furthermore, it explores their promise as prospective biomarkers, aiding in the elucidation of disease subtypes, assessment of disease severity, monitoring therapeutic responses, and as novel therapeutic targets.

MuSK Myasthenia Gravis-Potential Pathomechanisms and Treatment Directed against Specific Targets

Myasthenia gravis (MG) is an autoimmune disease in which autoantibodies target structures within the neuromuscular junction, affecting neuromuscular transmission. Muscle-specific tyrosine kinase receptor-associated MG (MuSK-MG) is a rare, often more severe, subtype of the disease with different pathogenesis and specific clinical features. It is characterized by a more severe clinical course, more frequent complications, and often inadequate response to treatment. Here, we review the current state of knowledge about potential pathomechanisms of the MuSK-MG and their therapeutic implications as well as ongoing research in this field, with reference to key points of immune-mediated processes involved in the background of myasthenia gravis.

The investigation of killer-cell immunoglobulin-like receptors (KIRs) and their HLA ligands in Iranian patients with myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is a disabling disease with the underlying pathophysiology of auto-antibodies attacking the postsynaptic acetylcholine receptors of neuromuscular junctions causing muscle weakness. Natural killer (NK) cells are innate immune cells that play an important regulative role in immune responses. The human killer-cell immunoglobulin-like receptors (KIRs) family is one of the receptors on NK cells that can either activate or inhibit NK cells. This study aimed to assess the possible role of KIR and their human leukocyte antigen (HLA) ligand genes susceptibility to MG in Iranian patients.

METHOD

One hundred and sixty-three patients with MG diagnosis based on the presence of clinical symptoms and laboratory tests and 400 healthy volunteers were studied. We used the polymerase chain reaction (PCR) technique for genotyping 15 KIRs and 5 HLA genes.

RESULTS

The results demonstrated that there was no significant difference in the frequency of KIR genes and inhibitory KIR genotypes between controls and patients. In MG patients, HLA-C1Asn80 was significantly less frequent than in matched controls. The frequency of HLA genotype number 7 was significantly lower in MG cases, compared to the controls. Analysis of activating KIR genotypes showed that genotype number 10 was significantly less frequent in MG cases than in matched controls.

CONCLUSION

Our results suggest that the presence HLA-C1Asn80 might play a protective role against the pathogenesis of MG. The significantly decreased prevalence of one activating KIR genotype and one of the HLA genotypes in MG cases suggest that these genotypes can reduce the risk of MG development. To specifically reveal the impact of KIR and HLA in MG, more studies are required.

Improving Neuromuscular Monitoring Through Education-Based Interventions and Studying Its Association With Adverse Postoperative Outcomes: A Retrospective Observational Study

BACKGROUND

We assessed the association between education-based interventions, the frequency of train-of-four (TOF) monitoring, and postoperative outcomes.

METHODS

We studied adults undergoing noncardiac surgery from February 1, 2020 through October 31, 2021. Our education-based interventions consisted of 3 phases. An interrupted time-series analysis, adjusting for patient- and procedure-related characteristics and secular trends over time, was used to assess the associations between education-based interventions and the frequency of TOF monitoring, postoperative pulmonary complications (PPCs), 90-day mortality, and sugammadex dosage. For each outcome and intervention phase, we tested whether the intervention at that phase was associated with an immediate change in the outcome or its trend (weekly rate of change) over time. In a sensitivity analysis, the association between education-based interventions and postoperative outcomes was adjusted for TOF monitoring.

RESULTS

Of 19,422 cases, 11,636 (59.9%) had documented TOF monitoring. Monitoring frequency increased from 44.2% in the first week of preintervention stage to 83.4% in the final week of the postintervention phase. During the preintervention phase, the odds of TOF monitoring trended upward by 0.5% per week (odds ratio [OR], 1.005; 95% confidence interval [CI], 1.002-1.007). Phase 1 saw an immediate 54% increase (OR, 1.54; 95% CI, 1.33-1.79) in the odds, and the trend OR increased by 3% (OR, 1.03; 95% CI, 1.01-1.05) to 1.035, or 3.5% per week (joint Wald test, P < .001). Phase 2 was associated with a further immediate 29% increase (OR, 1.29; 95% CI, 1.02-1.64) but no significant association with trend (OR, 0.96; 95% CI, 0.93-1.01) of TOF monitoring (joint test, P = .04). Phase 3 and postintervention phase were not significantly associated with the frequency of TOF monitoring (joint test, P = .16 and P = .61). The study phases were not significantly associated with PPCs or sugammadex administration. The trend OR for 90-day mortality was larger by 24% (OR, 1.24; 95% CI, 1.06-1.45; joint test, P = .03) in phase 2 versus phase 1, from a weekly decrease of 8% to a weekly increase of 14%. However, this trend reversed again at the transition from phase 3 to the postintervention phase (OR, 0.82; 95% CI, 0.68-0.99; joint test, P = .05), from a 14% weekly increase to a 6.2% weekly decrease in the odds of 90-day mortality. In sensitivity analyses, adjusting for TOF monitoring, we found similar associations between study initiatives and postoperative outcomes. TOF monitoring was associated with lower odds of PPCs (OR, 0.69; 95% CI, 0.55-0.86) and 90-day mortality (OR, 0.79; 95% CI, 0.63-0.98), but not sugammadex dosing (mean difference, -0.02; 95% CI, -0.04 to 0.01).

CONCLUSIONS

Our education-based interventions were associated with both TOF utilization and 90-day mortality but were not associated with either the odds of PPCs or sugammadex dosing. TOF monitoring was associated with reduced odds of PPCs and 90-day mortality.

Ocular Myasthenia Gravis As Unilateral Ptosis and External Ophthalmoplegia: A Case Report

Myasthenia gravis (MG) is an autoimmune disorder characterized by fluctuating weakness and fatigue in ocular, bulbar, limb, or respiratory muscles. Initially, more than half of MG patients experience isolated ocular symptoms, such as ptosis, diplopia, or muscle paresis. This case report presents a unique occurrence of MG in a four-year-old female, showcasing a two-year history of sudden onset, persistent yet fluctuating unilateral ptosis accompanied by exo-deviation and adduction deficit in the right eye. No diplopia or systemic features were observed. Positive findings in tests, including the ice pack test, Cogan twitch sign, fatiguability, and neostigmine test, indicated ocular myasthenia. Electromyography revealed a decremental response, while anti-acetylcholine antibodies showed borderline results. Computed tomography of the brain ruled out central causes, and routine laboratory testing yielded normal results. Treatment with pyridostigmine and corticosteroids led to significant improvement in symptoms. This case emphasizes the diverse presentation of MG in ophthalmology, with ocular signs serving as indicators in approximately half of the cases. Early diagnosis and prompt treatment are crucial for enhancing long-term prognosis. Emergency physicians should consider MG as a potential cause for unilateral ocular symptoms after excluding central causes. Accurate diagnosis and comprehensive management of MG are complex yet essential for ensuring optimal patient health.

Home Noninvasive Ventilation in Myasthenia Gravis

BACKGROUND

Noninvasive ventilation (NIV) plays an important role in avoiding endotracheal intubation during myasthenic crisis, yet there are few published data concerning long-term home NIV in stable out-patients with myasthenia gravis (MG). The aim of this study was to describe the prevalence of NIV in a cohort of subjects with stable MG and to analyze contributing factors that could predict the need of NIV.

METHODS

We performed a cross-sectional study that included subjects diagnosed with MG managed in the respiratory care unit over the previous year. Subjects underwent clinical analysis including demographic, clinical, and functional respiratory data.

RESULTS

Of the 50 subjects included, 35 (70%) were positive for nicotinic acetylcholine receptor antibodies, and 68% had a diagnosis of generalized MG. Bulbar symptoms developed in 16 (32%), and 10 (20%) subjects needed long-term home NIV. The only variable predicting the need for long-term NIV was MG severity measured with Myasthenia Gravis Foundation of America (MGFA), mainly grades IIB (odds ratio 0.14 [95% CI 0.02-0.85], P = .03) and IIIB (odds ratio 0.02 [95% CI 0.01-0.34], P = .01).

CONCLUSIONS

Home NIV was needed in a substantial percentage of medically stable subjects with MG, mainly in those with generalized type and with oropharyngeal and/or respiratory muscle involvement (MGFA grades IIB and IIIB).