Diagnosis of Myasthenia Gravis

Quantification of saccadic fatigability and diagnostic efficacy for myasthenia gravis

BACKGROUND AND OBJECTIVES

The diagnostic challenge of myasthenia gravis (MG) is exacerbated by the variable efficacy of current testing methodologies, necessitating innovative approaches to accurately identify the condition. This study aimed to assess ocular muscle fatigue in patients with MG using video-oculography (VOG) by examining repetitive saccadic eye movements and comparing these metrics to those of healthy control participants.

METHODS

This prospective, cross-sectional study was conducted at a tertiary care center and involved 62 patients diagnosed with MG (48 with ocular MG and 14 with generalized MG) and a control group of 31 healthy individuals, matched for age and sex. The assessment involved recording saccadic eye movements within a ± 15° range, both horizontally and vertically, at a rate of 15 saccades per minute over a 5-min period, resulting in 75 cycles. Participants were afforded a 3-min rest interval between each set to mitigate cumulative fatigue. The primary outcome was the detection of oculomotor fatigue, assessed through changes in saccadic waveforms, range, peak velocity, latency, and the duration from onset to target, with a focus on comparing the second saccade against the average of the last five saccades.

RESULTS

In the evaluation of repetitive saccadic movements, patients with MG exhibited a reduced saccadic range and a prolonged duration to reach the target, compared to healthy subjects. Furthermore, a significant elevation in the frequency of multistep saccades was observed among MG patients, with a marked rise observed over consecutive trials. Receiver operating characteristic (ROC) analysis revealed the discriminative performance of multistep saccade frequency, in conjunction with variations in saccadic range and duration from onset to target achievement between the second saccade and the mean of the final five saccades, as effective in distinguishing MG patients from healthy subjects. Although alterations in peak saccadic velocity and latency were less pronounced, they were nevertheless detectable.

DISCUSSION

The utilization of VOG for repetitive saccadic testing in the diagnosis of MG has demonstrated considerable diagnostic precision. This methodology affords significant accuracy in evaluating ocular muscle fatigue in MG patients, providing class III evidence supportive of its clinical application.

Statin-induced immune-mediated necrotizing myopathy with concomitant increase of anti-HMGCR and anti-ACHR antibodies

Statin-induced immune-mediated necrotizing myopathy (IMNM) is a rare systemic neuromuscular condition. We present a case of a patient with a severe phenotype of the disease that was found to have an increase in anti-HMGCR and anti-ACHR antibodies. A potential association between these antibodies have not been previously described. A 67-year-old male with hyperlipidemia, who was recently initiated on atorvastatin therapy, presented to the ED with progressive muscle weakness. Within a few days of admission, the patient developed complete flaccid paralysis and respiratory distress requiring intubation. The patient's CK was elevated to 24,000 and there was an increase of anti-HMGCR and anti-ACHR antibodies. Impressions from MRI and thigh biopsy solidified a diagnosis of statin-induced IMNM. The patient was treated with methylprednisolone, IVIG, and rituximab, which provided resolution of symptoms.

Role of recovery of acetylcholine release in compromised neuromuscular junction function

Everyday physical activities, such as walking, are enabled by repeated skeletal muscle contractions and require a well-functioning neuromuscular transmission. In myasthenic disorders, activities of daily living are debilitated by a compromised neuromuscular transmission leading to muscle weakness and fatiguability in patients. To enable physical activity, acetylcholine (ACh) is released repeatedly from the motor nerve, however, the role of the nerve terminals' capacity to sustain ACh release to support repetitive contractions under compromised neuromuscular transmission remains unclear. To explore this, we studied synaptic and contractile function during repeated contractions in healthy rat skeletal muscles under conditions of pharmacological induced compromised neuromuscular transmission. Using recordings of endplate potentials, compound muscle action potential (CMAP) and force production in isolated skeletal muscles and living, anesthetized animals, we found that force and CMAP were markedly reduced by even very light activity performed up to 5 s prior to contraction showing that recovery of ACh release was insufficient to maintain synaptic transmission strength. Our results suggest that the timing of depletion and restoration of ACh release may impact clinical signs of weakness and fatigability in patients with impaired neuromuscular transmission and affect the sensitivity of electromyographic recordings in the clinic.

Primary Sjogren's syndrome presenting as ptosis and eyelid swelling: A case report

Key Clinical Message

This unique case report of primary Sjogren's syndrome (pSS) shows bilateral ptosis and significant periorbital edema, compromising vision. To avoid misleading diagnosis, antibody tests must be evaluated and interpreted in the context of clinical findings.

Abstract

Primary Sjögren's syndrome is an idiopathic, autoimmune disorder involving the lacrimal and salivary glands characterized by both localized and systemic manifestations including xerostomia and keratoconjunctivitis sicca. Myasthenia Gravis (MG) is also an autoimmune disorder characterized by the development of auto-antibodies against nicotinic acetylcholine receptors that causes decreased muscle response to stimulation. It usually presents with ptosis and generalized body weakness. Ophthalmological involvement is common in both disorders but ptosis is very rarely seen in pSS. We report the case of a 27-year-old woman presenting to our clinic with the complaint of ptosis and eyelid swelling. She also had a positive anti-acetylcholine receptor antibody test and her initial presentation mimicked Myasthenia Gravis. Her autoimmune workup revealed a positive titer of Anti Ro SSA antibodies. Myasthenia Gravis was ruled out on electrodiagnostic studies which showed no decremental response, and pSS was confirmed on lip biopsy. Our case highlights that it is important to interpret the antibody test results in the context of clinical findings as we can have spurious results in autoimmune diseases. Autoimmune conditions can have varying presenting complaints hence, clinical judgment should always overrule diagnostic investigations and should thus guide patient management.

Myasthenia Gravis Mimicking Status Asthmaticus: The Hidden Crisis

Status asthmaticus is a severe form of aggravation of asthma, whereas myasthenia gravis (MG) is a rare neuromuscular condition characterised by exhaustion and muscle weakness. Myasthenic crisis can occasionally manifest with symptoms that resemble status asthmaticus, which can result in an incorrect diagnosis and ineffective therapy. In addition to discussing the therapeutic implications, this abstract attempts to draw attention to the difficulties in distinguishing between status asthmaticus and myasthenia crisis and the importance of diagnosing subtle signs of MG. In this case, we present a 55-year-old female, with a misdiagnosed case of bronchial asthma, who presented with shortness of breath at rest for two to three days and was suspected to have an acute exacerbating episode of asthma. She was later evaluated for non-respiratory causes of dyspnea on noticing subtle signs of ptosis and was found to have an active myasthenic crisis. Although this case presented typically as status asthmaticus, it did not respond to conventional treatment of it, and on the contrary, it worsened. Hence, it is necessary to look for subtle signs of MG and promptly differentiate it from other similar emergency events to help administer accurate treatment which can prove life-saving.

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.

Clinical features, treatments, their impact, and quality of life for Myasthenia Gravis patients in Australia

This survey provides an update on the experience of Myasthenia Gravis (MG) patients in Australia. Items were drawn from the 2011 Australian Survey and a 2019 US survey allowing for comparative discussion of survey findings. Patients were recruited through the Myasthenia Alliance Australia. Following consent, patients completed an online survey using REDCap software. Questions included demographics, clinical features, treatment side-effects and quality of life (QOL) scales. Samples for completion of survey sections ranged from N = 242-280 representing a power level of over 80%. Female and seronegative patients reported a significantly greater symptom load, earlier disease onset, longer time to diagnosis, more MG exacerbations, treatment side-effects, and poorer QOL. For exacerbation management there was a higher rate of oral corticosteroid use (66%), a lower use of Intravenous Immunoglobulin (IVIg, 47%) and particularly, Therapeutic Plasma Exchange (TPE, 4.5%) within this sample. Although steroid induced side-effects were rarer (9-34%), a comparatively high use of corticosteroids was reported for current and overall treatments including those for MG crises (52-83%). Common treatment side-effects reported by 57-85% of patients, included fatigue, weight gain, a decrease in the ability to fight infections, gastrointestinal symptoms, and muscle weakness. The impact of MG on daily activities and QOL was considerable, but those who had a thymectomy reported better QOL. The survey identified areas for potential practice improvement in MG treatments (corticosteroids, IVIg, TPE), particularly for exacerbation management, and review is recommended. Further research on gender and antibody status differentials regarding clinical features is required.

Machine learning strategy for identifying altered gut microbiomes for diagnostic screening in myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular junction disease with a complex pathophysiology and clinical variation for which no clear biomarker has been discovered. We hypothesized that because changes in gut microbiome composition often occur in autoimmune diseases, the gut microbiome structures of patients with MG would differ from those without, and supervised machine learning (ML) analysis strategy could be trained using data from gut microbiota for diagnostic screening of MG. Genomic DNA from the stool samples of MG and those without were collected and established a sequencing library by constructing amplicon sequence variants (ASVs) and completing taxonomic classification of each representative DNA sequence. Four ML methods, namely least absolute shrinkage and selection operator, extreme gradient boosting (XGBoost), random forest, and classification and regression trees with nested leave-one-out cross-validation were trained using ASV taxon-based data and full ASV-based data to identify key ASVs in each data set. The results revealed XGBoost to have the best predicted performance. Overlapping key features extracted when XGBoost was trained using the full ASV-based and ASV taxon-based data were identified, and 31 high-importance ASVs (HIASVs) were obtained, assigned importance scores, and ranked. The most significant difference observed was in the abundance of bacteria in the Lachnospiraceae and Ruminococcaceae families. The 31 HIASVs were used to train the XGBoost algorithm to differentiate individuals with and without MG. The model had high diagnostic classification power and could accurately predict and identify patients with MG. In addition, the abundance of Lachnospiraceae was associated with limb weakness severity. In this study, we discovered that the composition of gut microbiomes differed between MG and non-MG subjects. In addition, the proposed XGBoost model trained using 31 HIASVs had the most favorable performance with respect to analyzing gut microbiomes. These HIASVs selected by the ML model may serve as biomarkers for clinical use and mechanistic study in the future. Our proposed ML model can identify several taxonomic markers and effectively discriminate patients with MG from those without with a high accuracy, the ML strategy can be applied as a benchmark to conduct noninvasive screening of MG.

Diagnosis and therapy of myasthenia gravis-the patients' perspective: a cross-sectional study

The survey aimed to explore patients' perspectives with myasthenia gravis (MG) toward the diagnosis made and the therapy used to treat MG. The survey was conducted with a quantitative method, using the CAWI technique. A total of 321 people participated in the survey. More than half of the respondents (56.4%) had suffered from MG for less than 10 years. In three out of 10 cases (30.9%), the diagnosis of MG lasted 3 years or longer. The diagnostic delay was significantly longer in female respondents than in the males (p = 0.029). Cholinergic drugs were used in 92.9% of cases initially, and as maintenance therapy in 84.3% of cases. Corticosteroids were used in initiating therapy (45.8%) and as maintenance therapy (46.4%). One in four respondents (25.5%) reported experiencing very strong and strong side effects after using steroids. The side effects from steroid therapy very strong or strong affected overall physical health in 55.9% of respondents, very strong or strong affected self-acceptance in 52%, to a very large or large extent on mental health in 47.1%, and to a very strong or strong extent influenced the performance of daily activities in 28.2%. More than half of the respondents (57.0%) had had a thymectomy. Seven out of 10 respondents (72.0%) declared that the therapy they were on at the time of the survey allowed them (to varying degrees) to control their course of MG. Low therapy acceptance and less well controlled MG was associated with a preference for non-tablet therapies (p = 0.045). Regular follow-up and cooperation with the specialist health care system should improve MG symptoms, activities of daily living, and quality of life.

Myasthenic crisis as an initial presentation of myasthenia gravis in an 81-year-old following endoscopic myotomy for Zenker's diverticulum

In this article, we present the case of a patient with previously undiagnosed myasthenia gravis who underwent an endoscopic procedure for Zenker's diverticulum. The patient was readmitted due to ongoing dysphagia and severe respiratory distress caused by myasthenic crisis. This case demonstrates that myasthenia gravis, although rare, can occur in elderly patients and present with other sequelae that may mask the underlying diagnosis.

Microbiota dysbiosis and myasthenia gravis: Do all roads lead to Rome?

Dysregulated immune system with a failure to recognize self from non-self-antigens is one of the common pathogeneses seen in autoimmune diseases. The complex interplay of genetic and environmental factors is important for the occurrence and development of the disease. Among the environmental factors, disturbed gut microbiota (gut dysbiosis) has recently attracted particular attention, especially with advancement in human microbiome research. Although the alterations in microbiota have been seen in various autoimmune diseases, including those of nervous system, there is paucity of information on neuromuscular system diseases. Myasthenia gravis (MG) is one such rare autoimmune disease of neuromuscular junction, and is caused by generation of pathogenic autoantibodies to components of the postsynaptic muscle endplate. In the recent years, accumulating evidences have endorsed the key role of host microbiota, particularly those of gut, in the pathogenesis of MG. Differential microbiota composition, characterized by increased abundance of Fusobacteria, Bacteroidetes, and Proteobacteria, and decreased abundance of Actinobacteria and Firmicutes, has been seen in MG patients in comparison to healthy subjects. Disturbance of microbiota composition, particularly reduced ratio of Firmicutes/Bacteroidetes, alter the gut permeability, subsequently triggering the immunological response. Resultant reduction in levels of short chain fatty acids (SCFAs) is another factor contributing to the immunological response in MG patients. Modulation of gut microbiota via intervention of probiotics, prebiotics, synbiotics, postbiotics (metabiotics), and fecal microbiota transplantation (FMT) is considered to be the futuristic approach for the management of MG. This review summarizes the role of gut microbiota and their metabolites (postbiotics) in the progression of MG. Also, various bacteriotherapeutic approaches involving gut microbiota are discussed for the prevention of MG progression.

Exploring the role of immune checkpoint inhibitors in the etiology of myasthenia gravis and Lambert-Eaton myasthenic syndrome: A systematic review

Background

While immune checkpoint inhibitors (ICIs) have been revolutionary in the treatment of cancer, their administration has been associated with a variety of immune-related adverse events (irAEs), including myasthenia gravis (MG), and Lambert-Eaton myasthenic syndrome (LEMS).

Objective

To provide a comprehensive synthesis of the evidence supporting an etiological role for ICIs in MG and LEMS in patients with no prior history of autoimmune disease.

Hypothesis

ICIs may trigger MG and LEMS in patients with no prior susceptibility to autoimmune disease.

Methods

Relevant primary research on Medline was interrogated using a series of search algorithms. Search terms were constructed based on the PICOS tool endorsed by the Cochrane Collaboration, which describes population, intervention, comparison, outcomes, and study design. Papers were screened according to inclusion and exclusion criteria. Additional papers were retrieved from the reference lists of screened papers. Each paper included in the qualitative synthesis was assigned an integrated metric of evidence (IME) value, ranging from 0 to 7, based on study design, quality of data, likelihood of a causal link between the immune checkpoint inhibitor(s) and MG/LEMS, confidence of MG/LEMS diagnosis, and the number of patients treated with an ICI prior to MG/LEMS diagnosis.

Results

Ninety-four papers describing at least one patient treated with ICI(s) prior to the onset of MG and/or LEMS were documented. Overall evidence for a causal link between ICI administration and MG/LEMS was low, with a median IME value of 2.88 (range 2.05-6.61).

Conclusions

There is a paucity of evidence in support of an etiological relationship between ICIs and MG/LEMS, due largely to the lack of mechanistic studies and/or prospective clinical trials with relevant study endpoints. The current literature is dominated by case reports and retrospective cohort studies, which inherently yield only low-level evidence, supporting the need for further work in this area. A role of ICIs in the etiology of MG/LEMS remains plausible, arguing for continued vigilance for irAEs in patients treated with these drugs. We argue that there is a need for future mechanistic, high quality, large-scale studies specifically investigating the possible etiological role of ICIs in MG/LEMS.

Polyautoimmunity in systemic lupus erythematosus patients: New insights from a cross-sectional study

Objective

To assess the frequency of polyautoimmunity (PolyA) in a cohort of Colombian patients with systemic lupus erythematosus (SLE) and to identify associated factors.

Methods

This is an analytical cross-sectional study in a specialized center., a comprehensive review of the medical records of SLE patients was performed from 2015 to 2020 in order to obtain demographic, clinical data, laboratory, and treatment information. Associations between PolyA, demographic, and characteristics of the disease were explored.

Results

A total of 463 patients were included in the analysis. The average age was 47.3 ± 15 years. Most of this population were female (87.4%), whom were diagnosed with SLE in a long-term SLE (10.6 ± 10.1 years). Out of the total patients, 34.7% were diagnosed with PolyA. Among the most frequent clinical criteria for SLICC, arthritis (65%), kidney impairment (39.5%), and alopecia (34.8%) were found. The most frequent SLE-associated PolyA were antiphospholipid syndrome (APS) and Sjögren's syndrome (SS) (16.63% and 10.58%, respectively). PolyA-associated factors were age, xerophthalmia, central nervous system occlusion, and deep vein thrombosis (DVT). In contrast, renal impairment was significantly less frequent in PolyA patients after multivariate analysis.

Conclusion

The results have showed associated factors with PolyA like age, xerophthalmia, central nervous system occlusion, and deep vein thrombosis in this cohort. On the other hand, lupus nephritis was less frequent in patients with PolyA. This study provides a spotlight of a specific SLE population as real-life evidence for a better characterization of PolyA in the future.

Comparison of Fixed and Live Cell-Based Assay for the Detection of AChR and MuSK Antibodies in Myasthenia Gravis

BACKGROUND AND OBJECTIVES

Live cell-based assay (CBA) can detect acetylcholine receptors (AChRs) or muscle-specific tyrosine kinase (MuSK) antibodies (Abs) in a proportion of patients with radioimmunoassay (RIA)-double seronegative myasthenia gravis (dSN-MG). A commercial fixed CBA for AChR and MuSK Abs has recently become available; however, comparative studies on fixed and live CBAs are lacking. In this study, we compared the performance of fixed and live CBAs in patients with RIA-dSN MG and assessed their sensitivity in RIA-positive MG samples and their specificity.

METHODS

AChR and MuSK Abs were tested in 292 serum samples from 2 Italian MG referral centers by live and fixed CBAs: 192 from patients with MG and 100 from controls. All samples had been previously assessed by RIA: 66 were AChR positive, 40 MuSK positive, and 86 dSN. All controls were negative. Two independent raters assessed the CBA results. Fixed and live CBAs were compared with the McNemar test; interrater and interlaboratory agreement were assessed with Cohen's kappa or interclass correlation coefficient (ICC), as appropriate.

RESULTS

In 86 RIA-dSN samples, fixed CBA detected Abs in 10 cases (11.6%, 95% CI 5.7-20.3), whereas live CBA detected Abs in 16 (18.6%, 95% CI 11.0-28.5) (p = 0.0143). Of these sera, those positive by fixed CBA were also positive by live CBA. In addition, live CBA could detect MuSK Abs in 4 and AChR Abs in 2 samples that were negative by fixed CBA, providing an 8% (95% CI 2.9-16.6) further increase in the Ab detection rate. These results were confirmed by flow cytometry. In the RIA-positive cohort, the sensitivity for AChR Abs was 98.5% (95% CI 91.9%-99.9%) for fixed CBA and 100% (95% CI 94.6-100) for live CBA (p = 0.1573). For both assays, the sensitivity for MuSK Abs was 100% (95% CI 91.2-100), and the specificity was 100% (95% CI 96.4-100). Interrater agreement was almost perfect for live and fixed CBAs (Cohen's kappa 0.972 and 0.978, respectively), alike interlaboratory agreement. Interrater agreement for the CBA score ranged from good to excellent (ICC: 0.832-0.973).

DISCUSSION

Fixed CBA represents a valuable alternative to RIA for AChR and MuSK Ab detection in patients with MG and could be considered as a first-step diagnostic test. Live CBA can be useful in the serologic evaluation of RIA- and fixed CBA-negative samples.

COVID-19 infection and vaccination against SARS-CoV-2 in myasthenia gravis

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction which is typically presented with muscle weakness and excessive fatigability. Majority of MG patients require long-term immune suppression. Our aim was to analyze the frequency and severity of COVID-19 infection in MG patients, as well as the frequency of vaccinated MG patients against SARS-CoV-2.

METHODS

We included 125 MG patients from the central Belgrade municipalities-60% females, age at MG onset 50.1 ± 19.7 years, age at testing 61.7 ± 16.8 years, anti-acetylcholine receptor (anti-AChR) positive 78% and muscle specific tyrosine kinase (MuSK) positive 8.6%.

RESULTS

One-third of our MG patients had a COVID-19 infection and they were younger compared to those without verified COVID-19. Severe COVID-19 infection was registered in 28% of MG patients, mostly in elder subjects with comorbidities such as cardiac diseases and malignancies. MG worsening was noted in 21% of patients during/after COVID-19 and 42% had COVID-19 sequelae. Majority of MG patients were vaccinated against SARS-CoV-2 (almost 70%). Vaccination was more common among MG patients with diabetes and in those with a milder form of MG. The most common types of vaccines were Sinopharm (42%) and Pfizer-BioNTech (25.6%). Adverse events were observed in 36% of vaccinated patients, with flu-like symptoms (77%) and local reactions (13%) being the most common ones. MG worsening was noticed in 5 (5.8%) patients after vaccination.

CONCLUSION

COVID-19 has placed a significant new burden for MG patients. Elder MG patients and patients with comorbidities are in higher risk of having adverse outcome following SARS-CoV-2 infection. Percentage of vaccinated MG patients was higher than in general Serbian population.

D-penicillamine Induced Myasthenia Gravis in Wilson's Disease: A Case Report

Myasthenia gravis is a neuromuscular junction disorder characterised by fluctuating muscle weakness, improved by using anti-cholinesterase drugs. In addition to the autoimmune aetiology, various factors such as infections, surgery, and drugs are known to precipitate the condition. We report a case of a 15-year-old boy with D-penicillamine-induced myasthenia gravis who presented with facial diplegia, dysphagia, and drooling of saliva, 6 years after the initiation of treatment for Wilson's disease. Therefore, clinicians should be more vigilant while prescribing patients with chelating drugs like D-penicillamine with regular monitoring of the new symptoms and keeping a very low threshold for the suspicion of myasthenia gravis.

Keywords

d-penicillamine; myasthenia gravis; pyridostigmine; Wilson's disease.

The Dental Management of Pediatric Patient Diagnosed with Myasthenia Gravis: A Case Report

Myasthenia gravis (MG) is a rare autoimmune neurological disorder characterized by muscle weakness and can vary in severity from the mild form that affects the ocular muscles only to the generalized form that affects the other muscle groups. The prevalence of MG is 150 to 200 per million population over the past 50 years, and approximately 10% of these cases are pediatric patients where the disease onset starts before the age of 18 years. The etiology of MG is due to the blockage of neuromuscular transmission by circulating autoantibodies targeting mainly the nicotinic acetylcholine receptor (AChR) and associated proteins in the postsynaptic membrane of skeletal muscles. In MG patients, dental treatment is challenging due to the nature of the condition and its complexity. Moreover, dentists treating MG patients should acquire knowledge about the disease background and the special considerations that need to be taken. In this case report, our aim was to raise awareness about MG among dentists and discuss the dental management of the patients who have this disease and the precautions that should be taken. This case report presents a pediatric MG patient with poor oral hygiene, multiple decayed teeth, dental fluorosis, tongue thrust oral habit that led to anterior open-bite and uncomplicated crown fracture of the upper permanent central incisors. The decision was made to treat the patient under general anesthesia because of the medical condition and the extent of the dental treatment. In the process of preparing the patient for surgery, the patient was cleared from the treating physicians and was admitted under neurology care as per the primary physician. On the day of surgery, the patient received full-mouth dental rehabilitation under general anesthesia, including pulp therapy, crowns, restorations, and extractions. Furthermore, she was seen regularly in recall visits every 3 months.

Preferential X Chromosome Inactivation as a Mechanism to Explain Female Preponderance in Myasthenia Gravis

Myasthenia gravis (MG) is a neuromuscular autoimmune disease characterized by prevalence in young women (3:1). Several mechanisms proposed as explanations for gender bias, including skewed X chromosome inactivation (XCI) and dosage or sex hormones, are often involved in the development of autoimmunity. The skewed XCI pattern can lead to an unbalanced expression of some X-linked genes, as observed in several autoimmune disorders characterized by female predominance. No data are yet available regarding XCI and MG. We hypothesize that the preferential XCI pattern may contribute to the female bias observed in the onset of MG, especially among younger women. XCI analysis was performed on blood samples of 284 women between the ages of 20 and 82. XCI was tested using the Human Androgen Receptor Assay (HUMARA). XCI patterns were classified as random (XCI < 75%) and preferential (XCI ≥ 75%). In 121 informative patients, the frequency of skewed XCI patterns was 47%, significantly higher than in healthy controls (17%; p ≤ 0.00001). Interestingly, the phenomenon was observed mainly in younger patients (<45 years; p ≤ 0.00001). Furthermore, considering the XCI pattern and the other clinical characteristics of patients, no significant differences were found. In conclusion, we observed preferential XCI in MG female patients, suggesting its potential role in the aetiology of MG, as observed in other autoimmune diseases in women.

Bilateral Facial Palsy Without Ocular Muscle Involvement in Myasthenia Gravis: Case Report

Myasthenia gravis (MG) is an autoimmune neuromuscular junction disorder that is more common among women than men. It has two major subtypes, namely, ocular and generalized MG, and while facial weakness is common in generalized MG, facial weakness without the involvement of ocular muscle is exceedingly rare. Here, we describe the case of a middle-aged man who presented with bilateral facial palsy but without diplopia or proximal muscle weakness. The patient tested positive for acetylcholine receptor antibodies and exhibited amplitude decrement on repetitive nerve stimulation, which are diagnostic for MG. This report emphasizes the importance of neurodiagnostic and physiological testing in patients presenting with bilateral facial weakness alone.

Ocular myasthenia gravis: a review and practical guide for clinicians

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

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

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