Myasthenia gravis: Five new things

Anti-Muscle-Specific Kinase (MuSK) Antibody-Positive Myasthenia Gravis Presenting With Dyspnea in an Elderly Woman: A Case Report

Myasthenia gravis (MG) is an autoimmune disease and represents one of the most common disorders associated with neuromuscular transmission defects. Within MG, the anti-muscle-specific kinase antibody-positive subtype (MuSK-positive MG) is rare. While it shares similarities with the common form of MG by presenting with ocular weakness, MuSK-positive MG typically presents with more atypical symptoms. Although MuSK-positive MG can lead to type 2 respiratory failure due to respiratory weakness, there have been limited reports where initial presentation involves only respiratory compromise. This study details a case of MuSK-positive MG presenting dyspnea. An 84-year-old female presented to the emergency department due to a three-day history of progressive respiratory distress, characterized by increased respiratory effort and shallow breathing, resulting in a diagnosis of type 2 respiratory failure. Despite the absence of neurological abnormalities, she tested positive for anti-muscle-specific kinase antibodies, confirming a diagnosis of MuSK-positive MG. This case highlights the significance of considering MG in the context of type 2 respiratory failure, even in the absence of typical neurological symptoms, especially in elderly patients.

Cogan's Lid Twitch for Myasthenia Gravis: A Systematic Review

INTRODUCTION

Myasthenia gravis is an autoimmune condition affecting the neuromuscular junction of skeletal muscles and may be difficult to diagnose. Several clinical signs may have diagnostic utility, including Cogan's lid twitch. This systematic review aims to synthesise the literature on the accuracy of Cogan's lid twitch for diagnosing myasthenia gravis.

METHODS

A systematic search of the databases PubMed/MEDLINE, Embase and CENTRAL was performed from inception to August 2022. Risk of bias analysis and data extraction were performed in accordance with the PRISMA 2020 guidelines.

RESULTS

Seven articles satisfied the inclusion criteria. The results showed that for the diagnosis of myasthenia gravis, Cogan's lid twitch has a sensitivity between 50% and 99% and specificity between 75% and 100%.

CONCLUSIONS

Cogan's lid twitch is a physical examination finding with moderate diagnostic performance in the diagnosis of myasthenia gravis with ocular involvement. Future studies may seek to evaluate the performance of Cogan's lid twitch in conjunction with other signs of myasthenia gravis with ocular involvements, such as fatigable ptosis or a positive icepack test.

COVID-19 and Sepsis in an Atypical Case of Mixed Connective Tissue Disorder Presenting With a Myasthenic Crisis

Myasthenia gravis (MG) is an autoimmune illness that causes neuromuscular junctions to be damaged by anti-acetylcholine receptor antibodies. It is a very rare condition that is more common among women. Fatigable fluctuating diplopia or ptosis is the characteristic early appearance of this condition. Dysphagia or dysphonia may be present in rare cases. This illness can affect any group of skeletal muscles, including those in the neck and upper limbs. It can also affect the muscles that help you breathe, which can lead to breathing failure.

We present a case of a 20-year-old female diagnosed with mixed connective tissue disease presenting with acute respiratory failure as the initial presentation of MG. Clinicians have to have a high index of suspicion for myasthenia when patients arrive with fatigable muscle weakness. This will cut down on the amount of money spent on investigations and the risk of morbidity.

Immunomodulatory effects of curcumin in systemic autoimmune diseases

Systemic autoimmune diseases like rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus represent various autoimmune conditions identified by immune system dysregulation. The activation of immune cells, auto-antigen outbreak, inflammation, and multi-organ impairment is observed in these disorders. The immune system is an essential complex network of cells and chemical mediators which defends the organism's integrity against foreign microorganisms, and its precise operation and stability are compulsory to avoid a wide range of medical complications. Curcumin is a phenolic ingredient extracted from turmeric and belongs to the Zingiberaceae, or ginger family. Curcumin has multiple functions, such as inhibiting inflammation, oxidative stress, tumor cell proliferation, cell death, and infection. Nevertheless, the immunomodulatory influence of curcumin on immunological reactions/processes remains mostly unknown. In the present narrative review, we sought to provide current information concerning the preclinical and clinical uses of curcumin in systemic autoimmune diseases.

Characteristics, treatment, and outcomes of Myasthenia Gravis in COVID-19 patients: A systematic review

Objective

Recent studies suggest that the clinical course and outcomes of patients with coronavirus disease 2019 (COVID-19) and myasthenia gravis (MG) are highly variable. We performed a systematic review of the relevant literature with a key aim to assess the outcomes of invasive ventilation, mortality, and hospital length of stay (HLoS) for patients presenting with MG and COVID-19.

Methods

We searched the PubMed, Scopus, Web of Science, and MedRxiv databases for original articles that reported patients with MG and COVID-19. We included all clinical studies that reported MG in patients with confirmed COVID-19 cases via RT-PCR tests. We collected data on patient background characteristics, symptoms, time between MG and COVID-19 diagnosis, MG and COVID-19 treatments, HLoS, and mortality at last available follow-up. We reported summary statistics as counts and percentages or mean±SD. When necessary, inverse variance weighting was used to aggregate patient-level data and summary statistics.

Results

Nineteen studies with 152 patients (mean age 54.4 ± 12.7 years; 79/152 [52.0%] female) were included. Hypertension (62/141, 44.0%) and diabetes (30/141, 21.3%) were the most common comorbidities. The mean time between the diagnosis of MG and COVID-19 was7.0 ± 6.3 years. Diagnosis of COVID-19 was confirmed in all patients via RT-PCR tests. Fever (40/59, 67.8%) and ptosis (9/55, 16.4%) were the most frequent COVID-19 and MG symptoms, respectively. Azithromycin and ceftriaxone were the most common COVID-19 treatments, while prednisone and intravenous immunoglobulin were the most common MG treatments. Invasive ventilation treatment was required for 25/59 (42.4%) of patients. The mean HLoS was 18.2 ± 9.9 days. The mortality rate was 18/152 (11.8%).

Conclusion

This report provides an overview of the characteristics, treatment, and outcomes of MG in COVID-19 patients. Although COVID-19 may exaggerate the neurological symptoms and worsens the outcome in MG patients, we did not find enough evidence to support this notion. Further studies with larger numbers of patients with MG and COVID-19 are needed to better assess the clinical outcomes in these patients.

Myasthenia Gravis-An Analysis of Multimodal Evoked Potentials

INTRODUCTION

The aim of this study is a comprehensive analysis of the parameters of exogenous evoked potentials (visual, brainstem auditory, and somatosensory) in patients with myasthenia gravis (MG), a prototype of both neuromuscular junction disease and autoimmune disease. The study also seeks to isolate electrophysiological changes that may indicate disorders within the central and/or peripheral nervous system.

METHODS

A total of forty-two consecutive patients with myasthenia gravis (24 women, 18 men) were included in the study. All of the patients underwent EP examination. MR images were also analyzed.

RESULTS

In the group of MG patients, the latency of P100 (113.9 ± 13.9; p < 0.0001) VEP, wave III (3.92 ± 0.29; p = 0.015), wave V (5.93 ± 0.32; <0.0001), interlatency III-V (2.00 ± 0.12; p < 0.0001), interlatency I-V (4.20 ± 0.28; p < 0.001) BAEP, and all components of SEP (N9, P10, N13, P16, N20, P22) were significantly longer. Mean wave I and V amplitude BAEP were relatively lower.

CONCLUSIONS

The results of the study suggest the presence of disturbances in the bioelectric activities of the central and peripheral nervous system in MG patients.

Neuromuscular Respiratory Failure

Neuromuscular respiratory failure can result from any disease that causes weakness of bulbar and/or respiratory muscles. Once compensatory mechanisms are overwhelmed, hypoxemic and hypercapnic respiratory failure ensues. The diagnosis of neuromuscular respiratory failure is primarily clinical, but arterial blood gases, bedside spirometry, and diaphragmatic ultrasonography can help in early assessment. Intensive care unit (ICU) admission is indicated for patients with severe bulbar weakness or rapidly progressing appendicular weakness. Intubation should be performed electively, particularly in patients with dysautonomia. Patients with an underlying treatable cause have the potential to regain functional independence with meticulous ICU care.

A Co-Occurrence of Serologically Proven Myasthenia Gravis and Pharyngeal-Cervical-Brachial Variant of Guillain-Barré Syndrome

We report on a co-occurrence case of ocular myasthenia gravis with exacerbation leading to myasthenic crisis in addition to pharyngeal-cervical-brachial variant of Guillain-Barré syndrome in a patient with severe oropharyngeal dysphagia and acute respiratory failure.

Intensive Care Management of the Neuromuscular Patient

Neuromuscular emergencies are a distinct group of acute neurological diseases with distinct characteristic presentations. Patients who suffer from this group of diseases are at immediate risk of losing protection of their native airway as well as aspirating orogastric contents. This is secondary to weakness of the muscles of the oropharynx and respiratory muscles. Although some neuromuscular emergencies such as myasthenia gravis or Guillain-Barré syndrome are well understood, others such as critical illness myopathy and neuropathy are less well characterized. In this chapter, we have discussed the pathophysiology, diagnostic evaluation, and management options in patients who are admitted to the intensive care unit. We have also emphasized the importance of a thorough understanding of the use of pharmacological anesthetic agents in this patient population.

Myasthenic Crisis In Pregnancy

This case reviews the management of a 27-year-old pregnant female in myasthenic crisis. She presented to the emergency department in respiratory distress refractory to standard therapy, necessitating airway and ventilatory support and treatment with plasmapheresis. Myasthenic crisis in the setting of pregnancy is rare and presents unique management challenges for emergency physicians.

Memory B cell resurgence requires repeated rituximab in myasthenia gravis

The immunologic effects of rituximab (RTX) in myasthenia gravis (MG) remain to be explored. We aimed to clarify immunologic reactions and their association with response to RTX in MG. Regulatory T cell and B cell profiles of MG patients were monitored. Two patients presenting with generalized MG with anti-acetylcholine receptor antibodies were treated with RTX. The treatment led to sustained clinical improvement, discontinuation of intravenous immunoglobulin or plasma exchange, and reduction of prednisolone and other drugs. One patient was in remission for more than one year, whereas the other patient exhibited deterioration of symptoms within one year. Disease activity was associated with the repopulation of IgD^-CD27^- and IgD^-CD27⁺ memory B cells. Clinicians should be aware of the possibility that MG ranges in the duration of B cell depletion and additional RTX should be prescribed upon resurgence of memory B cells.

Bibliometric analysis of the scientific production as regards statin use for ophthalmological symptoms of myasthenia gravis

INTRODUCTION

The first symptoms of myasthenia gravis (MG) usually involve weakness of the ocular muscles, making it relevant that ophthalmologists have updated information on studies as regards its relationship with the consumption of drugs, such as statins.

MATERIALS AND METHODS

A bibliometric analysis was performed using the Scopus database and by a search strategy in the selection of documents containing descriptors related to statins in the «Title» («TI») field and the descriptors «ophthalm *', «myast *', «visual *' in other fields of the document (period 1986-2015).

RESULTS

The results showed that, while the number of scientific publications on ocular effects of statins has grown lineally (n=838; y=2.267x-4507.1; r=0.7221; time of duplication: 4.66 years, and rate of annual growth: 50.06%), the specific publications about MG have experienced an exponential growth (n=38; y=2E-262e^0.3001x; r=0.3892; time of duplication: 2.95 years, and rate of annual growth: 46.25%) without reaching the saturation postulated in Price theory of the expansion of the scientific literature. The majority of publications relating to MG are reports of cases linked to a worsening of the MG symptoms, and simvastatin and atorvastatin are the agents mentioned in most of the publications.

CONCLUSIONS

These results should enable ophthalmologists to expand their knowledge concerning the evolution of studies on statins and MG, pointing out the relevance of such causal relationships.

Late-onset myasthenia gravis is predisposed to become generalized in the elderly

Objective

The continuous increase in the number of patients presenting with late-onset myasthenia gravis (LOMG) underscores the need for a better understanding of the clinical course and the establishment of an optimal therapeutic strategy. We aimed to clarify factors associated with clinical outcomes in LOMG.

Methods

We retrospectively reviewed the clinical profiles of 40 patients with early-onset MG (EOMG) (onset age: 49 years or younger), 30 patients with non-elderly LOMG (onset age: 50–64 years), and 28 patients with elderly LOMG (onset age: 65 years or older) and compared the subgroups according to onset age and thymus status. The evaluated parameters were MGFA classification before treatment, MG-ADL score, complicating diseases, antibody titer, treatment, and MGFA post-intervention status.

Results

Elderly LOMG patients showed transition to generalized symptoms at a higher frequency and underwent thymectomy less frequently than EOMG and non-elderly LOMG patients (p < 0.001). The frequencies of crisis and plasmapheresis were significantly lower in thymectomized LOMG patients without thymoma than in thymectomized LOMG patients with thymoma or non-thymectomized LOMG patients (p < 0.01, P < 0.05, respectively). However, the outcome was not significantly different. All of the thymectomized LOMG patients without thymoma presenting with hyperplasia or thymic cyst had a favorable clinical course.

Conclusions

Our study showed that elderly LOMG patients are more prone to severity, suggesting that they require aggressive immunomodulatory therapy.

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Elderly LOMG patients showed transition to generalized symptoms at a higher frequency.

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Thymectomized LOMG patients without thymoma showed crisis less frequently.

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Our study showed that elderly LOMG patients are more prone to severity.

Anti-MuSK-positive myasthenia gravis diagnosed during pregnancy: new challenges for an old disease?

Myasthenia gravis is an autoimmune disorder affecting predominantly women in their reproductive age. The course of the disease during pregnancy is unpredictable, although it is more difficult to manage earlier in the gestation. Myasthenia gravis with antibodies against the muscle-specific receptor tyrosine kinase (anti-MuSK) has been described as a subtype of disease with more localised clinical features and a poorer response to treatment than acetylcholine receptor antibody (anti-AChR)-positive patients. Few cases have been reported in pregnant women, with deliveries being performed mainly by caesarean section. We report a successful case of vaginal delivery and describe our experience providing the first review of the management of this subtype of disease during pregnancy.