Management of myasthenia gravis during pregnancy

Recommendations for the management of myasthenia gravis in Belgium

International guidelines on the treatment of myasthenia gravis (MG) have been published but are not tailored to the Belgian situation. This publication presents recommendations from a group of Belgian MG experts for the practical management of MG in Belgium. It includes recommendations for treatment of adult patients with generalized myasthenia gravis (gMG) or ocular myasthenia gravis (oMG). Depending on the MG-related antibody a treatment sequence is suggested with therapies that can be added on if the treatment goal is not achieved. Selection of treatments was based on the level of evidence of efficacy, registration and reimbursement status in Belgium, common daily practice and the personal views and experiences of the authors. The paper reflects the situation in February 2024. In addition to the treatment considerations, other relevant aspects in the management of MG are addressed, including comorbidities, drugs aggravating disease symptoms, pregnancy, and vaccination. As many new treatments might potentially come to market, a realistic future perspective on the impact of these treatments on clinical practice is given. In conclusion, these recommendations intend to be a guide for neurologists treating patients with MG in Belgium.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Immunotherapies in MuSK-positive Myasthenia Gravis; an IgG4 antibody-mediated disease

Muscle-specific kinase (MuSK) Myasthenia Gravis (MG) represents a prototypical antibody-mediated disease characterized by predominantly focal muscle weakness (neck, facial, and bulbar muscles) and fatigability. The pathogenic antibodies mostly belong to the immunoglobulin subclass (Ig)G4, a feature which attributes them their specific properties and pathogenic profile. On the other hand, acetylcholine receptor (AChR) MG, the most prevalent form of MG, is characterized by immunoglobulin (Ig)G1 and IgG3 antibodies to the AChR. IgG4 class autoantibodies are impotent to fix complement and only weakly bind Fc-receptors expressed on immune cells and exert their pathogenicity via interfering with the interaction between their targets and binding partners (e.g. between MuSK and LRP4). Cardinal differences between AChR and MuSK-MG are the thymus involvement (not prominent in MuSK-MG), the distinct HLA alleles, and core immunopathological patterns of pathology in neuromuscular junction, structure, and function. In MuSK-MG, classical treatment options are usually less effective (e.g. IVIG) with the need for prolonged and high doses of steroids difficult to be tapered to control symptoms. Exceptional clinical response to plasmapheresis and rituximab has been particularly observed in these patients. Reduction of antibody titers follows the clinical efficacy of anti-CD20 therapies, a feature implying the role of short-lived plasma cells (SLPB) in autoantibody production. Novel therapeutic monoclonal against B cells at different stages of their maturation (like plasmablasts), or against molecules involved in B cell activation, represent promising therapeutic targets. A revolution in autoantibody-mediated diseases is pharmacological interference with the neonatal Fc receptor, leading to a rapid reduction of circulating IgGs (including autoantibodies), an approach already suitable for AChR-MG and promising for MuSK-MG. New precision medicine approaches involve Chimeric autoantibody receptor T (CAAR-T) cells that are engineered to target antigen-specific B cells in MuSK-MG and represent a milestone in the development of targeted immunotherapies. This review aims to provide a detailed update on the pathomechanisms involved in MuSK-MG (cellular and humoral aberrations), fostering the understanding of the latest indications regarding the efficacy of different treatment strategies.

Choices and Challenges With Treatment of Myasthenia Gravis in Pregnancy: A Systematic Review

Myasthenia gravis (MG) is an autoimmune disease affecting young women in their second and third decades, coinciding with their reproductive years. We aim to explore the choices and challenges in the treatment of MG in pregnancy. Cochrane, PubMed, Google Scholar, and Embase were the four databases systematically searched for studies with patients reporting pregnancy outcomes for women with MG during pregnancy using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) technique. Quality assessment was done using the Joanna Briggs Institute critical tool (JBI, Adelaide, Australia) for methodological quality. From 2000 to 2023, 40 studies from database search results were considered. There is a substantial risk of complications with MG, especially if it appears during pregnancy. In particular, widespread weakness is a cause of severe, life-threatening disorders, but several treatment options are available.

A Complicated Case of Postpartum Myasthenic Crisis

Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction (NMJ) of voluntary skeletal muscle. This disease is characterized by ptosis, diplopia, facial muscle weakness, bulbar muscle involvement including dysphagia and difficulty chewing, dysarthria, hypophonia, respiratory muscle fatigue, and sometimes generalized weakness. A myasthenic crisis (MC) is a complication of MG. MC is defined as severe worsening of respiratory function necessitating the need for mechanical ventilation. Precipitating factors include infection, certain drugs, pregnancy, childbirth, surgery, discontinuation of medical therapy, or even spontaneously with no inciting event. Here we present a complicated case of a 24-year-old patient with a long history of controlled who encounters many events that lead to an MC necessitating mechanical intubation, plasmapheresis, and high dose immunosuppressive therapy. She recently gave birth to a child, had an occult perforated appendicitis with multiple abscesses needing emergent exploratory laparotomy, and had an overlying COVID-19 infection. The complexity of this disease and its complications warrants careful consideration by physicians in any branch of specialty.

Clinical and pathophysiologic relevance of autoantibodies in neonatal myasthenia gravis

Between 10% and 20% of neonates born to mothers with myasthenia gravis (MG) develop neonatal MG due to the transfer of maternal autoantibodies across the placenta. Neonatal MG can occur in infants born not only from mothers with acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies but also from mothers without detectable muscle antibodies. The low incidence rate may be due to specific autoantibody characteristics that differ among individuals, but a genetic predisposition in some infants is possible. The majority of reported neonatal MG cases are anti-AChR antibody-positive (AChR-MG), and a high anti-fetal/anti-adult AChR titer ratio in the mother is predictive of its occurrence. However, patients with anti-MuSK antibody-positive MG (MuSK-MG) are more likely to experience exacerbations during pregnancy and have a higher probability of developing neonatal MG than AChR-MG patients. Moreover, maternal MuSK-MG may be associated with early-onset and more severe manifestations of neonatal MG. Although cholinesterase inhibitors have been effectively used for treating neonatal AChR-MG, neonatal MuSK-MG may be more difficult to treat with this type of medication. Maternal MuSK-MG usually greatly benefits from intravenous immunoglobulin (IVIG) and plasma exchange. In neonatal MG, IVIG is considered for severely affected infants with MuSK-MG, but the efficacy of IVIG remains unclear. Although exchange transfusion may be a management adjunct, its clinical benefits are controversial. As the therapy-induced reduction of autoantibodies may be advantageous for fetal outcomes, maternal MG should be effectively treated during pregnancy. However, caution of drug contraindication during pregnancy and lactation must be exercised to avoid unwanted effects for the fetus and neonate. In the future, MG caused by anti-lipoprotein receptor-related protein 4 or other antibodies might be also identified in pregnant women and neonates. Therefore, the determination of autoantibody specificity is essential for successful management.

Myasthenia gravis and covid-19 in pregnancy: a review of the literature and case series report

OBJECTIVES

The aim of our study was to investigate the interrelations of symptoms, clinical outcomes and treatment regimens in pregnant women, diagnosed with myasthenia gravis and superimposed COVID-19 infection.

METHODS

We conducted an observational retrospective study between August, 2020 and July, 2021. Five patients with preexisting MG and superimposed COVID- infection were included in our study. We investigated the duration of MG, the antibody patient status, any present comorbidities, MG baseline treatment and MG severity class prior to the COVID-19 infection, MG severity class and treatment during the COVID-infection, and last but not least, the maternal and fetal clinical outcome.

RESULTS

None of the participants were hospitalized as they were treated under quarantine at their homes. The most frequently reported complaints were anosmia, headache and fever, which were observed in 3 out of 5 patients. The MG severity was evaluated twice - before and after the quarantine period. Progression to a more advanced stage was found in 2 of our 5 patients. Three of the patients did not require any changes in the prescribed baseline MG treatment. In 2 patients the pyridostigmine dosage had to be increased. One patient received azithromycin and 4 patients were given LMWH (nadroparin) as specific anti-COVID measures. All patients fully recovered and gave birth to healthy newborns.

CONCLUSION

To our knowledge, this is the first study on pregnant MG patients with superimposed COVID-19 infection. Based on our observations in this study it would seem that the coexistence of MG and COVID-19 infection in pregnancy does not elicit exacerbation in neither of those conditions. Further research is needed to confirm or challenge these findings, especially with the prospects of new virus variants emerging in the future.

Myasthenia gravis during pregnancy: what care should be taken?

Myasthenia gravis (MG) is an autoimmune disease in which the peak incidence is among women of childbearing age. For this reason, there is an overlap between the occurrence of this disease and pregnancy. It is known that MG symptoms can worsen during pregnancy and postpartum, and that pregnancy has special characteristics in MG patients. Children born to myasthenic mothers are at risk of having transient neonatal myasthenia. We briefly review the main relationships between MG and pregnancy, and we make recommendations for MG therapy, pregnancy, delivery, breastfeeding and newborns.

Neurocritical Care of the Pregnant Patient

Purpose of review

To summarize recent changes in management and emerging therapies for pregnant neurocritical care patients.

Recent findings

Diagnostic and treatment options for managing neurologic emergencies in pregnant patients have expanded with both greater understanding of the effects of imaging modalities and medications on pregnancy and application of standard treatments for non-pregnant patients to pregnant populations. Specifically, this includes cerebrovascular diseases (pregnancy-associated ischemic stroke, pregnancy-associated intracerebral hemorrhage, cerebral venous sinus thrombosis), post-maternal cardiac arrest care, seizures and status epilepticus, myasthenia gravis, and fetal somatic support in maternal death by neurologic criteria.

Summary

With the exception of direct abdominal computed tomography (CT), most imaging studies are reasonably safe in pregnancy. When emergent imaging is needed to prevent maternal morbidity or mortality, any CT sequence with or without contrast is appropriate to pursue. Though new safety data on antiplatelets, antihypertensives, thrombolytics, and antiepileptic drugs have increased options for disease management in pregnancy, unfractionated and low-molecular weight heparin remain the safest options for anticoagulation. Early studies on hypothermia, ketamine, and immunomodulating therapies in pregnancy are promising. In myasthenia gravis, new data on adjunct devices may allow more patients to undergo safe vaginal delivery, avoiding cesarean section and the associated risk of crisis. When difficult decisions regarding preterm delivery arise, recent outcome studies can help inform discussion. Lastly, when the feared complication of maternal death by neurologic criteria occurs, fetal somatic support may help to save at least one life.

Zilucoplan: An Investigational Complement C5 Inhibitor for the Treatment of Acetylcholine Receptor Autoantibody-Positive Generalized Myasthenia Gravis

INTRODUCTION

Generalized myasthenia gravis (gMG) is an autoimmune disorder in which pathogenic autoantibodies damage the neuromuscular junction, causing disabling or life-threatening muscle weakness. Most treatments nonspecifically inhibit aspects of the immune system, do not directly address the causal mechanisms of tissue damage, and often have side-effect profiles that negatively impact patients. Understanding of the central pathogenic role of the complement cascade in gMG is advancing, and a new complement-targeting treatment is under investigation.

AREAS COVERED

We provide an overview of gMG etiology, the complement cascade, current treatments, and the investigational gMG therapy zilucoplan. Zilucoplan is a small, subcutaneously administered, macrocyclic peptide that inhibits cleavage of complement component C5 and the subsequent formation of the membrane attack complex.

EXPERT OPINION

In a randomized, double-blind, placebo-controlled, phase 2 clinical trial, zilucoplan demonstrated clinically meaningful complement inhibition in patients with acetylcholine receptor-positive gMG. Zilucoplan, a first-of-its-kind cyclic peptide targeting C5, appears to be a therapeutic option for the treatment of gMG based on available pharmacokinetic/pharmacodynamic data and phase 1 and 2 efficacy, safety, and tolerability data with limited long-term follow-up. Zilucoplan use earlier in the treatment paradigm would be suitable in this population should phase 3 efficacy and safety data be equally favorable.