Outcome and clinical features in juvenile myasthenia gravis: A systematic review and meta-analysis

Efficacy and Safety of Tacrolimus Therapy in Patients With Juvenile Myasthenia Gravis: A Single-Arm Meta-Analysis

BACKGROUND

Numerous guidelines recommend off-label use of tacrolimus (TAC) to treat myasthenia gravis (MG) in adults. This study aimed to evaluate whether TAC is beneficial in pediatric patients with juvenile MG (JMG).

METHODS

We conducted a systematic literature search using the keywords "Myasthenia Gravis," "TAC," "juveniles," and their synonyms. PubMed, Embase, Web of Science, Cochrane Library, and Chinese databases were searched for articles published until April 1, 2024. Two reviewers independently identified and extracted relevant retrospective/prospective comparison studies or randomized controlled trials and assessed the risk of bias for each study. Eligible studies were subsequently included in a meta-analysis that evaluated the clinical outcomes of TAC treatment for JMG using fixed- and random-effects models.

RESULTS

Of the 203 articles initially identified, nine were included in the meta-analysis. These studies included 313 children diagnosed with JMG, with ages ranging from 0 to 13.5 years. Among the included studies, two were comparison trials, whereas the remaining seven employed a single-group pretest-post-test design. Two studies were deemed to be of high quality, and seven were of moderate quality. The pooled overall response rate of the definite responder rate to TAC treatment in JMG was calculated as 3.92 (95% confidence interval: 2.06 to 7.45, I2 = 71%, P < 0.001).

CONCLUSIONS

This meta-analysis found that TAC improved symptoms and MG-related scores in patients with JMG with minimal adverse effects. These findings underscore the importance of TAC therapy for the treatment of JMG.

Juvenile Myasthenia Gravis in North Texas: Clinical Features, Treatment Response, and Outcomes

BACKGROUND

Juvenile myasthenia gravis (JMG) is a rare autoimmune disease that causes fatigable muscle weakness in children aged <18 years. There is currently no curative treatment or internationally accepted standard of care for JMG. The objective is to investigate relationships between clinical presentation, antibody status, severity of disease onset, electrodiagnostic evaluation, and response to therapy in JMG.

METHODS

This study was a retrospective chart review. Congenital myasthenic syndromes were excluded. Data on demographics, treatments, and outcomes were collected. Disease severity was evaluated using Myasthenia Gravis Foundation of America (MGFA) clinical classifications.

RESULTS

We identified 84 patients with JMG at Children's Medical Center Dallas between January 2014 and February 2022. It was found that 52% of patients presented with ocular JMG (median onset age 4.5 years) and 48% with generalized JMG (median onset age 11.5 years); 81% tested positive for acetylcholine receptor antibodies. Patients were 17% non-Hispanic white, 29% Hispanic, 39% black, and 12% Asian. There was a significant difference in average MGFA scores between ethnicities (P = 0.047) and age groups (P = 0.004), with postpubertal patients having higher average MGFA scores than prepubertal patients. Seventy-one percent of patients who underwent thymectomy experienced a decrease in MGFA scores postprocedure.

CONCLUSIONS

Our study showed that there were significant differences in disease severity between ethnicities and age groups and that most patients who underwent thymectomy showed clinical improvement. These outcomes highlight the need for additional therapies in the treatment of JMG and the importance of extending clinical trials to the pediatric population.

Comorbidity in myasthenia gravis: multicentric, hospital-based, and controlled study of 178 Italian patients

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disorder with fluctuating weakness that causes significant disability and morbidity. Comorbidities may influence the course of MG, particularly in specific subgroups. The aim of this study is to investigate the frequency of comorbidities in MG patients compared to healthy controls (HC) and to evaluate their distribution according to age at disease onset, sex, and disease severity.

METHODS

MG patients attending the University Hospital "Paolo Giaccone" in Palermo and "SS Annunziata" Hospital in Chieti were enrolled; HC were enrolled from the general population. Non-parametric statistics and logistic regression were used to assess the association of specific comorbidities according to age at disease onset, sex, disease subtypes, and severity of the disease.

RESULTS

A total of 356 subjects were included in the study: 178 MG patients (46% F; median age 60 years [51-71]) and 178 sex- and age-matched HC (46% F, median age 59 years [50-66]). Overall, 86% of MG patients and 76% of HC suffered from comorbidities, and MG patients had a higher number of comorbidities compared to HC. Patients with late-onset suffered from more comorbidities than those with early-onset MG. Hypertension was more common in male patients with MG, while thymic hyperplasia, osteoporosis, and autoimmune diseases were more common in females. Respiratory disorders and thymoma were more common in patients with more severe disease (p < 0.05 for all comparisons).

CONCLUSION

MG patients, particularly those with late onset, showed a higher prevalence of comorbidities than HC. Assessment of comorbidities in MG is an essential issue to identify the appropriate treatment and achieve the best management.

Immune mediated myasthenia gravis in children, current concepts and new treatments: A narrative review article

Myasthenia gravis (MG) is the most frequent transmission disease in the neuromuscular junction. Juvenile myasthenia gravis (JMG) is an autoimmune antibody-mediated disease of postsynaptic endplate defined as MG presentation in patients before the age of 18 years old. While many clinical features of JMG are identical to the adults, there are some significant differences between them regarding presentation, clinical course, antibody level, and thymus histopathology. In JMG, ocular symptoms are more frequent, the clinical course is comparably benign, and the outcome is better than adult MG. Antibodies attack the muscle endplate proteins in the postsynaptic membrane and interfere with transmission. These antibodies in most patients are against the acetylcholine receptors, but they may also be directed toward muscle-specific kinase, lipoprotein-related protein 4, and agrin. Findings show racial influences and genetic effects on the occurrence of JMG. The essential clinical symptom is fatigable weakness of muscles that can be in the form of isolated ocular type or more disseminated weakness. The diagnosis of JMG is essentially clinical, with fluctuating patterns of weakness and easy fatigability, but a series of diagnostic evaluations can confirm the diagnosis. Precise diagnostic evaluation and distinction from congenital myasthenic syndromes is critical. The treatment plan is conducted according to the clinical course (ocular or generalized), antibody type, and disease severity. The mainstay of treatment includes symptomatic therapy, long-lasting immunosuppressive treatment and treatment of myasthenic crisis. Novel medications are introduced and conducted to the specific pathophysiologic mechanisms of the disease, and they are used primarily in the refractory MG.

Thymectomy for juvenile myasthenia gravis: a narrative review

Background and Objective

Thymectomy as a management strategy for juvenile myasthenia gravis (JMG) has been increasingly adopted with the advent of minimally invasive surgical techniques. This review evaluates existing evidence regarding the surgical management of JMG, including the benefits of surgical compared to medical therapy, important considerations when evaluating surgical candidacy and determining optimal timing of intervention. In addition, we provide an overview of the open, thoracoscopic and robotic surgical approaches available for thymectomy and compare the existing data to characterize optimal surgical management.

Methods

A thorough literature review was conducted for full length research articles, including systematic reviews, retrospective cohort studies and case series, published between January 2000 and July 2023 regarding open, thoracoscopic or robotic thymectomy for management of JMG. Reference lists of the identified articles were manually searched for additional studies. Evidence was summarized in a narrative fashion with the incorporation of the authors' knowledge gained through clinical experience.

Key Content and Findings

Although data specific to JMG are limited to small retrospective cohort studies, available evidence supports equal to greater disease control following thymectomy versus pharmacologic management. Furthermore, outcomes may be optimized when surgery is performed earlier in the disease course, particularly for patients who are post-pubertal with generalized or severe disease and those necessitating high-dose steroid administration thereby limiting its metabolic and growth inhibitory effects. Open transsternal resection is the historic gold-standard; however, as surgeons become more comfortable with thoracoscopic and robotic-assisted thymectomy, an increasing proportion of patients are expected to undergo thymectomy. At present, the data available is unable to support conclusions regarding which surgical approach is superior; however, minimally invasive approaches may be non-inferior while offering superior cosmesis and decreased morbidity.

Conclusions

Higher-level investigation through the use of multi-institutional databases and randomized prospective trials is warranted in order to understand which child warrants thymectomy, at what point in their disease course and their development, and which surgical approach will optimize postoperative outcomes.

The Clinical Course and Treatment of a Case of Refractory Systemic Juvenile Myasthenia Gravis Successfully Treated with Thymectomy

Juvenile myasthenia gravis (JMG) exhibits a more favorable response to glucocorticoids and has a better prognosis than adult myasthenia gravis. However, no established treatment exists for refractory JMG. Although thymectomy has been performed in several patients with refractory systemic JMG, there are few detailed clinical descriptions of patients who underwent thymectomy. Here, we present the case of a 10-year-old boy with refractory systemic JMG who was successfully treated with thymectomy. The patient developed symptoms, including dysphagia, malaise, diurnal ptosis, and weakness in the trunk muscles, and he was diagnosed with generalized JMG. Despite undergoing various treatments, including steroids, tacrolimus, steroid pulse therapy, intravenous immunoglobulin, azathioprine (AZT), and rituximab, his symptoms did not improve. Therefore, he underwent a thoracoscopic thymectomy 24 months after disease onset. Thymectomy led to remission, as demonstrated by a significant reduction in the quantitative myasthenia gravis score and anti-acetylcholine receptor antibody levels, which persisted for 43 months after surgery. Our case demonstrates the effectiveness of thymectomy in systemic JMG patients with positive anti-acetylcholine receptor antibodies, despite therapeutic failure with AZT and rituximab, within 2 years of disease onset.