Thymectomy in patients with myasthenia gravis increases the risk of autoimmune rheumatic diseases: a nationwide cohort study

Rapid Progression of Skin Sclerosis Following Surgery for Carpal Tunnel Syndrome: A Case of Diffuse Cutaneous Systemic Sclerosis

Carpal tunnel syndrome (CTS) is a frequently encountered compressive neuropathy that is often treated surgically. Here, we present an unusual case of a 74-year-old female who developed a rapid emergence of skin sclerosis following CTS surgery. The condition was initially misdiagnosed as complex regional pain syndrome. However, since her skin condition progressed, she was referred to the rheumatology department. Subsequent evaluations confirmed the diagnosis of diffuse cutaneous systemic sclerosis, accompanied by interstitial lung disease. Treatment with mycophenolate mofetil did not notably alter the interstitial lung shadows but led to minor improvement in skin sclerosis. It is crucial to consider the possibility of rheumatic diseases in patients with unexpected postoperative symptoms.

Insights from a Case of Good's Syndrome (Immunodeficiency with Thymoma)

Immunodeficiency with thymoma was described by R.A. Good in 1954 and is also named after him. The syndrome is characterized by hypogammaglobulinemia associated with thymoma and recurrent infections, bacterial but also viral, fungal and parasitic. Autoimmune diseases, mainly pure red cell aplasia, other hematological disorders and erosive lichen planus are a common finding. We describe here a typical case exhibiting all these clinical features and report a detailed immunophenotypic assessment, as well as the positivity for autoantibodies against three cytokines (IFN-alpha, IL-6 and GM-CSF), which may add to known immune abnormalities. A review of the published literature, based on case series and immunological studies, offers some hints on the still unsolved issues of this rare condition.

Anti-dsDNA Is Associated with Favorable Prognosis in Myasthenia Gravis: A Retrospective Study

Objectives. To investigate the presence of serum antinuclear antibody (ANA) and anti-double-stranded DNA antibody (anti-dsDNA) in patients with myasthenia gravis (MG) and analyze the clinical characteristics and prognostic factors associated with MG. Methods. We retrospectively enrolled 363 patients with MG and analyzed the clinical characteristics and follow-up data between patients positive and negative for ANA and anti-dsDNA. We defined a Myasthenia Gravis Activities of Daily Living (MG-ADL) reduction as a main prognosis predictor and used logistic regression to determine independent factors associated with prognosis. We built a nomogram to predict prognosis and evaluate the internal validity of the model. Results. Ninety-eight (27.0%) patients were positive for ANA, and 51 (14.0%) were positive for anti-dsDNA. Patients positive for ANA and anti-dsDNA antibodies tended to be female and positive for acetylcholine receptor antibody (AChR-Ab). The rate of thymoma was higher in anti-dsDNA-positive patients with MG (p-dsDNA-MG) than in patients negative for anti-dsDNA (49.0% vs. 26.0%, $p=0.001$ ), and p-dsDNA-MG was associated with reduced MG-ADL score. Regression analysis showed that except for age of onset ( $\text{OR}=0.986$ , $95\%\text{CI}=0.973–0.999$ , $p=0.037$ ), anti-dsDNA ( $\text{OR}=2.800$ , $95\%\text{CI}=1.381–5.679$ , $p=0.004$ ), ptosis ( $\text{OR}=2.930$ , $95\%\text{CI}=1.827–4.699$ , $p<0.001$ ), and eye movement disorder ( $\text{OR}=2.815$ , $95\%\text{CI}=1.672–4.741$ , $p<0.001$ ) were independent predictive factors of a favorable prognosis of MG. These predictors were used to generate a nomogram with an excellent predictive value. Conclusions. Being female and the presence of AChR-Ab were features of ANA- or anti-dsDNA-positive MG. The presence of anti-dsDNA was associated with a favorable prognosis of MG.

Clinical characteristics of myasthenia gravis (MG) patients developing other autoimmune diseases after thymectomy from one single center cohort

BACKGROUND

Myasthenia gravis (MG) patients are reported to have a high risk of other autoimmune diseases (ADs), and thymectomy may increase the risk further. A cohort of MG patients in which thymectomy was performed were investigated to analyze the prevalence, types and features of the new onset ADs.

METHODS

Consecutive patients with MG who underwent thymectomy at Beijing Hospital between January 2012 and August 2021 were retrospectively enrolled. Patients with a postoperative follow-up period shorter than a year or incomplete clinical records were excluded. Clinical and follow-up data were collected. Statistical analyses were performed using SPSS version 22.0.

RESULTS

A total of 445 patients were included in this study. The median follow-up period was 72 months (range, 12-135 months). A total of 63 (14.2%) MG patients had concurrent ADs. The incidence rate was higher than the background prevalence of population (5%), and also higher than that of a former Chinese MG cohort (11.6%). A total of 47 patients (10.6%) were diagnosed with ADs before thymectomy, and 19 (4.3%) developed a new AD after thymectomy. The most common types of new onset ADs after thymectomy were Hashimoto's thyroiditis and rheumatoid arthritis (RA), which were different from those before thymectomy (hyperthyroidism and Hashimoto's thyroiditis). The incidence rate of new onset RA (1.35%) was higher than the frequency of RA before thymectomy (0.45%), and also higher than the incidence rate in a Chinese MG cohort (0.5%). There was a higher proportion of female patients (p = 0.026) with postoperative ADs. A younger age at operation may increase the risk of nonthymoma MG patients (p = 0.040) developing ADs. The postoperative treatment effect of MG was similar between patients with and without new onset ADs (p > 0.05).

CONCLUSIONS

We observed a higher incidence rate of autoimmune diseases, especially rheumatoid arthritis, in MG patients after thymectomy. The most common types of ADs after thymectomy were different from those before thymectomy. New onset ADs tended to occur in female and young nonthymoma MG patients. The postoperative effect of MG was not related with the new occurrence of ADs.

Poor responses and adverse outcomes of myasthenia gravis after thymectomy: Predicting factors and immunological implications

Myasthenia gravis (MG) has been recognized as a series of heterogeneous but treatable autoimmune conditions. As one of the indispensable therapies, thymectomy can achieve favorable prognosis especially in early-onset generalized MG patients with seropositive acetylcholine receptor antibody. However, poor outcomes, including worsening or relapse of MG, postoperative myasthenic crisis and even post-thymectomy MG, are also observed in certain scenarios. The responses to thymectomy may be associated with the general characteristics of patients, disease conditions of MG, autoantibody profiles, native or ectopic thymic pathologies, surgical-related factors, pharmacotherapy and other adjuvant modalities, and the presence of comorbidities and complications. However, in addition to these variations among individuals, pathological remnants and the abnormal immunological milieu and responses potentially represent major mechanisms that underlie the detrimental neurological outcomes after thymectomy. We underscore these plausible risk factors and discuss the immunological implications therein, which may be conducive to better managing the indications for thymectomy, to avoiding modifiable risk factors of poor responses and adverse outcomes, and to developing post-thymectomy preventive and therapeutic strategies for MG.

Rheumatoid arthritis and myasthenia gravis: a case-based review of the therapeutic options

Introduction

Myasthenia gravis is an autoimmune disease affecting the neuromuscular junction, often associated with other autoimmune diseases, including rheumatoid arthritis. Patients with rheumatoid arthritis present an increased prevalence of myasthenia gravis compared to the general population. While these two diseases share some therapeutic options, such as glucocorticoids, methotrexate, and rituximab, there are no guidelines for treating concomitant disease. We aim to review the available evidence and to discuss the efficacy and safety of the therapeutic options in patients with rheumatoid arthritis associated with myasthenia gravis.

Method

We described three patients with rheumatoid arthritis associated with myasthenia gravis and we performed a systematic review of the associated literature.

Results

A 48-year-old man and two women (48 and 55 years old) with concomitant diagnoses of active rheumatoid arthritis and well-controlled myasthenia gravis are described. They were treated with methotrexate, leflunomide, upadacitinib, and adalimumab. None of them experienced changes in their myasthenic symptoms. We found 9 additional cases from our literature review. Methotrexate, rituximab, upadacitinib, diphenyl sulfone, auranofin, and loxoprofen sodium did not show an impact on the seven patients with previously well-controlled myasthenia. Glucocorticoids, methotrexate, and rituximab proved effective in active myasthenia gravis and arthritis. Conflicting data emerged for Tumor-necrosis factor inhibitors.

Conclusions

Although the available evidence remains scarce, we consider glucocorticoids, methotrexate, and rituximab as safe and effective options. The role of tumor-necrosis factor inhibitors remains uncertain. Eventually, Janus Kinase inhibitors are a novel interesting option for these patients.

Key Points • To date, the only evidence on the treatment of patients with rheumatoid arthritis and concomitant myasthenia gravis derives from case reports. • Based on the review of the available case reports and on the cases we described, we consider glucocorticoids, methotrexate, and rituximab as safe and effective options, while the role of Tumor-necrosis factor inhibitors remains uncertain. • Based on the cases we described, Janus Kinase inhibitors are a novel interesting option for patients with concomitant rheumatoid arthritis and myasthenia gravis.

Coexistence of Pernicious Anemia and Myasthenia Gravis Presenting As Dyspnea

Dyspnea is a common symptom and may be due to a multitude of conditions, including cardiopulmonary insufficiency, anemia, neuromuscular disorders, obesity, or deconditioning. It is not uncommon that more than one process contributes to shortness of breath. Here, we present a patient with a complaint of worsening shortness of breath who was found to have two very rare causes of dyspnea simultaneously. The symptoms resolved with treatment of pernicious anemia and myasthenia gravis (MG). The coexistence of pernicious anemia and MG is extremely rare, with only two other cases reported so far.

Risk of subsequent atrial fibrillation in patients with myasthenia gravis: A population-based cohort study

The purpose of this study was to explore the association between myasthenia gravis (MG) and the risk of atrial fibrillation (AF) in an Asian population. The risk was analyzed in a cohort of 5528 patients with history of MG and 5528 individuals without MG using a hospitalization claim dataset. Both groups were matched by age, sex, index year and baseline comorbidities as an original analysis. A Cox proportional hazard model was used to estimate the hazard ratio and 95% confidence interval of AF after adjusting for demographic and relevant clinical covariates. The adjusted hazard ratio of the MG group compared with that of the non-MG group was 1.03 (95% confidence interval, 0.76-1.38) for AF. A stratified analysis showed that compared with the propensity score matched non-MG group, there was no increased risk of developing AF based on age categories, gender, or comorbidities. Different time follow-up periods results showed no increased risk of AF compared with the non-MG group. Overall, in the Taiwanese cohort, MG is not associated with an increased risk of AF.

What's in the Neuromuscular Junction Literature?

Four retrospective studies from the United States, Europe, and Asia address outcomes in juvenile myasthenia gravis. Common features include earlier onset with ocular myasthenia gravis (MG) and generally good outcomes overall. Patients who were seronegative, had equivocal acetylcholine receptor (AChR) antibodies, or had only clustered AChR antibodies had better outcomes. An article highlighting the utility of median nerve slow-repetitive stimulation is reviewed and another showing the high sensitivity of repetitive nerve stimulation in myasthenic crisis is covered. Two articles address the thymus and thymectomy in non-AChR antibody-positive autoimmune MG. Longer term data on eculizumab as well as studies of cyclophosphamide, rituximab, and tacrolimus are summarized. Other topics include the possible role of statins in MG and central nervous system autoimmune comorbidities.

Management of Juvenile Myasthenia Gravis

Juvenile Myasthenia Gravis (JMG) is a rare disorder, defined as myasthenia gravis in children younger than 18 years of age. While clinical phenotypes are similar to adults, there are a number of caveats that influence management: broader differential diagnoses; higher rates of spontaneous remission; and the need to initiate appropriate treatment early, to avoid the long-term physical and psychosocial morbidity. Current practice is taken from treatment guidelines for adult MG or individual experience, with considerable variability seen across centers. We discuss our approach to treating JMG, in a large specialist JMG service, and review currently available evidence and highlight potential areas for future research. First-line treatment of generalized JMG is symptomatic management with pyridostigmine, but early use of immunosuppression, where good control is not achieved is important. Oral prednisolone is used as first-line immunosuppression with appropriate prevention and monitoring of side effects. Second-line therapies including azathioprine and mycophenolate may be considered where there is: no response to steroids, inability to wean to a reasonable minimum effective dose or if side-effects are intolerable. Management of ocular JMG is similar, but requires close involvement of ophthalmology in young children to prevent amblyopia. Muscle-specific tyrosine kinase (MuSK)-JMG show a poorer response to pyridostigmine and anecdotal evidence suggests that rituximab should be considered as second-line immunosuppression. Thymectomy is indicated in any patient with a thymoma, and consideration should be given in acetylcholine receptor (AChR) positive JMG allowing time for spontaneous remission. The benefit is less clear in ocular JMG and is not advised in MuSK-JMG. Children experiencing a myasthenic crisis require urgent hospital admission with access to the intensive care unit. PLEX is preferred over IVIG due to rapid onset of action, but this needs to be balanced with feasibility in very young children. Key questions remain in the management of JMG: when to initiate both first- and second-line treatments, choosing between steroid-sparing agents, and determining the optimal dose and treatment duration. We feel that given the rarity of this disease, the establishment of national registries and collaboration across groups will be needed to address these issues and facilitate future drug trials in JMG.

Risk of incident autoimmune diseases in patients with thymectomy

OBJECTIVES

The data concerning the association between Tx and ADs remain unclear and are scarce. This study was undertaken to investigate whether people with Tx are more likely to develop ADs, compared to those without Tx.

METHODS

Individuals who received Tx between 2002 and 2015 were identified and matched on age and sex with individuals without Tx. We performed multivariate and stratified analysis using the Kaplan-Meier method and Cox proportional hazards models in order to estimate the association between Tx and the risk of developing ADs.

RESULTS

A total of 2550 thymectomized (Txd) patients and 24,664.941 non-Txd comparison subjects were selected from NHIRD. Tx-MG (myasthenia gravis) as compared with general population (nonTx-nonMG), adjusted hazard ratio (aHR) were higher for incident Addison disease (aHR = 10.40, 95% CI 1.01-107), autoimmune hemolytic anemia (aHR = 21.54, 95% CI 2.06-14.8), Hashmoto thyroiditis (aHR = 5.52, 95% CI 1.34-34.7), ankylosing spondylitis (aHR = 2.73, 95% CI 1.09-6.84), rheumatoid arthritis (aHR = 5.25, 95% CI 1.79-15.47), primary Sjogren syndrome (pSS) (aHR = 3.77, 95% CI 1.30-11.0), and systemic lupus erythemtoasus (aHR = 10.40). Tx-nonMG as compared with general population, aHR were higher for incident autoimmune hemolytic anemia (aHR = 25.50), Hashmoto thyroiditis (aHR = 6.75) and systemic lupus erythematosus (SLE) (aHR = 13.38). NonTx-MG as compared with general population, aHR were higher for incident Hashmoto thyroiditis (aHR = 6.57), pSS (aHR = 4.50), SLE (aHR = 17.29), and systemic vasculitis (aHR = 25.86).

INTERPRETATION

In conclusion, based on a retrospective cohort study throughout Taiwan, patients with Tx have a higher risk of new onset ADs than patients without Tx.

Neonatal thymectomy in children-accelerating the immunologic clock?

The thymus is critical for central tolerance and diverse T-lymphocyte repertoire development, to provide lifelong defense against pathogens while maintaining self-tolerance. Peak thymic output occurs in utero, during infancy, and in early childhood, diminishing throughout life. Infants with congenital heart disease requiring sternotomy often undergo thymectomy to clear the surgical field. The long-term effects of early thymectomy are just being appreciated. Many patients remain asymptomatic despite immunologic findings mirroring those of immunosenescence. Few develop increased infection or lymphoreticular malignancy risk. When considering the effects of infant thymectomy, patients with partial DiGeorge syndrome or hypomorphic recombination-activating gene (RAG) mutations may be instructive. These patients are lymphocytopenic, with increased early-onset infection and autoimmunity risk that is not seen in most patients who underwent thymectomy during infancy. The thymic structure of patients with partial DiGeorge syndrome or hypomorphic RAG is abnormal, with disrupted architecture inclining to perturbation of central tolerance. Similar findings may be seen in patients with myasthenia gravis, although disrupted peripheral tolerance may play a greater role in autoimmunity development. In conclusion, thymectomy during infancy may increase future risk of infection or autoimmunity, with premature immunosenescence mediated through disruption of central and peripheral tolerance mechanisms initiated by early cessation or diminution of thymic output. Ideally, some thymic tissue should be preserved at the time of surgery.