The mortality of myasthenia gravis with myocarditis: A single-center retrospective study

BACKGROUND

While numerous studies have investigated the onset features of myasthenia gravis (MG) complicated with myocarditis, there are few articles focusing on the prognosis of patients with both diseases. This study aims to examine mortality in patients with MG who also have myocarditis, and to summarize the clinical characteristics of deceased patients with both conditions.

RESULTS

A total of 91 patients with MG were included in our study, of which 19 (20.9 %) were diagnosed with myocarditis. Shorter MG duration, thymoma, history of myasthenia crisis (MC) and use of immune checkpoint inhibitors (ICIs) were risk factors for developing myocarditis in MG patients. Among the 13 myocarditis-MG patients who did not receive ICIs, 11(84.6 %) had thymoma and 5 (71.4 %) of the 7 tested were positive for titin-IgG. In all myocarditis-MG patients, 11 (57.9 %) died from myocarditis (average age 51 ± 18 years), with 9 (81.8 %) having thymoma and 5 (45 %) having a history of myasthenia crisis. Compared to the mortality rates of MC patients (16.1 %) and the general MG patients (1.8 %), the mortality rate of myocarditis-MG patients is significantly higher.

CONCLUSIONS

The study highlights that MG patients with myocarditis face a significantly increased risk of mortality. Thymoma and a history of MC were identified as potential risk factors for mortality, irrespective of prior ICI use.

Cardiovascular disease in thymic cancer patients

Introduction

Cancer patients may have increased risk for adverse cardiac events, but our understanding of cardiovascular risk in thymic cancer patients is not clear. We sought to characterize baseline cardiometabolic risk factors before thymic cancer diagnosis and the potential association between cancer treatment and subsequent cardiac events.

Methods

This was a retrospective cohort study evaluating patients with thymic cancer from 2003 to 2020 compared to age- and sex-matched controls without cancer. Baseline cardiovascular risk factors, cancer characteristics, and incidence of cardiac events were collected from the health information exchange. Multivariable regression was used to examine the impact of cardiovascular risk factors and cancer therapies.

Results

We compared 296 patients with pathology-confirmed thymic cancer to 2,960 noncancer controls. Prior to cancer diagnosis, thymic cancer patients (TCPs) had lower prevalence of hypertension, dyslipidemia, and diabetes mellitus and similar rates of obesity, tobacco use, and pre-existing cardiovascular disease (CVD) compared to controls. After diagnosis, high-risk TCPs (>2 cardiovascular risk factors or pre-existing CVD) had higher risk for cardiac events (HR 3.73, 95% CI 2.88-4.83, p < 0.001). In the first 3 years after diagnosis, TCPs had higher incidence of cardiac events (HR 1.38, 95% CI 1.01-1.87, p = 0.042). High-risk TCPs who received radiotherapy or chemotherapy had higher risk of cardiac events (HR 4.99, 95% CI 2.30-10.81, p < 0.001; HR 6.24, 95% CI 2.84-13.72, p < 0.001).

Discussion/conclusion

Compared to noncancer controls, TCPs experienced more cardiac events when adjusted for risk factors. Patients with multiple cardiovascular risk factors receiving radiotherapy or chemotherapy had higher incidence of cardiac events.

Anti-titin antibodies are associated with myocarditis in patients with myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) can affect cardiac muscles with variable presentations. Myocarditis is a rare but potentially serious cardiac manifestation of MG. Although thymomas and anti-titin antibodies have been suggested as risk factors for myocarditis in patients with MG, their independent influence on myocarditis has rarely been assessed.

METHODS

A retrospective chart review was conducted on 247 patients diagnosed with MG who were tested for anti-titin antibodies. Myocarditis was diagnosed on the basis of the European Society of Cardiology 2013 Task Force criteria for clinically suspected myocarditis. Patients were classified into myocarditis-positive and myocarditis-negative groups. Multivariate analysis was performed to analyze the risk factors for myocarditis.

RESULTS

Of the 247 patients, 25 (10.1%) were myocarditis-positive and 222 (89.9%) were myocarditis-negative. Anti-titin antibody positivity was higher in the myocarditis-positive group than in the myocarditis-negative group (68.0% vs. 28.4%, p < 0.001). A history of MG crisis was more frequent in the myocarditis-positive group than in the myocarditis-negative group (64.0% vs. 10.4%, p < 0.001). The presence of anti-titin antibodies (odds ratio [OR] 7.906; confidence interval [CI] 2.460-25.401) and MG crisis (OR 24.807; CI 7.476-82.311) was significantly associated with myocarditis. The Cox regression model showed that the anti-titin antibody levels (hazard ratio [HR] 3.639; 95% CI 1.557-8.505) and MG crisis (HR 6.137; 95% CI 2.639-14.272) were significant risk factors for the development of myocarditis.

CONCLUSION

The presence of anti-titin antibody was associated with myocarditis in patients with MG, whereas thymoma was not. Although rare, early suspicion of myocarditis could be required, especially in patients with MG having anti-titin antibodies.

Acquired myasthenia gravis with concurrent polymyositis and myocarditis secondary to a thymoma in a dog

Background:

Canine thymomas are associated with multiple paraneoplastic syndromes, among which myasthenia gravis (MG) is the most common. Acquired MG is an autoimmune disease characterized by the presence of antibodies against acetylcholine receptors (ACHRs). ACHRs antibodies are the most commonly formed, but the production of antistriational antibodies binding to skeletal and cardiac muscle proteins has also been recorded both in humans and dogs. An association between the occurrence of antistriational antibodies and a severe form of myocarditis, giant cell myocarditis, has been described in humans.

Case Description:

A 4-year-old mixed-breed dog was referred because of 1 month history of exercise-induced weakness, hypersalivation, and regurgitation. The neurologic examination was indicative of a neuromuscular junction disease, and MG was suspected. A computed tomographic scan examination showed the presence of a megaoesophagus and a thymic mass. Serum antibodies against ACHRs confirmed the diagnosis of MG. Treatment with pyridostigmine was started, and the thymic mass was surgically excised, and a diagnosis of thymoma was confirmed by histology. 24 hours after surgery, the dog developed a third-degree atrioventricular block. Severe arrhythmia and increased troponin serum levels suggested myocarditis which rapidly led to cardiopulmonary arrest. Histopathologic examination of the heart, esophagus and diaphragm revealed a lymphocytic and macrophagic infiltration, consistent with myocarditis and polymyositis. Scattered rare giant multinucleated cells were also detected in the myocardium.

Conclusion:

To the author’s knowledge, this is the first report of thymoma-associated MG with concurrent polymyositis and giant cell-like myocarditis in a dog.

A systematic review of myasthenia gravis complicated with myocarditis

Among many of the autoimmune diseases observed in patients with myasthenia gravis (MG), myocarditis is one of the most critical. The goal of this review is to systematically describe and investigate the characteristics of MG complicated with myocarditis. We identified 183 records in PubMed (MEDLINE), Web of Science, and EMBASE from 1948 to September 10, 2020. Studies were included if they presented clinical data on MG complicated with myocarditis. Of the 35 patients from 28 studies in this review, 57.14% (20/35) were males, with a mean age of 59.11 ± 15.87. Dyspnea was the most common cardiac symptom accounting for over 60% in the study. Among the 35 patients, 13 cases of myocarditis occurred concomitantly with MG and the longest interval between MG and myocarditis was 7 years. Forty percent of patients developed myocarditis caused by immune checkpoint inhibitors (ICI). Among the patients with myocarditis, over half of the patients were diagnosed by myocardial biopsy. After active immune regulation and symptomatic treatment, only 15 of 35 patients with MG complicated with myocarditis improved, 18 patients died during hospitalization, one patient died due to tumor progression and 1patient died 5 years later. The prognosis of patients with MG complicated with myocarditis is poor, and myocardial enzymes and other indexes need to be monitored for patients taking ICI drugs. Patients with dyspnea who are still not ideally treated by mechanical ventilation should be vigilant against the occurrence of MG complicated with myocarditis.

Giant cell myositis associated with concurrent myasthenia gravis: a case-based review of the literature

The term “giant cell myositis” has been used to refer to muscle diseases characterized histologically by multinucleated giant cells. Myasthenia gravis is an autoimmune neuromuscular junction disorder. The rare concurrence of giant cell myositis with myasthenia gravis has been reported; however, the clinical and histological features have varied widely. Here, we present such a case and a review of the literature. An 82-year-old woman admitted for subacute, progressive, proximal muscle weakness developed acute-onset dysphagia, dysphonia, and respiratory distress 5 days after admission. Laboratory findings were positive for acetylcholine receptor binding antibodies and striational muscle antibodies against titin. Muscle biopsy demonstrated widespread muscle fiber necrosis with multinucleated giant cells, consistent with giant cell myositis. She died despite treatment with pulse methylprednisolone and plasma exchange. A literature review of the PubMed and Scopus databases from 1944 to 2020 identified 15 additional cases of these co-existing diagnoses. We found that giant cell myositis with myasthenia gravis primarily affects female patients, is typically diagnosed in the 6–7th decades, and is characterized by the presence of thymoma. Muscle histology predominantly shows giant cell infiltrate without granulomas. The onset of myasthenia gravis symptoms may precede, follow, or coincide with symptoms of myositis. Treatment with thymectomy, anticholinesterase inhibitors, or immunosuppressive therapy may lead to favorable clinical outcomes.

Neurologic complications of myocarditis

Myocarditis, a nonischemic acquired cardiomyopathy, is an uncommon condition with multiple presentation patterns which may be initially difficult to recognize and may simulate other conditions such as acute myocardial infarction, pericarditis, septicemia, etc. There are four distinct clinical presentation patterns that include: (1) low-grade nonspecific symptoms such as fatigue; (2) symptoms that resemble an acute myocardial infarction, especially in younger individuals; (3) a heart failure presentation which may be acute, subacute, or chronic and may be associated with cardiac conduction system defects and arrhythmias; and (4) an arrhythmia presentation that may produce sudden cardiac death, especially in young athletes with minimal or no prodromal symptoms. This chapter will provide a brief overview of various myocarditis etiologies and diagnostic modalities. The ultimate focus will be directed toward neurologic manifestations of myocarditis and its subtypes, complications of specific therapies including extracorporeal membrane oxygenation (ECMO) for refractory heart failure, and review the current literature regarding the appropriate use of therapeutic anticoagulation in myocarditis and heart failure for stroke prevention. Covid-19 infection has been discovered to cause myocarditis. The emerging science will be discussed. Nuances of brain death (BD) determination in patients receiving venoarterial ECMO for heart failure refractory to standard medical therapies will be discussed.

Orbital giant cell myositis is an unusual and potentially lethal cause of bilateral ophthalmoplegia - A case report and literature review

We present a case of orbital giant cell myositis (OGCM), presenting with bilateral subacute progressive ophthalmoplegia and optic nerve dysfunction. An early extraocular muscle biopsy confirmed the diagnosis and guided appropriate management. Comprehensive investigation excluded any underlying systemic disease, including myocarditis. Twenty two months after presentation, the patient remains well on azathioprine with complete resolution of orbital signs.

Genetic Basis of Myocarditis: Myth or Reality?

The genetic basis of myocarditis remains an intriguing concept, at least as long as the definition of myocarditis constitutes the definitive presence of myocardial inflammation sufficient to cause the observed ventricular dysfunction in the setting of cardiotropic infections. Autoimmune or immune-mediated myocardial inflammation constitutes a complex area of clinical interest, wherein numerous and not yet fully understood role of hereditary auto-inflammatory diseases can result in inflammation of the pericardium and myocardium. Finally, myocardial involvement in hereditary immunodeficiency diseases, cellular and humoral, is a possible trigger for infections which may complicate the diseases themselves. Whether the role of constitutional genetics can make the patient susceptible to myocardial inflammation remains yet to be explored.

Immune checkpoint inhibitors for treatment of thymic epithelial tumors: how to maximize benefit and optimize risk?

A greater understanding of anti-tumor immunity has resulted in rapid development of immunotherapy for a wide variety of cancers. Antibodies targeting the immune checkpoints, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed death-1 (PD-1), or its ligand (PD-L1) have demonstrated clinical activity and are approved for treatment of melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, bladder cancer, head and neck cancers, esophageal cancer, hepatocellular carcinoma, and Hodgkin lymphoma, among others. Treatment is generally well tolerated with relatively few adverse events compared with standard treatments such as chemotherapy. However, immune activation can potentially affect any organ system and a small fraction of patients are at risk for developing severe immune-related adverse events. Immune checkpoint inhibitors (ICIs) and other immunotherapeutic modalities such as cancer vaccines are in nascent stages of development for treatment of thymic epithelial tumors (TETs). Since the thymus plays a key role in the development of immune tolerance, thymic tumors have a unique biology which can influence the risk-benefit balance of immunotherapy. Indeed, early results from clinical trials have demonstrated clinical activity, albeit at a cost of a higher incidence of immune-related adverse events, which seem to particularly affect skeletal and cardiac muscle and the neuromuscular junction. In this paper we describe the effects of thymic physiology on the immune system and review the results of clinical trials that have evaluated immunotherapy for treatment of relapsed thymoma and thymic carcinoma. We review ongoing efforts to mitigate the risk of immune-related complications in patients with TETs receiving immunotherapy and offer our thoughts for making immunotherapy a feasible alternative for treatment of thymic tumors.