Silent myocarditis in myasthenia gravis. Role of cardiovascular magnetic resonance imaging

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.

COVID-19-induced silent myocarditis and newly developed hypertension in a 3-year-old boy

BACKGROUND

COVID-19 myocarditis occurs in 7-28% of patients admitted in the hospital with or without multisystem inflammatory syndrome. It may present as fulminant myocarditis. Dilated cardiomyopathy as a sequela of COVID-19 myocarditis has been reported in the pediatric population. However, to date, no case of silent COVID-19 myocarditis progressing to dilated cardiomyopathy has been reported in children. Furthermore, although newly developed hypertension as a sequela of COVID-19 infection has been reported in adults, there is no report of newly developed COVID-induced hypertension in children. We report a 3-year-old boy with silent COVID-19 myocarditis progressing to dilated cardiomyopathy and newly developed systemic hypertension.

CASE PRESENTATION

A 3-year-old boy was referred to the emergency department because of respiratory distress. The parents gave a history of SARS-CoV-2 infection in the child 5 months ago that was manifested as fever and cough, for which he was treated as an outpatient. Echocardiographic examination revealed a severe decrease in left ventricular systolic function in favor of dilated cardiomyopathy. Cardiac magnetic resonance imaging established the diagnosis of myocarditis. The patient left ventricular systolic function did not improve after 2 weeks of intravenous inotropic support. Therefore, the child was transferred to another tertiary center with extracorporeal membrane oxygenation and pediatric cardiac transplantation facilities.

CONCLUSIONS

COVID-19 can induce silent myocarditis with progression to dilated cardiomyopathy and newly developed systemic hypertension. Thus, a thorough examination of the heart and measurement of blood pressure are mandatory in every child with COVID-19 infection. Cardiac MR is an indispensable tool in the diagnosis, follow-up, and prognostication of COVID-19 myocarditis. Moreover, four-chamber speckle tracking strain imaging showed apical rocking in all the four heart chambers in this child with opposite direction in the failed left ventricle compared with other cardiac chambers. Lastly, the presence of septal flash on M-mode echocardiography, apical rocking and prestretch-rebound stretch patterns on longitudinal strain imaging of the failed left ventricle in this child may be of predictive value for response to cardiac resynchronization therapy.

Respiratory insufficiency from myasthenia gravis and polymyositis due to malignant thymoma triggering Takotsubo syndrome

BACKGROUND

Takotsubo syndrome (TTS) is a non-ischaemic cardiomyopathy with sudden but transient systolic dysfunction. TTS mimics myocardial infarction clinically, chemically, and electrocardiographically but echocardiography typically shows apical ballooning and coronary angiography is normal. TTS has not been reported in a patient with myasthenia gravis (MG) and polymyositis due to a malignant thymoma.

CASE REPORT

Two weeks prior to admission, a 76-year-old female developed dysarthria, chronic coughing and disabling myalgias of the entire musculature. Since there was hyper-CKemia and elevated troponin, myocardial infarction was suspected. During swallowing of the antithrombotic medication on admission, she experienced apnoea, requiring cardio-pulmonary resuscitation with intubation and mechanical ventilation. Further diagnostic work-up precluded coronary heart disease but revealed TTS. Upon neurologic work-up, MG and polymyositis were diagnosed but the response to cholinergic drugs and plasmapheresis was poor. TTS was attributed to stress and anxiety from MG-associated respiratory insufficiency. The further course was complicated by recurrent supraventricular bradyarrhythmias and respiratory insufficiency. Upon thoracic CT a thymoma was suspected. Two months after admission, the mediastinal tumour was resected and malignant thymoma WHO BII infiltrating the mediastinum (modified Masaoka-Koga II/2) was diagnosed.

CONCLUSIONS

This case shows that TTS may be triggered by stress from respiratory insufficiency during a myasthenic crisis, MG may be associated with polymyositis, cholinergic medication may trigger bradyarrhythmias, and cholinergic drugs and plasmapheresis may exhibit a poor effect if malignant thymoma and polymyositis are present.

Myocarditis: A Clinical Overview

PURPOSE OF REVIEW

In this paper we will review the modern diagnostic approach to patients with clinically suspected myocarditis as well as the treatment modalities and strategy in light of up-to-date clinical experience and scientific evidence.

RECENT FINDINGS

Rapidly expanding evidence suggests that myocardial inflammation is frequently underdiagnosed or overlooked in clinical practice, although new therapeutic options have been validated. Moreover, the available evidence suggests that subclinical cardiac involvement has negative prognostic impact on morbidity and mortality and should be actively investigated and adequately treated. Myocarditis represents a growing challenge for physicians, due to increased referral of patients for endomyocardial biopsy (EMB) or cardiac magnetic resonance (CMR), and requires a highly integrated management by a team of caring physicians.

What's in the Literature?

The Guillain-Barré syndrome (GBS) is one of the few neuropathies well known to the general public, in part because of its association with swine flu vaccinations in 1976. GBS has again reached the general public with its possible association with Zika virus. The virus, borne by infected Aedes aegypti mosquitos, is being linked to birth defects when pregnant women are bitten and infected. There are early reports also linking GBS to Zika infection, which could expose a wider range of infected people to the neuropathy. This summer infected Aedes mosquitos will likely reach southern portions of the United States, and travelers to countries where Aedes is endemic will increase. It is important to appreciate that the neurologic consequences of Zika virus are being actively investigated, and firm associations and consequences are yet to be established. Small fiber neuropathies are common and can be due to a number of underlying diseases, and a recent review also indicates that many are idiopathic. One cause is Sjögren syndrome, and a case series reviews clinical features. The diagnosis and underlying features of primary lateral sclerosis are a clinical challenge. Similarities between primary lateral sclerosis and hereditary spastic paraparesis (HSP) have long been noted. With a wide spectrum of gene mutations associated with HSP, clinical distinction between the 2 disorders is problematic. A review covers the wide spectrum of HSP. With no cure, the progression of amyotrophic lateral sclerosis (ALS) to respiratory failure is predictable. This could easily result in marked depression among patients, and 2 studies have explored the frequency and severity of depression. The cause of ALS remains unknown, and when no hereditary factor is apparent, environmental questions arise as possible contributing factor(s). The most notable association is with military service, although specific occupational or environmental linkages are not well sorted out. Two recent reports address these issues. There is good news for ALS patients with muscle cramps with the results of a multicenter randomized and placebo-controlled trial showing that mexiletine is effective in reducing this common symptom. The treatment of myasthenia gravis with various agents, the use of patient-reported outcome measures in myasthenia gravis, and the occurrence of myocarditis in this disease are reviewed. Necrotizing autoimmune neuropathies, the co-occurrence of inclusion body myositis and a form of T-cell leukemia are discussed as are valosin-containing protein (VCP)-opathy and bone health in patients with dystrophinopathy.