Immune suppressive treatment in paediatric myocarditis: still awaiting the evidence

Diagnosis and Management of Myocarditis: An Evidence-Based Review for the Emergency Medicine Clinician

BACKGROUND

Myocarditis is a potentially fatal condition that can be misdiagnosed in the emergency department (ED) setting.

OBJECTIVE

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of myocarditis, with a focus on emergency clinicians.

DISCUSSION

Myocarditis occurs when inflammation of the heart musculature causes cardiac dysfunction. Symptoms may range from mild to severe and are often preceded by a viral prodrome. Laboratory assessment and an electrocardiogram can be helpful for the diagnosis, but echocardiography is the ideal test in the ED setting. Some patients may also require advanced imaging, though this will often occur during hospitalization or follow-up. Treatment is primarily focused on respiratory and hemodynamic support. Initial hemodynamic management includes vasopressors and inotropes, whereas more severe cases may require an intra-aortic balloon pump, extracorporeal membrane oxygenation, or a ventricular assist device. Nonsteroidal anti-inflammatory drugs should be avoided while intravenous immunoglobulin is controversial.

CONCLUSION

Myocarditis is a serious condition with the potential for significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

In-hospital and post-discharge outcomes of pediatric acute myocarditis underwent after high-dose steroid or intravenous immunoglobulin therapy

Background

High-dose steroids and intravenous immunoglobulin (IVIG) are controversial treatments for pediatric patients with acute myocarditis. This study aimed to investigate their efficacies in the Taiwanese pediatric population.

Methods

This study evaluated 5563 acute myocarditis patients from the Taiwan’s National Health Insurance Research Database and identified 1542 pediatric patients hospitalized for acute myocarditis between January 1, 2001 and December 31, 2011. The exclusion criteria were age of > 11 years, associated cardiovascular comorbidities, autoimmune disease, malignancy before the index hospitalization, extracorporeal membrane oxygenation, intra-aortic balloon pumping, and dual therapy using IVIG and high-dose steroids.

Results

After 2:1 propensity score matching, we identified 208 subjects without steroid therapy and 104 subjects who received high-dose steroids. The mean age in that cohort was 2.6 ± 2.9 years, and high-dose steroid therapy had no significant effects on major in-hospital complications and post-discharge outcomes. After 2:1 propensity score matching, we identified 178 subjects without IVIG therapy and 89 subjects who received IVIG. The mean age in that cohort was 2.0 ± 2.1 years, and IVIG had no significant effects on the major outcomes.

Conclusions

The present study revealed that high-dose steroid or IVIG therapy had no significant effects on major in-hospital complications, late heart failure hospitalization, and long-term mortality.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

Immunosuppressive Treatment for Myocarditis in the Pediatric Population: A Meta-Analysis

The use of immunosuppressants in the treatment of myocarditis in children remains controversial. The aim of this meta-analysis is to summarize the current empirical evidence for immunosuppressive treatment for myocarditis in the pediatric population. We searched PubMed, MEDLINE, and Embase for articles to identify studies analyzing the efficiency of immunosuppressive treatment in the pediatric population. Pooled estimates were generated using fixed- or random-effect models. Heterogeneity within studies was assessed using Cochran's Q and I ² statistics. Funnel plots and Begg's rank correlation method were constructed to evaluate publication bias. Sensitivity analyses were also conducted to evaluate the potential sources of heterogeneity. After a detailed screening of 159 studies, six separate studies were identified, with 181 patients in the immunosuppressive treatment group, and 199 in the conventional treatment group. The immunosuppressive treatment group showed a significant improvement in left ventricular ejection fraction (LVEF) [mean difference 1.10; 95% CI: 0.41, 1.79] and significantly decreased left ventricular end-diastolic dimension (LVEDD) [mean difference -0.77 mm, 95% CI: -1.35 to -0.20 mm] when compared to the conventional treatment group. Furthermore, the risk of death and heart transplant in conventional treatment was significantly higher than in the immunosuppressive treatment group [relative risk (RR): 4.74; 95% CI: 2.69, 8.35]. No significant heterogeneity across the studies was observed. There was no evidence of publication bias when assessed by Begg's test. Conclusions: There may be a possible benefit, in the short term, to the addition of immunosuppressive therapy in the management of myocarditis in the pediatric population. However, further prospective investigation is warranted to validate this finding.

Myocarditis in Paediatric Patients: Unveiling the Progression to Dilated Cardiomyopathy and Heart Failure

Myocarditis is a challenging and potentially life-threatening disease associated with high morbidity in some paediatric patients, due to its ability to present as an acute and fulminant disease and to ultimately progress to dilated cardiomyopathy. It has been described as an inflammatory disease of the myocardium caused by diverse aetiologies. Viral infection is the most frequent cause of myocarditis in developed countries, but bacterial and protozoal infections or drug hypersensitivity may also be causative agents. The prompt diagnosis in paediatric patients is difficult, as the spectrum of clinical manifestation can range from no myocardial dysfunction to sudden cardiac death. Recent studies on myocarditis pathogenesis have revealed a triphasic nature of this disease, which influences the diagnostic and therapeutic strategies to adopt in each patient. Endomyocardial biopsy remains the gold standard for diagnosing myocarditis, and several non-invasive diagnostic tools can be used to support the diagnosis. Intravenous immunoglobulin has become part of routine practice in the treatment of myocarditis in paediatric patients at many centres, but its true effect on the cardiac function has been the target of many studies. The aim of this review is to approach the recently discovered facets of paediatric myocarditis regarding its progression to dilated cardiomyopathy.

Acute viral myocarditis: role of immunosuppression: a prospective randomised study

OBJECTIVE

To conduct a prospective randomised study to show the efficacy of immune suppression with prednisolone, administered at the 3-month duration of acute myocarditis.

METHODS

The diagnosis of acute viral myocarditis was made based on echocardiography and serum viral antibodies. The inclusion criterion was acute myocarditis of 3 months duration. In all, 68 of 173 children were available for randomisation into a prednisolone-treated group of 44 and a control group of 24 children. The follow-up period in the prednisolone-treated group was 15.1 plus or minus 9.2 months and 13.6 plus or minus 10.6 months for the control group.

RESULTS

Compared with controls, 1 month after randomisation significantly more children in the prednisolone-treated group increased their ejection fraction to more than 40% (p = 0.029). Discrete analysis of change in the ejection fraction from the one at randomisation to one after 1 month of randomisation of greater than 10% and less than 10% or no change between groups showed a significantly greater number with improvement in the prednisolone-treated group (p = 0.019). At the end of the follow-up visits, a significantly larger number of children in the prednisolone-treated group had an ejection fraction of more than 60% compared with the control group (p = 0.049).

CONCLUSION

It is concluded that immune suppression with prednisolone, administered at 3 months of the onset of acute myocarditis, is effective in significantly bringing about improvement and cure in persistent left ventricular failure.

Clinical practice: heart failure in children. Part I: clinical evaluation, diagnostic testing, and initial medical management

Current evidence suggests that almost half of all children with cardiomyopathy and symptomatic heart failure will die or require a cardiac transplant within 5 years of diagnosis. The recognition, diagnostic assessment, and treatment of heart failure in children are therefore challenging undertakings, to say the least. It involves an assessment of cardiac appearance and function, adaptation of the child as a whole, and a diagnostic approach that evaluates many possible root causes. This review is intended to assist the practicing pediatrician and cardiologist by providing a framework for this diagnostic assessment and to give an overview of the treatment options available for children with heart failure. In this first part, we will focus on clinical evaluation, diagnostic testing, and initial medical management. In the second part of this series, the maintenance treatment and treatment options applicable when medical treatment is insufficient will be addressed.

Clinical profiles and outcomes for Omani children with dilated cardiomyopathy seen in a regional referral hospital

OBJECTIVE

To provide an account of paediatric dilated cardiomyopathy as seen in a region of Oman, analysing the data from 32 consecutive children who received care in our unit between January, 1999, and August, 2007.

RESULTS

The patients, of whom 17 were male, were aged between 5 weeks and 8 years at presentation, with a median of 7 months. The disease was deemed to be myocarditis-induced in one-third, and idiopathic in half. Cardiac failure, seen in almost four-fifths, was the most frequent presenting feature. Correspondingly, the cardiothoracic ratios were increased, to a mean of 68% in 20 infants, and to 65% in 8 older children, and the left ventricular ejection fraction depressed, to a mean of 41%, in the 23 patients in whom it could be evaluated. Patients in cardiac failure received various combinations of diuretics, inotropes, and captopril. In addition, 6 received carvedilol, and 3 intravenous immunoglobulin. Death occurred in 2 patients shortly after admission, one left the hospital against medical advice, and the remaining 29 were followed-up for a mean of 37 months, with a range from 2 to 102 months. Recovery was noted in one-third of the patients, with one-quarter showing improvement but still requiring anti-failure medications. Slightly over two-fifths died. Of those with the idiopathic form, 40% died, with death occurring in 46% of those deemed to have myocarditis-induced disease, in half of those presenting in infancy, and in 57% of those who presented in cardiac failure.

CONCLUSION

Dilated cardiomyopathy was often severe in our patients, albeit that the cause was frequently uncertain, and the response to standard anti-failure treatment unsatisfactory. Efforts should be intensified for unravelling its aetiology and improving medical treatment.

Immune tolerance to cardiac myosin induced by anti-CD4 monoclonal antibody in autoimmune myocarditis rats

Autoimmune myocarditis is a T-cell-mediated autoimmune disease. CD4-positive T cells are believed to be the most important for the initiation and mediation of the disease. This study was aimed at evaluating whether anti-CD4 monoclonal antibody could induce immune tolerance to porcine cardiac myosin and whether the immune tolerance could protect rats with autoimmune myocarditis from myocardial injury. Lewis rats were immunized with porcine cardiac myosin to induce experimental autoimmune myocarditis. Immune tolerance was induced by injections of anti-CD4 monoclonal antibody on days -2, -1, 0, and 1. Results showed that cardiac function of antibody-treated rats was significantly increased compared with untreated rats 18 days postimmunization examined by transthoracic echocardiography. Typical cardiac histopathological changes were observed obviously in untreated group but not in antibody-treated group. Lymphocytes obtained from antibody-treated group had no proliferative response to porcine cardiac myosin examined by lymphocyte proliferation assay. Serological examination showed that rats immunized with cardiac myosin could produce high levels of anti-cardiac myosin antibody. The administration of anti-CD4 monoclonal antibody significantly prevented the increase of them. Serum levels of Th1 cytokines were significantly down-regulated by antibody administration, while the production of Th2 cytokines were up-regulated or unaffected evaluated by enzyme-linked immunosorbent assay. It concluded that immune tolerance to porcine cardiac myosin could be induced by anti-CD4 monoclonal antibody in vivo, and cardiac dysfunction and myocardial injury could be prevented by induction of immune tolerance.

Therapy for pediatric myocarditis

Pediatric myocarditis is most often associated with the acute or subacute onset of congestive heart failure in a previously healthy child. Myocarditis presenting with acute, severe symptomatology, termed fulminant myocarditis, has a high rate of recovery. Aggressive supportive care is indicated in fulminant myocarditis, including mechanical circulatory support. For subacute heart failure, supportive care remains the mainstay of therapy for myocarditis. A number of uncontrolled pediatric studies using both immunosuppressive therapy and/or immunomodulating therapy with intravenous gamma globulin have suggested these therapies are safe and useful in treating pediatric myocarditis. However, translating these results into recommended, routine therapy for pediatric myocarditis is complicated by the high rate of spontaneous improvement of myocarditis with supportive care, and the lack of demonstrable benefit for immunosuppressive and immunomodulating therapies in blinded, randomized, placebo-controlled trials in adult myocarditis. Heart transplantation remains the final therapeutic option for children with myocarditis and intractable severe heart failure.