Clinicopathological features of paediatric deaths due to myocarditis: an autopsy series

Endocardial fibroelastosis in infants and young children: a state-of-the-art review

Endocardial fibroelastosis (EFE) is a rare cardiac condition characterized by excessive endocardial thickening secondary to fibroelastic tissues that commonly present in infants and young children. Most of endocardial fibroelastosis cases are secondary forms, which occur in conjunction with other cardiac diseases. Endocardial fibroelastosis has been associated with poor prognosis and outcomes. In light of recent advancements in understanding pathophysiology, several new data have revealed compelling evidence that abnormal endothelial-to-mesenchymal transition is the root cause of endocardial fibroelastosis. This article aims to review the recent development in pathophysiology, diagnostic workup, and management, and to discuss possible differential diagnoses.

Clinical characteristics and mortality risk prediction model in children with acute myocarditis

BACKGROUND

Acute myocarditis (AMC) can cause poor outcomes or even death in children. We aimed to identify AMC risk factors and create a mortality prediction model for AMC in children at hospital admission.

METHODS

This was a single-center retrospective cohort study of AMC children hospitalized between January 2016 and January 2020. The demographics, clinical examinations, types of AMC, and laboratory results were collected at hospital admission. In-hospital survival or death was documented. Clinical characteristics associated with death were evaluated.

RESULTS

Among 67 children, 51 survived, and 16 died. The most common symptom was digestive disorder (67.2%). Based on the Bayesian model averaging and Hosmer-Lemeshow test, we created a final best mortality prediction model (acute myocarditis death risk score, AMCDRS) that included ten variables (male sex, fever, congestive heart failure, left-ventricular ejection fraction < 50%, pulmonary edema, ventricular tachycardia, lactic acid value > 4, fulminant myocarditis, abnormal creatine kinase-MB, and hypotension). Despite differences in the characteristics of the validation cohort, the model discrimination was only marginally lower, with an AUC of 0.781 (95% confidence interval = 0.675-0.852) compared with the derivation cohort. Model calibration likewise indicated acceptable fit (Hosmer‒Lemeshow goodness-of-fit, P¼ = 0.10).

CONCLUSIONS

Multiple factors were associated with increased mortality in children with AMC. The prediction model AMCDRS might be used at hospital admission to accurately identify AMC in children who are at an increased risk of death.

Are clinical features and cardiac biomarkers at admission related to severity in pediatric acute myocarditis?: Clinical features and cardiac biomarkers in pediatric acute myocarditis

OBJECTIVES

To evaluate the factors associated with intensive care requirement and mortality in pediatric myocarditis.

METHODS

Children aged 28 days to 18 years who were diagnosed with acute myocarditis in a pediatric emergency department between January 2010 and September 2020 were enrolled in the study retrospectively. Demographic and clinical features, cardiac biomarkers, and imaging findings were evaluated. Length of hospital stay, need for hospitalization in the pediatric intensive care unit (PICU), treatments, and survival outcomes were recorded. To define the severity of disease, three groups were created and the data were compared in terms of clinical, laboratory, and imaging findings. The patients treated in the pediatric ward were compared with those hospitalized in the PICU. Ventricular dysfunction was defined in patients with a left ventricular ejection fraction (LVEF) of <50% and these patients were compared with those who had an LVEF of >50%. Also, survivor and non-survivor patients were compared.

RESULTS

A total number of 62 patients with a median age of 8 years were included. Chest pain and tachycardia were the most common findings on physical examination. The mean LVEF was 59.3 ± 13.0% at admission. Of the patients, 17 were hospitalized in the PICU (27.4%). Chest pain was more common in patients hospitalized in the pediatric ward (p<0.001), and hypotension, vomiting, arrhythmia, were more common and LVEF was lower in patients in the PICU (p = 0.017, p = 0.008, p = 0.006, and p = 0.025, respectively). The children treated in the PICU were younger than those in the pediatric ward (p = 0.009). Troponin I levels were significantly higher in the pediatric ward (p = 0.035), and brain natriuretic peptide (BNP) levels were higher in patients in the PICU (p = 0.012). Death occurred in four patients. Hypotension and vomiting were significantly more common in non-survivors (p = 0.020 and 0.004, respectively). Inotropes and intravenous immunoglobulin (IVIG) were more commonly used in non-survivors (p = 0.001 and p = 0.015, respectively). BNP levels were higher in non-survivors (p = 0.008), and troponin I levels were not different between survivors and non-survivors (p = 0.260).

CONCLUSION

In pediatric acute myocarditis, lower LVEF, increased BNP, as well as the presence of hypotension and arrhythmia were found to be related to intensive care requirement. Hypotension and vomiting were found to be more common in non-survivors. Due to the possibility of rapidly worsening disease, physicians should be alert to the presence of these findings.

Machine Learning Approaches to Determine Feature Importance for Predicting Infant Autopsy Outcome

INTRODUCTION

Sudden unexpected death in infancy (SUDI) represents the commonest presentation of postneonatal death. We explored whether machine learning could be used to derive data driven insights for prediction of infant autopsy outcome.

METHODS

A paediatric autopsy database containing >7,000 cases, with >300 variables, was analysed by examination stage and autopsy outcome classified as 'explained (medical cause of death identified)' or 'unexplained'. Decision tree, random forest, and gradient boosting models were iteratively trained and evaluated.

RESULTS

Data from 3,100 infant and young child (<2 years) autopsies were included. Naïve decision tree using external examination data had performance of 68% for predicting an explained death. Core data items were identified using model feature importance. The most effective model was XG Boost, with overall predictive performance of 80%, demonstrating age at death, and cardiovascular and respiratory histological findings as the most important variables associated with determining medical cause of death.

CONCLUSION

This study demonstrates feasibility of using machine-learning to evaluate component importance of complex medical procedures (paediatric autopsy) and highlights value of collecting routine clinical data according to defined standards. This approach can be applied to a range of clinical and operational healthcare scenarios.

Myocarditis Presenting as Sudden Death in Infants and Children: A Single Centre Analysis by ESGFOR Study Group

BACKGROUND

Acute myocarditis is an inflammatory disease of the heart mostly diagnosed in young people, which can present as sudden death. The etiology includes infectious agents (mostly viruses), systemic diseases and toxins. We aim to characterize infants and children with myocarditis at post-mortem presenting as sudden deaths.

METHODS

Retrospective evaluation of 813 post-mortems in infants and children dying suddenly and unexpectedly between 2009-2019. Data retrieved included histological features, microbiology and clinical history.

RESULTS

23 of 813 post-mortems reviewed corresponded to acute myocarditis and 1 to dilated cardiomyopathy related to remote Parvovirus infection. PCR identified enterovirus (7), parvovirus (7 cases, 2 also with HHV6 and 1 case with EVB), Influenza A (1), Parainfluenza type 3 (1). Two cases corresponded to hypersensitivity myocarditis, 1 was Group A Streptococcus and 5 idiopathic myocarditis. Enterovirus was frequent in infants (7/10), and in newborns was associated with meningoencephalitis or congenital myocarditis. More than 50% were less than 2 years of age and all remained clinically unsuspected.

CONCLUSION

Myocarditis represents almost 3% of all sudden pediatric deaths. Enterovirus and parvovirus were the most common viruses. This retrospective analysis showed that patients experienced viral symptoms but remained unsuspected, highlighting the need for more clinical awareness of myocarditis.

Big Tests in Little People

Can laboratory tests that are routinely used in adult patients also be used in pediatric patients? Does the current literature support the routine use of troponin, brain natriuretic peptide, D-dimer, and lactate in children? Adult problems such as acute coronary syndrome and pulmonary embolism are rare in pediatrics, and there is a paucity of literature on how blood tests commonly used to help diagnose these conditions in adults play a role in the diagnosis and management of children. This article presents the literature about 4 common blood tests and examines the clinical applications of each.

The use of extracorporeal membrane oxygenation in children with acute fulminant myocarditis

Acute fulminant myocarditis (AFM) occurs as an inflammatory response to an initial myocardial insult. Its rapid and deadly progression calls for prompt diagnosis with aggressive treatment measures. The demonstration of its excellent recovery potential has led to increasing use of mechanical circulatory support, especially extracorporeal membrane oxygenation (ECMO). Arrhythmias, organ failure, elevated cardiac biomarkers, and decreased ventricular function at presentation predict requirement for ECMO. In these patients, ECMO should be considered earlier as the clinical course of AFM can be unpredictable and can lead to rapid haemodynamic collapse. Key uncertainties that clinicians face when managing children with AFM such as timing of initiation of ECMO and left ventricular decompression need further investigation.

Benefit of a wearable cardioverter defibrillator for detection and therapy of arrhythmias in patients with myocarditis

Aims

Myocarditis may lead to malignant arrhythmias and sudden cardiac death. As of today, there are no reliable predictors to identify individuals at risk for these catastrophic events. The aim of this study was to evaluate if a wearable cardioverter defibrillator (WCD) may detect and treat such arrhythmias adequately in the peracute setting of myocarditis.

Methods and results

In this observational, retrospective, single centre study, we reviewed patients presenting to the Charité Hospital from 2009 to 2017, who were provided with a WCD for the diagnosis of myocarditis with reduced ejection fraction (<50%) and/or arrhythmias. Amongst 259 patients receiving a WCD, 59 patients (23%) were diagnosed with myocarditis by histology. The mean age was 46 ± 14 years, and 11 patients were women (19%). The mean WCD wearing time was 86 ± 63 days, and the mean daily use was 20 ± 5 h. During that time, two patients (3%) had episodes of sustained ventricular tachycardia (VT; four total) corresponding to a rate of 28 sustained VT episodes per 100 patient‐years. Consequently, one of these patients underwent rhythm stabilization through intravenous amiodarone, while the other patient received an implantable cardioverter defibrillator. Two patients (3.4%) were found to have non‐sustained VT.

Conclusions

Using a WCD after acute myocarditis led to the detection of sustained VT in 2/59 patients (3%). While a WCD may prevent sudden cardiac death after myocarditis, our data suggest that WCD may have impact on clinical management through monitoring and arrhythmia detection.

Implications of SARS-CoV-2-Associated Myocarditis in the Medical Evaluation of Athletes

CONTEXT

Myocarditis is a known cause of death in athletes. As we consider clearance of athletes to participate in sports during the COVID-19 pandemic, we offer a brief review of the myocardial effects of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) through the lens of what is known about myocarditis and exercise. All athletes should be queried about any recent illness suspicious for COVID-19 prior to sports participation.

EVIDENCE ACQUISITION

The PubMed database was evaluated through 2020, with the following keywords: myocarditis, COVID-19, SARS-CoV-2, cardiac, and athletes. Selected articles identified through the primary search, along with position statements from around the world, and the relevant references from those articles, were reviewed for pertinent clinical information regarding the identification, evaluation, risk stratification, and management of myocarditis in patients, including athletes, with and without SARS-CoV-2.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

Since myocarditis can present with a variety of symptoms, and can be asymptomatic, the sports medicine physician needs to have a heightened awareness of athletes who may have had COVID-19 and be at risk for myocarditis and should have a low threshold to obtain further cardiovascular testing. Symptomatic athletes with SARS-CoV-2 may require cardiac evaluation including an electrocardiogram and possibly an echocardiogram. Athletes with cardiomyopathy may benefit from cardiac magnetic resonance imaging in the recovery phase and, rarely, endocardial biopsy.

CONCLUSION

Myocarditis is a known cause of sudden cardiac death in athletes. The currently reported rates of cardiac involvement of COVID-19 makes myocarditis a risk, and physicians who clear athletes for participation in sport as well as sideline personnel should be versed with the diagnosis, management, and clearance of athletes with suspected myocarditis. Given the potentially increased risk of arrhythmias, sideline personnel should practice their emergency action plans and be comfortable using an automated external defibrillator.

Complement C9 expression is associated with damaged myocardial cells in pediatric sudden death cases of fulminant myocarditis

Background

Because disease progression is so fast in sudden death of acute fulminant myocarditis, damage of myocardial cells is not evident in routine hematoxylin and eosin staining. To understand damage to myocardial cells and the mechanism of sudden death, immunohistochemical staining was performed for two forensic autopsy cases.

Case presentation

The patients were a healthy 5-year-old girl and 8-year-old boy. They suddenly died within 2 days of appearance of flu-like symptoms. An autopsy showed accumulation of yellowish-clear pericardial fluid containing fibrin deposits, fluid blood in the heart, and congestion of visceral organs. Histologically, minor necrosis or degeneration of myocardial cells with mainly lymphocytic infiltration was observed sometimes in tissue sections. Immunohistochemically, positive complement C9 staining and negative sirtuin 1 staining were found. These findings suggested wide damage of myocardial cells, even in regions with no marked changes in myocardial cells with hematoxylin and eosin staining. These areas corresponded to those with strong accumulation of lymphocytes.

Conclusions

Immunohistochemistry for complement C9 and sirtuin 1 might become a new tool for evaluating damage of myocardial cells of fulminant acute myocarditis.

Diagnosis, Evaluation, and Treatment of Myocarditis in Children

Myocarditis in the pediatric population can be a challenging diagnosis to make and often requires utilization of multiple diagnostic modalities. The cause is often due to a viral infection with activation of the innate and acquired immune response with either recovery or disease progression. Laboratory testing often includes inflammatory markers, cardiac troponin levels, and natriuretic peptides. Noninvasive testing should include electrocardiogram, echocardiogram, and possibly an MRI. Treatment of myocarditis remains controversial with most providers using immune modulators with intravenous immunoglobulin and corticosteroids.

Echocardiographic Parameters During and Beyond Onset of Kawasaki Disease Correlate with Onset Serum N-Terminal pro-Brain Natriuretic Peptide (NT-proBNP)

The N-terminal proBNP (NT-proBNP), produced by cardiomyocytes, has several reported utilities and associations in acute Kawasaki disease (KD). The objective of this study is to examine the relationship between serum values of NT-proBNP at time of KD diagnosis with cardiac systolic, diastolic function and electrocardiographic changes, at onset of the disease and during the first year of follow-up. KD was diagnosed in 127 children between March 2007 and July 2014, mean diagnostic age 3.5 ± 2.9 years. Coronary artery maximum z score was 2.6 ± 2.8 (range - 0.6 to + 18.9), with giant aneurysm in 5/122 (4.1%). Age-adjusted NT-proBNP was 2.6 ± 1.6 z score, 78/122 (63.9%) > 2.0. There was a crescendo correlation between onset NT-proBNP z score and C-Reactive protein (CRP) serum levels (slope + 0.49, p < 0.001). There was a crescendo correlation between NT-proBNP z score and indexed left ventricular (LV) mass (slope + 1.86, p = 0.02), LV diastolic function parameter E/e' ratio (slope + 0.31, p = 0.04) and a decrescendo correlation with age-adjusted LV shortening fraction (SF) (- 0.63, p = 0.02). Lower SF z score, higher left ventricular mass index and E/e' ratio were associated with higher NT-proBNP z score, but without correlation with CRP levels. Within 2-3 months from the onset of the disease, there was a resolution of the systolic dysfunction. Electrocardiographic parameter changes were associated with decreased LV shortening fraction but not with NT-proBNP. KD patients with elevated NT-proBNP at onset have sub-clinical myocardial involvement and might benefit from follow-up and continued evaluation, even in the absence of coronary artery involvement.

Factors Associated With In-hospital Mortality of Children With Acute Fulminant Myocarditis on Extracorporeal Membrane Oxygenation

Aim: To analyze the factors associated with in-hospital mortality of children with acute fulminant myocarditis on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Methods: This was a retrospective cohort study using chart reviews of patients diagnosed with acute fulminant myocarditis at the pediatric intensive care unit of two tertiary medical centers between January 1, 2005 and December 31, 2017. The inclusion criteria for this study were: (1) age from 1 month to 18 years; (2) diagnosed with acute myocarditis; (3) cardiogenic shock and need vasoactive-inotropic score ≥20 within 48 h after the use of vasoactive-inotropic agents; and (4) the need for ECMO placement. Results: Thirty-three children with acute fulminant myocarditis who needed ECMO were included. Clinical parameters were retrospectively reviewed. The overall survival rate was 69.6%. Higher levels of pre-ECMO troponin-I and pre-ECMO lactate, and lower post-ECMO left ventricular ejection fraction (LVEF) were significantly associated with in-hospital mortality in univariate analysis. Only higher pre-ECMO lactate and lower post-ECMO LVEF remained as predictors for in-hospital mortality in multivariate analysis. The areas under the curve of pre-ECMO lactate and post-ECMO LVEF in predicting survival were 0.848 (95% CI, 0.697-0.999, p = 0.002) and 0.824 (95% CI, 0.704-0.996, p = 0.01), respectively. A pre-ECMO lactate level of 79.8 mg/dL and post-ECMO LVEF of 39% were appropriate cutoff points to predict mortality. Conclusion: Pre-ECMO lactate level was associated with mortality in children with acute fulminant myocarditis, with an optimal cutoff value of 79.8 mg/dL. After VA-ECMO implantation, post-ECMO LVEF was associated with mortality, with an optimal cutoff value of 39%. The use of LVADs or urgent heart transplantation should be considered if the post-ECMO LVEF does not improve.

Histoplasmosis Myocarditis in an Immunocompetent Host After a Recreational Mud Run

Mud runs are an increasingly popular recreational fitness activity across the United States, combining a running race through an obstacle course with submersion in mud. Recent reports estimate 4 million people have participated in these types of events over the last 5 years. We describe an atypical case of myocarditis and multiorgan failure from disseminated histoplasmosis in a previously healthy pediatric patient, likely acquired during participation in a mud run. Although cases of histoplasmosis-associated endocarditis and pericarditis have been reported in the literature, cases of histoplasmosis myocarditis are rare.

When Lightning Strikes Twice in Pediatrics: Case Report and Review of Recurrent Myocarditis

Myocarditis is an important but incompletely understood cause of cardiac dysfunction. Children with fulminant myocarditis often require inotropic or mechanical circulatory support, and researchers in some studies suggest that up to 42% of children who die suddenly have evidence of myocarditis. Recurrent myocarditis is extremely rare, and the vast majority of reported cases involve adult patients. Pediatric providers who suspect a recurrence of myocarditis have limited evidence to guide patient management because the literature in this domain is sparse. Here we present a unique, illustrative pediatric case of recurrent myocarditis. A 14-year-old boy presented for the second time in 2 years with a clinical history strongly suggestive of myocarditis. Although myocarditis was suggested in the results of cardiac MRI, no pathogen was identified during his first presentation. During his second episode of myocarditis, parvovirus was confirmed by polymerase chain reaction testing of an endomyocardial specimen that also met Dallas criteria for myocarditis. With each presentation, he had decreased ventricular function that subsequently normalized. To the best of our knowledge, there are no reports of recurrent myocarditis in children in whom the diagnosis was confirmed by using MRI and/or biopsy data. Reviewing this distinctive case and the existing literature may help characterize this entity and raise awareness among care providers.

When is myocarditis indeed the cause of death?

Attribution of death to myocarditis continues to be a controversial issue in forensic pathology, despite the existence of established histopathological criteria as well as complementary investigations. The aim of the study was two-fold: (a) to retrospectively analyse the data obtained from a series of clinical and forensic autopsies in order to assess the number of cases with death attributed to myocarditis, and (b) to reevaluate these cases in order to assess how properly the histopathological diagnosis of myocarditis conformed to established criteria and therefore how accurately these were used on the basis of all postmortem investigation findings to conclude the cause of death. 2474 clinical and forensic autopsies were taken into consideration. Myocarditis was recorded as the official, underlying cause of death in 48 cases. Of those, 8 cases were considered to accurately conform to the histopathological Dallas criteria for the presence of myocarditis and could therefore be classified as cases of fatal myocarditis. In 19 out of 48 cases, description of focal myocarditis was considered to accurately fulfill the histopathological Dallas criteria for the presence of myocarditis. However, data provided by histological analysis and virology testing result reevaluation allowed alternative causes of death to be speculated. In another 21 out of 48 cases, description of focal myocardial inflammation was considered to inaccurately meet the histopathological Dallas criteria for the presence of myocarditis. The findings of our own study appear to be in agreement with previous observations in similar study groups and highlight that since myocarditis may occur in association with many diseases, a great deal of evidence is required before settling on categorical conclusions.

Contemporary Postnatal Incidence of Acquiring Acute Myocarditis by Age 15 Years and the Outcomes From a Nationwide Birth Cohort

OBJECTIVES

Acute myocarditis can be lethal, but the incidence remains unclear because of its wide manifestation spectrum. We investigated the postnatal incidence of acute myocarditis and risk factors for morbidity and mortality.

DESIGN

Retrospective derived birth cohort study.

SETTING

Taiwan National Health Insurance Database for the period 2000-2014.

PATIENTS

Children born between 2000 and 2009 with complete postnatal medical care data for at least 5 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From among 2,150,590 live births, we identified 965 patients (54.8% male) admitted with the diagnosis of acute myocarditis, accounting for an overall incidence of 0.45/1,000. The cumulative incidence rates were 0.19/1,000, 0.38/1,000, 0.42/1,000, and 0.48/1,000 by ages 1, 5, 10, and 15 years, respectively. Male predominance was noted in infants and school age children (age group 6-14 yr). Arrhythmias, including tachyarrhythmia (4.8%) and bradyarrhythmia (1.1%), occurred in 56 patients. Extracorporeal membrane oxygenation support was provided to 62 patients (6.4%) and additional left ventricular assist devices in six of them. The mortality at discharge was 6.3%. The presence of ventricular tachyarrhythmia, bradyarrhythmia, and an onset at school age (6-14 yr) were associated with increased odds for the need for extracorporeal membrane oxygenation, which was the only predictor for mortality at discharge (hazard ratio, 7.85; 95% CI, 3.74-9.29). In patients who survived the acute myocarditis, late mortality was relatively low (36/904 = 4.0%). The overall survival of children with acute myocarditis were 90.9%, 90.3%, and 89.8% by the intervals of 1, 5, and 10 years after the myocarditis, respectively.

CONCLUSIONS

This birth cohort study determined the cumulative incidence of acute myocarditis for neonates by 15 years old to be one in 2,105. In an era of extracorporeal membrane oxygenation, the need of extracorporeal membrane oxygenation may reflect the severity of acute myocarditis and predict its outcome.

Occurrence and Features of Childhood Myocarditis: A Nationwide Study in Finland

Background

Epidemiology of myocarditis in childhood is largely unknown. Men are known to have a higher incidence of myocarditis than women in adults aged <50 years, but whether this is true by sex in pediatric age groups is unknown. We set out to study the occurrence and potential sex differences of myocarditis in a general pediatric population.

Methods and Results

Data of all hospital admissions with myocarditis in Finland occurring in patients aged ≤15 years from 2004 to 2014 were collected from a mandatory nationwide registry. All patients with myocarditis as a primary, secondary, or tertiary cause of admission were included. Total and age‐ and sex‐specific incidence rates were calculated using corresponding population data. There were 213 admissions with myocarditis in pediatric patients. Myocarditis was the primary cause of admission in 86%. The overall incidence rate of myocarditis was 1.95/100 000 person‐years. Of all patients, 77% were boys, but sex differences in incidence rates were age‐dependent. In children aged 0 to 5 years, there was no sex difference in the occurrence of myocarditis. Boys aged 6 to 10 years had a higher incidence rate compared with girls (72% boys; incidence rate ratio: 2.46; 95% confidence interval, 1.03–5.89; P=0.04). Sex difference further increased in children aged 11 to 15 years (80% boys; incidence rate ratio: 3.5; 95% confidence interval, 2.68–5.67; P<0.0001).

Conclusions

Myocarditis leading to hospital admission is relatively uncommon in children, but occurrence of myocarditis increases with age. There is no sex difference in the risk of myocarditis during the first 6 years of life, but boys have a significantly higher risk at ages 6 to 15 years.

Cardiovascular pre-participation screening in young athletes: Recommendations of the Association of European Paediatric Cardiology

Sudden death in young competitive athletes can be avoided by implementation of pre-participation screening programmes. A screening programme should be performed only by trained physicians and should include the athlete's personal and family history, physical examination results, and the readings from a 12-lead-electrocardiogram. The athlete should undergo this screening programme every second year to detect progressive diseases. In addition, the programme should include detailed instructions to the athletes to pause training during infections in order to prevent sudden death due to myocarditis.

Fulminant Influenza B Myocarditis in a Pediatric Patient

Influenza B is a common viral illness in childhood. We report a 5-year-old previously healthy girl admitted with facial edema that developed severe acute myocarditis from influenza B infection. As her clinical course progressed, she ultimately developed severe, acute heart failure requiring extracorporeal membrane oxygenation for support.

Demographic, clinical and pathological features of sudden deaths due to myocarditis: Results from a state-wide population-based autopsy study

Causes of sudden cardiac deaths have been widely reported with limited data focused specifically on myocarditis. A retrospective review of cases from the Office of the Chief Medical Examiner (OCME), State of Maryland yielded a total of 103 sudden unexpected deaths (SUDs) due to myocarditis (0.17% of all SUDs and 0.70% of autopsied SUDs) from 2005 through 2014. Most deaths occurred in patients <30 years of age with a male:female ratio 1.3:1. Of the 103 cases, 45 (43.7%) patients were witnessed collapsed. Four deaths occurred during exertion, such as exercising at the gym or performing heavy physical work, and 2 deaths were associated with emotional stress. The common cardiac macroscopic findings included ventricular dilatation (39.8%), mild coronary stenosis (17.5%), mottled myocardial appearance (15.5%), and myocardial fibrosis (10.7%). The histological classification of myocarditis was based on the predominant type of inflammatory cell infiltration. In our study group, lymphocytic myocarditis was most common, accounting for 56 cases (54.4%), followed by neutrophilic (32 cases, 31.7%), eosinophilic (13 cases, 12.6%) and giant cell type (2 cases, 1.9%). Microscopic examination revealed myocyte necrosis in 69 cases (67.0%) and interstitial or perivascular fibrosis in 48 cases (46.6%). The percentage of myocyte necrosis was 75.0% (42/58 cases) in lymphocytic, 65.6% (21/31 cases) in neutrophilic, 30.8% (4/13 cases) in eosinophilic, and 100% (2/2 cases) in giant cell myocarditis. Determination of myocarditis as cause of death continues to present a major challenge to forensic pathologists, because histopathologic findings can be subtle and the diagnosis of myocarditis remains difficult.

Myocarditis

Myocarditis is an inflammatory disease of the heart that can cause devastating disease in otherwise healthy children. Inciting agents such as viral infection cause direct damage to the myocardial cells, which triggers an inflammatory response that enhances myocardial toxicity and associated morbidity. Severe cases typically present with respiratory distress and cardiovascular collapse, whereas subclinical cases are unnoticed by the medical community. The initial workup in suspected cases should include an electrocardiogram, chest radiograph, and cardiac troponin T. Treatment is concentrated on hemodynamic stabilization with optimization of heart failure management, dysrhythmia protocol, and supportive therapy. The purpose of this review was to provide the emergency medicine practitioner a concise and current review of the basic pathophysiology as well as a functional and evidence-based approach to the diagnosis and treatment of myocarditis in the pediatric population.

Reference ranges for organ weights of infants at autopsy: results of >1,000 consecutive cases from a single centre

Background

Infancy is the most common period for childhood death, including both neonatal deaths from obstetric or medical complications and sudden unexpected infant deaths. The weighing of organs at autopsy is an established process and is recommended in current protocols. However, minimal contemporary data is available regarding reference ranges for organ weights of infants.

Methods

Organ weight data for consecutive infant autopsies over a 14 year period performed at a single tertiary centre, including >1,000 cases, were examined in order to provide up to date reference ranges across this age range, using linear regression modelling and the standard LMS method.

Results

1,525 infant autopsies were analysed, of which 1,190 were subsequently used in the creation of linear regression models prior to performance of the LMS method. Organ weight charts were produced for the 5th, 25th, 50th, 75th and 95th centiles for the heart, lungs, liver, spleen, kidneys, pancreas, thymus gland and adrenal glands.

Conclusion

This study provides the largest single centre contemporary dataset of infant autopsies allowing provision of up-to-date ‘normal’ ranges for all major organ weights across this age range.

Changes in cardiac output and stroke volume as measured by non-invasive CO monitoring in infants with RSV bronchiolitis

OBJECTIVES

The primary aim of the study was to determine the changes, if any, in cardiac output (CO) and stroke volume (SV) in normal infants with RSV bronchiolitis. The secondary aim was to determine whether changes in CO (ΔCO) and SV (ΔSV) are associated with changes in respiratory rate (ΔRR).

METHODS

Non-invasive CO recordings were obtained within 24 h of admission and discharge. Changes in CO, SV, and HR measurements were compared using paired t-tests. The effect of fluid boluses during the first 24 h (<60 or ≥60 cc/kg) on CO was assessed by 2 way ANOVA with time and group as main effect. The relationship between ΔRR and ΔCO or ΔSV was assessed by linear regression. Data is presented as Mean ± SEM and mean differences with 95 % confidence interval (p < 0.05 considered significant).

RESULTS

15 infants with RSV bronchiolitis were studied. CO (1.31 ± 0.13 to 1.11 ± 0.11 l/min (0.21 [0.04-0.37]) and SV (9.42 ± 1.10 to 7.75 ± 0.83 ml/beat (1.67 [0.21-3.12]) decreased significantly while HR (142.1 ± 4.0 to 145.2 ± 3.1 beats/min 3.0 [-5.3 to 11.3]) was unchanged. SV (p = 0.02) and CO (p = 0.04) significantly decreased only in the 7 infants that received ≥60 cc/kg. ΔRR correlated significantly with ΔCO (r (2) = 0.28, p = 0.04); but not with ΔSV (r (2) = 0.20, p = 0.09).

CONCLUSIONS

∆CO was related to ΔSV and not Δ HR. The ∆CO and ΔSV were affected by fluid boluses. ΔRR correlated with ΔCO. Non-invasive CO monitoring can trend CO and SV in infants with bronchiolitis during hospitalization.

Recurrent congestive heart failure in a child due to probable myocarditis

Recurrent congestive heart failure (CHF) attributable to myocarditis is a seldom-discussed entity in the scientific literature. This report describes the case of an 8-year-old girl who had three clinically identical episodes of CHF, beginning at the age of 5 years, with each episode preceded by a viral prodrome. The clinical features and the echocardiography and electrocardiogram findings were most supportive of myocarditis. Symptoms and investigations completely normalized between episodes. The third episode, associated with influenza A (strain H1N1) infection, led to cardiac arrest and death on day 2 after admission. Autopsy showed mild cardiomegaly with microscopic foci of myocardial fibrosis and extensive contraction band necrosis. This report is the first to describe recurrent CHF due to probable myocarditis in a pediatric patient.

Undiagnosed heart disease leading to sudden unexpected death in childhood: a retrospective study

OBJECTIVES

Heart disease accounts for a significant proportion of sudden unexpected deaths among children. We describe here demographic features, pathological conditions, and the frequency of premonitory symptoms in a retrospective series of cases of sudden unexpected cardiac death (SUCD) attributable to undiagnosed structural heart disease.

METHODS

A chart review of autopsies involving children 0 to 17 years of age that were performed at the Hospital for Sick Children (Toronto, Ontario, Canada) between 1984 and 2003 was conducted. Cases of sudden unexpected death within 24 hours after clinical presentation with previously undetected fatal heart disease were included. Cases with multiple or thoracic trauma and chronic or multisystem disease were excluded.

RESULTS

During the 20-year study period, 4926 autopsies were performed. A total of 103 cases (2.1%), involving 51 male patients and 52 female patients 1 day to 15 years of age (mean: 2.9 ± 4.2 years), were diagnosed as having SUCD. The most common diagnoses were myocarditis (n = 37 [35.9%]), hypoplastic left heart syndrome (HLHS) (n = 19 [18.4%]), dilated cardiomyopathy (DCM) (n = 16 [16.5%]), coronary artery anomalies (n = 6 [5.8%]), and aortic stenosis (n = 5 [4.9%]). There was a significant difference in the mean age of presentation between leading causes of SUCD (6.5 days for HLHS, 1.7 years for DCM, and 5.4 years for myocarditis; P < .0001). Of 103 cases, 27 (26.2%) had premonitory symptoms documented.

CONCLUSION

SUCD accounted for 2.1% of all autopsies, and HLHS, DCM, and myocarditis were the 3 most common diagnoses, which presented at increasing ages.

Management and outcomes in pediatric patients presenting with acute fulminant myocarditis

OBJECTIVE

To investigate factors associated with mechanical circulatory support and survival in patients with acute fulminant myocarditis (AFM).

STUDY DESIGN

Retrospective cohort of AFM patients admitted to the cardiac intensive care unit during 1996-2008. AFM was defined as distinct onset of symptoms ≤14 days before admission, rapid-onset cardiogenic shock, and normal left ventricular size. Demographic and physiological variables were compared between patients treated with extracorporeal membrane oxygenation (ECMO) and those who were not and between survivors and nonsurvivors.

RESULTS

Twenty patients (median age 12.7 years) met inclusion criteria. Seventeen patients (85%) survived to hospital discharge. One underwent heart transplantation. Ten (50%) patients required ECMO, and 7 (70%) of these survived. On admission, patients requiring ECMO had elevated lactate (9 vs 1 mmol/L), creatinine (0.8 vs 0.6 mg/dL), and aspartate aminotransferase (256 vs 35 IU/L) (all P < .05) and a trend towards increased incidence of dysrhythmias (80% vs 30%, P = .07). During hospitalization, non-survivors had higher peak lactate (10 vs 3 mmol/L), creatinine (1.5 vs 0.8 mg/dL), and aspartate aminotransferase (3007 vs 156 IU/L) (all P < .05) compared with survivors.

CONCLUSIONS

Patients with AFM with end organ dysfunction or arrhythmias on admission may require mechanical circulatory support. The transplant-free survival rate in this critically ill cohort was excellent (80%).

Myocarditis in the setting of RSV bronchiolitis

Myocarditis in the pediatric population is commonly caused by viral pathogens, notably entero virus and adeno virus. Respiratory syncytial virus, although widespread among this population, is rarely associated with myocarditis. The incidence of myocarditis is unknown due to the variability of clinical presentation and diagnostic limitations. Data regarding prognosis is lacking in children. Patients should be monitored in a pediatric intensive care unit secondary to the risk of hemodynamic compromise. We present the case of fulminant myocarditis in a seven-month old female in the setting of respiratory syncytial virus bronchiolitis.

The challenges of prompt identification and resuscitation in children with acute fulminant myocarditis: case series and review of the literature

AIM

To describe the clinical presentation, triage, resuscitation and outcome of acute fulminant myocarditis in children presenting to district hospitals and referred for cardiac intensive care.

METHODS

Case series describing five patients (from 2 weeks to 12 years old) with a diagnosis of acute fulminant myocarditis, presented to outlying hospitals between December 2006 and December 2007 and retrieved to a cardiac intensive care unit.

RESULTS

All children were admitted with non-specific symptoms such as vomiting, cough and poor feeding to their local hospital, where various provisional diagnoses such as viral gastroenteritis, bronchitis or renal failure were considered. Acute physiological deterioration usually prompted the referral for intensive care. Two children died at the referring hospital during stabilisation by the retrieval team. Three children survived transport to intensive care and to hospital discharge; two received mechanical support and one underwent urgent orthotopic heart transplantation. Enterovirus and parvovirus were identified as causative agents in two patients. In one case, macrophage activation syndrome was diagnosed although no clear viral trigger was identified. Median length of hospitalisation among survivors was 33 days, and mechanical cardiac support was required for a median of 12 days.

CONCLUSIONS

The diagnosis and initial management of acute fulminant myocarditis is extremely challenging. Prognosis for patients admitted to a cardiac centre for early mechanical support can be very favourable, while a delay in considering the diagnosis may result in poor outcome. The diagnosis of myocarditis should be considered in any previously well child presenting with a viral prodrome and non-specific organ dysfunction associated with dysrhythmias, shock or acute heart failure, even in the absence of cardiomegaly.

Extracorporeal membrane oxygenation for the support of infants, children, and young adults with acute myocarditis: a review of the Extracorporeal Life Support Organization registry

OBJECTIVE

To describe survival outcomes for pediatric patients supported with extracorporeal membrane oxygenation for severe myocarditis and identify risk factors for in-hospital mortality.

DESIGN

Retrospective review of Extracorporeal Life Support Organization registry database.

SETTING

Data reported to Extracorporeal Life Support Organization from 116 extracorporeal membrane oxygenation centers.

PATIENTS

Patients < or = 18 yrs of age supported with extracorporeal membrane oxygenation for myocarditis during 1995 to 2006.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 19,348 reported pediatric extracorporeal membrane oxygenation uses from 1995 to 2006, 260 runs were for 255 patients with a diagnosis of myocarditis (1.3%). Survival to hospital discharge was 61%. Seven patients (3%) underwent heart transplantation and six patients survived to discharge. Of 100 patients not surviving to hospital discharge, extracorporeal membrane oxygenation support was withdrawn in 70 (70%) with multiple organ failure as the indication in 58 (83%) patients. In a multivariable model, female gender (adjusted odds ratio, 2.3, 95% confidence interval, 1.3-4.2), arrhythmia on extracorporeal membrane oxygenation (adjusted odds ratio, 2.7, 95% confidence interval, 1.5-5.1), and renal failure requiring dialysis (adjusted odds ratio, 5.1, 95% confidence interval, 2.3-11.4) were associated with increased odds of in-hospital mortality.

CONCLUSION

Extracorporeal membrane oxygenation is a valuable tool to rescue children with severe cardiorespiratory compromise related to myocarditis. Female gender, arrhythmia on extracorporeal membrane oxygenation, and need for dialysis during extracorporeal membrane oxygenation were associated with increased mortality.

Myocarditis

Myocarditis is an uncommon, potentially life-threatening disease that presents with a wide range of symptoms in children and adults. Viral infection is the most common cause of myocarditis in developed countries, but other etiologies include bacterial and protozoal infections, toxins, drug reactions, autoimmune diseases, giant cell myocarditis, and sarcoidosis. Acute injury leads to myocyte damage, which in turn activates the innate and humeral immune system, leading to severe inflammation. In most patients, the immune reaction is eventually down-regulated and the myocardium recovers. In select cases, however, persistent myocardial inflammation leads to ongoing myocyte damage and relentless symptomatic heart failure or even death. The diagnosis is usually made based on clinical presentation and noninvasive imaging findings. Most patients respond well to standard heart failure therapy, although in severe cases, mechanical circulatory support or heart transplantation is indicated. Prognosis in acute myocarditis is generally good except in patients with giant cell myocarditis. Persistent, chronic myocarditis usually has a progressive course but may respond to immunosuppression.

Cardiac troponin-I as a screening tool for myocarditis in children hospitalized for viral infection

AIM

The incidence of myocarditis in children is uncertain because patients with minor symptoms can remain undiagnosed. We hypothesized that screening all children who are hospitalized for an acute infection with troponin-I (TnI) would reveal myocarditis cases and performed a prospective screening study.

METHODS

Between October 2005 and July 2008, a blood sample for TnI measurement was taken every time a sample for C-reactive protein measurement was drawn. If TnI value was above the screening limit (0.06 microg/L), electrocardiogram (ECG) and cardiac ultrasound were performed. TnI measurements were repeated until at normal level.

RESULTS

Altogether, 1009 children were screened during the 33 months. TnI was above the screening limit (0.06 microg/L) in six children. None of them had any signs of myocarditis in ECG or cardiac ultrasound. Five of those six children were younger than 30 days. All had a respiratory infection as a cause for hospitalization, three of which was caused by RSV. In four children, all younger than 30 days, TnI levels remained high (>0.37 microg/L) for two months, but decreased after that to normal levels.

CONCLUSION

The incidence of myocarditis during viral infections is low and a routine TnI screening for asymptomatic myocarditis is not useful.

First report of sudden death due to myocarditis caused by adenovirus serotype 3

Myocarditis is a rare cause of sudden death in childhood. We describe the sudden death of a child from viral myocarditis, which we demonstrate was likely caused by an uncontrolled inflammatory response to a disseminated adenovirus serotype 3 infection originating in the tonsil.

An infantile case of asphyxia with coincidental myocarditis

A six-month-old infant was found dead in a small dustbin in an upside-down position. The police investigation showed that there was no criminal environment including negligence. Analysis at the scene suggested death caused by asphyxia (wedging death). Microscopically, however, diffuse lymphocyte infiltration was observed in the interstitial spaces of the myocardium. Common symptoms of infantile myocarditis are generally non-specific, and the predominant neurological problem is a decrease in activity. The records of rectal temperature suggested that the decedent was dead without a high fever. In the present case, there was no obvious relationship between myocarditis and movement of the infant. We conclude that myocarditis was coincidental to the cause of death by asphyxia.