Surveillance of COVID-19-Associated Multisystem Inflammatory Syndrome in Children, South Korea

The complex landscape of immune dysregulation in multisystem inflammatory syndrome in children with COVID-19

The immune responses following SARS-CoV-2 infection in children are still under investigation. While coronavirus disease 2019 (COVID-19) is usually mild in the paediatric population, some children develop severe clinical manifestations or multisystem inflammatory syndrome in children (MIS-C) after infection. MIS-C, typically emerging 2-6 weeks after SARS-CoV-2 exposure, is characterized by a hyperinflammatory response affecting multiple organs. This review aims to explore the complex landscape of immune dysregulation in MIS-C, focusing on innate, T cell-, and B cell-mediated immunity, and discusses the role of SARS-CoV-2 spike protein as a superantigen in MIS-C pathophysiology. Understanding these mechanisms is crucial for improving the management and outcomes for affected children.

Decreased incidence of Kawasaki disease in South Korea during the SARS-CoV-2 pandemic

Purpose

Analyzing Kawasaki disease epidemiology during the SARS-CoV-2 pandemic in South Korea using 2012-2020 National Health Insurance Service data.

Methods

The incidence of Kawasaki disease for 2012-2020 was investigated to identify changes in incidence after the start of the pandemic. National Health Insurance Service data from the Republic of Korea were used. Kawasaki disease was defined based on the International Statistical Classification of Diseases and Related Health Problems, the Tenth Revision diagnostic code (M30.3), and the intravenous immunoglobulin prescription code. Prescription history was collected for the following medications: intravenous immunoglobulin, aspirin, corticosteroids, tumor necrosis factor-α antagonist, clopidogrel, and anticoagulation drugs.

Results

The Kawasaki disease incidence per 100,000 individuals younger than 5 years was 238.9, 230.0, and 141.2 in 2018, 2019, and 2020, respectively. Regarding the incidence from 2012 to 2020, it was the highest in 2018 and decreased to 141.2 (p < 0.001) in 2020, after the start of the pandemic. In 2020, 28.3% of all patients with KD were infants, a percentage significantly higher than that of the previous year (p < 0.001). There was biphasic seasonality in the monthly Kawasaki disease incidence. The Kawasaki disease incidence was the highest in winter followed by that in early summer.

Conclusion

After the start of the pandemic, the Kawasaki disease incidence decreased, and the percentage of patients with Kawasaki disease aged <1 year increased. These findings provide support for the hypothesis suggesting an infectious trigger in Kawasaki disease.

Clinical manifestations and outcomes associated with PICU admission in children with multisystem inflammatory syndrome in Taiwan: A retrospective cohort study

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a rare and serious systemic inflammatory disorder that occurs following a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study aims to investigate the clinical manifestations, risk factors associated with pediatric intensive care unit (PICU) admission, and outcome among children with MIS-C in Taiwan.

METHODS

A retrospective analysis was conducted among pediatric patients diagnosed with MIS-C between June 2022 and February 2023 at Chang Gung Memorial Hospital, Linkou, Taiwan. Data on demographics, clinical features, laboratory findings, treatment modalities, and outcomes were collected and analyzed.

RESULTS

Twenty-eight MIS-C patients, including 9 boys and 19 girls, with an average age of 5.3 ± 3.8 years old, were enrolled. Most of the cases (78.6%) were diagnosed following the first pandemic wave of COVID-19 in Taiwan. The leading clinical manifestations observed were fever (100%), skin rash (64.3%), tachycardia (46.4%), and vomiting (46.4%). Nine patients (32.1%) were admitted to the PICU due to hypotension or neurological manifestations. Higher levels of band-form white blood cells, procalcitonin, ferritin, d-dimer, prothrombin time, NT-proBNP, and lower platelet levels on arrival were associated with PICU admission (p = 3.9 × 10-2 ,9 × 10-3 , 4 × 10-3 ,1 × 10-3 , 5 × 10-3 , 4.1 × 10-2 , and 3.4 × 10-2 , respectively). Arrhythmia in one case (3.5%) and coronary artery abnormalities, including dilatation in two cases (7.1%) and small aneurysms in one case (3.5%) were identified. Regardless of ICU admission, no patients experienced systolic dysfunction or mortality following treatment.

CONCLUSION

MIS-C cases in Taiwan have a favorable outcome. Although one-third of the patients required PICU admission, none of the MIS-C cases resulted in severe cardiovascular morbidity or mortality. This study provides valuable insights into the clinical manifestations and outcomes associated with PICU admission in children with MIS-C in Taiwan.

Understanding COVID-19 in children: immune determinants and post-infection conditions

Coronavirus disease 2019 in children presents with milder clinical manifestations than in adults. On the other hand, the presence of a wide range of inflammatory manifestations, including multisystem inflammatory syndrome in children (MIS-C), in the period after infection suggests a particular susceptibility of some children toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Both protective factors that prevent evolution to severe forms and risk factors for post-infectious conditions are likely to be found in age-related differences in the immune system. The prompt innate response with type I IFN production and the generation of neutralizing antibodies play a crucial role in containing the infection. The greater number of naive and regulatory cells in children helps to avoid the cytokine storm while the causes of the intense inflammatory response in MIS-C need to be elucidated. This review aims to analyze the main results of the recent literature assessing immune response to SARS-CoV-2 over the pediatric age group. We summarized such observations by dividing them into innate and acquired immunity, then reporting how altered immune responses can determine post-infectious conditions. IMPACT: The main immune markers of acute SARS-CoV-2 infection in children are summarized in this review. This paper reports a broad overview of age-related differences in the immune response to SARS-CoV-2 and emerging post-infection conditions. A summary of currently available therapies for the pediatric age group is provided.

Change in Severity and Clinical Manifestation of MIS-C Over SARS-CoV-2 Variant Outbreaks in Korea

BACKGROUND

There is difference in the incidence of multi-system inflammatory syndrome in children (MIS-C) in patients with different variants of severe acute respiratory syndrome coronavirus 2, however, little is known about the epidemiology in Asian countries. We investigated and compared the epidemiology of the MIS-C during omicron-dominant period with that of previous periods in South Korea.

METHODS

We obtained clinical, epidemiological and laboratory data on MIS-C cases from national MIS-C surveillance in South Korea. We defined pre-delta period as January 2020-May 2021; delta period as June 2021-December 2021; and omicron period as January 2022-April 2022. We describe the clinical characteristics and outcomes of MIS-C patients by period.

RESULTS

A total of 91 cases were assessed to be MIS-C cases. Number of MIS-C cases have increased from six cases during pre-delta period to 66 cases during omicron period, while the incidence rate (the number of MIS-C cases per 100,000 cases of reported coronavirus disease 2019) has decreased from 38.5 cases per 100,000 (95% confidence interval [CI], 14.1-83.9) during pre-delta period to 1.6 cases per 100,000 (95% CI, 1.2-2.0) during omicron periods. During pre-delta period, 66.7% and 100% had hypotension and gastrointestinal involvement, respectively; while during omicron period, 12.1% and 6.1% had such clinical manifestations. Fifty percent of pre-delta MIS-C patients were taken intensive care unit (ICU) cares, while 10.6% of patients during omicron periods were in ICUs.

CONCLUSION

Omicron period were associated with less severe clinical manifestation compared to pre-delta and delta periods. Although incidence rate of MIS-C was lower for the omicron period than pre-delta and delta periods, number of patients reported with MIS-C may pose a substantial clinical burden.

The First Case in Japan of Fulminant Myocarditis Due to Multisystem Inflammatory Syndrome in Children (MIS-C) That Required Mechanical Circulatory Support

Multisystem inflammatory syndrome in children (MIS-C) is a novel hyperinflammatory syndrome that is associated with severe acute respiratory syndrome coronavirus 2 infections. Reports describing the mechanical circulatory support (MCS) and myocardial biopsy for fulminant myocarditis due to MIS-C are limited.A 13-year-old male patient with MIS-C underwent treatment, including immunosuppressive therapy and MCS devices, and managed to recover from pulseless electrical activity cardiac arrest.This is the first patient in Japan with MIS-C who required MCS devices in Japan. Appropriate and immediate treatment with immunosuppressive therapy and MCS devices is important.

Multisystem inflammatory syndrome in children in Singapore

Introduction: Multisystem inflammatory syndrome in children (MIS-C) is a rare inflammatory syndrome with multisystem involvement affecting children exposed to COVID-19. This condition is rarely reported in East Asia and was not detected in Singapore until 2021. We present 12 cases of MIS-C diagnosed in KK Women’s and Children’s Hospital (KKH) from October 2021 to December 2021. Method: We conducted an observational study on cases fulfilling the Singapore Ministry of Health criteria for MIS-C from January 2020 to December 2021 in KKH. Medical records were reviewed to obtain information on clinical presentation, disease course, treatment received and outcomes. Results: In the 12 cases detected, the median age was 7.50 years (interquartile range 4.00–9.25); 8 were male. All patients had mucocutaneous symptoms similar to Kawasaki disease. Other commonly involved systems were: haematological (coagulopathy 100%, lymphopaenia 91.70% and thrombocytopaenia 75.00%), gastrointestinal (75.00%) and cardiovascular (83.30%). Six patients (50.00%) had shock and were admitted to the intensive care unit. The majority of patients received treatment within 2 days of hospitalisation with intravenous immunoglobulin (IVIg) and steroids. All survived; the majority had normal echocardiograms and no long-term organ sequelae at 6 months post-discharge. Conclusion: MIS-C emerged in Singapore as the incidence of COVID-19 in the community increased in 2021. The clinical presentation of our patients is similar to earlier reports, with some significant differences from Kawasaki disease. Multidisciplinary management, timely diagnosis, and early initiation of treatment with IVIg and steroids likely contributed to comparatively good outcomes. Our cases highlight the need for continued awareness of MIS-C among physicians, and surveillance of its incidence, short- and long-term outcomes. Keywords: COVID-19, children, MIS-C, inflammation, paediatrics

A Suspected Case of Multisystem Inflammatory Disease in Children Following COVID-19 Vaccination: A Case Report and Systematic Literature Review

Multisystem inflammatory syndrome in children (MIS-C) is rare but can be a potentially serious complication following SARS-CoV-2 infection in children. 1 Introduction of coronavirus disease 2019 (COVID-19) vaccines are effective in lowering the burden due to SARS-CoV-2. However, there have been reports of MIS occurrence following COVID-19 vaccination in adults. 2 The potential public health implication of MIS-C following COVID-19 vaccination is not clear in children. Our objective is to describe the spectrum of clinical disease, therapy, and outcomes of MIS-C following COVID-19 vaccination in children.

Multisystem inflammatory syndrome in children (MIS-C) showing disseminated aspergillosis, cytomegalovirus reactivation and persistent SARS-COV-2: Case report with autopsy review

Multisystem inflammatory syndrome in children (MIS-C) is an emerging phenomenon associated with SARS-COV-2 infection (COVID-19) occurring in < 1 % of infected children. MIS-C is characterized by a hyperinflammatory state with excessive cytokine release ('storm') leading to hemodynamic compromise and multiorgan failure, with a death rate of ∼2 %. Autopsy examination can play a particularly important role in helping to understand the pathogenesis of MIS-C. Yet, only five autopsy studies have been reported to date. We report a fatal case of MIS-C involving a previously healthy, 5-year-old Thai boy admitted with MIS-C, one month after exposure to SARS-COV-2. While in intensive care, he was found to have a hypertrophic cardiomyopathy, and despite immunosuppressive treatment for MIS-C, developed shock and died. Multiorgan inflammation was not found at autopsy, implying that the MIS-C had responded to treatment. However, there was disseminated aspergillosis and cytomegalovirus reactivation, attributed to the immunosuppression. SARS-COV-2 virus was also found in multiple organs. To the best of our knowledge, this is the first reported autopsy of an MIS-C patient from Asia, and the first report of aspergillosis in MIS-C. This case underscores that the risks of immunosuppression are also a concern in MIS-C. Although MIS-C is generally considered to be a post-infectious hyperimmune reaction, persistence of SARS-COV-2 is a feature in all autopsies of MIS-C patients reported to date, suggesting a possible role in the pathogenesis, at least in fatal cases.

Clinical presentation and short-term outcomes of multisystemic inflammatory syndrome in children in Lagos, Nigeria during the COVID-19 pandemic: A case series

Background

Multisystemic inflammatory syndrome in children (MIS-C) has increasingly been documented globally with the progression of the COVID-19 pandemic and a significant proportion of cases have been noted in children of Black descent. There has been a noticeable discrepancy in the presentation and outcomes of COVID-19 infection in sub-Saharan Africa compared to the rest of the world. We documented the demography, clinical features, laboratory and imaging findings, therapeutic management, and short-term outcomes of paediatric patients with MIS-C diagnosed during the COVID-19 pandemic in Lagos, Nigeria.

Methods

We carried out a retrospective review of MIS-C cases seen in nine public and private hospitals in Lagos from July 10, 2020 to July 30, 2021. Data on clinical presentation, laboratory investigations, therapy as well as outcomes at 2 weeks, 6 weeks, 3 months and 6 months were analyzed.

Findings

28 children and adolescents with median age of 7·5 (IQR 2·3 - 9·4) years were diagnosed with MIS-C. MIS-C was suspected in 24 patients (85·7%) at initial clinical evaluation and mucocutaneous, gastrointestinal and cardiovascular manifestations were identified in 75·0%, 71·4% and 89·3% of patients respectively. Acute kidney injury and aseptic meningitis were noted in 32·1% and 17·9% of patients respectively. Cardiac manifestations at presentation included coronary dilatation and pericardial effusion in 46·4% each, ventricular dysfunction (32·1%), atrioventricular valve regurgitation (25·0%), prolonged QTc interval (40·0%) and first-degree atrioventricular block (16·0%). Therapy included aspirin in 89·3%, steroids in 75·0% and intravenous immunoglobulin (IVIG) infusion in 60·7%. All patients survived and were discharged after a mean of 11·14 (SD 5·65) days. Frequency of coronary dilatation had reduced from 46·4% to 7·1% by 3 months follow up and prolonged QTc interval persisted until the 6 week follow up in 4.5% of patients. Echocardiogram and electrocardiogram findings were normal in all patients assessed at 6 months follow up.

Interpretation

MIS-C is an important diagnosis in children presenting with prolonged fever during the COVID-19 pandemic. Cardiovascular manifestations occurred in several children with MIS-C and improved by 6 months follow up. Early diagnosis and prompt institution of a combination of antiplatelet therapy, steroids and IVIG appear to be beneficial.

Funding

None.

Changes in the Clinical Characteristics of Kawasaki Disease After Coronavirus Disease (COVID-19) Pandemic: A Database Analysis

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on Kawasaki disease (KD) has not yet been established. We investigated changes in the observed number and severity of KD cases and accompanying coronary artery complications during the COVID-19 pandemic in Korea.

METHODS

This retrospective observational study included patients aged < 18 years with acute-phase KD diagnosed between March 2018 and February 2021. Data were extracted from the Clinical Data Warehouse that houses data from five affiliated university hospitals in Korea. We analyzed changes in the number of patient admissions and clinical characteristics, including cardiac complications, before and after the onset of the COVID-19 pandemic.

RESULTS

A total of 475 admissions were included in the analysis. After March 2020, we observed a significant decrease of 33% in the number of hospitalizations for KD compared with the average number of hospitalizations during the previous 2 years. The number of admissions per month significantly decreased by 7.9 persons/month (95% confidence interval, -13.8 to -2.0; P < 0.05) compared with that before COVID-19. By contrast, the proportion of patients aged < 1 year with KD increased. The proportion of patients with refractory KD and the rate of cardiac complications did not change significantly.

CONCLUSION

Since the onset of the COVID-19 pandemic, the total number of hospital admissions for KD has decreased in Korea. Although the proportion of admissions of infants aged < 1 year increased, no changes were observed in clinical courses and complications.

Multisystem Inflammatory Syndrome and COVID-19 in children and adolescents: epidemiological aspects, Brazil, 2020-20211

ABSTRACT This study describes epidemiological aspects of the Multisystemic Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 and mortality by COVID-19 in children (0-9 years old) and adolescents (10-19 years old). The data sources, for 2020-2021, were the Epidemiological Surveillance System for MIS-C and Mortality Information System for COVID-19, both managed by the Ministry of Health. There were 1,503 cases, more frequent in children (77%) than in adolescents (23%), and 93 reported deaths due to MIS-C in 26 of the 27 States of the Country. The highest number of cases in children was reported in São Paulo (268), but the highest incidence took place in the Federal District (7.8 per 100,000 inhabitants). The rate of deaths due to MIS-C was 5.4% in children and 8.7% in adolescents. There were 2,329 deaths due to COVID-19 in the population under 20 years old, with a higher rate in adolescents (4.4 per 100,000 inhabitants) than in children (2.7); the highest rate occurred in Roraima. We recommend intensifying immunization against COVID-19 in such population, increasing protection against the negative effects of COVID-19 and MIS-C, which may have short, medium and/or long-term consequences, so as not to compromise the full integration of these citizens into society.

Síndrome Inflamatória Multissistêmica e Covid-19 em crianças e adolescentes: aspectos epidemiológicos, Brasil, 2020-2021

RESUMO Este estudo descreve aspectos epidemiológicos da Síndrome Inflamatória Multissistêmica Pediátrica (SIM-P) associada à Covid-19 e óbitos por Covid-19 em crianças (0-9 anos de idade) e adolescentes (10-19 anos de idade). As fontes de dados, de 2020-2021, foram os Sistemas de Vigilância Epidemiológica para SIM-P e de Informação sobre Mortalidade para Covid-19, gerenciados pelo Ministério da Saúde. Foram notificados 1.503 casos, mais frequentes em crianças (77%) do que em adolescentes (23%); e 93 óbitos por SIM-P em 26 das 27 Unidades da Federação. O maior número de casos em crianças foi notificado em São Paulo (268), contudo, a maior incidência ocorreu no Distrito Federal (7,8/100 mil habitantes). A proporção de óbitos por SIM-P foi 5,4% em crianças e 8,7% em adolescentes. No período avaliado, houve 2.329 óbitos por Covid-19 em menores de 20 anos de idade, com maior taxa em adolescentes (4,4/100 mil habitantes) do que em crianças (2,7/100 mil habitantes), com maiores taxas em Roraima. Recomenda-se intensificação da imunização contra Covid-19 nessa população, aumentando a proteção contra os efeitos negativos dessa doença e da SIM-P, que podem apresentar consequências em curto, médio e/ou longo prazo, de modo a não comprometer a inserção plena destes cidadãos na sociedade.

The clinical characteristics of pediatric coronavirus disease 2019 in 2020 in Japan

BACKGROUND

The COVID-19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms.

METHODS

We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID-19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society.

RESULTS

Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID-19-positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID-19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively).

CONCLUSIONS

COVID-19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID-19 among children.

IVIG Compared With IVIG Plus Infliximab in Multisystem Inflammatory Syndrome in Children

OBJECTIVES

To compare initial treatment with intravenous immunoglobulin (IVIG) versus IVIG plus infliximab in multisystem inflammatory syndrome in children (MIS-C).

METHODS

Single-center retrospective cohort study of patients with MIS-C who met Centers for Disease Control and Prevention criteria and received treatment from April 2020 to February 2021. Patients were included and compared on the basis of initial therapy of either IVIG alone or IVIG plus infliximab. The primary outcome was need for additional therapy 24 hours or more after treatment initiation.

RESULTS

Seventy-two children with MIS-C met inclusion criteria. Additional therapy was needed in 13 of 20 (65%) who received IVIG alone and 16 of 52 (31%) who received IVIG plus infliximab (P = .01). The median (interquartile range) ICU lengths of stay were 3.3 (2.2 to 3.8) and 1.8 (1.1 to 2.1) days, respectively (P = .001). New or worsened left ventricular dysfunction developed in 4 of 20 (20%) and 2 of 52 (4%) (P = .05), and new vasoactive medication requirement developed in 3 of 20 (15%) and 2 of 52 (4%), respectively (P = .13). The median percentage changes in the C-reactive protein level at 24 hours posttreatment compared with pretreatment were 0% (-29% to 66%) and -46% (-62% to -15%) (P < .001); and at 48 hours posttreatment, -5% (-41% to 57%) and -70% (-79% to -49%) respectively (P < .001). There was no significant difference in hospital length of stay, time to fever resolution, vasoactive medication duration, or need for diuretics.

CONCLUSIONS

Patients with MIS-C initially treated with IVIG plus infliximab compared with those treated with IVIG alone were less likely to require additional therapy and had decreased ICU length of stay, decreased development of left ventricular dysfunction, and more rapid decline in C-reactive protein levels.

Multisystem inflammatory syndrome in children and Kawasaki disease: a critical comparison

Children and adolescents infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are predominantly asymptomatic or have mild symptoms compared with the more severe coronavirus disease 2019 (COVID-19) described in adults. However, SARS-CoV-2 is also associated with a widely reported but poorly understood paediatric systemic vasculitis. This multisystem inflammatory syndrome in children (MIS-C) has features that overlap with myocarditis, toxic-shock syndrome and Kawasaki disease. Current evidence indicates that MIS-C is the result of an exaggerated innate and adaptive immune response, characterized by a cytokine storm, and that it is triggered by prior SARS-CoV-2 exposure. Epidemiological, clinical and immunological differences classify MIS-C as being distinct from Kawasaki disease. Differences include the age range, and the geographical and ethnic distribution of patients. MIS-C is associated with prominent gastrointestinal and cardiovascular system involvement, admission to intensive care unit, neutrophilia, lymphopenia, high levels of IFNγ and low counts of naive CD4⁺ T cells, with a high proportion of activated memory T cells. Further investigation of MIS-C will continue to enhance our understanding of similar conditions associated with a cytokine storm.

Impact of Social Distancing on Kawasaki Disease-associated Hospitalization, South Korea

We conducted a cohort study to estimate the impact of social distancing on incidence of Kawasaki disease (KD) in Korean children, using the nationally representative data. The KD-related hospitalization rate has declined significantly from -38.8% (April) to 81.7% (June). The decrease in diagnosis of KD adds clue for infectious etiology of KD and the establishment of preventive measures.

Clinical features of multisystem inflammatory syndrome in children

PURPOSE OF REVIEW

To review diagnosis, clinical characteristics and treatment of multisystem inflammatory syndrome in children (MIS-C) associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RECENT FINDINGS

MIS-C emerged in spring 2020 as a hyperinflammatory syndrome following SARS-CoV-2 exposure in children. Despite growing awareness of MIS-C, diagnosis remains challenging due to the range of phenotypes and severity. Fever accompanied by shock, cardiac dysfunction, gastrointestinal symptoms, or mucocutaneous signs suggestive of Kawasaki disease, especially in the presence of known or suspected coronavirus disease 2019 exposure, should trigger consideration of MIS-C. However, clinical presentations are highly varied and may overlap with other infectious diseases. Clinicians must maintain a high index of suspicion for MIS-C and be aware that patients may develop coronary artery aneurysms and myocarditis even with few or no Kawasaki disease symptoms. More precise diagnostic criteria and specific biomarkers are needed to aid diagnosis. Intravenous immunoglobulin (IVIG) is first-line therapy, and steroids should be considered as initial adjunctive treatment for patients with severe manifestations or other risk factors. Prompt treatment is essential, as patients may worsen acutely, though overall prognosis is reassuring.

SUMMARY

MIS-C associated with SARS-CoV-2 has varied clinical manifestations. Clinicians must be aware of the common presentation and potential for decompensation and cardiac sequalae to guide appropriate evaluation and treatment.

Epidemiology and Clinical Features of Myocarditis/Pericarditis before the Introduction of mRNA COVID-19 Vaccine in Korean Children: a Multicenter Study

BACKGROUND

Korean health authority plans to vaccinate adolescents against coronavirus disease 2019 (COVID-19) starting high school seniors during the summer vacation of 2021. However, the myocarditis/pericarditis following COVID-19 vaccine has been reported recently in adolescents and young adults. This study was performed to answer the urgent questions about the basic epidemiology and clinical course of myocarditis/pericarditis in hospitalized patients prior to the introduction of COVID-19 vaccines in pediatric population.

METHODS

A retrospective medical record analysis including frequency, clinical characteristics, etiology and outcome of myocarditis/pericarditis was conducted in 17 years and younger patients who were hospitalized in two referral hospitals in Korea between 2010 and 2019.

RESULTS

Total 142 patients with myocarditis (n = 119) and/or pericarditis (n = 23) were identified. Median age was 5.4 years (interquartile range, 0.6-12.9 years; range, 11 days-17.8 years), and male was 61%. In adolescents aged 12-17 years, the male to female ratio was 3.2. Myocarditis/pericarditis occurred 0.70 per 1,000 in-patients during the study period: 0.96 (< 1 year), 0.50 (1-5 years), 0.67 (6-11 years) and 1.22 (12-17 years) per 1,000 in-patients, respectively. There was an increasing tendency for the annual frequency from 0.34 in 2010 to 1.25 per 1,000 in-patients in 2019 (P = 0.021). Among the 56 (40%) proven pathogens at admission, Mycoplasma pneumoniae (n = 11, 8%) and enterovirus (n = 10, 7%) were most common. Of the 142 patients, 99 (70%) required pediatric intensive care unit care and 10 (7%) received heart transplantation. In addition, 61 patients (61/131, 47%) without heart medication at admission needed heart medication when they were discharged. Eleven (7.7%) patients died, of which five patients were previously healthy. The median age of deceased patients was lower than the survival group (0.8 vs. 6.3 years, P = 0.014).

CONCLUSION

The frequency of myocarditis/pericarditis was highest among male adolescent in-patients; however, the outcome was favorable in this group without any mortality.

Pediatric Kawasaki Disease Trends Prior to and During COVID-19 Outbreak in Singapore

Kawasaki disease (KD, typical/atypical/partial) admissions (n = 644) were surveyed from 2017 to 2020 and compared to urinary tract infection (UTI) admissions and COVID-19 in 2020. KD admissions decreased by 27% and median KD age decreased in 2020, whereas UTI admissions remained steady. KD admissions showed a seasonality with a peak in April and nadir in February-March. All KD/KD-related pediatric intensive care unit cases tested negative for COVID-19, and no multisystem inflammatory syndrome in children was found.

Public Health Interventions for COVID-19 Reduce Kawasaki Disease in Taiwan

Background: Kawasaki disease (KD) is a syndrome of unknown cause that results in high fever and coronary vasculitis in children. The incidence of KD increased in Taiwan over the past few decades. Taiwanese government executed domains of early screening, effective methods for isolation or quarantine, and digital technologies for identifying potential cases for the early elimination strategy for coronavirus disease 2019 (COVID-19) and public health interventions for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 pandemic, leading to an effective reduction of the risk of airway infections in children. The purpose of this study is to analyze whether those public health interventions reduce the incidence of KD in 2020. Methods: Patients with KD who visited Chang Gung Memorial Hospital (CGMH) between 1 January, 2018, and 31 December, 2020 were included for trend analysis. This is a retrospective case series study conducted at the CGMH, which consists of a network of seven hospital branches equipped with more than 10,000 beds in different areas of Taiwan. Results: Compared with the 2018 and 2019 databases, the incidence of KD decreased significantly by 30% and 31%, respectively (p < 0.05) in 2020, when public health interventions were comprehensively implemented in Taiwan. This result shows that the incidence of KD decreased during the COVID-19 pandemic in Taiwan without change of the presentation KD (typical or incomplete) and percentage of IVIG resistance in 2020. Conclusion: As public health interventions were carried out for the SARS-CoV-2 pandemic, the incidence of KD was significantly reduced in Taiwan. Is KD a preventable disease?

A case of multisystem inflammatory syndrome in children in a Japanese boy: with discussion of cytokine profile

The new disease concept of multisystem inflammatory syndrome in children (MIS-C), which is a systemic inflammatory syndrome with multiple organ involvement after SARS-CoV2 infection, was established in 2020. MIS-C is common in Hispanic and black children in Europe and North America, with few reports in East Asians. A significant portion of patients with MIS-C develop Kawasaki disease (KD)-like symptoms. Therefore, differential diagnosis is challenging, especially in East Asia, where KD is most prevalent. No Japanese cases have been reported in the literatures so far. We report a case of MIS-C in Japan with KD-like symptoms. A 9-year-old Japanese boy, who was infected with SARS-CoV2 1 month previously along with his family, was admitted to our hospital owing to fever for 6 d and erythema mainly in the groyne and pubic area. He also had conjunctivitis, strawberry tongue and diarrhoea. His laboratory findings were as follows: WBC, 12,840/µL (lymphocytes, 4%); CRP, 22.6 mg/dL, pro-calcitonin, 1.8 ng/mL (normal, <0.50 ng/mL); NT pro-BNP, 7627 pg/mL (<125 pg/mL); and troponin T, 0.14 ng/mL (<0.01 ng/mL). His cardiac function was normal. We initially diagnosed him with KD. His fever rapidly resolved with intravenous immunoglobulin (IVIG) and there were no coronary artery lesions. Desquamation of the fingers was observed later. Finally, a history of SARS-COV2 infection, his age, atypical skin rash, elevation of markers of inflammation and heart failure and lymphopenia suggested the diagnosis of MIS-C rather than KD. Differentiation between KD and MIS-C is necessary even in Japan, especially in patients with atypical features of KD.

Similarities and differences between multiple inflammatory syndrome in children associated with COVID-19 and Kawasaki disease: clinical presentations, diagnosis, and treatment

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been spreading rapidly around the world, while "multisystem inflammatory syndrome in children" (MIS-C) is a new type of syndrome that has now been reported in many countries. Similar and different characteristics between KD and MIS-C have been reported in a variety of literature. We aimed to focus on reviewing clinical presentations, diagnosis, and treatment of KD and MIS-C.

METHODS

We searched articles in the electronic databases, including the Cochrane Library database, EMBASE, and MEDLINE with the keywords "multiple inflammatory syndrome" and/or "COVID-19" and/or "Kawasaki disease" and "children".

RESULTS

Main presentations of MIS-C and KD include fever, rashes, mucous membrane involvement, conjunctivitis, hands and feet erythema/edema, and cervical lymphadenopathy. However, compared with the highest incidence of KD among some Asian countries, MIS-C is common among Black and Hispanic children. MIS-C is common in older children and teenagers, whereas classic KD is common in children under five years of age. Gastrointestinal symptoms, shock, and coagulopathy are common in MIS-C patients but are not common in classic KD. Cardiac manifestations are more common than KD, including myocarditis with cardiac dysfunction and coronary artery dilation or aneurysms. Severe cases in MIS-C present with vasodilated or cardiogenic shock that requires fluid resuscitation, muscular support, and even mechanical ventilation and extracorporeal membrane oxygenation (ECMO), whereas KD rarely presents with these manifestations and requires these treatments. Increased serum ferritin, leukopenia, lymphopenia and thrombocytopenia are common in MIS-C. However, thrombocytosis is a characteristic feature of KD. Intravenous immunoglobulin (IVIG) and moderate-high dose aspirin are still a standard recommended treatment for KD. In addition to the above-mentioned medications, steroids and biological drugs are frequently used in patients with MIS-C. Most of the children with KD have a good prognosis; however, the long-term clinical outcomes of MIS-C are not clear.

CONCLUSIONS

The overall presentation and treatment of MIS-C appear to overlap with KD. However, there are still great differences between the syndromes, and it is controversial to say whether MIS-C is a new entity or is a "severe type" of KD.

Case Report: Changes in Cytokine Kinetics During the Course of Disease in a Japanese Patient With Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a severe disease that is reportedly linked to coronavirus disease 2019. Affected patients present with gastrointestinal symptoms and cardiovascular dysfunction, in addition to Kawasaki disease-like features, suggesting the potential for overlapping disease mechanisms. Kawasaki disease has been reported among individuals of East Asian ethnicities, whereas there is minimal clinical literature regarding the occurrence of MIS-C among individuals of Asian ethnicities. A few reports thus far have described changes in cytokine kinetics during the course of disease in patients with MIS-C. We followed the temporal cytokine kinetics in a 9-year-old Japanese girl who exhibited a classical trajectory of MIS-C. The patient exhibited right cervical swelling and pain, abdominal pain, vomiting, and lip reddening, which developed 31 days after she was diagnosed with severe acute respiratory syndrome coronavirus-2 infection. The patient was diagnosed with Kawasaki disease on her fifth day of illness; because she fulfilled the criteria for MIS-C, she was also diagnosed with this disease on her fifth day of illness. Her fever rapidly resolved upon administration of intravenous immunoglobulin, aspirin, and prednisolone. On the patient's sixth day of illness, she developed acute myocarditis, which was treated with two diuretics and one vasodilator; the myocarditis ameliorated within a few days. Analyses of temporal kinetics for 71 serum cytokines revealed several patterns of cytokine changes that were consistent with the patient's clinical course of disease. Importantly, there was a clear distinction between cytokines that did and did not decrease rapidly following post-treatment fever resolution. These findings may be useful for the assessment of disease status and selection of therapy in patients with similar symptoms; they may also provide insights for basic and clinical research regarding MIS-C.