American College of Rheumatology Clinical Guidance for Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Hyperinflammation in Pediatric COVID-19: Version 3

Mapping the vast landscape of multisystem complications of COVID-19: Bibliometric analysis

Background

With the rapid global spread of COVID-19, it has become evident that the virus can lead to multisystem complications, leading to a significant increase in related publications. Bibliometrics serves as a valuable tool for identifying highly cited literature and research hotspots within specific areas.

Objective

The aim of this study is to identify current research hotspots and future trends in COVID-19 complications.

Methods

The dataset was obtained from the Web of Science Core Collection, covering COVID-19 complications from December 8, 2019, to October 31, 2022. Various aspects, including publication general information, authors, journals, co-cited authors, co-cited references, research hotspots, and future trends, were subjected to analysis. Visual analysis was conducted using VOSviewer, The Online Analysis Platform of Literature Metrology, and Charticulator.

Results

There were 4597 articles in the study. The top three countries with the most published articles are the USA (n = 1350, 29.4 %), China (n = 765, 16.6 %), and Italy (n = 623, 13.6 %). USA and China have the closest collaborative relationship. The institute with the largest number of publications is Huazhong University of Science and Technology, followed by Harvard Medical School. Nevertheless, half of the top 10 institutes belong to the USA. "Rezaei, Nima" published 13 articles and ranked first, followed by "Yaghi, Shadi" with 12 articles and "Frontera, Jennifer" with 12 articles. The journal with the largest number of publications is "Journal of Clinical Medicine". The top 3 co-cited authors are "Zhou, Fei", "Guan, Wei-Jie", "Huang, Chaolin". The top 3 co-cited references addressed COVID-19's clinical features in China and noticed that COVID-19 patients had a wide range of complications. We also list four research hotspots.

Conclusions

This study conducted a bibliometric visual analysis of the literature on COVID-19 complications and summarized the current research hotspots. This study may provide valuable insights into the complications of COVID-19.

Multisystem inflammatory syndrome in children: A review

AIM

To comprehensively review the literature on multisystem inflammatory syndrome in children (MIS-C).

METHODS

Narrative review of relevant studies published between April 2020 and January 2024.

RESULTS

MIS-C is a SARS-CoV-2-related hyperinflammatory syndrome developing 2-6 weeks after COVID-19 in genetically susceptible individuals. Persisting fever, mucocutaneous manifestations, GI and cardiac involvement, together with lymphopenia and elevated inflammatory and cardiac markers are the main clinical features. It is believed to recognise some pathogenetic and clinical overlap with Kawasaki disease. New case definitions have been proposed after an assessment of the diagnostic performance of existing criteria; epidemiological criterion is however progressively losing its usefulness as the pandemic turns into an endemic and in the areas with the highest rates of COVID-19 vaccination. Current guidelines recommend both intravenous immunoglobulin and glucocorticoids in the first-line immunomodulatory treatment, mainly based on comparative retrospective cohorts; the actual role of biologics remains to be adequately established. Strict follow-up is mandatory, especially for those with severe cardiac involvement, as longitudinal studies evaluate the long-term evolution of cardiac damage.

CONCLUSION

In this paper, we review the epidemiological, pathogenetic, clinical and prognostic features of MIS-C, and outline the main questions which still remain unanswered after more than 3 years of research.

Cardiovascular involvement in children with COVID-19 temporally related multisystem inflammatory syndrome (MIS-C): can cardiac magnetic resonance arrive to the heart of the problem?

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) shows a significant overlap of symptoms with other hyper-inflammatory diseases such as Kawasaki disease (KD), but the real difference of the two conditions is still matter of debate. Coronary artery lesions (CAL) are the most relevant complication in KD. Nonetheless, CAL, myocarditis, pericarditis, arrhythmia are the main cardiovascular complications in MIS-C. A close clinical assessment is mandatory, both at the diagnosis and during the follow-up, by ECG and echocardiography. Cardiac magnetic resonance (MRI) adds important data to ultrasound findings. However, cardiac MRI studies in MIS-C are limited to a small number of cohorts.

METHODS

We enrolled 20 children (age:1-16 years; 11 F; 9 M) with cardiac involvement secondary to MIS-C, all evaluated by cardiac MRI.

RESULTS

8 children showed pathological cardiac MRI: 2 showed pericardial effusion; 2 showed myocardial oedema; 1 showed aortic insufficiency; 3 showed delayed enhancement (one for acute myocarditis with oedema; 2 for myocardial fibrosis). Delayed enhancement was reduced significantly 5.6-9 months after the first MRI evaluation. 25% of patients with pathological MRI had CAL associated with valvular insufficiency of 2 valves. 17% of patients with normal MRI had CAL, associated with valvular insufficiency of 1 valve in 1 patient. The correlations between haematological, clinical, cardiologic parameters, treatment, did not reach the statistical significance. 4 patients were treated with anakinra. Among those, 2 patients showed a normal cardiac MRI. Cardiac lesions resolved in all the patients during the follow-up. Some patients with pathological cardiac MRI could not underwent a control with MRI, for the low compliance. However, echocardiography and ECG, documented the resolution of the pathological data in these cases.

CONCLUSIONS

A higher risk of CAL was documented in patients with an association of other cardiac lesions. Cardiac MRI is difficult to perform routinely; however, it is useful for evaluating the acute myocardial damage and the outcome of patients with MIS-C.

Treatment of multisystem inflammatory syndrome in children

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C), a relatively uncommon but severe pediatric complication, is associated with coronavirus disease 2019 (COVID-19). A variety of treatment approaches, including intravenous immunoglobulins (IVIGs), glucocorticoids (GCs) and biologic agents, such as anakinra and infliximab, have been described for the management of COVID-19-related MIS-C. Anticoagulant therapy is also important. However, a well-developed treatment system has not been established, and many issues remain controversial. Several recently published articles related to the treatment of MIS-C have been released. Hence, in this review, we identified relevant articles published recently and summarized the treatment of MIS-C more comprehensively and systematically.

DATA SOURCES

We reviewed the literature on the treatment of MIS-C through 20 September 2023. The PubMed/Medline, Web of Science, EMBASE, and Cochrane Library databases were searched with the combination of the terms "multisystem inflammatory syndrome", "MIS-C", "PIMS-TS", "therapy", "treatment", "drug", "IVIG", "GCs", "intravenous immunoglobulin", "corticosteroids", "biological agent", and "aspirin".

RESULTS

The severity of MIS-C varies, and different treatment schemes should be used according to the specific condition. Ongoing research and data collection are vital to better understand the pathophysiology and optimal management of MIS-C.

CONCLUSIONS

MIS-C is a disease involving multiple systems and has great heterogeneity. With the accumulation of additional experience, we have garnered fresh insights into its treatment strategies. However, there remains a critical need for greater standardization in treatment protocols, alongside the pressing necessity for more robust and meticulously conducted studies to deepen our understanding of these protocols. Supplementary file1 (MP4 208044 kb).

Multisystem inflammatory syndrome in children (MIS-C): A nationwide collaborative study in the Greek population

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe hyperinflammatory condition that may occur following SARS-CoV-2 infection. This retrospective, descriptive study of children hospitalized with multisystem inflammatory syndrome in children (MIS-C) in 12 tertiary care centers from 3/11/2020 to 12/31/2021. Demographics, clinical and laboratory characteristics, treatment and outcomes are described. Among 145 patients (95 males, median age 8.2 years) included, 123 met the WHO criteria for MIS-C, while 112 (77%) had serological evidence of SARS-CoV-2 infection. Fever was present in 99%, gastrointestinal symptoms in 77%, mucocutaneous involvement in 68% and respiratory symptoms in 28%. Fifty-five patients (38%) developed myocarditis, 29 (20%) pericarditis and 19 (13%) coronary aneurysms. Among the above cases 11/55 (20%), 1/29 (3.4%) and 5/19 (26.3%), respectively, cardiac complications had not fully resolved at discharge. Underlying comorbidities were reported in 18%. Median CRP value was 155 mg/l, ferritin 535 ng/ml, PCT 1.6 ng/ml and WBC 14.2 × 109/mm3. Most patients had elevated troponin (41.3%) and/or NT-pro-BNP (49.6%). Intravenous immunoglobulin plus corticosteroids were used in 117/145 (80.6%), monotherapy with IVIG alone in 13/145 (8.9%) and with corticosteroids alone in 2/145 (1.3%). Anti-IL1 treatment was added in 15 patients (10.3%). Thirty-three patients (23%) were admitted to the PICU, 14% developed shock and 1 required ECMO. Mortality rate was 0.68%. The incidence of MIS-C was estimated at 0.69/1000 SARS-CoV-2 infections. Patients who presented with shock had higher levels of NT-pro-BNP compared to those who did not (p < 0.001). Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

CONCLUSION

MIS-C is a novel, infrequent but serious disease entity. Cardiac manifestations included myocarditis and pericarditis, which resolved in most patients before discharge. Timely initiation of immunomodulatory therapy was shown to be effective. NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. Further research is required to elucidate the pathogenesis, risk factors and optimal management, and long-term outcomes of this clinical entity.

WHAT IS KNOWN

• MIS-C is an infrequent but serious disease entity. • Patients with MIS-C present with multi-organ dysfunction, primarily involving the gastrointestinal and cardiovascular systems.

WHAT IS NEW

• NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. • Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

Multisystem inflammatory syndrome in children associated with COVID-19: from pathophysiology to clinical management and outcomes

Multisystem inflammatory syndrome in children (MIS-C), also known as pediatric inflammatory multisystem syndrome (PIMS), is a new postinfectious illness associated with COVID-19, affecting children after SARS-CoV-2 exposure. The hallmarks of this disorder are hyperinflammation and multisystem involvement, with gastrointestinal, cardiac, mucocutaneous, and hematologic disturbances seen most commonly. Cardiovascular involvement includes cardiogenic shock, ventricular dysfunction, coronary artery abnormalities, and myocarditis. Now entering the fourth year of the pandemic, clinicians have gained some familiarity with the clinical presentation, initial diagnosis, cardiac evaluation, and treatment of MIS-C. This has led to an updated definition from the Centers for Disease Control and Prevention in the USA driven by increased experience and clinical expertise. Furthermore, the available evidence established expert consensus treatment recommendations supporting a combination of immunoglobulin and steroids. However, the pathophysiology of the disorder and answers to what causes this remain under investigation. Fortunately, long-term outcomes continue to look promising, although continued follow-up is still needed. Recently, COVID-19 mRNA vaccination is reported to be associated with reduced risk of MIS-C, while further studies are warranted to understand the impact of COVID-19 vaccines on MIS-C. We review the findings and current literature on MIS-C, including pathophysiology, clinical features, evaluation, management, and medium- to long-term follow-up outcomes.

NT-proBNP course during MIS-C post-COVID-19: an observational study

Multisystem inflammatory syndrome in children (MIS-C or PIMS-TS) is a severe disease. N-terminal pro-B-type natriuretic peptide (NT-proBNP) is used for positive and differential diagnosis, diagnosis of complications and severity, and cardiogenic shock prediction. However, contrasting cut-offs have been suggested. The aims of the present study were to compare NT-proBNP values depending on the time of measurement and to describe the NT-proBNP course during the MIS-C episode. The data from a single-centre cohort observational study on the impact of time to diagnosis, defined as the time from first symptom to diagnosis of MIS-C, were used for the purpose of this study, with an extended period of inclusion from May 2020 to April 2023. The timing and level of all NT-proBNP samples available for each patient were retrospectively collected. Thirty-seven children (18 (49%) females, median age 8.8 years, 14 (38%) with shock) were included. Until diagnosis, NT-proBNP increased with time and was significantly higher at 6 days from first symptoms than at 3 days (median (interquartile range) 32,933 (7773-61,592) versus 1994 (1291-4190) pg/mL, respectively, p = 0.031). From diagnosis, NT-proBNP decreased by at least 50% after 3.0 (2.1-5.3) days (n = 12) when NT-proBNP at diagnosis was low ≤ 11,000 pg/mL versus 1.8 (0.7-3.4) days (n = 16) when NT-proBNP at diagnosis was high (p = 0.040), and after 3.6 (2.4-5.9) days (n = 7) when fever persisted after 48 h versus 1.8 (0.8-3.0) days (n = 21) when fever resolved before 48 h (p = 0.004).  Conclusions: During the MIS-C episode, NT-proBNP increased over time until diagnosis and treatment. It dropped faster thereafter in children with high NT-proBNP at diagnosis > 11,000 pg/mL and slower in case of persistent fever. What is Known: • NT-proBNP is useful in MIS-C for positive and differential diagnosis, diagnosis of complications and severity, and cardiogenic shock prediction. • Contrasting cut-offs for differential diagnosis and severity assessment have been suggested. What is New: • Before diagnosis, NT-proBNP increases with time and is significantly higher at 6 days from first symptoms than at 3 days suggesting different cut-offs depending on the timing of measurement. • From diagnosis and treatment initiation, the 50% NT-proBNP drop occurs earlier in children with high NT-proBNP at diagnosis > 11,000 pg/mL and later in children with persistent fever.

Epidemiological and clinical evolution of multisystem inflammatory syndrome in children throughout the SARS-CoV-2 pandemic in a tertiary Italian children's hospital

Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening disease temporally linked to SARS-CoV-2 whose incidence and clinical presentation may have been altered by the different SARS-CoV-2 variants and by vaccination.

METHODS

We retrospectively collected the data of all MIS-C cases admitted to the Gaslini Children's Hospital, the hub for SARS-CoV-2 related diseases in Liguria region, Italy, from 01 October 2020, to 30 November 2022, evaluating the ratio between MIS-C cases and (1) COVID-19 paediatric cases in our region, (2) emergency department admissions and (3) emergency department febrile patients. We also compared MIS-C incidence in pre- post-vaccination periods.

RESULTS

We observed a significant global decline in the incidence of MIS-Cover the four variant periods and after the starting of vaccination whereas clinical features, therapeutic management and severity did not significantly vary.

CONCLUSIONS

In our setting, we demonstrated a significant decrease of MIS-C incidence according to the predominant variant and including not vaccinated children. Regardless of variant type, the patients showed similar phenotypes and severity throughout the pandemic. SARS-CoV-2 variants as well as immune protection after previous infections and/or vaccination may have interacted by playing different roles and reducing the incidence of MIS-C.

COVID-19 Associated Cardiovascular Disease-Risks, Prevention and Management: Heart at Risk Due to COVID-19

The SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) virus and the resulting COVID-19 pandemic have had devastating and lasting impact on the global population. Although the main target of the disease is the respiratory tract, clinical outcomes, and research have also shown significant effects of infection on other organ systems. Of interest in this review is the effect of the virus on the cardiovascular system. Complications, including hyperinflammatory syndrome, myocarditis, and cardiac failure, have been documented in the context of COVID-19 infection. These complications ultimately contribute to worse patient outcomes, especially in patients with pre-existing conditions such as hypertension, diabetes, or cardiovascular disease (CVD). Importantly and interestingly, reports have demonstrated that COVID-19 also causes myocardial injury in adults without pre-existing conditions and contributes to systemic complications in pediatric populations, such as the development of multisystem inflammatory syndrome in children (MIS-C). Although there is still a debate over the exact mechanisms by which such complications arise, understanding the potential paths by which the virus can influence the cardiovascular system to create an inflammatory environment may clarify how SARS-CoV-2 interacts with human physiology. In addition to describing the mechanisms of disease propagation and patient presentation, this review discusses the diagnostic findings and treatment strategies and the evolution of management for patients presenting with cardiovascular complications, focusing on disease treatment and prevention.

Subcutaneous anakinra in the management of refractory MIS-C in France

Introduction

Multisystemic inflammatory syndrome in children (MIS-C) is a therapeutic emergency and can lead to myocardial dysfunction (17%-75%) and heart failure (52%-53%). Intravenous immunoglobulins (IVIG) and corticosteroids (CST) have been validated for the management of this condition. Recent reports suggest that an interleukin-1 (IL-1) receptor antagonist, namely anakinra, may be a valuable add-on to the 2019 novel coronavirus disease (COVID-19) treatment for refractory patients. The purpose of this study was to describe the clinico-biological characteristics of patients treated with anakinra as well as the efficacy and safety of subcutaneous anakinra therapy in this condition.

Methods

The prospective multicentre study of children hospitalized for MIS-C between March 2020 and September 2022, including 23 international paediatric centres, followed for a mean duration of 3.072 ± 3.508 months. The patient data were extracted from the Juvenile Inflammatory Rheumatism (JIR) cohort. The clinico-pathological characteristics, cardiac ultrasound data, and adverse events were reported in patients receiving anakinra.

Results

Of the 470 children admitted with MIS-C, 18 French patients (50% girls) with a mean age of 10.06 ± 3.9 years were treated with subcutaneous anakinra. Anakinra was used in two situations, macrophage activation syndrome (MAS) (4 patients) and heart failure (14 patients) with a median left ventricular ejection fraction (LVEF) of 39.5% (30%-45%). The average dose of anakinra received was 2.53 ± 1.3 mg/kg/day for a median duration of 3 days. Prior to introduction, 78% (n = 14/18) of the patients had received CST and 56% (n = 10/18) had received IVIG. Only two patients received IVIG alone and six received CST alone plus anakinra. In 10% of cases, IVIG was poorly tolerated from a cardiovascular point of view and was discontinued. Transient elevations in serum transaminases were noted in four patients on anakinra without the need for treatment or dose modification. In all patients, rapid (48 h) improvement in myocardial function was observed (LVEF > 55%) with a concomitant significant decrease in myocardial enzymes (p < 0.05). All patients survived with complete recovery of cardiac function without sequelae.

Conclusions

Subcutaneous anakinra appears to be a safe and effective treatment for the management of heart failure or MAS in MIS-C patients. The value of IVIG in these two situations remains to be reviewed.

IL-1RA autoantibodies: insights into mechanisms and associated diseases

The association of neutralizing autoantibodies targeting interleukin-1 receptor antagonist (IL-1RA) with multisystem inflammatory syndrome, IgG4-related disease, and vaccine-related myocarditis is increasingly recognized. The detection of IL-1RA autoantibodies can be notably affected by the techniques and methods employed. Two categories of assays are available: solid-phase immunoassays, which detect binding of IL-1RA autoantibodies, and functional IL-1 signaling reporter cell assays, which offer greater specificity by determining whether circulating autoantibodies can impede interleukin (IL)-1β signal transduction pathways. It is as yet unclear why only a minority of individuals produce pathogenic anti-IL-1RA autoantibodies in response to coronavirus disease 2019 (COVID19) or vaccination. This review article discusses our current knowledge of the process of IL-1RA autoantibody generation, the underlying pathogenesis, detection, and potential treatment strategies for associated diseases.

Early anakinra treatment improves cardiac outcome of multisystem inflammatory syndrome in children, regardless of disease severity

OBJECTIVE

The main aim of this study was to define the best treatment option for multisystem inflammatory syndrome in children (MIS-C) and to analyse the role of anakinra.

METHODS

This is a multicentre retrospective cohort study. Patients were treated according to the attending physician's decision. The patients were divided into four groups on the basis of the first treatment at time of admittance: (i) IVIG, (ii) IVIG and methylprednisolone (≤2 mg/kg/day), (iii) IVIG with high-dose methylprednisolone (>2 mg/kg/day) and (iv) anakinra with or without IVIG and/or methylprednisolone. Primary outcomes were defined as the presence of at least one of the following features: death, the failure of initial treatment, meaning the need for additional treatment for clinical worsening and cardiac involvement at the end of follow-up.

RESULTS

Two hundred thirty-nine patients were recruited. At univariate analysis, persistent heart involvement at discharge was more frequent in those not receiving anakinra as initial treatment (3/21 vs 66/189; P = 0.047). After comparisons between the four treatment regimens, adjusting for the propensity score, we observed that early treatment with anakinra was associated with a lower probability of developing persistent heart disease at the end of follow-up (odds ratio: 0.6; 95% CI: 0.4-1.0).

CONCLUSION

We report that early treatment with anakinra is safe and very effective in patients with severe MIS-C. In addition, our study suggests that early treatment with anakinra is the most favourable option for patients with a higher risk of developing a severe disease outcome.

One-Year Follow-Up Results of MIS-C Patients with Coronary Artery Involvement: A Multi-center Study

Multisystem inflammatory syndrome (MIS-C) in children is a rare complication of SARS-CoV-2 infection. Knowing the course of the affected or unaffected coronary arteries in the patients under follow-up is important in terms of defining the long-term prognosis of the disease and determining the follow-up plan. This is a multicenter and retrospective study. The data were obtained from nine different centers. Between May 2020 and August 2022, 68 of 790 patients had coronary artery involvement. One-year echocardiographic data of 67 of 789 MIS-C patients with coronary artery involvement were analyzed. Existing pathologies of the coronary arteries were grouped as increased echogenicity, dilatation and aneurysm according to Z scores, and their changes over a 1-year period were determined. The data of all three groups are defined as frequency. SPSS Statistics version 22 was used to evaluate the data. In our study, aneurysm was observed in 16.4%, dilatation in 68.7% and increased echogenicity in 13.4% of the patients. All of the patients with involvement in the form of increased echogenicity recovered without sequelae by the end of the first month. No progression to aneurysm was observed in any of the patients with dilatation. No new-onset involvement was observed in patients with previously healthy coronary arteries during the convalescent period. In addition, from the sixth month follow-up period, there was no worsening in the amount of dilatation in any of the patients. At least 94% of the patients who completed the 12th month control period returned to normal.

New insight into the intravenous immunoglobulin treatment in Multisystem Inflammatory Syndrome in children and adults

Within 6 months of the coronavirus pandemic, a new disease entity associated with a multisystem hyperinflammation syndrome as a result of a previous infection with the SARS-CoV-2 virus is increasingly being identified in children termed Multisystem Inflammatory Syndrome in Children (MIS-C) and more recently in adults(MIS-A). Due to its clinical similarity with Kawasaki Disease, some institutions have used intravenous immunoglobulins and steroids as first line agents in the management of the disease. We seek to find how effective intravenous immunoglobulin therapy is across these two disease entities. A comprehensive English literature search was conducted across PubMed, MEDLINE, and EMBASE databases using the keywords multisystem inflammatory syndrome in children/adults and treatment. All major online libraries concerning the diagnosis and treatment of MIS-C and MIS-A were searched. Relevant papers were read, reviewed, and analyzed. The use of intravenous immunoglobulins (IVIG) and steroids for the treatment of multisystemic inflammatory syndrome in children(MIS-C) is well established and recommended by multiple pediatric governing institutions. However, there is still no optimal treatment guideline or consensus on the use of IVIG in adults. The use of IVIG in both the child and adult populations may lower the risk of treatment failure and the need for adjunctive immunomodulatory therapy. Despite the promising results of IVIG use for the management of MIS-C and MIS-A, considering the pathophysiological differences between MIS-C and MIS-A, healthcare professionals need to further assess the differences in disease risk and treatment. The optimal dose, frequency, and duration of treatment are still unknown, more research is needed to establish treatment guidelines.

[Multisystem inflammatory syndrome in children in the context of coronavirus disease 2019 pandemic]

Multisystem inflammatory syndrome in children (MIS-C) is a complex syndrome characterized by multi-organ involvement that has emerged in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak. The clinical presentation of MIS-C is similar to Kawasaki disease but predominantly presents with fever and gastrointestinal symptoms, and severe cases can involve toxic shock and cardiac dysfunction. Epidemiological findings indicate that the majority of MIS-C patients test positive for SARS-CoV-2 antibodies. The pathogenesis and pathophysiology of MIS-C remain unclear, though immune dysregulation following SARS-CoV-2 infection is considered a major contributing factor. Current treatment approaches for MIS-C primarily involve intravenous immunoglobulin therapy and symptomatic supportive care. This review article provides a comprehensive overview of the definition, epidemiology, pathogenesis, clinical presentation, diagnosis, treatment, and prognosis of MIS-C.

"When," "Where," and "How" of SARS-CoV-2 Infection Affects the Human Cardiovascular System: A Narrative Review

Coronavirus disease 2019 (COVID-19) is caused by the novel severe acute respiratory coronavirus-2 (SARS-CoV-2). Several explanations for the development of cardiovascular complications during and after acute COVID-19 infection have been hypothesized. The COVID-19 pandemic, caused by SARS-CoV-2, has emerged as one of the deadliest pandemics in modern history. The myocardial injury in COVID-19 patients has been associated with coronary spasm, microthrombi formation, plaque rupture, hypoxic injury, or cytokine storm, which have the same pathophysiology as the three clinical variants of Kounis syndrome. The angiotensin-converting enzyme 2 (ACE2), reninaldosterone system (RAAS), and kinin-kallikrein system are the main proposed mechanisms contributing to cardiovascular complications with the COVID-19 infection. ACE receptors can be found in the heart, blood vessels, endothelium, lungs, intestines, testes, neurons, and other human body parts. SARS-CoV-2 directly invades the endothelial cells with ACE2 receptors and constitutes the main pathway through which the virus enters the endothelial cells. This causes angiotensin II accumulation downregulation of the ACE2 receptors, resulting in prothrombotic effects, such as hemostatic imbalance via activation of the coagulation cascade, impaired fibrinolysis, thrombin generation, vasoconstriction, endothelial and platelet activation, and pro-inflammatory cytokine release. The KKS system typically causes vasodilation and regulates tissue repair, inflammation, cell proliferation, and platelet aggregation, but SARS-CoV-2 infection impairs such counterbalancing effects. This cascade results in cardiac arrhythmias, cardiac arrest, cardiomyopathy, cytokine storm, heart failure, ischemic myocardial injuries, microvascular disease, Kounis syndrome, prolonged COVID, myocardial fibrosis, myocarditis, new-onset hypertension, pericarditis, postural orthostatic tachycardia syndrome, pulmonary hypertension, stroke, Takotsubo syndrome, venous thromboembolism, and thrombocytopenia. In this narrative review, we describe and elucidate when, where, and how COVID-19 affects the human cardiovascular system in various parts of the human body that are vulnerable in every patient category, including children and athletes.

Kawasaki Disease in the Time of COVID-19 and MIS-C: The International Kawasaki Disease Registry

BACKGROUND

Patients with multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) have overlapping clinical features. We compared demographics, clinical presentation, management, and outcomes of patients according to evidence of previous SARS-CoV-2 infection.

METHODS

The International Kawasaki Disease Registry (IKDR) enrolled KD and MIS-C patients from sites in North, Central, and South America, Europe, Asia, and the Middle East. Evidence of previous infection was defined as: Positive (household contact or positive polymerase chain reaction [PCR]/serology), Possible (suggestive clinical features of MIS-C and/or KD with negative PCR or serology but not both), Negative (negative PCR and serology and no known exposure), and Unknown (incomplete testing and no known exposure).

RESULTS

Of 2345 enrolled patients SARS-CoV-2 status was Positive for 1541 (66%) patients, Possible for 89 (4%), Negative for 404 (17%) and Unknown for 311 (13%). Clinical outcomes varied significantly among the groups, with more patients in the Positive/Possible groups presenting with shock, having admission to intensive care, receiving inotropic support, and having longer hospital stays. Regarding cardiac abnormalities, patients in the Positive/Possible groups had a higher prevalence of left ventricular dysfunction, and patients in the Negative and Unknown groups had more severe coronary artery abnormalities.

CONCLUSIONS

There appears to be a spectrum of clinical features from MIS-C to KD with a great deal of heterogeneity, and one primary differentiating factor is evidence for previous acute SARS-CoV-2 infection/exposure. SARS-CoV-2 Positive/Possible patients had more severe presentations and required more intensive management, with a greater likelihood of ventricular dysfunction but less severe coronary artery adverse outcomes, in keeping with MIS-C.

Severe acute respiratory syndrome coronavirus 2 infection rate among pediatric patients with respiratory symptoms

BACKGROUND

The incidence of coronavirus disease 2019 (COVID-19) in children has been increasing worldwide since the onset of the pandemic. This study examined the risk factors and characteristics of COVID-19 among pediatric patients compared to other respiratory viral infections.

METHODS

This was a prospective cross-sectional study. Patients aged 0-18 years presenting with respiratory symptoms from October 2020 to December 2021 were included. Demographic and clinical data were reviewed.

RESULTS

In total, 738 pediatric patients were enrolled. Of these, 48.5% had COVID-19, and 41.3% were infected with another respiratory virus. The COVID-19 incidence increased from 0.5% during the original strain outbreak (October 2020 to March 2021) to 56.5% and 73.4% during the alpha (April to June 2021) and delta (July to December 2021) periods, respectively. Children aged 6-18 years, being female, obesity, exposure to household members with COVID-19, and the delta period were risk factors for COVID-19. Being aged 1-5 years, obesity, shortness of breath, productive cough, and chest pain were associated with COVID-19 pneumonia. Children aged 5-18 years, underlying neurological disease, a history of COVID-19 pneumonia, and the delta period were associated with long COVID.

CONCLUSIONS

Pediatric COVID-19 patients presenting with respiratory symptoms who are obese or have been exposed to household members with COVID-19 should be tested for COVID-19. COVID-19 patients who are obese, younger than five years old, or who present with shortness of breath, productive cough, or chest pain should be evaluated for pneumonia. COVID-19 patients with a history of COVID-19 pneumonia or underlying neurological disease should receive follow-up for long COVID.

Emerging and re-emerging pediatric viral diseases: a continuing global challenge

The twenty-first century has been marked by a surge in viral epidemics and pandemics, highlighting the global health challenge posed by emerging and re-emerging pediatric viral diseases. This review article explores the complex dynamics contributing to this challenge, including climate change, globalization, socio-economic interconnectedness, geopolitical tensions, vaccine hesitancy, misinformation, and disparities in access to healthcare resources. Understanding the interactions between the environment, socioeconomics, and health is crucial for effectively addressing current and future outbreaks. This scoping review focuses on emerging and re-emerging viral infectious diseases, with an emphasis on pediatric vulnerability. It highlights the urgent need for prevention, preparedness, and response efforts, particularly in resource-limited communities disproportionately affected by climate change and spillover events. Adopting a One Health/Planetary Health approach, which integrates human, animal, and ecosystem health, can enhance equity and resilience in global communities. IMPACT: We provide a scoping review of emerging and re-emerging viral threats to global pediatric populations This review provides an update on current pediatric viral threats in the context of the COVID-19 pandemic This review aims to sensitize clinicians, epidemiologists, public health practitioners, and policy stakeholders/decision-makers to the role these viral diseases have in persistent pediatric morbidity and mortality.

Cardiac assessment and inflammatory markers in children with paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV2 (PIMS-TS) treated with methylprednisolone versus intravenous immunoglobulins: 6-month follow-up outcomes of the randomised controlled Swissped RECOVERY trial

Background

Previous findings from the Swissped RECOVERY trial showed that patients with Pediatric Inflammatory Multisystem Syndrome-Temporally Associated with SARS-CoV-2 (PIMS-TS) who were randomly assigned to intravenous immunoglobulins or methylprednisolone have a comparable length of hospital stay. Here, we report the 6-month follow-up outcomes of cardiac pathologies and normalisation of clinical or laboratory signs of inflammation from this study population.

Methods

This pre-planned follow-up of patients with PIMS-TS included the Swissped RECOVERY Trial reports on the 6-month outcomes of the cohort after randomisation, with a focus on cardiac, haematological, and biochemical findings. The trial was an investigator-initiated randomised multicentre open-label two-arm trial in children and adolescents hospitalised with PIMS-TS at ten hospitals in Switzerland. Cardiological assessments and laboratory analyses were prospectively collected in the intention-to-treat analysis on pre-defined intervals after hospital discharge. Differences between randomised arms were investigated using Chi-square test for categorical and Wilcoxon test for continuous variables. The trial is registered with the Swiss National Clinical Trials Portal (SNCTP000004720) and ClinicalTrials.gov (NCT04826588).

Findings

Between May 21, 2021 and April 15, 2022, 75 patients with a median age of 9.1 years (IQR 6.2-12.2) were included in the intention-to-treat population (37 in the methylprednisolone group and 38 in the intravenous immunoglobulin group). During follow-up, the incidence of abnormal left ventricular systolic function, coronary artery aneurysms (CAA), and other signs of inflammation were comparable in both groups. However, we detected cardiac abnormalities with low incidence and a mild degree grade of pathology. CAAs were observed in 2/38 children (5.3%) in the IVIG group and 1/37 children (2.7%) in the methylprednisolone group at 6-month follow-up (difference proportion 0.75; 95% confidence interval (CI) -0.05 to 1.0; p = 0.39).

Interpretation

Methylprednisolone alone may be an acceptable first-line treatment as left ventricular systolic dysfunction and clinical/laboratory evidence for inflammation quickly resolved in all children. However, our findings need further confirmation through larger studies as our sample size is likely to be of insufficient power to address rare clinically relevant adverse outcomes.

Funding

NOMIS, Vontobel, and Gaydoul Foundation.

Updated Case Definition of MIS-C and Implications for Clinical Care

OBJECTIVES

A broad, surveillance case definition was implemented when multisystem inflammatory syndrome in children (MIS-C) emerged in 2020. In 2023, a revised MIS-C case definition was constructed to improve specificity and reduce misclassification with other pediatric inflammatory conditions. This study aims to describe the impact of the updated definition on the classification of patients with MIS-C and Kawasaki Disease (KD).

METHODS

Patients hospitalized from March 2020 to November 2022 with clinician-diagnosed KD and MIS-C at a single center were studied retrospectively. Specificity and positive predictive value were assessed; McNemar test was used to compare specificity.

RESULTS

Among 119 patients with MIS-C per the 2020 definition, 20 (17%) did not fulfill the 2023 definition. Six of these 20 (30%) had shock or cardiac involvement. Of 59 KD patients, 10 (17%) met the 2020 MIS-C definition. Five patients (8%) met the 2023 MIS-C definition. Specificity for the 2020 and 2023 MIS-C definitions among KD patients were 83.1% and 91.5% respectively (McNemar, P = .0736). Positive predictive value was higher for the 2023 MIS-C case definition compared with the 2020 MIS-C case definition (95.2% vs 92.2%).

CONCLUSIONS

Approximately 1 in 5 patients diagnosed with MIS-C using the 2020 case definition did not meet the 2023 definition, including patients with cardiovascular dysfunction. Overlap persisted between patients meeting KD and 2023 MIS-C case definitions, with a false positive rate of 8%. Implications for treatment should be considered, particularly in settings where presumed MIS-C may be treated with corticosteroid monotherapy.

Cardiac Biomarkers Aid in Differentiation of Kawasaki Disease from Multisystem Inflammatory Syndrome in Children Associated with COVID-19

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 show clinical overlap and both lack definitive diagnostic testing, making differentiation challenging. We sought to determine how cardiac biomarkers might differentiate KD from MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C pediatric patients from 42 sites from January 2020 through June 2022. The study population included 118 KD patients who met American Heart Association KD criteria and compared them to 946 MIS-C patients who met 2020 Centers for Disease Control and Prevention case definition. All included patients had at least one measurement of amino-terminal prohormone brain natriuretic peptide (NTproBNP) or cardiac troponin I (TnI), and echocardiography. Regression analyses were used to determine associations between cardiac biomarker levels, diagnosis, and cardiac involvement. Higher NTproBNP (≥ 1500 ng/L) and TnI (≥ 20 ng/L) at presentation were associated with MIS-C versus KD with specificity of 77 and 89%, respectively. Higher biomarker levels were associated with shock and intensive care unit admission; higher NTproBNP was associated with longer hospital length of stay. Lower left ventricular ejection fraction, more pronounced for MIS-C, was also associated with higher biomarker levels. Coronary artery involvement was not associated with either biomarker. Higher NTproBNP and TnI levels are suggestive of MIS-C versus KD and may be clinically useful in their differentiation. Consideration might be given to their inclusion in the routine evaluation of both conditions.

The impact of the COVID-19 pandemic on pediatric rheumatology practice: an international, cross-sectional survey study

OBJECTIVE

The COVID-19 pandemic has affected patient care in general. We aimed to analyze the impact of the pandemic on pediatric rheumatology practice.

METHODS

An online survey including 22 questions was created by the representatives of the Emerging RheumatoloGists and rEsearchers (EMERGE) group of the Pediatric Rheumatology European Society (PReS) on SurveyMonkey. The descriptive analysis of the responses was performed on SurveyMonkey.

RESULTS

Overall, 469 pediatric rheumatologists (F/M: 2.9) from 70 countries completed the survey. The practice of drug prescription is not affected by the pandemic, according to 65.3 % of the respondents, while 24.3 % and 16.5 % are prescribing biologic drugs and corticosteroids less often, respectively. Over 40 % of the respondents have seen an increased number of patients with vasculitis or chilblains during the pandemic. One-third of the respondents stated no adjustments in their clinical practice after 2.5 years of COVID-19 pandemic. The rest indicated implementing various changes, with an emphasis on incorporating telemedicine. Telemedicine constitutes ≥10 % of the clinical practice for one-third of the participants. Nonetheless, 35.5 % agree that there are still delays in patient care due to the pandemic. However, most (∼90 %) think our practice is returning to the pre-pandemic routine.

CONCLUSION

The findings of our study indicate a significant alteration in pediatric rheumatology practice due to the pandemic. This includes increased caution when prescribing anti-rheumatic drugs, a transition towards telemedicine utilization, delays in routine care, and a rise in COVID-19-related inflammatory conditions. It is imperative to address these aspects in order to improve patient care in pediatric rheumatology.

A Multicenter Retrospective Cohort Study to Characterize Patients Hospitalized With Multisystem Inflammatory Syndrome in Adults and Coronavirus Disease 2019 in the United States, 2020-2021

BACKGROUND

The diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated multisystem inflammatory syndrome in adults (MIS-A) requires distinguishing it from acute coronavirus disease 2019 (COVID-19) and may affect clinical management.

METHODS

In this retrospective cohort study, we applied the US Centers for Disease Control and Prevention case definition to identify adults hospitalized with MIS-A at 6 academic medical centers from 1 March 2020 to 31 December 2021. Patients MIS-A were matched by age group, sex, site, and admission date at a 1:2 ratio to patients hospitalized with acute symptomatic COVID-19. Conditional logistic regression was used to compare demographic characteristics, presenting symptoms, laboratory and imaging results, treatments administered, and outcomes between cohorts.

RESULTS

Through medical record review of 10 223 patients hospitalized with SARS-CoV-2-associated illness, we identified 53 MIS-A cases. Compared with 106 matched patients with COVID-19, those with MIS-A were more likely to be non-Hispanic black and less likely to be non-Hispanic white. They more likely had laboratory-confirmed COVID-19 ≥14 days before hospitalization, more likely had positive in-hospital SARS-CoV-2 serologic testing, and more often presented with gastrointestinal symptoms and chest pain. They were less likely to have underlying medical conditions and to present with cough and dyspnea. On admission, patients with MIS-A had higher neutrophil-to-lymphocyte ratio and higher levels of C-reactive protein, ferritin, procalcitonin, and D-dimer than patients with COVID-19. They also had longer hospitalization and more likely required intensive care admission, invasive mechanical ventilation, and vasopressors. The mortality rate was 6% in both cohorts.

CONCLUSIONS

Compared with patients with acute symptomatic COVID-19, adults with MIS-A more often manifest certain symptoms and laboratory findings early during hospitalization. These features may facilitate diagnosis and management.

Clinical Syndromes Related to SARS-CoV-2 Infection and Vaccination in Pediatric Age: A Narrative Review

This narrative review aims to report the main clinical manifestations, therapeutic strategies, outcomes, and complications of acute SARS-CoV-2 infection in childhood and to summarize the data relating the SARS-CoV-2 vaccination efficacy and safety in pediatric age. SARS-CoV-2 infection mostly occurs asymptomatically in the pediatric population, while multisystem inflammatory syndrome in children (MIS-C) represents the most severe coronavirus disease 2019 (COVID-19)-related illness, a life-threatening event with a high morbidity rate. After the development of SARS-CoV-2 vaccines and their subsequent approval in children, the rate of infection as well as the number of its related complications have shown a drastic decrease. Fully vaccinated children are protected from the risk of developing a severe disease and a similar protective role has been observed in the reduction of complications, in particular MIS-C. However, long-lasting immunity has not been demonstrated, booster doses have been required, and reinfection has been observed. With regards to vaccine safety, adverse events were generally mild to moderate in all age groups: local adverse events were the most commonly reported. Nevertheless, a potential association between SARS-CoV-2 vaccine and the subsequent development of inflammatory manifestations has been suggested. Myocarditis has rarely been observed following vaccination; it appeared to be more frequent among adolescent males with a mild clinical course leading to a complete recovery. SARS-CoV-2 vaccine-related MIS-C cases have been described, although a univocal definition and an exact time interval with respect to vaccination has not been reported, thus not establishing a direct causal link. Current evidence about COVID-19 vaccination in children and adolescents suggest that benefits outweigh potential risks. Long-term data collection of the post-authorization safety surveillance programs will better define the real incidence of SARS-CoV-2 vaccine-related complications in the pediatric population.

COVID-19 and MIS-C treatment in children-results from an international survey

Children have been mostly excluded from COVID-19 clinical trials, and, as a result, most medicines approved for COVID-19 have no pediatric indication. In addition, access to COVID-19 therapeutics remains limited. Collecting physicians' experiences with off-label use of therapeutics is important to inform global prioritization processes and better target pediatric research and development. A standardized questionnaire was designed to explore the use of therapeutics used to treat COVID-19 and multisystem inflammatory syndrome in children (MIS-C) in pediatric patients globally. Seventy-three physicians from 29 countries participated. For COVID-19, steroids were used by 75.6% of respondents; remdesivir and monoclonal antibodies were prescribed by 48.6% and 27.1% of respondents, respectively. For MIS-C, steroids were prescribed by 79.1% of respondents and intravenous immunoglobulins by 69.6%. The use of these products depended on their pediatric approval and the limited availability of antivirals and most monoclonal antibodies in Africa, South America, Southeast Asia, and Eastern Europe. Off-label prescription resulted widespread due to the paucity of clinical trials in young children at the time of the survey; though, based on our survey results, it was generally safe and led to clinical benefits.  Conclusion: This survey provides a snapshot of current practice for treating pediatric COVID-19 worldwide, informing global prioritization efforts to better target pediatric research and development for COVID-19 therapeutics. Off-label use of such medicines is widespread for the paucity of clinical trials under 12 years and 40 kg, though appears to be safe and generally results in clinical benefits, even in young children. However, access to care, including medicine availability, differs widely globally. Clinical development of COVID-19 antivirals and monoclonal antibodies requires acceleration to ensure pediatric indication and allow worldwide availability of therapeutics that will enable more equitable access to COVID-19 treatment. What is Known: • Children have been mostly excluded from COVID-19 clinical trials, and, as a result, most medicines approved for COVID-19 have no pediatric indication. • Access to care differs widely globally, so because of the diversity of national healthcare systems; the unequal availability of medicines for COVID-19 treatment represents an obstacle to the pediatric population's universal right to health care. What is New: • Off-label COVID-19 drug prescription is widespread due to the lack of clinical trials in children younger than 12 years and weighing less than 40 kg, but relatively safe and generally leading to clinical benefit. • The application of the GAP-f framework to COVID-19 medicines is crucial, ensuring widespread access to all safe and effective drugs, enabling the rapid development of age-appropriate formulations, and developing specific access plans (including stability, storage, packaging, and labeling) for distribution in low- and middle-income countries (LMICs). Antivirals and monoclonal antibodies may benefit from the acceleration to reach widespread and equal diffusion.

Epidemiology and Severity of Illness of MIS-C and Kawasaki Disease During the COVID-19 Pandemic

BACKGROUND AND OBJECTIVES

Multisystem inflammatory syndrome in children (MIS-C) is a novel, severe condition following severe acute respiratory syndrome coronavirus 2 infection. Large epidemiologic studies comparing MIS-C to Kawasaki disease (KD) and evaluating the evolving epidemiology of MIS-C over time are lacking. We sought to understand the illness severity of MIS-C compared with KD and evaluate changes in MIS-C illness severity over time during the coronavirus disease 2019 pandemic compared with KD.

METHODS

We included hospitalizations of children with MIS-C and KD from April 2020 to May 2022 from the Pediatric Health Information System administrative database. Our primary outcome measure was the presence of shock, defined as the use of vasoactive/inotropic cardiac support or extracorporeal membrane oxygenation. We examined the volume of MIS-C and KD hospitalizations and the proportion of hospitalizations with shock over time using 2-week intervals. We compared the proportion of hospitalizations with shock in MIS-C and KD patients over time using generalized estimating equations adjusting for hospital clustering and age, with time as a fixed effect.

RESULTS

We identified 4868 hospitalizations for MIS-C and 2387 hospitalizations for KD. There was a higher proportion of hospitalizations with shock in MIS-C compared with KD (38.7% vs 5.1%). In our models with time as a fixed effect, we observed a significant decrease in the odds of shock over time in MIS-C patients (odds ratio 0.98, P < .001) but not in KD patients (odds ratio 1.00, P = .062).

CONCLUSIONS

We provide further evidence that MIS-C is a distinct condition from KD. MIS-C was a source of lower morbidity as the pandemic progressed.

Multisystem inflammatory syndrome in children (MIS-C) and sepsis differentiation by a clinical and analytical score: MISSEP score

Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. The aims were to evaluate the differences between pediatric patients with MIS-C and sepsis and to develop a score to distinguish both entities. This was a retrospective study that compared demographic, clinical, diagnostic, and therapeutic data of pediatric patients with MIS-C (cohort 2020-2022) and sepsis (cohorts 2010-2014 and 2017-2018) admitted to a Pediatric Intensive Care Unit (PICU) of a tertiary care hospital. A diagnostic score was developed with variables that differentiated the two conditions. Twenty-nine patients with MIS-C were identified, who were matched 1:3 with patients with sepsis (n = 87). Patients with MIS-C were older (10 vs. 4 years old), and the majority were male (69%). Clinical characteristics that demonstrated differences were prolonged fever and signs and symptoms affecting skin-mucosa and gastrointestinal system. Leukocytes, PCT, and ferritin were higher in sepsis, while thrombocytopenia, lymphopenia, and elevated fibrinogen and adrenomedullin (biomarker with a role for the detection of invasive infections) were more frequent in MIS-C. MIS-C patients presented greater myocardial dysfunction (p < 0.001). Five criteria were selected and included in the MISSEP score after fitting them into a multivariate logistic regression model: fever > 48 hours (20 points), thrombocytopenia < 150 × 103/µL (6 points), abdominal pain (15 points), conjunctival erythema (11 points), and Vasoactive Inotropic Score (VIS) > 10 (7 points). The cutoff > 25 points allowed to discriminate MIS-C from sepsis with a sensitivity of 0.89 and specificity of 0.95.     Conclusion: MIS-C phenotype overlaps with sepsis. MISSEP score could be useful to distinguish between both entities and direct specific treatment. What is Known: • Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. • It is essential to establish an accurate initial diagnosis and early specific treatment in both cases of MIS-C and sepsis to improve the prognosis of these patients. What is New: • Patients with MIS-C are older and have characteristic symptoms of prolonged fever, gastrointestinal symptoms, skin-mucosal involvement, and greater myocardial dysfunction, compared to patients with sepsis. • The use of diagnostic scores, such as the MISSEP score, can be very useful to distinguish between the two entities and help direct specific treatment.

Preliminary Evidence of the Differential Expression of Human Endogenous Retroviruses in Kawasaki Disease and SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a postinfectious sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some clinical features overlapping with Kawasaki disease (KD). Our research group and others have highlighted that the spike protein of SARS-CoV-2 can trigger the activation of human endogenous retroviruses (HERVs), which in turn induces inflammatory and immune reactions, suggesting HERVs as contributing factors in COVID-19 immunopathology. With the aim to identify new factors involved in the processes underlying KD and MIS-C, we analysed the transcriptional levels of HERVs, HERV-related genes, and immune mediators in children during the acute and subacute phases compared with COVID-19 paediatric patients and healthy controls. The results showed higher levels of HERV-W, HERV-K, Syn-1, and ASCT-1/2 in KD, MIS-C, and COV patients, while higher levels of Syn-2 and MFSD2A were found only in MIS-C patients. Moreover, KD and MIS-C shared the dysregulation of several inflammatory and regulatory cytokines. Interestingly, in MIS-C patients, negative correlations have been found between HERV-W and IL-10 and between Syn-2 and IL-10, while positive correlations have been found between HERV-K and IL-10. In addition, HERV-W expression positively correlated with the C-reactive protein. This pilot study supports the role of HERVs in inflammatory diseases, suggesting their interplay with the immune system in this setting. The elevated expression of Syn-2 and MFSD2A seems to be a distinctive trait of MIS-C patients, allowing to distinguish them from KD ones. The understanding of pathological mechanisms can lead to the best available treatment for these two diseases, limiting complications and serious outcomes.

Anti-Inflammatory and Immunomodulatory Effect of High-Dose Immunoglobulins in Children: From Approved Indications to Off-Label Use

BACKGROUND

The large-scale utilization of immunoglobulins in patients with inborn errors of immunity (IEIs) since 1952 prompted the discovery of their key role at high doses as immunomodulatory and anti-inflammatory therapy, in the treatment of IEI-related immune dysregulation disorders, according to labelled and off-label indications. Recent years have been dominated by a progressive imbalance between the gradual but constant increase in the use of immunoglobulins and their availability, exacerbated by the SARS-CoV-2 pandemic.

OBJECTIVES

To provide pragmatic indications for a need-based application of high-dose immunoglobulins in the pediatric context.

SOURCES

A literature search was performed using PubMed, from inception until 1st August 2023, including the following keywords: anti-inflammatory; children; high dose gammaglobulin; high dose immunoglobulin; immune dysregulation; immunomodulation; immunomodulatory; inflammation; intravenous gammaglobulin; intravenous immunoglobulin; off-label; pediatric; subcutaneous gammaglobulin; subcutaneous immunoglobulin. All article types were considered.

IMPLICATIONS

In the light of the current imbalance between gammaglobulins' demand and availability, this review advocates the urgency of a more conscious utilization of this medical product, giving indications about benefits, risks, cost-effectiveness, and administration routes of high-dose immunoglobulins in children with hematologic, neurologic, and inflammatory immune dysregulation disorders, prompting further research towards a responsible employment of gammaglobulins and improving the therapeutical decisional process.

Acute Ischemic Stroke in a Teenage Patient: Are We "MIS-C"ing Something?

The reported annual incidence of acute ischemic stroke (AIS) among pediatric and young adults is 1-13/100,000. In adults, ischemic stroke is attributed to several risk factors such as smoking, hypertension, atherosclerosis, and diabetes. Alternatively, pediatric ischemic stroke is associated with a broad spectrum of etiologies including prematurity, congenital heart disease, arteriopathies like moyamoya, chronic inflammatory disease, sickle cell, hypercoagulability, and malignancy. In rare cases, AIS has been associated with multisystem inflammatory syndrome in children (MIS-C), a Kawasaki-like inflammatory disease affecting patients younger than 21 years of age. This recently recognized and rare condition has been linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and presentations can vary widely in terms of severity and systemic involvement. While the exact reason behind this association is unknown, there is a growing body of evidence in adult literature that links SARS-CoV-2 infection to hypercoagulability and immune-mediated thrombosis. In pediatric patients, this association is not very clear. We report a case of a 17-year-old, previously healthy male who presented with acute-onset expressive aphasia, right-sided hemiparesis, and facial droop after two weeks from experiencing coronavirus disease 2019 (COVID-19)-like symptoms. A non-contrast head CT revealed an acute left M2 territory infarct while serum workup was consistent with MIS-C. Providers must maintain a high degree of suspicion and consider AIS in pediatric patients presenting with even mild neurological changes and a recent history of SARS-CoV-2 infection.

Clinical phenotypes and outcomes in children with multisystem inflammatory syndrome across SARS-CoV-2 variant eras: a multinational study from the 4CE consortium

Background

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infection. It remains unclear how MIS-C phenotypes vary across SARS-CoV-2 variants. We aimed to investigate clinical characteristics and outcomes of MIS-C across SARS-CoV-2 eras.

Methods

We performed a multicentre observational retrospective study including seven paediatric hospitals in four countries (France, Spain, U.K., and U.S.). All consecutive confirmed patients with MIS-C hospitalised between February 1st, 2020, and May 31st, 2022, were included. Electronic Health Records (EHR) data were used to calculate pooled risk differences (RD) and effect sizes (ES) at site level, using Alpha as reference. Meta-analysis was used to pool data across sites.

Findings

Of 598 patients with MIS-C (61% male, 39% female; mean age 9.7 years [SD 4.5]), 383 (64%) were admitted in the Alpha era, 111 (19%) in the Delta era, and 104 (17%) in the Omicron era. Compared with patients admitted in the Alpha era, those admitted in the Delta era were younger (ES -1.18 years [95% CI -2.05, -0.32]), had fewer respiratory symptoms (RD -0.15 [95% CI -0.33, -0.04]), less frequent non-cardiogenic shock or systemic inflammatory response syndrome (SIRS) (RD -0.35 [95% CI -0.64, -0.07]), lower lymphocyte count (ES -0.16 × 109/uL [95% CI -0.30, -0.01]), lower C-reactive protein (ES -28.5 mg/L [95% CI -46.3, -10.7]), and lower troponin (ES -0.14 ng/mL [95% CI -0.26, -0.03]). Patients admitted in the Omicron versus Alpha eras were younger (ES -1.6 years [95% CI -2.5, -0.8]), had less frequent SIRS (RD -0.18 [95% CI -0.30, -0.05]), lower lymphocyte count (ES -0.39 × 109/uL [95% CI -0.52, -0.25]), lower troponin (ES -0.16 ng/mL [95% CI -0.30, -0.01]) and less frequently received anticoagulation therapy (RD -0.19 [95% CI -0.37, -0.04]). Length of hospitalization was shorter in the Delta versus Alpha eras (-1.3 days [95% CI -2.3, -0.4]).

Interpretation

Our study suggested that MIS-C clinical phenotypes varied across SARS-CoV-2 eras, with patients in Delta and Omicron eras being younger and less sick. EHR data can be effectively leveraged to identify rare complications of pandemic diseases and their variation over time.

Funding

None.

SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children (MIS-C): A Case Report from Iraq

The novel coronavirus disease (COVID-19) continues to evolve. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated multisystem inflammatory syndrome in children (MIS-C) is a rare post-COVID-19 complication that affects children with critical outcomes. Few MIS-C reports were available from Arab-Asian ethnicities. We here describe a presentation mimicking a head injury overlapping the manifestations of MIS-C in a child from Iraq. A 10-year-old boy presented with blunt trauma in a shock-like status, and a head injury was suspected. Since he was febrile two days before the trauma, another pathology was assumed. Imaging and laboratory evaluations were performed, and after excluding gross neurosurgical etiology, he was initially treated as a toxic shock syndrome. Meanwhile, he was deteriorating with continuous fever, impaired consciousness, and seizure on the following day. Although not considered initially, close monitoring with a multidisciplinary approach and serial investigations revealed that the child met the criteria of MIS-C. SARS-CoV-2 IgG was shown to be high, while the RT-PCR of COVID-19 was negative. Once he received immunoglobulin and methylprednisolone, he improved dramatically. In conclusion, this report aimed to increase awareness about MIS-C among health workers and emphasized the need for a multidisciplinary team approach in Iraq due to the importance of timely treatment.

Multisystem Inflammatory Syndrome in an Adult on Hemodialysis with Markedly Elevated Procalcitonin and Ferritin Levels

A 21-year-old man on hemodialysis was hospitalized for coronavirus disease 2019 (COVID-19) pneumonia. After admission, he had a persistent high fever and developed erythema induratum on his extremities. Laboratory tests conducted 25 days after onset showed markedly increased procalcitonin (PCT) levels (>100 ng/mL). The patient developed impaired consciousness and hypotensive shock and required endotracheal intubation. Based on the presence of erythema induratum and multiorgan dysfunction, he was diagnosed with multisystem inflammatory syndrome (MIS). The MIS resolved after treatment with intravenous immunoglobulin and methylprednisolone. This report illustrates that MIS can occur in adults and may be accompanied by high PCT levels.

Thrombotic complications in children with Coronavirus disease 2019 and Multisystem Inflammatory Syndrome of Childhood

Coronavirus disease 2019 (COVID-19) associated coagulopathy is multifactorial and involves inflammation driven hypercoagulability, endothelial dysfunction, platelet activation, and impaired fibrinolysis. Hospitalized adults with COVID-19 are at an increased risk of both venous thromboembolism and ischemic stroke, resulting in adverse outcomes, including increased mortality. Although COVID-19 in children follows a less severe course, both arterial and venous thromboses have been reported in hospitalized children with COVID-19. Additionally, some children develop a postinfectious, hyperinflammatory illness termed multisystem inflammatory syndrome of childhood (MIS-C), which is also associated with hypercoagulability and thrombosis. Several randomized trials have evaluated the safety and efficacy of antithrombotic therapy in adults with COVID-19, although similar pediatric data are lacking. In this narrative review, we discuss the postulated pathophysiology of COVID-19 coagulopathy and summarize principal findings of the recently completed adult trials of antithrombotic therapy. We provide an up-to-date summary of pediatric studies investigating the rate of venous thromboembolism and ischemic stroke in COVID-19 and multisystem inflammatory syndrome of childhood in addition to reviewing the findings of the single, nonrandomized pediatric trial investigating the safety of prophylactic anticoagulation. Lastly, we outline adult and pediatric consensus guidelines on the use of antithrombotic therapy in this cohort. A detailed discussion of the practical implementation and current limitations of published data will hopefully address the knowledge deficits surrounding the use of antithrombotic therapy in children with COVID-19 and generate hypotheses for future research.

Multisystem inflammatory syndrome drug treatment in countries with different income profiles: a scoping review

Objective: The purpose of this study was to map and describe the studies that have investigated therapeutic alternatives for the management of paediatric multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. Considering the origin of the studies performed (low-, middle- and high-income countries), a systematic scoping review was conducted with primary studies that reported the use of medications for the treatment of patients with MIS-C. Sources: The searches were performed in MEDLINE, Embase, Lilacs, Epistemonikos, CINAHL, and CENTRAL, in the grey literature (theses and dissertations from CAPES, ProQuest, and PROSPERO) and in clinical trial databases until May 2022. The selection and extraction of studies were performed independently by two reviewers. Summary of the findings: A total of 173 studies were included, most of which were published as case reports or series. No randomized controlled clinical trials (RCTs) were identified. The investigated drugs were immunoglobulins, glucocorticoids, monoclonal antibodies, anticoagulants, and antiplatelet agents. Conclusion: The dosages, when reported, were heterogeneous among the studies. The ethnicity and comorbidity of the participants were poorly reported. Monoclonal antibodies, drugs with higher costs, were mostly described in studies of high-income countries.

Outcomes of MIS-C patients treated with anakinra: a retrospective multicenter national study

Background

The treatment of multisystem inflammatory syndrome in children unresponsive to first-line therapies (IVIG and/or steroids) is challenging. The effectiveness of IL-1 receptor antagonist, anakinra, is debated.

Patients and methods

We conducted an anonymous retrospective multicenter study on MIS-C patients treated with anakinra in Italy from January 2020 to February 2021. Our study outcomes included the percentage of patients who required further therapeutic step-up, the percentage of patients who experienced fever resolution within 24 h and a reduction of CRP by half within 48 h, and the percentage of patients who developed Coronary Artery Anomalies (CAA) during follow-up.

Results

35 cases of MIS-C were treated in 10 hospitals. Of these, 13 patients started anakinra while in the ICU, and 22 patients started anakinra in other wards. 25 patients (71.4%) were treated with corticosteroids at a starting dose 2-30 mg/Kg/day plus IVIG (2 g/Kg), 10 patients (28.6%) received only corticosteroids without IVIG. Anakinra was administered intravenously to all patients in Group A (mean dose 8 mg/Kg/day), and subcutaneously in Group B (mean dose 4 mg/Kg/day). Only two patients required further treatment step-up and no patients developed CAA after receiving anakinra. The most commonly observed side effect was an increase in ALT, occurring in 17.1% of patients.

Conclusions

In this retrospective cohort of severe MIS-C patients treated with anakinra we report favorable clinical outcomes with a low incidence of side effects. The simultaneous use of steroids ± IVIG in these patients hinders definitive conclusions regarding the need of IL-1 inhibition in MIS-C treatment.

Variation in Early Anakinra Use and Short-Term Outcomes in Multisystem Inflammatory Syndrome in Children

OBJECTIVE

Evidence regarding effectiveness of interleukin-1 receptor antagonism in multisystem inflammatory syndrome in children (MIS-C) is lacking. We characterized variation in initial treatment with anakinra and evaluated cardiovascular outcomes associated with adding anakinra to standard initial therapy.

METHODS

We conducted a retrospective cohort study of MIS-C cases in a US surveillance registry from November 2020 to December 2021. Day 0 was the first calendar day of immunomodulatory treatment. Factors associated with initial anakinra use (days 0-1) were identified. We compared cases in patients ages 2-20 years receiving intravenous immunoglobulin (IVIG) and glucocorticoids versus anakinra plus IVIG and/or glucocorticoids on days 0-1, using inverse probability weighting to balance disease severity. Primary outcomes were vasopressor requirement on day 3 and impaired left ventricular ejection fraction on days 3-4. The secondary outcome was 50% reduction in C-reactive protein on day 3.

RESULTS

Among 1,516 MIS-C cases at 44 sites, 193 (13%) patients received anakinra alone or with other immunomodulators as initial treatment (range 0-74% by site). Site accounted for 59% of residual variance in anakinra use. After balancing disease severity, initial treatment with anakinra plus IVIG and/or glucocorticoids (n = 121) versus IVIG plus glucocorticoids (n = 389) was not associated with significant differences in vasopressor requirement (25.6% versus 20.1%, respectively; risk ratio [RR] 1.27 [95% confidence interval (95% CI) 0.88-1.84]), ventricular dysfunction (33.7% versus 25.7%, respectively; RR 1.31 [95% CI 0.98-1.75]), or C-reactive protein reduction.

CONCLUSION

We identified substantial variation in initial anakinra use in a real-world population of children with MIS-C, but no average short-term improvement in cardiovascular outcomes associated with early addition of anakinra to IVIG and/or glucocorticoids compared to IVIG and glucocorticoids alone.

COVID-19 and Thromboembolic Events in the Pandemic and Pre-Pandemic Era: A Pediatric Cohort

The Coronavirus disease 2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C) have been variably associated with thromboembolic events (TEs) in children. The aim of our study was to assess the prevalence of TEs in children hospitalized during a five-year period in a tertiary pediatric hospital, particularly in patients with COVID-19 and MIS-C. Overall, 38 patients were discharged with the diagnosis of TE: 20 in the pre-pandemic and 18 in the pandemic period. The prevalence of TEs was the same (0.08%) in the pre-pandemic and pandemic periods. The occurrence of TEs was higher in patients with COVID-19 or MIS-C (6/517, 1.16%) when compared to children without these conditions in the pandemic and in the pre-pandemic periods. The prevalence of TEs in children with MIS-C was significantly higher than the prevalence in patients with COVID-19. Five out of six of the patients with COVID-19 or MIS-C developing a TE had at least one predisposing factor to thrombosis. In conclusion, our study shows an increased prevalence of TEs in children hospitalized with COVID-19 or MIS-C, if compared to children without COVID-19 or MIS-C in the pandemic period and in the pre-pandemic period. The prevalence of TEs was significantly higher in patients with MIS-C.

Neurological and Psychological Sequelae Associated With Multisystem Inflammatory Syndrome in Children

Importance

Acute neurological involvement occurs in some patients with multisystem inflammatory syndrome in children (MIS-C), but few data report neurological and psychological sequelae, and no investigations include direct assessments of cognitive function 6 to 12 months after discharge.

Objective

To characterize neurological, psychological, and quality of life sequelae after MIS-C.

Design, Setting, and Participants

This cross-sectional cohort study was conducted in the US and Canada. Participants included children with MIS-C diagnosed from November 2020 through November 2021, 6 to 12 months after hospital discharge, and their sibling or community controls, when available. Data analysis was performed from August 2022 to May 2023.

Exposure

Diagnosis of MIS-C.

Main Outcomes and Measures

A central study site remotely administered a onetime neurological examination and in-depth neuropsychological assessment including measures of cognition, behavior, quality of life, and daily function. Generalized estimating equations, accounting for matching, assessed for group differences.

Results

Sixty-four patients with MIS-C (mean [SD] age, 11.5 [3.9] years; 20 girls [31%]) and 44 control participants (mean [SD] age, 12.6 [3.7] years; 20 girls [45%]) were enrolled. The MIS-C group exhibited abnormalities on neurological examination more frequently than controls (15 of 61 children [25%] vs 3 of 43 children [7%]; odds ratio, 4.7; 95% CI, 1.3-16.7). Although the 2 groups performed similarly on most cognitive measures, the MIS-C group scored lower on the National Institutes of Health Cognition Toolbox List Sort Working Memory Test, a measure of executive functioning (mean [SD] scores, 96.1 [14.3] vs 103.1 [10.5]). Parents reported worse psychological outcomes in cases compared with controls, particularly higher scores for depression symptoms (mean [SD] scores, 52.6 [13.1] vs 47.8 [9.4]) and somatization (mean [SD] scores, 55.5 [15.5] vs 47.0 [7.6]). Self-reported (mean [SD] scores, 79.6 [13.1] vs 85.5 [12.3]) and parent-reported (mean [SD] scores, 80.3 [15.5] vs 88.6 [13.0]) quality of life scores were also lower in cases than controls.

Conclusions and Relevance

In this cohort study, compared with contemporaneous sibling or community controls, patients with MIS-C had more abnormal neurologic examinations, worse working memory scores, more somatization and depression symptoms, and lower quality of life 6 to 12 months after hospital discharge. Although these findings need to be confirmed in larger studies, enhanced monitoring may be warranted for early identification and treatment of neurological and psychological symptoms.

Pediatric multisystem inflammatory syndrome associated with COVID-19: Insights in pathogenesis and clinical management

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a major challenge to be faced in recent years. While adults suffered the highest morbidity and mortality rates of coronavirus disease 2019, children were thought to be exclusively asymptomatic or to present with mild conditions. However, around April 2020, there was an outbreak of a new clinical syndrome related to SARS-CoV-2 in children - multisystemic inflammatory syndrome in children (MIS-C) - which comprises a severe and uncon-trolled hyperinflammatory response with multiorgan involvement. The Centers for Disease Control and Prevention considers a suspected case of MIS-C an individual aged < 21 years presenting with fever, high inflammatory markers levels, and evidence of clinically severe illness, with multisystem (> 2) organ involvement, no alternative plausible diagnoses, and positive for recent SARS-CoV-2 infection. Despite its severity, there are no definitive disease management guidelines for this condition. Conversely, the complex pathogenesis of MIS-C is still not completely understood, although it seems to rely upon immune dysregulation. Hence, in this study, we aim to bring together current evidence regarding the pathogenic mechanisms of MIS-C, clinical picture and management, in order to provide insights for clinical practice and implications for future research directions.

Case Report: Multisystem inflammatory syndrome in children with associated proximal tubular injury

Introduction

SARS-CoV-2 infection in the pediatric population can be associated with a multiorgan inflammatory syndrome called children's multisystem inflammatory syndrome (MIS-C). The kidneys can be affected by a broad spectrum of possible injuries, whose pathogenetic mechanisms are still unclear.Case report: We report the case of a 5-year-old boy with severe cardiac involvement in the context of MIS-C. After two weeks of hospitalization, an abdominal ultrasound showed massive bladder "debris", followed by the onset of normoglycemic glycosuria. Over time, there was a progressive increase in glycosuria, and the presence of a mat of amorphous phosphate crystals was evidenced on urinary sediment. Together with the findings of hypo-uricemia, increased urinary uric acid, and globally increased urinary amino acids, a clinical picture of kidney proximal tubular damage with secondary Fanconi-like syndrome took shape.

Discussion

This case report describes the case of a patient with MIS-C with cardiac and kidney involvement characterized by proximal tubular damage, which slowly improved but still persisted at the 8-month follow-up. The pathogenesis of the damage is unclear and probably multifactorial.