Multisystem Inflammatory Syndrome in U.S. Children and Adolescents

Multisystem inflammatory syndrome in children: another COVID-19 sequel

With the rapid expansion of the COVID-19 pandemic, the disease burden and its consequences on the paediatric population has been progressively recognised. Although COVID-19 infection in children presents as asymptomatic to mild illness, instances of hyperinflammation and multi-organ involvement following the viral infection have been described. This condition, known as the multisystem inflammatory syndrome in children (MIS-C), has gained a wide global attention. Despite the global efforts to uncover the disease characteristics and management, a clear pathogenesis and a unified treatment regimen have not been reached yet. This paper tackles the epidemiology of the MIS-C, discusses its suggested pathogenesis, drives through its varying clinical presentations, and evaluates the different treatment regimens employed in managing MIS-C.

Evolving trends in inpatient paediatric dermatology

PURPOSE OF REVIEW

This review provides updates in the evaluation and management of key dermatologic diseases encountered in the hospitalized child.

RECENT FINDINGS

Our understanding of dermatologic disorders in children continues to evolve. Staphylococcal scalded skin syndrome (SSSS) is a potentially severe blistering disorder typically seen in children under the age of 4 with an incidence that is increasing in the United States. Recent research has highlighted that the majority of cases are due to methicillin-sensitive Staphylococcus aureus (MSSA) and most patients can be adequately managed with beta-lactams. Toxic epidermal necrolysis (TEN) is one of the most feared dermatologic disorders. Currently, there is a lack of consensus on the most efficacious first-line systemic therapy. Etanercept is increasingly being used based on studies showing a shorter time to re-epithelization and decreased mortality. Lastly, the COVID-19 pandemic introduced the novel inflammatory condition multisystem inflammatory syndrome in children (MIS-C) in which approximately three out of four children present with a mucocutaneous eruption. Early recognition of the dermatologic features of MIS-C is important in potentially establishing a diagnosis and differentiating it from the many other causes of childhood fever and rash.

SUMMARY

There are no clear universal treatment guidelines for these rare diagnoses, and therefore, clinicians must remain informed of the latest findings in diagnosis and therapeutics.

Predicting Delayed Shock in Multisystem Inflammatory Disease in Children: A Multicenter Analysis From the New York City Tri-State Region

OBJECTIVES

Patients with multisystem inflammatory disease in children (MIS-C) are at risk of developing shock. Our objectives were to determine independent predictors associated with development of delayed shock (≥3 hours from emergency department [ED] arrival) in patients with MIS-C and to derive a model predicting those at low risk for delayed shock.

METHODS

We conducted a retrospective cross-sectional study of 22 pediatric EDs in the New York City tri-state area. We included patients meeting World Health Organization criteria for MIS-C and presented April 1 to June 30, 2020. Our main outcomes were to determine the association between clinical and laboratory factors to the development of delayed shock and to derive a laboratory-based prediction model based on identified independent predictors.

RESULTS

Of 248 children with MIS-C, 87 (35%) had shock and 58 (66%) had delayed shock. A C-reactive protein (CRP) level greater than 20 mg/dL (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 2.4-12.1), lymphocyte percent less than 11% (aOR, 3.8; 95% CI, 1.7-8.6), and platelet count less than 220,000/uL (aOR, 4.2; 95% CI, 1.8-9.8) were independently associated with delayed shock. A prediction model including a CRP level less than 6 mg/dL, lymphocyte percent more than 20%, and platelet count more than 260,000/uL, categorized patients with MIS-C at low risk of developing delayed shock (sensitivity 93% [95% CI, 66-100], specificity 38% [95% CI, 22-55]).

CONCLUSIONS

Serum CRP, lymphocyte percent, and platelet count differentiated children at higher and lower risk for developing delayed shock. Use of these data can stratify the risk of progression to shock in patients with MIS-C, providing situational awareness and helping guide their level of care.

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.

Rare genetic variants involved in multisystem inflammatory syndrome in children: a multicenter Brazilian cohort study

Introduction

Despite the existing data on the Multisystem Inflammatory Syndrome in Children (MIS-C), the factors that determine these patients evolution remain elusive. Answers may lie, at least in part, in genetics. It is currently under investigation that MIS-C patients may have an underlying innate error of immunity (IEI), whether of monogenic, digenic, or even oligogenic origin.

Methods

To further investigate this hypothesis, 30 patients with MIS-C were submitted to whole exome sequencing.

Results

Analyses of genes associated with MIS-C, MIS-A, severe covid-19, and Kawasaki disease identified twenty-nine patients with rare potentially damaging variants (50 variants were identified in 38 different genes), including those previously described in IFNA21 and IFIH1 genes, new variants in genes previously described in MIS-C patients (KMT2D, CFB, and PRF1), and variants in genes newly associated to MIS-C such as APOL1, TNFRSF13B, and G6PD. In addition, gene ontology enrichment pointed to the involvement of thirteen major pathways, including complement system, hematopoiesis, immune system development, and type II interferon signaling, that were not yet reported in MIS-C.

Discussion

These data strongly indicate that different gene families may favor MIS- C development. Larger cohort studies with healthy controls and other omics approaches, such as proteomics and RNAseq, will be precious to better understanding the disease dynamics.

Exploring Factors Influencing Changes in Incidence and Severity of Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome (MIS-C) is a rare condition associated with COVID-19 affecting children, characterized by severe and aberrant systemic inflammation leading to nonspecific symptoms, such as gastrointestinal, cardiac, respiratory, hematological, and neurological disorders. In the last year, we have experienced a progressive reduction in the incidence and severity of MIS-C, reflecting the worldwide trend. Thus, starting from the overall trend in the disease in different continents, we reviewed the literature, hypothesizing the potential influencing factors contributing to the reduction in cases and the severity of MIS-C, particularly the vaccination campaign, the spread of different SARS-CoV-2 variants (VOCs), and the changes in human immunological response. The decrease in the severity of MIS-C and its incidence seem to be related to a combination of different factors rather than a single cause. Maturation of an immunological memory to SARS-CoV-2 over time, the implication of mutations of key amino acids of S protein in VOCs, and the overall immune response elicited by vaccination over the loss of neutralization of vaccines to VOCs seem to play an important role in this change.

Principles of Rational COVID-19 Therapy in Pediatrics

The purpose of this review was to conduct a comparative assessment of the concepts of therapy for pediatric patients with COVID-19 in the framework of global clinical practice. A structural analysis of the range of drugs and treatment strategies in the context of etiotropic, pathogenetic, and symptomatic therapy has shown that in the global context and in real clinical practice, the etiotropic-pathogenetic approach based on information about the effectiveness of individual medical technologies prevails today. It has been established that eight international nonproprietary/grouping names are present in international practice as means of etiotropic therapy for pediatric patients with COVID-19, and 18 positions are used for pathogenetic therapy. In terms of frequency of occurrence, the leading positions are occupied by remdesivir and the combination of nirmatrelvir with ritonavir, as well as dexamethasone and tocilizumab. The paper emphasizes the relevance of research in the field of evaluating the effectiveness of individual treatment regimens as well as the analysis of the delayed consequences of pathology suffered in childhood under the conditions of using various approaches to pharmacotherapy.

[Multisystemic inflammatory syndrome in children after severe acute respiratory syndrome coronavirus 2 infection: a clinical analysis of four cases]

OBJECTIVES

To investigate the clinical features and treatment strategies of multisystemic inflammatory syndrome in children (MIS-C) after severe acute respiratory syndrome coronavirus 2 infection.

METHODS

A retrospective analysis was performed on the medical data of four children with MIS-C who were admitted to the Department of Cardiology, Xuzhou Children's Hospital, Xuzhou Medical Universityfrom January to February 2023.

RESULTS

All four children had multiple organ involvements and elevated inflammatory markers, with a poor response to standard therapy for Kawasaki disease after admission. Two children were treated with intravenous immunoglobulin therapy pulse therapy twice, and all four children were treated with glucocorticoids. The children had a good prognosis after the treatment.

CONCLUSIONS

MIS-C often appears within 4-6 weeks or a longer time after severe acute respiratory syndrome coronavirus 2 infection, and anti-inflammatory therapy in addition to the standard treatment regimen for Kawasaki disease can help to achieve a favorable treatment outcome.

Surveillance for Multisystem Inflammatory Syndrome in US Children Aged 5-11 Years Who Received Pfizer-BioNTech COVID-19 Vaccine, November 2021 through March 2022

Multisystem inflammatory syndrome in children (MIS-C) is a complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; in the United States, reporting of MIS-C after coronavirus disease 2019 (COVID-19) vaccination is required for vaccine safety monitoring. Pfizer-BioNTech COVID-19 vaccine was authorized for children aged 5-11 years on 29 October 2021. Covering a period when approximately 7 million children received vaccine, surveillance for MIS-C ≤ 90 days postvaccination using passive systems identified 58 children with MIS-C and laboratory evidence of past/recent SARS-CoV-2 infection, and 4 without evidence. During a period with extensive SARS-CoV-2 circulation, MIS-C illness in children after COVID-19 vaccination who lacked evidence of SARS-CoV-2 infection was rare (<1 per million vaccinated children).

A framework for future national pediatric pandemic respiratory disease severity triage: The HHS pediatric COVID-19 data challenge

Introduction

With persistent incidence, incomplete vaccination rates, confounding respiratory illnesses, and few therapeutic interventions available, COVID-19 continues to be a burden on the pediatric population. During a surge, it is difficult for hospitals to direct limited healthcare resources effectively. While the overwhelming majority of pediatric infections are mild, there have been life-threatening exceptions that illuminated the need to proactively identify pediatric patients at risk of severe COVID-19 and other respiratory infectious diseases. However, a nationwide capability for developing validated computational tools to identify pediatric patients at risk using real-world data does not exist.

Methods

HHS ASPR BARDA sought, through the power of competition in a challenge, to create computational models to address two clinically important questions using the National COVID Cohort Collaborative: (1) Of pediatric patients who test positive for COVID-19 in an outpatient setting, who are at risk for hospitalization? (2) Of pediatric patients who test positive for COVID-19 and are hospitalized, who are at risk for needing mechanical ventilation or cardiovascular interventions?

Results

This challenge was the first, multi-agency, coordinated computational challenge carried out by the federal government as a response to a public health emergency. Fifty-five computational models were evaluated across both tasks and two winners and three honorable mentions were selected.

Conclusion

This challenge serves as a framework for how the government, research communities, and large data repositories can be brought together to source solutions when resources are strapped during a pandemic.

Seizure as Presenting Symptom of Multisystem Inflammatory Syndrome in Children

We describe the case of a 13-year-old girl who presented with a new-onset seizure and fever and subsequently developed severe cardiac dysfunction, coronary artery dilation, and shock due to the surprising diagnosis of multisystem inflammatory syndrome in children (MIS-C). Although the clinical entity we now call MIS-C was first mentioned in the medical literature in April 2020, the full picture of this disease process is still evolving. Neurologic involvement has been described in cases with MIS-C; however, seizures are not a typical presenting symptom. Additionally, because children infected with SARS-CoV-2 are often asymptomatic, a documented preceding COVID-19 infection might not be available to raise suspicion of MIS-C early on. Febrile seizures, meningitis, and encephalitis are childhood illnesses that pediatricians are generally familiar with, but associating these clinical pictures with MIS-C is uncommon. Given the possibility of rapid clinical cardiogenic decline, as seen in our patient, a prompt diagnosis and appropriate monitoring and treatment are of utmost importance. This case report aims to raise awareness that new-onset seizures with fevers can be early or the first presenting symptoms in children with MIS-C, and further workup and close monitoring may be required.

Risk and Benefit of mRNA COVID-19 Vaccines for the Omicron Variant by Age, Sex, and Presence of Comorbidity: A Quality-Adjusted Life Years Analysis

The development of the mutant omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the coronavirus disease 2019 (COVID-19) pandemic raised the importance of reevaluating the risk and benefit of COVID-19 vaccines. With a decision tree model, we calculated the benefit-risk ratio and the benefit-risk difference of receiving monovalent messenger RNA (mRNA) COVID-19 vaccine (primary 2 doses, a third dose, and a fourth dose) in the 4-5 months after vaccination using quality-adjusted life years. The analysis was stratified by age, sex, and the presence of comorbidity. Evidence from peer-reviewed publications and gray literature was reviewed on September 16, 2022, to inform the study. Benefit-risk ratios for receipt of the BNT162b2 vaccine (Pfizer-BioNTech) ranged from 6.8 for males aged 12-17 years without comorbidity for the primary doses to 221.3 for females aged ≥65 years with comorbidity for the third dose. The benefit-risk ratios for receipt of the mRNA-1273 vaccine (Moderna) ranged from 7.2 for males aged 18-29 years without comorbidity for the primary doses to 101.4 for females aged ≥65 years with comorbidity for the third dose. In all scenarios of the one-way sensitivity analysis, the benefit-risk ratios were more than 1, irrespective of age, sex, comorbidity status, and type of vaccine, for both primary and booster doses. The benefits of mRNA COVID-19 vaccines in protecting against the omicron variant outweigh the risks, irrespective of age, sex, and comorbidity.

Clinical and biological heterogeneity of multisystem inflammatory syndrome in adults following SARS-CoV-2 infection: a case series

Importance

Multisystem inflammatory syndrome in adults (MIS-A) is a poorly understood complication of SARS-CoV-2 infection with significant morbidity and mortality.

Objective

Identify clinical, immunological, and histopathologic features of MIS-A to improve understanding of the pathophysiology and approach to treatment.

Design

Three cases of MIS-A following SARS-CoV-2 infection were clinically identified between October 2021 - March 2022 using the U.S. Centers for Disease Control and Prevention diagnostic criteria. Clinical, laboratory, imaging, and tissue data were assessed.

Findings

All three patients developed acute onset cardiogenic shock and demonstrated elevated inflammatory biomarkers at the time of hospital admission that resolved over time. One case co-occurred with new onset Type 1 diabetes and sepsis. Retrospective analysis of myocardial tissue from one case identified SARS-CoV-2 RNA. All three patients fully recovered with standard of care interventions plus immunomodulatory therapy that included intravenous immunoglobulin, corticosteroids, and in two cases, anakinra.

Conclusion

MIS-A is a severe post-acute sequela of COVID-19 characterized by systemic elevation of inflammatory biomarkers. In this series of three cases, we find that although clinical courses and co-existent diseases vary, even severe presentations have potential for full recovery with prompt recognition and treatment. In addition to cardiogenic shock, glucose intolerance, unmasking of autoimmune disease, and sepsis can be features of MIS-A, and SARS-CoV-2 myocarditis can lead to a similar clinical syndrome.

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.

Development of a Model to Identify Febrile Children at Low Risk for Multisystem Inflammatory Syndrome

OBJECTIVES

The case definition for multisystem inflammatory syndrome in children (MIS-C) is broad and encompasses symptoms and signs commonly seen in children with fever. Our aim was to identify clinical predictors that, independently or in combination, identify febrile children presenting to the emergency department (ED) as low risk for MIS-C.

METHODS

We conducted a retrospective single-center study of otherwise healthy children 2 months to 20 years of age presenting to the ED with fever and who had a laboratory evaluation for MIS-C between April 15, 2020, and October 31, 2020. We excluded children with a diagnosis of Kawasaki disease. Our outcome was an MIS-C diagnosis defined by the Centers for Disease Control and Prevention criteria. We conducted multivariable logistic regression analyses to identify variables independently associated with MIS-C.

RESULTS

Thirty-three patients with and 128 patients without MIS-C were analyzed. Of those with MIS-C, 16 of 33 (48.5%) had hypotension for age, signs of hypoperfusion, or required ionotropic support. Four variables were independently associated with the presence of MIS-C; known or suspected SARS CoV-2 exposure (adjusted odds ratio [aOR], 4.0; 95% confidence interval [CI], 1.4-11.9) and the following 3 symptoms and signs: abdominal pain on history (aOR, 4.8; 95% CI, 1.7-15.0), conjunctival injection (aOR, 15.2; 95% CI, 5.4-48.1), and rash involving the palms or soles (aOR, 12.2; 95% CI, 2.4-69.4). Children were at low risk of MIS-C if none of the 3 symptoms or signs were present (sensitivity 87.9% [95% CI, 71.8-96.6]; specificity 62.5% [53.5-70.9], negative predictive value 95.2% [88.3-98.7]). Of the 4 MIS-C patients without any of these 3 factors, 2 were ill-appearing in the ED and the other 2 had no cardiovascular involvement during their clinical course.

CONCLUSIONS

A combination of 3 clinical symptoms and signs had moderate to high sensitivity and high negative predictive value for identifying febrile children at low risk of MIS-C. If validated, these factors could aid clinicians in determining the need to obtain or forego an MIS-C laboratory evaluation during SARS-CoV-2 prevalent periods in febrile children.

Anticoagulation and Thrombotic Events in the Multisystem Inflammatory Syndrome in Children: Experience of a Single-center Cohort and Review of the Literature

The multisystem inflammatory syndrome in children (MIS-C) is a severe clinical entity affecting the coagulative system; although thromboembolic events (TEs) are not common, most patients receive anticoagulation. We retrospectively assessed patients below 18 years admitted with MIS-C at Meyer Children's Hospital (Florence, Italy). Data on baseline clinical and laboratory presentation, treatment, and outcome, including differences between patients with and without thrombotic prophylaxis, were analyzed. Thirty-two children 1 to 15 years were included. Seventeen patients (53.1%) required intensive care admission, 2 (8.7%) had obesity, 7 (30.4%) a central venous catheter, and 14 (43.8%) an impaired cardiac function. Twelve patients (37.5%) received prophylactic anticoagulation: they had more frequent cardiac involvement (91.7 vs. 50%, P =0.02) and higher ferritin levels (median 1240 vs. 501.5 ng/mL, P <0.001). No differences were found in median d -dimers between the 2 groups. Twenty-one patients (65.6%) had d -dimers >5×upper limit of normal but the indication for anticoagulation was not driven by d -dimers. No patient had hemorrhagic events and only 1 patient (3.1%) had a superficial thrombotic event (under thromboprophylaxis). Our series and the available literature data on MIS-C and thromboembolic events suggest that TEs are a rare complication of MIS-C that is frequently associated with high d -dimer values. However, also in MIS-C, the well-established risk factors of pediatric TEs (ie, older age, central venous catheter, obesity, and cancer) should guide thromboembolic risk assessment.

Segmental and global longitudinal strain differences between Kawasaki disease and multi-system inflammatory syndrome in children

BACKGROUND

Multi-system inflammatory syndrome in children and Kawasaki disease have overlapping clinical features but comparative echocardiographic studies are lacking.

METHODS

We reviewed echocardiography findings of all multi-system inflammatory syndrome cases between 1st April and 31st July, 2020 and typical Kawasaki disease patients with coronary arteries abnormalities consecutively followed between 1st October, 2016 and June 30th, 2019.

RESULTS

We included 40 multi-system inflammatory syndrome children (25 males, 62.5%) and 45 Kawasaki disease patients (31 males, 68.9%) at a mean age of 6.4 years old and 8 years old, respectively. Four out of 40 multi-system inflammatory syndrome children had coronary arteries abnormalities. Left ventricle ejection fraction was normal in both groups. Global longitudinal strain was normal although Kawasaki disease group had significantly lower values (-20.0 versus -21.7%; p = 0.02). Basal segments were the most affected in Kawasaki disease patients with significant differences in the basal anterior, anterolateral, and anteroseptal strain: -18.2 versus -23.0% (p = 0.002), -16.7 versus -22.0% (p < 0.001), -16.7 versus -19.5% (p = 0.034), respectively. The basal anterolateral and anteroseptal segments in Kawasaki disease patients were the only ones with an absolute reduction of longitudinal strain (-16.7% both) consistent with the greater left main coronary involvement in this cohort.

CONCLUSIONS

Our findings are consistent with the transient cardiac involvement in multi-system inflammatory syndrome, as opposed to the subtle and chronic myocardial involvement in Kawasaki disease children with coronary arteries abnormalities. We speculate that the mechanism of cardiac impairment in the few multi-system inflammatory syndrome children with reduced global longitudinal strain is not related to coronary arteries abnormalities.

The Role of Mean Platelet Volume in Multisystem Inflammatory Syndrome in Children With Cardiac Manifestations

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a novel pediatric disorder associated with coronavirus disease 2019. However, no laboratory parameters can diagnose MIS-C. This study aimed to determine the changes in mean platelet volume (MPV) and investigate its relationship with cardiac involvement in MIS-C.

METHODS

In this single-center retrospective study, 35 children with MIS-C, 35 healthy children and 35 febrile children were enrolled. Patients with MIS-C were further subdivided depending on the presence of cardiac involvement. For all patients, the white blood cell, absolute neutrophil, absolute lymphocyte, platelet counts, MPV and C-reactive protein levels were recorded. Ferritin, D-dimer, troponin and CK-MB levels and the day when IVIG was administered were recorded and compared between groups.

RESULTS

Thirteen patients with MIS-C had cardiac involvement. The mean MPV of the MIS-C group was significantly higher than those of the healthy ( P = 0.0001) and febrile ( P = 0.027) groups. Using a cutoff of >7.6 fL, the MPV had a sensitivity of 82.86% and specificity of 82.75%, and the area under the MPV receiver operating characteristics curve was 0.896 (0.799-0.956). The MPV was significantly higher in patients with cardiac involvement than in those without ( P = 0.031). Logistic regression analysis revealed that the association between the MPV and cardiac involvement was significant (odds ratio, 2.28; 95% confidence interval, 1.04-2.95; P = 0 .039).

CONCLUSIONS

The MPV may indicate cardiac involvement in patients with MIS-C. Large cohort studies are needed to define an accurate cutoff value for the MPV.

Cardiac involvement in multisystem inflammatory syndrome in children: single-centre experience

BACKGROUND

This study aimed to evaluate electrocardiographic and echocardiographic findings, Holter recordings of the multisystem inflammatory syndrome in children, and to identify prognostic factors for cardiac involvement.

METHODS

We retrospectively reviewed demographic characteristics, medical data, laboratory findings, electrocardiogram and echocardiographic findings, 24-hour Holter recordings, need for an ICU, and extracorporeal membrane oxygenation in multisystem inflammatory syndrome in children. Acute left ventricular systolic dysfunction was defined as left ventricular ejection fraction (EF) ≤%55 on echocardiography.

RESULTS

Sixty-seven children were included in the study. 24-hour Holters were recorded in 61.2% of the patients and 49.2% were normal. On echocardiographic examination, 14.9% of the patients had systolic dysfunction (EF ≤ 55%). While 32.8% of patients had mild mitral regurgitation, 3% had moderate mitral regurgitation, and 6% had mild aortic regurgitation. There was no statistically significant difference in EF values between the group with arrhythmia in Holter and the group with normal Holter results (p ≥ 0.05). B-type natriuretic peptide was positively correlated with C-reactive protein, ferritin, and fibrinogen. Significant effectivity of the B-type natriuretic peptide value was observed in the differentiation of those with EF ≤ and > 55%. Extracorporeal membrane oxygenation support was needed for three (4.5%) patients. One patient who died had systemic juvenile idiopathic arthritis.

CONCLUSIONS

Neutrophil/lymphocyte ratio, C-reactive protein, D-dimer, ferritin, troponin, and B-type natriuretic peptide were found to be significantly higher in patients with systolic dysfunction. Also, the cut-off value of 1700 pg/ml for B-type natriuretic peptide was significantly effective. These parameters may indicate the severity of the disease but should be supported by prospective studies.

Expanding the Differential for Alternative Diagnoses in the Workup of Multisystem Inflammatory Syndrome in Children

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a rare inflammatory syndrome associated with SARS-CoV-2 infection. Children are increasingly admitted for MIS-C evaluation, but instead found to have alternative diagnoses.

METHODS

Retrospective study of all pediatric patients <21 years of age hospitalized between August 1, 2020, and July 31, 2021, with clinical concern for MIS-C at the time of presentation were identified through use of an institutional computerized MIS-C order entry set. Final diagnoses were then collected through primary review of the medical record from the time of initial presentation through 1-month postdischarge.

RESULTS

Of 359 cases identified through the MIS-C order entry set, 126 (35.1%) met criteria for MIS-C, 28 had Kawasaki Disease (KD) (7.8%), and 11 cases met criteria for both MIS-C and KD (3.1%), leaving 194 (54.0%) patients ruled out and categorized as "MIS-C mimickers." Infectious diagnoses were the most common MIS-C mimickers (78.9%). Of the infectious etiologies, bacterial (51.0%) and viral (52.3%) etiologies were seen with similar frequency.

CONCLUSIONS

We describe MIS-C mimickers spanning multiple subspecialties, with infectious etiologies predominating, which can aid clinicians in the consideration of diagnostic testing, with the goal of achieving timely and accurate diagnoses.

Diagnosis of Multisystem Inflammatory Syndrome in Children by a Whole-Blood Transcriptional Signature

BACKGROUND

To identify a diagnostic blood transcriptomic signature that distinguishes multisystem inflammatory syndrome in children (MIS-C) from Kawasaki disease (KD), bacterial infections, and viral infections.

METHODS

Children presenting with MIS-C to participating hospitals in the United Kingdom and the European Union between April 2020 and April 2021 were prospectively recruited. Whole-blood RNA Sequencing was performed, contrasting the transcriptomes of children with MIS-C (n = 38) to those from children with KD (n = 136), definite bacterial (DB; n = 188) and viral infections (DV; n = 138). Genes significantly differentially expressed (SDE) between MIS-C and comparator groups were identified. Feature selection was used to identify genes that optimally distinguish MIS-C from other diseases, which were subsequently translated into RT-qPCR assays and evaluated in an independent validation set comprising MIS-C (n = 37), KD (n = 19), DB (n = 56), DV (n = 43), and COVID-19 (n = 39).

RESULTS

In the discovery set, 5696 genes were SDE between MIS-C and combined comparator disease groups. Five genes were identified as potential MIS-C diagnostic biomarkers (HSPBAP1, VPS37C, TGFB1, MX2, and TRBV11-2), achieving an AUC of 96.8% (95% CI: 94.6%-98.9%) in the discovery set, and were translated into RT-qPCR assays. The RT-qPCR 5-gene signature achieved an AUC of 93.2% (95% CI: 88.3%-97.7%) in the independent validation set when distinguishing MIS-C from KD, DB, and DV.

CONCLUSIONS

MIS-C can be distinguished from KD, DB, and DV groups using a 5-gene blood RNA expression signature. The small number of genes in the signature and good performance in both discovery and validation sets should enable the development of a diagnostic test for MIS-C.

Severe SARS-CoV-2 and respiratory syncytial virus co-infection in two children

The Coronavirus Disease 2019 (COVID-19) caused by a novel coronavirus (SARS-CoV-2) affects mainly older adults. Those with comorbidities are at a higher risk of severe disease and even death. The symptomatic infection rate of children is lower, manifestations are milder, and severe forms are scarce. We present here two children with severe COVID-19 and a respiratory syncytial virus, with the goal of emphasizing the possibility of coinfection with a severe course and a different result. The microbiological diagnosis was made using multiplex PCR. This assay not only provided an early and accurate diagnosis but also aided in the implementation of contact precautions. Further research should be done to determine the influence of coinfection on the clinical course and outcome of pediatric patients.

[Kawasaki disease and multisystem inflammatory syndrome in children. Differences, and similarities in a pediatric center in Mexico]

OBJECTIVE

To evaluate the differences and similarities in clinical picture, laboratory findings and outcomes between children's with Kawasaki Disease (KD) versus multisystem inflammatory syndrome (MIS-C).

METHODS

We conducted a retrospective, comparative study from children with Kawasaki Disease (KD) hospi-talized in Sinaloa Pediatric Hospital from January 1, 2004, to March 31, 2020, and patients with multisystem inflammatory syndrome (MIS-C) according with World Health Organization (WHO) case definition criteria be-tween May 1, 2020 and May 31, 2021. Demographic characteristics, epidemiological data, clinical features, laboratory findings, type of treatment and clinical outcomes were compared among both groups.

RESULTS

Eighty-one patients were included (62 patients with KD and 19 with MIS-C). several clinical and lab-oratory differences were found among these two entities. Median age was lower in KD vs. MIS-C (25 vs 79 months). Those finding more frequent in KD were male gender (64.5 vs. 47.4%), Mucocutaneous features (93.5 vs. 63.2%): Oral changes (83.9 vs. 63.2%) and extremity changes (77.4 vs. 57.9%); complete form of KD was (75.8 vs. 47.4%), Coronary artery aneurysm (16.1 vs. 11.8%). Secondly, findings that were more frequent in MIS-C than KD were Gastrointestinal involvement (89.4 vs. 9.6%), shock (57.9 vs. 3.2%), neurological symp-toms (63.1 vs. 11.2%), kidney involvement (52.6 vs. 16.1%), heart disease in general (52.9% vs 29%): Myocardial dysfunction (23.5 vs. 11.3%) and pericardial effusion (17.6 vs. 2.9%). Lymphocyte count (2.07 + 2.03 vs. 4.28 + 3.01/mm3), platelet count (197.89 + 187.51 vs. 420.37 + 200.08/mm3); serum albumin (2.29 + 0.65 vs. 3.33 + 0.06g/dL), and CPR (21.4 + 11.23 vs. 14.26 + 12.37 mg/dL). KD vs. MIS-C types of Treatment: IVIG (96.8 vs. 94.7%), systemic steroids (4.82 vs. 94.7%), IVIG resistance (19.4 vs. 15.8). Finally, mortality in KD was 0% and 5.3% in MIS-C.

CONCLUSIONS

Similarities were found in both groups such as fever, rash, and conjunctivitis. Nevertheless, signifi-cant differences such as severity of clinical presentation with multi-organ involvement and worst inflammato-ry response were found more frequently in MIS-C group than KD group, requiring more fluid replacement, use of inotropic agents and higher steroids dosages. Also, mortality rate was higher in patients with MIS-C thanpatients with KD. Similar results have been observed in other studies where both disorders were compared.

Immunomodulatory Therapy for MIS-C

CONTEXT

Studies comparing initial therapy for multisystem inflammatory syndrome in children (MIS-C) provided conflicting results.

OBJECTIVE

To compare outcomes in MIS-C patients treated with intravenous immunoglobulin (IVIG), glucocorticoids, or the combination thereof.

DATA SOURCES

Medline, Embase, CENTRAL and WOS, from January 2020 to February 2022.

STUDY SELECTION

Randomized or observational comparative studies including MIS-C patients <21 years.

DATA EXTRACTION

Two reviewers independently selected studies and obtained individual participant data. The main outcome was cardiovascular dysfunction (CD), defined as left ventricular ejection fraction < 55% or vasopressor requirement ≥ day 2 of initial therapy, analyzed with a propensity score-matched analysis.

RESULTS

Of 2635 studies identified, 3 nonrandomized cohorts were included. The meta-analysis included 958 children. IVIG plus glucocorticoids group as compared with IVIG alone had improved CD (odds ratio [OR] 0.62 [0.42-0.91]). Glucocorticoids alone group as compared with IVIG alone did not have improved CD (OR 0.57 [0.31-1.05]). Glucocorticoids alone group as compared with IVIG plus glucocorticoids did not have improved CD (OR 0.67 [0.24-1.86]). Secondary analyses found better outcomes associated with IVIG plus glucocorticoids compared with glucocorticoids alone (fever ≥ day 2, need for secondary therapies) and better outcomes associated with glucocorticoids alone compared with IVIG alone (left ventricular ejection fraction < 55% ≥ day 2).

LIMITATIONS

Nonrandomized nature of included studies.

CONCLUSIONS

In a meta-analysis of MIS-C patients, IVIG plus glucocorticoids was associated with improved CD compared with IVIG alone. Glucocorticoids alone was not associated with improved CD compared with IVIG alone or IVIG plus glucocorticoids.

Mechanisms of impairment of interferon production by SARS-CoV-2

Interferons (IFNs) are crucial components of the cellular innate immune response to viral infections. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown a remarkable capacity to suppress the host IFN production to benefit viral replication and spread. Thus far, of the 28 known virus-encoded proteins, 16 have been found to impair the host's innate immune system at various levels ranging from detection and signaling to transcriptional and post-transcriptional regulation of expression of the components of the cellular antiviral response. Additionally, there is evidence that the viral genome encodes non-protein-coding microRNA-like elements that could also target IFN-stimulated genes. In this brief review, we summarise the current state of knowledge regarding the factors and mechanisms by which SARS-CoV-2 impairs the production of IFNs and thereby dampens the host's innate antiviral immune response.

Impacts of SARS-CoV-2 on diabetes mellitus: A pre and post pandemic evaluation

The coronavirus disease 2019 (COVID-19) pandemic caused by the novel beta coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) crippled the whole world and has resulted in large number of morbidity and mortality. The origin of the SARS-CoV-2 is still disputed. The risk of infection with SARS-CoV-2 is dependent on several risk factors as observed in many studies. The severity of the disease depends on many factors including the viral strain, host immunogenetics, environmental factors, host genetics, host nutritional status and presence of comorbidities like hypertension, diabetes, Chronic Obstructive Pulmonary Disease, cardiovascular disease, renal impairment. Diabetes is a metabolic disorder mainly characterized by hyperglycemia. Diabetic individuals are intrinsically prone to infections. SARS-CoV-2 infection in patients with diabetes result in β-cell damage and cytokine storm. Damage to the cells impairs the equilibrium of glucose, leading to hyperglycemia. The ensuing cytokine storm causes insulin resistance, especially in the muscles and liver, which also causes a hyperglycemic state. All of these increase the severity of COVID-19. Genetics also play pivotal role in disease pathogenesis. This review article focuses from the probable sources of coronaviruses and SARS-CoV-2 to its impacts on individuals with diabetes and host genetics in pre- and post-pandemic era.

Kawasaki Disease and Inborn Errors of Immunity: Exploring the Link and Implications

The exact etiopathogenesis of Kawasaki disease (KD), the most common childhood vasculitis, remains unknown; however, an aberrant immune response, possibly triggered by an infectious or environmental agent in genetically predisposed children, is believed to be the underlying pathogenetic mechanism. Patients with inborn errors of immunity (IEI) are predisposed to infections that trigger immune dysregulation due to an imbalance in various arms of the immune system. KD may develop as a complication in both primary and secondary immunodeficiencies. KD may occur either at disease presentation or have a later onset in IEIs. These include X-linked agammaglobulinemia (XLA), selective IgA deficiency, transient hypogammaglobulinemia of infancy; Wiskott-Aldrich syndrome (WAS), hyper IgE syndrome (HIES); chronic granulomatous disease (CGD), innate and intrinsic immunity defects, and autoinflammatory diseases, including PFAPA. Hitherto, the association between KD and IEI is confined to specific case reports and case series and, thus, requires extensive research for a comprehensive understanding of the underlying pathophysiological mechanisms. IEIs may serve as excellent disease models that would open new insights into the disease pathogenesis of children affected with KD. The current review highlights this critical association between KD and IEI supported by published literature.

Comparison of Clinical Manifestations of Kawasaki Disease According to SARS-CoV-2 Antibody Positivity

BACKGROUND

Kawasaki disease (KD) is the most common cause of acquired heart disease in paediatric patients, with infectious agents being the main cause. This study aimed to determine whether there are differences in the clinical manifestations of KD between patients with and without severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies.

METHODS

From January 1, 2021 to August 15, 2022, 82 patients with analysable echocardiographic data were diagnosed with KD. Twelve patients with multisystem inflammatory syndrome in children were excluded. Serologic tests were performed by chemiluminescence immunoassay for both the nucleocapsid (N) and the spike (S) proteins in blood samples. Among the 70 patients diagnosed with KD at Jeonbuk University Children's Hospital, the SARS-CoV-2 antibody test was performed in 41 patients.

RESULTS

The SARS-CoV-2 antibody test results for the N antigen were positive in 12 patients, while those for S protein were positive in 14 patients. N antigen SARS-CoV-2 antibody-positive KD was different from N antigen SARS-CoV-2 antibody-negative KD in terms of sex (male predominance in the positive group, 83.3% vs. female predominance in the negative group 62.1%, P = 0.008) and the incidence of refractory KD (41.7% vs. 10.3%, P = 0.034). The pro-B-type natriuretic peptide level was lower in the N-antigen SARS-CoV-2 antibody-positive KD group than that in the negative group (518.9 ± 382.6, 1,467.0 ± 2,417.6, P = 0.049). No significant differences in the echocardiographic findings between both groups were noted. In the multi-variable analysis, SARS-CoV-2 antibody (N antigen) was the only predictor of refractory KD (odds ratio, 13.70; 95% confidence interval, 1.63-115.44; P = 0.016).

CONCLUSION

High incidence of intravenous immunoglobulin-refractory KD may occur in up to 40% of the patients having recent history of coronavirus disease 2019. For patients having KD with N-type SARS-CoV-2 antibody positivity, adjunctive treatment, such as corticosteroids, can be considered as the first line of treatment.

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.

Platelet role in the prediction of MIS-C severity

Introduction

Multisystem inflammatory syndrome in children (MIS-C) has been reported as one of the cytokine storm syndromes associated with COVID-19. Despite the several proposed diagnostic criteria, MIS-C remains a diagnostic and clinical challenge. Recent studies have demonstrated that platelets (PLTs) play a crucial role in COVID-19 infection and its prognosis. This study aimed to investigate the clinical importance of PLT count and PLT indices in predicting MIS-C severity in children.

Patients and methods

We conducted a retrospective single-center study at our university hospital. A total of 43 patients diagnosed with MIS-C during a 2-year period (from October 2020 to October 2022) were included in the study. MIS-C severity was evaluated according to the composite severity score.

Results

Half of the patients were treated in the pediatric intensive care unit. No single clinical sign was associated with a severe condition, except for shock (p = 0.041). All the routine biomarkers, such as complete blood count (CBC) and C-reactive protein (CRP), used for MIS-C diagnosis were significant in predicting MIS-C severity. Single PLT parameters, such as mean PLT volume, plateletcrit, or PLT distribution width, did not differ between the severity groups. However, we found that a combination of PLT count and the previously mentioned PLT indices had the potential to predict MIS-C severity.

Conclusions

Our study emphasizes the importance of PLT in MIS-C pathogenesis and severity. It revealed that together with routine biomarkers (e.g., CBC and CRP), it could highly improve the prediction of MIS-C severity.

Long COVID in Children: A Multidisciplinary Review

Long COVID syndrome has emerged as a long-lasting consequence of acute SARS-CoV-2 infection in adults. In addition, children may be affected by Long COVID, with potential clinical issues in different fields, including problems in school performance and daily activities. Yet, the pathophysiologic bases of Long COVID in children are largely unknown, and it is difficult to predict who will develop the syndrome. In this multidisciplinary clinical review, we summarise the latest scientific data regarding Long COVID and its impact on children. Special attention is given to diagnostic tests, in order to help the physicians to find potential disease markers and quantify impairment. Specifically, we assess the respiratory, upper airways, cardiac, neurologic and motor and psychological aspects. Finally, we also propose a multidisciplinary clinical approach.

Coronavirus disease 2019 and gastrointestinal disorders in children

During the past 3 years, the coronavirus disease 2019 (COVID-19) pandemic has had a great impact on people all over the world. However, it has become evident that disease manifestations and severity differ across age groups. Most children have a milder disease course than adults but possibly more pronounced gastrointestinal (GI) symptoms. Given the child's developing immune system, the impact of COVID-19 on disease development may differ compared to adults. This study reviews the potential bi-directional relationship between COVID-19 and GI diseases in children, focusing on common pediatric conditions such as functional GI disorders (FGID), celiac disease (CeD), and inflammatory bowel disease (IBD). Children with GI diseases, in general, and CeD and IBD, in particular, do not seem to have an increased risk of severe COVID-19, including risks of hospitalization, critical care need, and death. While infections are considered candidate environmental factors in both CeD and IBD pathogenesis, and specific infectious agents are known triggers for FGID, there is still not sufficient evidence to implicate COVID-19 in the development of either of these diseases. However, given the scarcity of data and the possible latency period between environmental triggers and disease development, future investigations in this field are warranted.

Cytokine Storm Syndromes in Pediatric Patients

Cytokine storm syndromes (CSS) represent a diverse group of disorders characterized by severe overactivation of the immune system. In the majority of patients, CSS arise from a combination of host factors, including genetic risk and predisposing conditions, and acute triggers such as infections. CSS present differently in adults than in children, who are more likely to present with monogenic forms of these disorders. Individual CSS are rare, but in aggregate represent an important cause of severe illness in both children and adults. We present 3 rare, illustrative cases of CSS in pediatric patients that describe the spectrum of CSS.

Identification of Multisystem Inflammatory Syndrome in Children Classes and Development of Hyperinflammation Score in Pediatric COVID-19

The aim of this study is to describe characteristics and hospital course of children admitted with COVID-19 to a tertiary care pediatric center in Southeastern United States, and to present the frequency of three classes of multisystem inflammatory syndrome in children (MIS-C) and develop pediatric COVID-19 associated hyperinflammation score (PcHIS). A retrospective cohort study of 68 children was performed. Critical illness was defined as any child requiring respiratory or cardiovascular support or renal replacement therapy. PcHIS was developed by using six variables: fever, hematological dysfunction, coagulopathy, hepatic injury, macrophage activation, and cytokinemia. Centers for Disease Control and Prevention criteria were used to identify MIS-C, and three classes of MIS-C were identified based on the findings of recently published latent class analysis (Class 1: MIS-C without Kawasaki like disease, Class 2: MIS-C with respiratory disease, and Class 3: MIS-C with Kawasaki like disease). The median age was 6.4 years. Fever, respiratory, and gastrointestinal were common presenting symptoms. MIS-C was present in 32 (47%), critical COVID-19 illness in 11 (16%), and 17 (25%) were admitted to the PICU. Children with critical illness were adolescents with elevated body mass index and premorbid conditions. PcHIS score of 3 had a sensitivity of 100% and a specificity of 77% for predicting critical COVID-19 illness. Among MIS-C patients, 15 (47%) were in Class 1, 8 (25%) were in Class 2, and 9 (28%) were in Class 3. We conclude that most children with COVID-19 have mild-to-moderate illness. Critical COVID-19 is mainly seen in obese adolescents with premorbid conditions. Three Classes of MIS-C are identifiable based on clinical features. Validation and clinical implication of inflammation score in pediatric COVID-19 need further investigation.

MIS-C across three SARS-CoV-2 variants: Changes in COVID-19 testing and clinical characteristics in a cohort of U.S. children

As new variants of SARS-Co-V 2 have emerged over time and Omicron sub-variants have become dominant, the severity of illness from COVID-19 has declined despite greater transmissibility. There are fewer data on how the history, diagnosis, and clinical characteristics of multisystem inflammatory syndrome in children (MIS-C) have changed with evolution in SARS-CoV-2 variants. We conducted a retrospective cohort study of patients hospitalized with MIS-C between April 2020 and July 2022 in a tertiary referral center. Patients were sorted into Alpha, Delta, and Omicron variant cohorts by date of admission and using national and regional data on variant prevalence. Among 108 patients with MIS-C, significantly more patients had a documented history of COVID-19 in the two months before MIS-C during Omicron (74%) than during Alpha (42%) (p = 0.03). Platelet count and absolute lymphocyte count were lowest during Omicron, without significant differences in other laboratory tests. However, markers of clinical severity, including percentage with ICU admission, length of ICU stay, use of inotropes, or left ventricular dysfunction, did not differ across variants. This study is limited by its small, single-center case series design and by classification of patients into era of variant by admission date rather than genomic testing of SARS- CoV-2 samples.     Conclusion: Antecedent COVID-19 was more often documented in the Omicron than Alpha or Delta eras, but clinical severity of MIS-C was similar across variant eras. What is Known: • There has been a decrease in incidence of MIS-C in children despite widespread infection with new variants of COVID-19. • Data has varied on if the severity of MIS-C has changed over time across different variant infections. What is New: • MIS-C patients were significantly more likely to report a known prior infection with SARS-CoV-2 during Omicron than during Alpha. • There was no difference in severity of MIS-C between the Alpha, Delta, and Omicron cohorts in our patient population.

Respiratory Care in Children with COVID-19

The novel coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is causing significant morbidity and mortality worldwide. The common presentations in children include involvement of respiratory system leading to pneumonia and acute respiratory distress syndrome, as well as multiorgan dysfunction syndrome and multisystem inflammatory syndrome in children (MIS-C). Pediatric COVID-19 is a milder disease as compared with the adults. Also, there is rise in MIS-C cases which is a hyperinflammatory condition temporally associated with SARS-CoV-2. Since respiratory system is predominantly involved, few of these critically ill children often require respiratory support which can range from simple oxygen delivery devices, high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), invasive mechanical ventilation, and extracorporeal membrane oxygenation (ECMO). Most of the oxygen delivery devices and respiratory interventions generate aerosols and pose risk of transmission of virus to health care providers (HCPs). The use of HFNC and NIV should be limited to children with mild respiratory distress preferably in negative pressure rooms and with adequate personal protective equipment (PPE). However, there should be low thresholds for intubation and invasive mechanical ventilation in the event of clinical deterioration while on any respiratory support. The principle of providing respiratory support requires special droplet and air-borne precautions to limit exposure or transmission of virus to HCPs and at the same time ensuring safety of the patient.

Severity and mortality associated with COVID-19 among children hospitalised in tertiary care centres in India: a cohort study

Background

It is critical to identify high-risk groups among children with COVID-19 from low-income and middle-income countries (LMICs) to facilitate the optimum use of health system resources. The study aims to describe the severity and mortality of different clinical phenotypes of COVID-19 in a large cohort of children admitted to tertiary care hospitals in India.

Methods

Children aged 0-19 years with evidence of SARS-CoV-2 infection (real time polymerase chain reaction or rapid antigen test positive) or exposure (anti-SARS-CoV-2 antibody, or history of contact with SARS-CoV-2) were enrolled in the study, between January 2021 and March 2022 across five tertiary hospitals in India. All study participants enrolled prospectively and retrospectively were followed up for three months after discharge. COVID-19 was classified into severe (Multisystem Inflammatory Syndrome in Children (MIS-C), severe acute COVID-19, 'unclassified') or non-severe disease. The mortality rates were estimated in different phenotypes.

Findings

Among 2468 eligible children enrolled, 2148 were hospitalised. Signs of illness were present in 1688 (79%) children with 1090 (65%) having severe disease. High mortality was reported in MIS-C (18.6%), severe acute COVID-19 (13.3%) and the unclassified severe COVID-19 disease (12.3%). Mortality remained high (17.5%) when modified MIS-C criteria was used. Non-severe COVID-19 disease had 14.1% mortality when associated with comorbidity.

Interpretation

Our findings have important public health implications for low resource settings. The high mortality underscores the need for better preparedness for timely diagnosis and management of COVID-19. Children with associated comorbidity or coinfections are a vulnerable group and need special attention. MIS-C requires context specific diagnostic criteria for low resource settings. It is important to evaluate the clinical, epidemiological and health system-related risk factors associated with severe COVID-19 and mortality in children from LMICs.

Funding

Department of Biotechnology, Govt of India and Department of Maternal, Child and Adolescent Health and Aging, WHO, Geneva, Switzerland.

Management of Multisystem Inflammatory Syndrome in Children: Decision-Making Regarding a New Condition in the Absence of Clinical Trial Data

Multisystem inflammatory syndrome in children (MIS-C) is a new illness that evolved during the COVID-19 pandemic with initial reports of severe disease including use of extracorporeal membrane oxygenation and death. Institutions rapidly assembled task forces to develop treatment algorithms. At the national/international levels, collaboratives and associations assembled consensus writing groups to draft guidelines. These guidelines and algorithms were initially on the basis of expert opinion and small case series. Some groups used the Delphi approach, and the resultant guidelines often mimicked those for other conditions that resembled MIS-C, like Kawasaki disease (KD). For instance, intravenous immunoglobulin (IVIG), a known effective treatment for KD, was recommended for MIS-C. Early in the pandemic many favoured IVIG over steroids as first-line therapy. As evidence evolved so did some guidelines, which now endorse the dual use of IVIG with steroids as first-line therapy. In contrast, withholding immunotherapy became an option for some MIS-C patients with mild symptoms. Herein, we review guidelines and discuss the evidence informing early recommendations, how this has evolved, the role and limitations of expert opinion and observational data, and the importance of leveraging existing research infrastructures, such as the intensive care unit collaborative (Overcoming COVID-19 surveillance registry), and the International Kawasaki Disease Registry. Finally, we discuss strategies to rapidly develop, deploy, and adapt clinical trials evaluating the treatment of such rare conditions in children, which might include alternatives to conventional clinical trial design. The emergence of MIS-C during the COVID-19 pandemic has highlighted unmet needs regarding research of a new condition.

SARS-CoV-2 Infection and COVID-19 in Children

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is common in children, and clinical manifestations can vary depending on age, underlying disease, and vaccination status. Most children will have asymptomatic or mild infection, but certain baseline characteristics can increase the risk of moderate to severe disease. The following article will provide an overview of the clinical manifestations of coronavirus disease 2019 in children, including the post-infectious phenomenon called multisystem inflammatory syndrome in children. Currently available treatment and prophylaxis strategies will be outlined, with the caveat that new therapeutics and clinical efficacy data are constantly on the horizon.

Risk Factors for Multisystem Inflammatory Syndrome in Children: A Case-control Investigation

BACKGROUND

In a 2020 pilot case-control study using medical records, we reported that non-Hispanic Black children were more likely to develop multisystem inflammatory syndrome in children (MIS-C) after adjustment for sociodemographic factors and underlying medical conditions. Using structured interviews, we investigated patient, household, and community factors underlying MIS-C likelihood.

METHODS

MIS-C case patients hospitalized in 2021 across 14 US pediatric hospitals were matched by age and site to outpatient controls testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within 3 months of the admission date. Caregiver interviews queried race/ethnicity, medical history, and household and potential community exposures 1 month before MIS-C hospitalization (case-patients) or after SARS-CoV-2 infection (controls). We calculated adjusted odds ratios (aOR) using mixed-effects multivariable logistic regression.

RESULTS

Among 275 case patients and 496 controls, race/ethnicity, social vulnerability and patient or family history of autoimmune/rheumatologic disease were not associated with MIS-C. In previously healthy children, MIS-C was associated with a history of hospitalization for an infection [aOR: 4.8; 95% confidence interval (CI): 2.1-11.0]. Household crowding (aOR: 1.7; 95% CI: 1.2-2.6), large event attendance (aOR: 1.7; 95% CI: 1.3-2.1), school attendance with limited masking (aOR: 2.6; 95% CI: 1.1-6.6), public transit use (aOR: 1.8; 95% CI: 1.4-2.4) and co-resident testing positive for SARS-CoV-2 (aOR: 2.2; 95% CI: 1.3-3.7) were associated with increased MIS-C likelihood, with risk increasing with the number of these factors.

CONCLUSIONS

From caregiver interviews, we clarify household and community exposures associated with MIS-C; however, we did not confirm prior associations between sociodemographic factors and MIS-C.

Emerging Insights Into the Pathophysiology of Multisystem Inflammatory Syndrome Associated With COVID-19 in Children

Multisystem inflammatory syndrome in children (MIS-C) has emerged as a rare delayed hyperinflammatory response to SARS-CoV-2 infection and causes severe morbidity in the pediatric age group. Although MIS-C shares many clinical similarities to Kawasaki disease (KD), important differences in epidemiologic, clinical, immunologic, and potentially genetic factors exist and suggest potential differences in pathophysiology and points to be explored and explained. Epidemiologic features include male predominance, peak age of 6 to12 years, and specific racial or ethnicity predilections. MIS-C is characterized by fever, prominent gastrointestinal symptoms, mucocutaneous manifestations, respiratory symptoms, and neurologic complaints, and patients often present with shock. Cardiac complications are frequent and include ventricular dysfunction, valvular regurgitation, pericardial effusion, coronary artery dilation and aneurysms, conduction abnormalities, and arrhythmias. Emerging evidence regarding potential immunologic mechanisms suggest that an exaggerated T-cell response to a superantigen on the SARS-CoV-2 spike glycoprotein-as well as the formation of autoantibodies against cardiovascular, gastrointestinal, and endothelial antigens-are major contributors to the inflammatory milieu of MIS-C. Further studies are needed to determine both shared and distinct immunologic pathway(s) that underlie the pathogenesis of MIS-C vs both acute SARS-CoV-2 infection and KD. There is evidence to suggest that the rare risk of more benign mRNA vaccine-associated myopericarditis is outweighed by a reduced risk of more severe MIS-C. In the current review, we synthesize the published literature to describe associated factors and potential mechanisms regarding an increased risk of MIS-C and cardiac complications, provide insights into the underlying immunologic pathophysiology, and define similarities and differences with KD.

Multi-Inflammatory Syndrome in Children (MIS-C) in 2023: Is It Time to Forget about It?

Multisystem inflammatory syndrome in children (MIS-C) is defined as a clinically serious condition requiring hospitalization involving fever, multi-system organ dysfunction, and an increase in inflammatory biomarkers. The syndrome was originally described as a post-infectious complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which usually causes COVID-19. During the COVID-19 pandemic, not only did the virus undergo mutations but vaccines against SARS-CoV-2 were also developed. Both these conditions led to a decrease in the incidence of MIS-C. This narrative review summarizes the recent updates for MIS-C, particularly regarding the change in incidence, the link between the SARS-CoV-2 vaccine and MIS-C, and new updates of MIS-C treatments.

Clinical characteristics of COVID-19 associated vasculopathic diseases

Coronavirus disease 19 (COVID-19) has shown to be an infectious disease affecting not only of the respiratory system, but also cardiovascular system leading to different COVID-19-associated vasculopathies. Venous and arterial thromboembolic events have been frequently described among hospitalized patients with COVID-19 and inflammatory vasculopathic changes have also been observed. Several of the reported COVID-19 associated vasculopathies exhibit differences on epidemiology, clinical characteristics and outcome compared to non-COVID-19 types. This review focuses on the epidemiology, clinical, diagnostic and therapeutic characteristics as well as outcome data of COVID-19 associated thromboembolic events and inflammatory vasculopathies, elaborating similarities and differences with non-COVID-19 cohorts.

Case report: Fatal lung hyperinflammation in a preterm newborn with SARS-CoV-2 infection

Vertical transmission of SARS-CoV-2 from mother to fetus is widely accepted. Whereas most infected neonates present with mild symptoms or are asymptomatic, respiratory distress syndrome (RDS) and abnormal lung images are significantly more frequent in COVID-19 positive neonates than in non-infected newborns. Fatality is rare and discordant meta-analyses of case reports and series relating perinatal maternal COVID-19 status to neonatal disease severity complicate their extrapolation as prognostic indicators. A larger database of detailed case reports from more extreme cases will be required to establish therapeutic guidelines and allow informed decision making. Here we report an unusual case of a 28 weeks' gestation infant with perinatally acquired SARS-CoV-2, who developed severe protracted respiratory failure. Despite intensive care from birth with first line anti-viral and anti-inflammatory therapy, respiratory failure persisted, and death ensued at 5 months. Lung histopathology showed severe diffuse bronchopneumonia, and heart and lung immunohistochemistry confirmed macrophage infiltration, platelet activation and neutrophil extracellular trap formation consistent with late multisystem inflammation. To our knowledge, this is the first report of SARS CoV-2 pulmonary hyperinflammation in a preterm newborn with fatal outcome.

Left atrial strain in multisystem inflammatory syndrome in children (MIS-C) and associations with systemic inflammation and cardiac injury

Background

Multisystem inflammatory syndrome in children (MIS-C) commonly involves cardiac injury with both systolic and diastolic dysfunction. Left atrial strain (LAS) detects subclinical diastolic dysfunction in adults but is infrequently used in children. We evaluated LAS in MIS-C and the associations with systemic inflammation and cardiac injury.

Methods

In this retrospective cohort study, conventional parameters and LAS (reservoir [LAS-r], conduit [LAS-cd], and contractile [LAS-ct]) obtained from admission echocardiograms of MIS-C patients were compared to healthy controls and between MIS-C patients with and without cardiac injury (BNP >500 pg/ml or troponin-I >0.04 ng/ml). Correlation and logistic regression analyses were performed to assess LAS associations with admission inflammatory and cardiac biomarkers. Reliability testing was performed.

Results

Median LAS components were reduced in MIS-C patients (n=118) compared to controls (n=20) (LAS-r: 31.8 vs. 43.1%, p<0.001; LAS-cd: -28.8 vs. -34.5%, p=0.006; LAS-ct: -5.2 vs. -9.3%, p<0.001) and reduced in MIS-C patients with cardiac injury (n=59) compared to no injury (n=59) (LAS-r: 29.6 vs. 35.8%, p=0.001; LAS-cd: -26.5 vs. -30.4%, p=0.036; LAS-ct: -4.6 vs. -9.3%, p=0.008). An LAS-ct peak was absent in 65 (55%) MIS-C patients but present in all controls (p<0.001). Procalcitonin had strong correlation with averaged E/e' (r=0.55, p=0.001); ESR had moderate correlation with LAS-ct (r=-0.41, p=0.007); BNP had moderate correlation with LAS-r (r=-0.39, p<0.001) and LAS-ct (r=0.31, p=0.023), and troponin-I had only weak correlations. No strain indices were independently associated with cardiac injury on regression analysis. Intra-rater reliability was good for all LAS components; and inter-rater reliability was good to excellent for LAS-r, and fair for LAS-cd and LAS-ct.

Conclusions

LAS analysis, particularly the absence of a LAS-ct peak, was reproducible and may be superior to conventional echocardiographic parameters for detecting diastolic dysfunction in MIS-C. No strain parameters on admission were independently associated with cardiac injury.

COVID-19 musculoskeletal involvement in children

Since the early phases of the COVID-19 pandemic, it has become clear that children are affected by mild respiratory symptoms rather than the critical pneumonia typical in adults. Nevertheless, it took longer to understand that pediatric patients with SARS-COV2 may develop a severe multisystem inflammatory response (a.k.a. multisystem inflammatory syndrome in children (MIS-C)), which can include musculoskeletal symptoms, and/or arthritis and myositis independently from MIS-C. Diagnostic imaging significantly contributed to the assessment of pulmonary disease due to COVID-19 but it has been rarely applied to evaluate musculoskeletal involvement in children with or without previous rheumatic diseases. Despite the paucity of radiological literature, muscle edema at magnetic resonance and synovitis at ultrasound have been described. Further use of diagnostic imaging for children with articular and muscular symptoms due to COVID-19 is strongly encouraged.

Home-Based Exercise Training in the Recovery of Multisystem Inflammatory Syndrome in Children: A Case Series Study

OBJECTIVE

To assess the potential therapeutic role of exercise on health-related quality of life, assessed by the Pediatric Outcomes Data Collection Instrument (PODCI), coronary flow reserve (CFR), cardiac function, cardiorespiratory fitness, and inflammatory and cardiac blood markers in multisystemic inflammatory syndrome in children (MIS-C) patients.

METHODS

This is a case series study of a 12-wk, home-based exercise intervention in children and adolescents after MIS-C diagnosis. From 16 MIS-C patients followed at our clinic, 6 were included (age: 7-16 years; 3 females). Three of them withdrew before the intervention and served as controls. The primary outcome was health-related quality of life, assessed PODCI. Secondary outcomes were CFR assessed by 13N-ammonia PET-CT imaging, cardiac function by echocardiography, cardiorespiratory fitness, and inflammatory and cardiac blood markers.

RESULTS

In general, patients showed poor health-related quality of life, which seemed to be improved with exercise. Additionally, exercised patients showed improvements in coronary flow reserve, cardiac function, and aerobic conditioning. Non-exercised patients exhibited a slower pattern of recovery, particularly in relation to health-related quality of life and aerobic conditioning.

CONCLUSIONS

Our results suggest that exercise may play a therapeutic role in the treatment of post-discharge MIS-C patients. As our design does not allow inferring causality, randomized controlled trials are necessary to confirm these preliminary findings.

Profile of Cardiac Involvement in Children After Exposure to COVID-19

OBJECTIVE

To evaluate the incidence and pattern of cardiac involvement in children post-COVID (coronavirus disease) infection in a tertiary care referral hospital in India.

METHODS

A prospective observational study was conducted including all consecutive children with suspected MIS-C referred to the cardiology services.

RESULTS

Of the 111 children with mean (SD) age was 3.5 (3.6) years, 95.4% had cardiac involvement. Abnormalities detected were coronary vasculopathy, pericardial effusion, valvular regurgitation, ventricular dysfunction, diastolic flow reversal in aorta, pulmonary hypertension, bradycardia and intra-cardiac thrombus. The survival rate post treatment was 99%. Early and short-term follow-up data was available in 95% and 70%, respectively. Cardiac parameters improved in majority.

CONCLUSION

Cardiac involvement post COVID-19 is often a silent entity and may be missed unless specifically evaluated for. Early echocardiography aided prompt diagnosis, triaging, and treatment, and helps in favorable outcomes.