Three-Dimensional Echocardiography and Global Longitudinal Strain in Follow-Up After Multisystem Inflammatory Syndrome in Children: Six-Month, Single-Center, Prospective Study.

OBJECTIVE: To assess the potential long-term cardiac effects after multisystem inflammatory syndrome in children (MIS-C) with cardiovascular involvement in the acute phase. STUDY DESIGN: Our prospective study involved children consecutively diagnosed with MIS-C between October 2020 and February 2022 and followed 6 weeks and 6 months after the disease. In patients with severe cardiac involvement during the acute phase, an additional check-up after 3 months was scheduled. In all patients at all check-ups, 3-dimensional echocardiography and global longitudinal strain (GLS) were used to assess ventricular function. RESULTS: The study enrolled 172 children aged 1-17 years (median, 8 years). The means of ejection fraction (EF) and GLS for both ventricles were within normal limits after 6 weeks with no relationship with initial severity: left ventricular EF (LVEF) 60% (59%-63%), LV GLS -21.08% (-18.63% to -23.2%), right ventricular (RV) EF 64% (62%-67%), and RV GLS -22.8% (-20.5% to -24.5%). Further, statistically significant improvement of LV function was observed after 6 months-LVEF 63% (62%-65%) and LV GLS -22.55% (-21.05% to -24.25%; P < .05); however, RV function remained unchanged. The group with severe cardiac involvement showed LV function recovery pattern with no significant improvement between 6 weeks and 3 months after MIS-C, while still improving between 3 and 6 months after discharge. CONCLUSIONS: LV and RV function is within normal limits 6 weeks after MIS-C regardless of severity of cardiovascular involvement; LV function improves further between 6 weeks and 6 months after the disease. The long-term prognosis is optimistic with full recovery of cardiac function.

SARS-COV-2 Infection in Children and Young People in Bulgaria - A Prospective, Single-Center, Cohort Study

Compared to other respiratory viruses, the proportion of hospitalizations due to SARS-CoV-2 among children is relatively low. While severe illness is not common among children and young individuals, a particular type of severe condition called multisystem inflammatory syndrome in children (MIS-C) has been reported. The aim of this prospective cohort study, which followed a group of individuals under the age of 19, was to examine the characteristics of patients who had contracted SARS-CoV-2, including their coexisting medical conditions, clinical symptoms, laboratory findings, and outcomes. The study also aimed to investigate the features of children who met the WHO case definition of MIS-C, as well as those who required intensive care. A total of 270 patients were included between March 2020 and December 2021. The eligible criteria were individuals between 0-18 with a confirmed SARS-CoV-2 infection at the Infectious Disease Hospital "Prof. Ivan Kirov"in Sofia, Bulgaria. Nearly 76% of the patients were <= 12 years old. In our study, at least one comorbidity was reported in 28.1% of the cases, with obesity being the most common one (8.9%). Less than 5% of children were transferred to an intensive care unit. We observed a statistically significant difference in the age groups, with children between 5 and 12 years old having a higher likelihood of requiring intensive care compared to other age groups. The median values of PaO2 and SatO2 were higher among patients admitted to the standard ward, while the values of granulocytes and C-reactive protein were higher among those transferred to the intensive care unit. Additionally, we identified 26 children who met the WHO case definition for MIS-C. Our study data supports the evidence of milder COVID-19 in children and young individuals as compared to adults. Older age groups were associated with higher incidence of both MIS-C and ICU admissions.Copyright © 2023 P. Velikov et al., published by Sciendo.

Factors affecting disease severity of multisystem inflammatory syndrome in children

Purpose: Multisystem inflammatory syndrome that occurs after SARS-Cov-2 infection with fever, cardiogenic shock and hyperinflammation in children, can be life threatening. In this study, it was aimed to investigate the effects of the complaint and duration at diagnosis on the severity of multisystem inflammatory syndrome in children. Materials and methods: The medical records of 99 pediatric patients, who were diagnosed multisystem inflammatory syndrome between September 2020 and August 2021 according to Centers for Disease Control and Prevention, were evaluated retrospectively. Demographic features, initial findings, and admission time of patients were noted. Patients were categorized according to intensive care necessity. Results: The median age of the patients was 10 (2-18) and 62 (62.6%) of patients were male. The median duration before admission was 4 (1-10) days. All patients has fever, 81.8% had gastrointestinal and 75.8% had cardiovascular involvement at admission. The patients (56.6%) who were accepted as severe and moderate MIS-C required intensive care. Prolonged fever, delayed admission, cardiovascular involvement, high inflammatory markers, lymphopenia and thrombocytopenia were found to key parameters determining the need for intensive care. Conclusion: Multisystem inflammatory syndrome in children is a new disease characterized by fever, signs of inflammation and organ dysfunction associated with SARS-CoV-2 infection. Delayed admission, high cardiac and inflammatory markers at diagnosis increase the need for intensive care. © 2022, Pamukkale University. All rights reserved.

Anti-SARS-CoV-2 antibodies important in diagnostics of acute hepatitis in children

The most common causes of acute hepatitis in children are hepatitis A and autoimmune hepatitis. Hepatitis in the course of Wilson's disease is sporadically registered in adolescents. An increase of activity of aminotransferases both in the course of multisystem inflammatory syndrome in children (MIS-C) and in the course of COVID-19 has been observed. Hepatitis is common in children with MIS-C and is associated with a more severe presentation and persistent elevation of liver function tests. To date, no cases of acute hepatitis in children due to COVID-19 have been reported. We present 2 cases of acute hepatitis in children where the only cause seems to be a previous asymptomatic SARS-CoV-2 infection.Copyright © 2023 Termedia Publishing House Ltd.. All rights reserved.

Clinical profile and management of patients with pediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 - single-center experience

Introduction and aim. Pediatric Inflammatory Multisystem Syndrome (PIMS-TS) is a new condition that has emerged in children during the COVID-19 pandemic. Many clinical signs and symptoms resemble those found in Kawasaki disease (KD). Material and methods. The following data were considered: clinical presentation, comorbidities, laboratory findings, abnormalities in additional tests, exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the child and his family members, applied treatment and return to full health. Results. In the presented study nineteen children were analyzed. Fever was a universal finding in our group and it's mean duration was 7 days (range 5-9). Other common symptoms included abdominal pain and severe weakness (in 89.5%), rash and conjunctivitis (in 84.2%), vomiting (in 73.7%) and mucous membrane involvement (in 63.2%). In nearly half of cases, echocardiography revealed fluid in the pericardial sac and left ventricular systolic dysfunction (in 52.6% and 47.4% respectively). 21.1% of patients had coronary artery abnormalities. 26, 3% of the children required treatment with dopamine and/or milrinone. In 15.7% ICU admissions and assisted ventilation was necessary. No deaths were recorded. Conclusion. One should bear in mind that PIMS-TS can mimic KD, appendicitis and meningitis, which may pose a diagnostic challenge. © 2022 Publishing Office of the University of Rzeszow. All Rights Reserved.

Report of the Association Between Multisystem Inflammatory Syndrome and Severe Myocarditis

Introduction: The people worldwide have been affected by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection since its appearance in December, 2019. Kawasaki disease-like hyperinflammatory shock associated with SARS-CoV-2 infection in previously healthy children has been reported in the literature, which is now referred to as a multisystem inflammatory syndrome in children (MIS-C). Some aspects of MIS-C are similar to those of Kawasaki disease, toxic shock syndrome, secondary hemophagocytic syndrome, and macrophage activation syndrome. Case Presentation: This study reported an 11-year-old boy with MIS-C presented with periorbital and peripheral edema, abdominal pain, elevated liver enzymes, severe right pleural effusion, moderate ascites, and severe failure of right and left ventricles. Conclusion(s): Due to the increasing number of reported cases of critically ill patients afflicted with MIS-C and its life-threatening complications, it was recommended that further studies should be carried out in order to provide screening tests for myocardial dysfunction. Adopting a multidisciplinary approach was found inevitable.Copyright © 2023, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.

Inherited deficiency of the OAS-RNase L pathway in children with MIS-C

Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic dsRNA-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the ssRNA-degrading RNase L. Consistent with the absence of pneumonia in these patients, epithelial cells and fibroblasts defective for this pathway restricted SARS-CoV-2 normally. This contrasted with IFNAR1-deficient cells from patients prone to hypoxemic pneumonia without MIS-C. Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNASEL deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or SARS-CoV- 2 stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-but not RNase L- deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by MAVS deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C.Copyright © 2023 Elsevier Inc.

Cyclosporin for treatment of refractory multisystemic inflammatory syndrome in a child.

Multisystemic inflammatory syndrome in children is an inflammatory condition with multiorgan dysfunction that manifest late in the course of Severe acute respiratory syndrome coronavirus 2 infection. We present a 12-year-old boy with a history of fever, vomiting, diarrhoea, and abdominal pain. He developed shock with ventricular dysfunction and pericardial effusion. He was diagnosed with multisystemic inflammatory syndrome in children and treatment with intravenous immunoglobulins, corticosteroids, and tocilizumab proved to be ineffective. Eventually, the patient responded to cyclosporin-A treatment. Multisystemic inflammatory syndrome in children has been treated with immunoglobulins and glucocorticoids and in refractory cases biologics and cyclosporin-A have been used. Intravenous and oral cyclosporin-A seems to be a safe and effective alternative treatment for refractory multisystemic inflammatory syndrome in children patients.

Autoimmune Polyendocrinopathy in a Pediatric Patient Presenting With Multisystem Inflammatory Syndrome in Children (MIS-C).

Multisystem inflammatory syndrome (MIS) is a well-known potential sequela of COVID-19 infection. Though prevalence is higher in certain populations, this syndrome is a rare occurrence in children. Beyond MIS, there has been increasing research into COVID infection and the subsequent onset of autoimmune conditions, such as diabetes. However, evidence of a poly-endocrinopathy developing after COVID infection is lacking, and evidence within the pediatric population is virtually nonexistent. In this case, we present the evolution of an autoimmune polyglandular syndrome (APS) type 2 phenotype, consisting of type 1 diabetes, Graves' disease, and adrenal insufficiency, after diagnosis of multisystem inflammatory syndrome of children (MIS-C) in a pediatric patient.  A 15-year-old biracial female without significant past medical history tested positive for COVID-19 and two weeks later presented with respiratory symptoms and other systemic signs. She was admitted for further evaluation and was found to have elevated inflammatory markers, EKG (electrocardiogram) abnormalities, and lab evidence of organ damage. The patient was diagnosed with MIS-C, and treatment was initiated with eventual discharge. One year after this initial visit, the patient returned to the hospital due to weight loss, difficulty breathing, polyuria, polydipsia, nausea, vomiting, and fatigue. A steroid course for MIS-C treatment had been completed three months prior. Exam and lab results confirmed diabetic ketoacidosis (DKA), and the patient was diagnosed with new-onset type 1 diabetes. Further testing determined that she was glutamic acid decarboxylase 65 (GAD-65) positive. DKA was managed in the hospital, and the patient was subsequently discharged with an insulin regimen and endocrine follow-up. A couple of months later, the patient returned to the emergency department (ED) due to two weeks of dyspnea on exertion and dizziness. Since her previous admission for DKA, the patient had contracted COVID-19 again and recovered from her respiratory symptoms. Physical exam and labs were grossly unremarkable; however, the patient had EKG abnormalities and an episode of severe bradycardia, prompting hospitalization. Thyroid workup revealed thyrotoxicosis due to Graves' disease. Due to intermittent hypotension, adrenal labs were obtained. She was found to have adrenal insufficiency as well, with a positive 21-hydroxylase antibody. Throughout these hospitalizations, the patient suffered from skin and hair changes as well, ultimately requiring dermatological intervention.

Longitudinal Assessment of Left Ventricular Function in Patients with Myopericarditis After mRNA COVID-19 Vaccination.

BACKGROUND: Multiple reports have described myopericarditis following mRNA COVID-19 vaccination. However, data on the persistence of subclinical myocardial injury assessed by left ventricular (LV) longitudinal strain (LVLS) is limited. OBJECTIVES: Our aim was to assess LV function longitudinally in our cohort of COVID-19 vaccine-related myopericarditis using ejection fraction (EF), fractional shortening (FS), LVLS, and diastolic parameters. METHODS: Retrospective, single-center review of demographic, laboratory, and management data was performed on 20 patients meeting diagnostic criteria for myopericarditis after mRNA COVID-19 vaccination. Echocardiographic images were obtained on initial presentation (time 0), at a median of 12 days (7.5, 18.5; time 1), and at a median of 44 days (29.5, 83.5; time 2). FS was calculated by M-mode, EF by 5/6 area-length methods, LVLS by utilization of TOMTEC software, and diastolic function by tissue Doppler. All parameters were compared across pairs of these time points using Wilcoxon signed-rank test. RESULTS: Our cohort consisted predominantly of adolescent males (85%) with mild presentation of myopericarditis. The median EF was 61.6% (54.6, 68.0), 63.8% (60.7, 68.3), 61.4% (60.1, 64.6) at times 0, 1, and 2, respectively. Upon initial presentation, 47% of our cohort had LVLS < -18%. The median LVLS was -18.6% (-16.9, -21.0) at time 0, -21.2% at time 1 (-19.4, -23.5) (p = 0.004) and -20.8% (-18.7, -21.7) at time 2 (p = 0.004, as compared to time 0). CONCLUSIONS: Though many of our patients had abnormal strain during acute illness, LVLS improved longitudinally, indicating myocardial recovery. LVLS can be used as marker of subclinical myocardial injury and risk stratification in this population.

Incidence and Prevalence of Multisystem Inflammatory Syndrome in Children (MIS-C) in Southern Italy.

Multisystem inflammatory syndrome in children (MIS-C) is a pediatric hyperinflammatory syndrome related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection whose epidemiology is not very well known at present. The objective of the study was to better understand the incidence of MIS-C in the Apulia region in southern Italy. Our primary goal was to estimate the incidence of newly identified cases of MIS-C in children aged 0-18 years, during a period of six months, encompassing the second pandemic wave. We also analyzed the characteristics of our cohort in terms of clinical features, treatment, and outcomes. The cumulative incidence of MIS-C was 3.27 per 100,000 residents between 0 and 18 years of age. In our cohort, gastrointestinal, mucocutaneous, and cardiac involvement were the most common clinical features. With our step-up approach to therapy, no patients required intensive care unit (ICU) admission and no cardiac sequelae after 6 months of onset were found in echocardiograms. Conclusion: Our epidemiological study of MIS-C in southern Italy showed unexpectedly overlapping figures with other US studies.

Multisystem Inflammatory Syndrome in Children (MIS-C), Possibly Due to COVID-19 mRNA Vaccination.

Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening childhood disease caused by SARS-CoV-2 infection, manifested by the persistence of fever and multi-organ dysfunction, elevated inflammatory markers, and the lack of an alternative diagnosis. It is still unknown if vaccination can precipitate or abrogate MIS-C or if a natural infection preceding or occurring at the time of vaccination plays any role. We present one case of MIS-C in a 16-year-old girl who was fully immunized against COVID-19 (Pfizer), with the second dose received three weeks prior to onset of the disease. She had no history of COVID-19 disease or contact with COVID-19 patients. At admission, she was somnolent, pale, and dehydrated, with cyanotic lips and cold extremities; she was hypotensive with tachycardia and poorly palpable pulses. Initial laboratory results revealed elevated levels of inflammatory markers, and high level of SARS-CoV-2 IgG spike antibodies, while testing for SARS-CoV-2 acute infection and other inflammatory etiologies were negative. Vaccine-related MIS-C was suspected in our case due to the development of MIS-C three weeks following the second dose of the COVID-19 mRNA vaccine, the absence of previous infection or exposure to SARS-CoV-2, and a positive result for IgG anti-spike (S) antibodies.

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.

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 by evidence of prior SARS-CoV-2 infection. METHODS: The International KD Registry (IKDR) enrolled KD and MIS-C patients from sites from North, Central and South America, Europe, Asia and Middle East. Evidence of prior infection was defined as: Positive (+ve household contact or positive 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 89 (4%), Negative 404 (17%) and Unknown for 311 (13%) patients. Clinical outcomes varied significantly between 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, while patients in the Negative and Unknown groups had more severe coronary artery abnormalities. results CONCLUSION: : 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 prior acute SARS CoV2 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.

First confirmed case of multisystem inflammatory syndrome in adult in Egypt.

Key Clinical Message: Our case report demonstrates extremely uncommon data associated with MIS-A, such as cholestatic jaundice, anemia, and quickly progressing pneumonia. IVIG and pulse steroid medications are the best treatments for improving clinical outcomes. Abstract: We report a case of multiple organ dysfunctions due to MIS-A in an adult with a history of suspected COVID-19. Our case demonstrates extremely uncommon data associated with MIS-A, such as cholestatic jaundice, anemia, and quickly progressing pneumonia. IVIG and pulse steroid medications are the best treatments for improving clinical outcomes.

SARS-CoV-2 Infection in Venezuelan Pediatric Patients-A Single Center Prospective Observational Study.

Several studies suggest that children infected with SARS-CoV-2 have fewer clinical manifestations than adults; when they develop symptoms, they rarely progress to severe disease. Different immunological theories have been proposed to explain this phenomenon. In September 2020, 16% of the active COVID-19 cases in Venezuela were children under 19 years. We conducted a cross-sectional study of pediatric patients' immune response and clinical conditions with SARS-CoV-2 infection. The patients were admitted to the COVID-19 area of the emergency department of Dr José Manuel de los Ríos Children's Hospital (2021-2022). The lymphocyte subpopulations were analyzed by flow cytometry, and IFNγ, IL-6, and IL-10 serum concentrations were quantified using commercial ELISA assays. The analysis was conducted on 72 patients aged one month to 18 years. The majority, 52.8%, had mild disease, and 30.6% of the patients were diagnosed with MIS-C. The main symptoms reported were fever, cough, and diarrhea. A correlation was found between IL-10 and IL-6 concentrations and age group, lymphocyte subpopulations and nutritional status and steroid use, and IL-6 concentrations and clinical severity. The results suggest a different immune response depending on age and nutritional status that should be considered for treating pediatric COVID-19 patients.

Thrombectomy of an Acute Ischemic Stroke in a Child with COVID-19 and MIS-C: Case Analysis and Literature Context.

We describe a very young child who developed an acute ischemic stroke from a LAO, while affected by COVID-19 and MIS-C, and whom we treated successfully with thrombectomy. We compare his clinical and imaging findings with those of the existing case reports, and we explore the multifactorial nature of such a neurovascular complication, particularly in the context of the most recent publications regarding the multifactorial endothelial derangements produced by the illness.

Multisystem Inflammatory Syndrome in Children: Two Years' Worth of Learning.

Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening sequela of SARS-CoV-2 infection. Limited data are available regarding risk-stratification or long-term outcomes in MIS-C. This study sought to determine associations between serologic markers and severity of illness and understand long-term cardiac outcomes. This series includes 46 cases (mean age 8.1 years; 63.0% male) of MIS-C. Pearson's chi-squared analysis showed an erythrocyte sedimentation rate (ESR) greater than 30 mm/h and 50 mm/h were disproportionately associated with pediatric intensive care unit (PICU) admission (χ2 = 4.44, P = .04) and use of vasopressors (χ2 = 6.06, P = .01), respectively. Ferritin less than 175.6 ng/mL was associated with use of vasopressors (χ2 = 5.28, P = .02). There was a negative correlation between ESR and ejection fraction (EF) (r = -0.39, P = .009). Most patients with abnormal echocardiograms had resolution of abnormalities within 30 days. Therefore, inflammatory markers may be helpful in predicting which patients may require specific interventions or experience cardiac dysfunction, but MIS-C does not appear to be associated with complications at 1 year.

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.