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

Multisystem inflammatory syndrome in children and Kawasaki disease

This narrative review aims to analyze and compare the current literature on multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD), with a focus on case definitions, clinical features, diagnostic approaches, treatment strategies, and outcomes. Through a comprehensive review of relevant studies, including screening titles, abstracts, and full-text articles, key similarities and differences were identified. Both MIS-C and KD involve immune system dysregulation and share clinical manifestations such as rash, gastrointestinal symptoms, and cardiovascular involvement, with treatments often centered around immunomodulatory therapies. However, significant differences were observed, particularly in terms of age distribution, demographic prevalence, clinical presentation, and diagnostic criteria, with KD primarily affecting younger children and being associated more prominently with coronary artery abnormalities. While both diseases raise concerns about severe cardiac involvement and the need for intensive care, their pathogenic mechanisms have not been fully understood. Ongoing research is critical to elucidating these mechanisms, refining diagnostic criteria, and optimizing therapeutic approaches to improve outcomes for affected children. This comparative analysis is essential for advancing the understanding of both conditions, as accurately distinguishing between MIS-C and KD has significant implications for clinical decision-making and patient management. Given their overlapping yet distinct clinical features, precise differentiation is critical for ensuring timely diagnosis, optimizing therapeutic strategies, and improving patient outcomes. The concern among pediatric patients stems from the potential for severe complications, particularly cardiac involvement, which underscores the need for heightened awareness, early recognition, and evidence-based treatment strategies to minimize long-term morbidity and mortality.

Factors Associated With Shock at Presentation in Kawasaki Disease Versus Multisystem Inflammatory Syndrome in Children Associated With Covid-19

BACKGROUND

While clinical overlap between Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) has been evident, information regarding those presenting with shock has been limited. We sought to determine associations with shock within and between diagnosis groups.

METHODS

The International KD Registry enrolled contemporaneous patients with either KD or MIS-C from 39 sites in 7 countries from January 1, 2020, to January 1, 2023. Demographics, clinical features and presentation, management, laboratory values, and outcomes were compared between the diagnosis and shock groups.

RESULTS

Shock at presentation was noted for 19 of 672 KD patients (2.8%) and 653 of 1472 MIS-C patients (44%; P < 0.001). Within both groups, patients with shock were significantly more likely to be admitted to the intensive care unit, to receive inotropes, and to have greater laboratory abnormalities indicative of hyperinflammation and organ dysfunction, including abnormal cardiac biomarkers. Patients with KD and shock had a greater maximum coronary artery z score (median +2.62) vs KD patients without shock (+1.36; P < 0.001) and MIS-C patients with shock (+1.45 [vs +1.32 for MIS-C patients without shock]; P < 0.001). They were also more likely to have large coronary artery aneurysms. In contrast, MIS-C patients with shock had lower left ventricular ejection fraction (mean 51.6%) vs MIS-C patients without shock (56.6%; P < 0.001) and KD patients with shock (56.7% [vs 62.8% for KD patients without shock]; P = 0.04).

CONCLUSIONS

Although patients with KD presenting with shock are clinically similar to patients with MIS-C, especially those with shock, they have more severe coronary artery involvement, whereas MIS-C patients with shock have lower left ventricular ejection fraction.

Severity of Pediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 Diminished During Successive Waves of the COVID-19 Pandemic: Data from a Nationwide German Survey

OBJECTIVE

To elucidate how the clinical presentation of Pediatric Inflammatory Multisystem Syndrome temporally associated with Severe Acute Respiratory Syndrome-related Coronavirus 2 (PIMS-TS) was influenced by the successive variants of concern (VOC) and patient age.

STUDY DESIGN

A nationwide PIMS-TS registry was established in Germany in May 2020, shortly after the first cases were described in the US and United Kingdom. The registry captured information on patient characteristics, clinical course, laboratory findings, imaging, and outcome. All pediatric hospitals in Germany, along with one in Austria, were invited to participate. Between March 18, 2020, and April 30, 2023, 920 cases were reported.

RESULTS

By examining a combination of data on clinical features, laboratory findings, treatment, imaging results, and outcomes, our analysis demonstrated disease severity to have continuously declined over the course of the Wildtype, Alpha, Delta, and Omicron waves. Based on clinical symptoms, laboratory and diagnostic findings, and intensive care unit admission rates, older children, irrespective of the related VOC, were shown to experience more severe, acute PIMS-TS; however, they had lower rates of coronary aneurysm.

CONCLUSIONS

During the course of COVID-19 pandemic, as each new VOC emerged, PIMS-TS lessened in severity. In parallel, older children came to experience more debilitating disease.

ICU Admission Prediction for Patients With Kawasaki Disease or MIS-C Using Machine Learning

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) show a broad spectrum of clinical severity, from a relatively benign clinical course to requiring admission to the intensive care unit (ICU). With either, clinical deterioration may be rapid and unexpected.

OBJECTIVES

The aim of the study was to develop a machine learning (ML) model to predict future ICU admission for patients with KD or MIS-C to augment clinical decision-making.

METHODS

We developed a prediction model for ICU admission using 2,539 patients <18 years of age with MIS-C or KD enrolled in the International Kawasaki Disease Registry. Using discrete time-point clinical features and engineered time-series clinical features, we developed predictive snapshot and window ML models with logistic regression, XGBoost, and random forest. Performance was compared between the various iterations of the models.

RESULTS

ML models effectively predicted admission to the ICU within the next 48 hours of the time of prediction. The time-series window-XGBoost model outperformed other models with an AUROC of 0.92 and an area under the precision-recall curve of 0.86. The incorporation of engineered time-series features improved the precision and recall independent of the length of the sampling time window. Higher ferritin level, treatment with anticoagulant or unfractionated heparin, higher C-reactive protein level, and lower platelet count were identified as the most predictive features for positive ICU prediction.

CONCLUSIONS

ML algorithms can effectively predict ICU admission for pediatric patients with MIS-C or KD. These models may prompt physicians to pre-emptively implement supportive measures, possibly mitigating the risk of clinical deterioration.

Cellular and soluble plasma immune markers at presentation in multisystem inflammatory syndrome in children and Kawasaki disease in South Africa: An observational study

Immune and inflammatory alterations in multisystem inflammatory syndrome in children (MIS-C) as compared to Kawasaki disease (KD) were investigated in South Africa, a region of unique genetic background and high infectious disease burden. The observational study included MIS-C and KD patients during 4 severe acute respiratory syndrome coronavirus 2 waves (June 1, 2020-March 31, 2023) plus 12 healthy controls. Clinical features, routine inflammatory markers, hematological parameters, lymphocyte subsets and plasma inflammatory cytokines/chemokines were compared between groups. We enrolled 68 MIS-C, 18 KD, and 12 healthy controls. MIS-C patients had higher rates of Intensive Care Unit admission compared to KD (46% vs 17%; P = .03) and longer hospital stay (8.5 vs 6 days; P < .001). 8 MIS-C but no KD patients had an ejection fraction of < 40% (P = .07). Median lymphocyte counts were decreased in MIS-C, 1.2 cells/μL (interquartile range 0.7-2.3) versus KD 2.5 cells/μL (interquartile range 1.2-3.7), P = .02. Median CD3 + T-cell counts were lower in MIS-C (P = .04). Children with MIS-C had a higher median N-terminal pro-B-type natriuretic peptide of 5836 ng/L (1784-25,698) versus 7 ng/L (88-3262), P < .001 and Troponin T 25 ng/L (9-73) versus 7 ng/L (4-24), P = .01. Majority of cytokines/chemokines were elevated in both MIS-C and KD. When MIS-C was stratified by severity, significant differences in C-reactive protein (P < .001), total lymphocytes (P = .01), and N-terminal pro-B-type natriuretic peptide (P = .01) were observed. Inflammatory cytokine and chemokine levels were markedly raised in both KD and MIS-C. 3 markers were highlighted as indicators of MIS-C severity. There is a strong overlap in inflammatory marker alterations between MIS-C and KD at presentation in the African setting.

Neurological complications caused by SARS-CoV-2

SUMMARYSARS-CoV-2 can not only cause respiratory symptoms but also lead to neurological complications. Research has shown that more than 30% of SARS-CoV-2 patients present neurologic symptoms during COVID-19 (A. Pezzini and A. Padovani, Nat Rev Neurol 16:636-644, 2020, https://doi.org/10.1038/s41582-020-0398-3). Increasing evidence suggests that SARS-CoV-2 can invade both the central nervous system (CNS) (M.S. Xydakis, M.W. Albers, E.H. Holbrook, et al. Lancet Neurol 20: 753-761, 2021 https://doi.org/10.1016/S1474-4422(21)00182-4 ) and the peripheral nervous system (PNS) (M.N. Soares, M. Eggelbusch, E. Naddaf, et al. J Cachexia Sarcopenia Muscle 13:11-22, 2022, https://doi.org/10.1002/jcsm.12896), resulting in a variety of neurological disorders. This review summarized the CNS complications caused by SARS-CoV-2 infection, including encephalopathy, neurodegenerative diseases, and delirium. Additionally, some PNS disorders such as skeletal muscle damage and inflammation, anosmia, smell or taste impairment, myasthenia gravis, Guillain-Barré syndrome, ICU-acquired weakness, and post-acute sequelae of COVID-19 were described. Furthermore, the mechanisms underlying SARS-CoV-2-induced neurological disorders were also discussed, including entering the brain through retrograde neuronal or hematogenous routes, disrupting the normal function of the CNS through cytokine storms, inducing cerebral ischemia or hypoxia, thus leading to neurological complications. Moreover, an overview of long-COVID-19 symptoms is provided, along with some recommendations for care and therapeutic approaches of COVID-19 patients experiencing neurological complications.

Serum endocan (ESM-1) as diagnostic and prognostic biomarker in Multisystem inflammatory syndrome in children (MIS-C)

Endothelial-cell-specific molecule-1 (ESM-1) also called endocan is a well-known biomarker for detecting inflammation, endothelial dysfunction (ED), and cardiovascular (CV) risk in COVID-19 patients. Upon SARS-CoV-2 infection, a small percentage of children develop Multisystem Inflammatory Syndrome in children (MIS-C). Whether endocan can be used as a biomarker of MIS-C is unknown. In this study, we assessed ESM-1 levels in MIS-C (n = 19) and healthy controls (HC; n = 17). We observed a significant increase in serum ESM-1 levels in MIS-C vs HC (p = 0.0074). In addition, ROC curve analysis demonstrated that this factor has a reasonable discriminatory power between MIS-C patients and HC (AUC of 0.7585). Notably, after one week of hospitalization and care, ESM-1 levels decreased, and this reduction was observed also for other inflammatory and pro-thrombotic markers like C-reactive protein, procalcitonin, fibrinogen, D-dimer, and ferritin, suggesting a general recovery trend in MIS-C patients. In fact, we observed that serum ESM-1 levels positively correlated with procalcitonin (PCT) (r = 0.468; p = 0.043). Finally, logistic regression analysis demonstrated an association between endocan levels and cardiac complications like myocarditis. Therefore, this study suggests that ESM-1 is a valuable diagnostic and prognostic biomarker in patients with MIS-C that may help identify those MIS-C patients at higher risk for cardiovascular complications and guide treatment strategies.

Cardiac manifestations and outcomes of COVID-19 vaccine-associated myocarditis in the young in the USA: longitudinal results from the Myocarditis After COVID Vaccination (MACiV) multicenter study

Background

We aimed to study the clinical characteristics, myocardial injury, and longitudinal outcomes of COVID-19 vaccine-associated myocarditis (C-VAM).

Methods

In this longitudinal retrospective observational cohort multicenter study across 38 hospitals in the United States, 333 patients with C-VAM were compared with 100 patients with multisystem inflammatory syndrome in children (MIS-C). We included patients ≤30 years of age with a clinical diagnosis of acute myocarditis after COVID-19 vaccination based on clinical presentation, abnormal biomarkers and/or cardiovascular imaging findings. Demographics, past medical history, hospital course, biochemistry results, cardiovascular imaging, and follow-up information from April 2021 to November 2022 were collected. The primary outcome was presence of myocardial injury as evidenced by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging.

Findings

Patients with C-VAM were predominantly white (67%) adolescent males (91%, 15.7 ± 2.8 years). Their initial clinical course was more likely to be mild (80% vs. 23%, p < 0.001) and cardiac dysfunction was less common (17% vs. 68%, p < 0.0001), compared to MIS-C. In contrast, LGE on CMR was more prevalent in C-VAM (82% vs. 16%, p < 0.001). The probability of LGE was higher in males (OR 3.28 [95% CI: 0.99, 10.6, p = 0.052]), in older patients (>15 years, OR 2.74 [95% CI: 1.28, 5.83, p = 0.009]) and when C-VAM occurred after the first or second dose as compared to the third dose of mRNA vaccine. Mid-term clinical outcomes of C-VAM at a median follow-up of 178 days (IQR 114-285 days) were reassuring. No cardiac deaths or heart transplantations were reported until the time of submission of this report. LGE persisted in 60% of the patients at follow up.

Interpretation

Myocardial injury at initial presentation and its persistence at follow up, despite a mild initial course and favorable mid-term clinical outcome, warrants continued clinical surveillance and long-term studies in affected patients with C-VAM.

Funding

The U.S. Food and Drug Administration.

Invasive Group A Streptococcal Meningitis Following COVID-19 Infection Complicated by Multisystem Inflammatory Syndrome: A Case Report

We present a case of a 60-year-old woman who developed invasive group A streptococcal (GAS) meningitis following a COVID-19 infection, complicated by multisystem inflammatory syndrome (MIS). Initially diagnosed with COVID-19 based on fever, nasal obstruction, cough, and sore throat, her symptoms improved with symptomatic treatment, except for a persistent sore throat. She later presented with hematemesis and was found to have bacterial pneumonia and dehydration. Despite treatment with ceftriaxone, her condition worsened with the development of a headache, shivering, and worsening respiratory and circulatory symptoms. Cerebrospinal fluid analysis confirmed bacterial meningitis, and treatment was escalated to include ceftriaxone, ampicillin, and vancomycin. An MRI revealed a parapharyngeal space abscess, and subsequent blood cultures identified GAS as the causative organism. The patient was treated with ampicillin for 14 days, followed by oral amoxicillin. Her condition improved, and she was discharged with no neurological deficits. This case underscores the need for vigilance in detecting secondary bacterial infections in post-COVID-19 patients, especially in MIS, where atypical presentations can delay diagnosis. Early recognition and aggressive treatment are vital to preventing complications and ensuring favorable outcomes.

Clinical and Laboratory Parameters Associated with PICU Admission in Children with Multisystem Inflammatory Syndrome Associated with COVID-19 (MIS-C)

Background/Objectives: Multisystem Inflammatory Syndrome in children (MIS-C) is a rare but severe post-infectious complication of COVID-19 that often requires admission to the Pediatric Intensive Care Unit (PICU). The present study aimed to compare the demographic, clinical, and laboratory characteristics of children diagnosed with MIS-C who were admitted to the PICU and those who did not require PICU admission. Methods: Children diagnosed with MIS-C from September 2020 to April 2023 were included in this case-control study. Demographic, clinical, and laboratory data were collected from medical records. Results: Fifty children with MIS-C were included in the study [median (IQR) age: 7.5 (4.3, 11.4) years, 28/50 (56%) males]. Twenty-two (22/50, 44%) children required admission to the PICU. In the multivariate regression analysis, hepatic (OR: 12.89, 95%CI: 1.35-123.41, p-value = 0.03) and cardiological involvement (OR: 34.55, 95%CI: 2.2-541.91, p-value = 0.01) were significantly associated with hospitalization at the PICU. Regarding the laboratory and imaging parameters during the first 48 h from admission, D-dimer levels higher than 4 μg/mL and decreased Left Ventricular Ejection Fraction (LVEF) were associated with an increased risk of PICU admission (OR: 7.95, 95%CI: 1.48-42.78, p-value = 0.02 and OR = 1.28, 95%CI: 1.07-1.53, p-value = 0.01). Children who were admitted to the PICU were more likely to develop complications during their hospitalization (10/22, 45.5% vs. 3/28, 10.7%, p-value = 0.005) and were hospitalized for more days than children in the pediatric ward (median length of stay (IQR): 20 (15, 28) days vs. 8.5 (6, 14) days, p-value < 0.001). Conclusions: The findings of this study indicate that cardiovascular and hepatic involvement and increased D-dimer levels in children with MIS-C might be associated with admission to the PICU.

The Spectrum of Postacute Sequelae of COVID-19 in Children: From MIS-C to Long COVID

The effects of SARS-CoV-2 infection on children continue to evolve following the onset of the COVID-19 pandemic. Although life-threatening multisystem inflammatory syndrome in children (MIS-C) has become rare, long-standing symptoms stemming from persistent immune activation beyond the resolution of acute SARS-CoV-2 infection contribute to major health sequelae and continue to pose an economic burden. Shared pathophysiologic mechanisms place MIS-C and long COVID within a vast spectrum of postinfectious conditions characterized by intestinal dysbiosis, increased gut permeability, and varying degrees of immune dysregulation. Insights obtained from MIS-C will help shape our understanding of the more indolent and prevalent postacute sequelae of COVID and ultimately guide efforts to improve diagnosis and management of postinfectious complications of SARS-CoV-2 infection in children.

Complications of Multisystem Inflammatory Syndrome Associated with SARS-CoV-2 Infection-Many Facets of One Disease-A Literature Review Based on a Case Report

Multisystem inflammatory syndrome in children (MIS-C) is a disease that made its mark in the early days of the COVID-19 pandemic due to the diverse course and symptoms affecting multiple body systems. It is a condition that develops in pediatric patients about 2-6 weeks after contact with a person infected with the SARS-CoV-2 virus. In many instances, MIS-C has caused multiple organ failure, with particularly severe complications involving the cardiovascular system and manifesting as hypotension, various cardiac arrhythmias, myocarditis or coronary artery lesions resembling those seen in Kawasaki disease. Currently, the incidence of MIS-C is about 1-3 per 1000 children, with a decreasing trend in recent years due to the introduction of immunization against the SARS-CoV-2 virus for children as young as 6 months. In our paper, we present the case of a patient with a severe course of MIS-C with numerous cardiovascular and neurological complications, in whom the symptoms of the disease were managed by administering biological treatment. We also present a review of the literature on the subject, which shows how many different facets this disease can have and that physicians still need to remain alert, as there are cases of severe MIS-C, especially in unvaccinated patients.

Incomplete Kawasaki disease with muscular weakness and bladder retention: a case report

BACKGROUND

Kawasaki disease (KD) is an acute systemic immune vasculitis affecting multiple organs and systems in children, and is prevalent in children under 5 years of age. Muscular weakness is a rare manifestation of KD, and only 11 pediatric patients with KD combined with muscular weakness have been reported, of which evidence of myositis was found in 2/3 of the patients, and 1/3 could not be explained by myositis, the mechanism of which is still unclear. Cases of KD combined with bladder retention are even more rare, and there has been only 1 case report of KD combined with bladder retention in a child with no previous underlying disease.

CASE PRESENTATION

We report a 22-month-old Asian child with incomplete Kawasaki disease (IKD) who initially presented with fever and progressive muscular weakness in the lower extremities, followed by the bladder and bowel retention abnormalities and rapid onset of heart failure, respiratory failure and shock. The child developed coronary artery ectasia (CAA) without the main clinical features of KD such as rash, conjunctival congestion, desquamation of the extremity endings, orofacial changes and enlarged lymph nodes in the neck. Creatine kinase and electromyography were normal. Temperature gradually normalized and muscle strength recovered slightly after intravenous immunoglobulin. The child could be helped to walk after 1 week of aspirin combined with steroid therapy.

CONCLUSIONS

We present the case of a 22-month-old child with IKD. The child began with progressive muscular weakness in the extremities, followed by the bladder and bowel retention abnormalities, and rapidly developed heart failure, respiratory failure, and shock. Despite early failure to detect the disease, the child recovered rapidly and had a favorable prognosis. KD comorbidities with muscular weakness as the main manifestation are uncommon. This is the first case report of IKD combined with both muscular weakness and bladder and bowel retention, which may provide clinicians with diagnostic and therapeutic ideas, as well as a basis for future exploration of the mechanisms of KD combined with muscular weakness or bladder and bowel retention abnormalities.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Long-term outcomes and immune profiling in children with multisystem inflammatory syndrome (MIS-C)

BACKGROUND AND AIM

Existing follow-up data after MIS-C is limited.

PURPOSE OF THE STUDY

to investigate the long-term consequences in children who have undergone MIS-C.

METHODS

The retrospective study included 93 children. The identified changes were divided into the following periods: occurred within first 6 months, 1 year, 2 years, and more than 2 years after MIS-C. Besides, 31 children underwent prospective immunophenotyping of peripheral blood and the determination of cytokines during the acute period of the disease and after discharge.

RESULTS

Outpatient monitoring events included pneumonia (9.6%), somatic disorder syndrome (11.8%), visual impairment (7.5%), joint damage (6.6%), weight changes (2.2%), and MIS-C recurrence (2.2%). A study of the cardiovascular system showed a statistically significant decrease in the frequency of the right and left heart dilatation, left ventricular dysfunction, pericarditis, pulmonary arterial hypertension, coronaritis, mitral regurgitation. But at the same time an increase in pulmonary and tricuspid valve regurgitation and arrhythmias compared with the acute period was detected. Most of the changes took place within first year of observation. Immune profiling showed reconstitution of CD3, CD4 T-lymphocytes, NK-cells, maintenance of a high relative value of CD8, reduction of CD19+ B-cells, expression of CD3-HLA-DR+, CD25, CD279, CD95.

CONCLUSIONS

After the history of MIS-C, children in the long-term follow-up had various somatic disorders and disease recurrence. Most patients (64.1%) showed subclinical signs of myocardial involvement within first year of observation. Low expression of CD95 may justify an certain role in the pathogenesis of the disease.

Multisystem inflammatory syndrome in systemic lupus erythematosus patient with COVID-19: Case report and review

Multisystem inflammatory syndrome in adults (MIS-A) is considered a rare and serious complication of coronavirus disease 2019, which more frequently occurs in young, male, and either non-Hispanic black or Hispanic persons. Here we present a Chinese woman aged 50 years with systemic lupus erythematosus diagnosed with MIS-A. She experienced unexpected sudden cardiac and liver injuries and hemodynamic collapse, and her platelet count dropped sharply on hospital day 2. Unfortunately, the patient's condition gradually deteriorated despite maximum support and she died on day 3. We present this rare case to emphasize that MIS-A in autoimmune diseases may be more severe and its management may be more difficult.

Cardiovascular effects of COVID-19 in children

Introduction

Although severe acute respiratory failure is the primary cause of morbidity and mortality in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, this viral infection leads to cardiovascular disease in some individuals. Cardiac effects of the virus include myocarditis, pericarditis, arrhythmias, coronary aneurysms and cardiomyopathy, and can result in cardiogenic shock and multisystem organ failure.

Method

This review summarises cardiac manifesta-tions of SARS-CoV-2 in the paediatric population. We performed a scoping review of cardiovascular disease associated with acute coronavirus disease 2019 (COVID-19) infection, multisystem inflammatory syndrome in children (MIS-C), and mRNA COVID-19 vaccines. Also examined are special considerations for paediatric athletes and return to play following COVID-19 infection.

Results

Children presenting with acute COVID-19 should be screened for cardiac dysfunction and a thorough history should be obtained. Further cardiovascular evaluation should be considered following any signs/symptoms of arrhythmias, low cardiac output, and/or myopericarditis. Patients admitted with severe acute COVID-19 should be monitored with continuous cardiac monitoring. Laboratory testing, as clinically indicated, includes tests for troponin and B-type natriuretic peptide or N-terminal pro-brain natriuretic peptide. Echocardiography with strain evaluation and/or cardiac magnetic resonance imaging should be considered to evaluate diastolic and systolic dysfunction, coronary anatomy, the pericardium and the myocardium. For patients with MIS-C, combination therapy with intravenous immunoglobulin and glucocorticoid therapy is safe and potentially disease altering. Treatment of MIS-C targets the hyperimmune response. Supportive care, including mechanical support, is needed in some cases.

Conclusion

Cardiovascular disease is a striking feature of SARS-CoV-2 infection. Most infants, children and adolescents with COVID-19 cardiac disease fully recover with no lasting cardiac dysfunction. However, long-term studies and further research are needed to assess cardiovascular risk with variants of SARS-CoV-2 and to understand the pathophysiology of cardiac dysfunction with COVID-19.

Roles of Oxidative Injury and Nitric Oxide System Derangements in Kawasaki Disease Pathogenesis: A Systematic Review

Kawasaki disease (KD) is an acute febrile vasculitis that occurs mostly in children younger than five years. KD involves multiple intricately connected inflammatory reactions activated by a cytokine cascade. Despite therapeutic advances, coronary artery damage may develop in some patients, who will be at risk of clinical cardiovascular events and even sudden death. The etiology of KD remains unclear; however, it may involve both genetic and environmental factors leading to aberrant inflammatory responses. Given the young age of onset, prenatal or perinatal exposure may be etiologically relevant. Multisystem inflammatory syndrome in children, a post-infectious hyper-inflammatory disorder associated with severe acute respiratory syndrome coronavirus 2, has features that overlap with those of KD. Available evidence indicates that vascular endothelial dysfunction is a critical step in the sequence of events leading to the development of cardiovascular lesions in KD. Oxidative stress and the dysregulation of the nitric oxide (NO) system contribute to the pathogenesis of inflammatory responses related to this disease. This review provides current evidence and concepts highlighting the adverse effects of oxidative injury and NO system derangements on the initiation and progression of KD and potential therapeutic strategies for cardiovascular pathologies in affected children.

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

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

Short- and mid-term outcomes of multisystem inflammatory syndrome in children: a longitudinal prospective single-center cohort study

Background

Multisystem inflammatory syndrome in children (MIS-c) emerged during the coronavirus disease 2019 pandemic and is associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the extensively studied clinical manifestation of acute condition, the short- and long-term effects of MIS-c on children's health are unknown.

Methods

This was a prospective longitudinal cohort study. Children aged <18 years who met the Centers for Disease Prevention and Control (CDC) diagnostic criteria and who were admitted to the Children's Clinical University Hospital of Latvia (CCUH) between July 1, 2020, and April 15, 2022, were enrolled in the study. An outpatient follow-up program was initiated in July 2020. All children were evaluated at 2 weeks, 2 months (1-3 months), and 6 months (5-7 months) after discharge. The face-to-face interviews comprised four domains as follows: symptom assessment, physical examination, laboratory testing, and cardiological investigation [including electrocardiogram (ECG) and echocardiography (echo)].

Results

Overall, 21 patients with MIS-c were enrolled. The median age of the study group was 6 years. At the 2-week follow-up, almost half of the patients (N = 10, 47.6%) reported exercise intolerance with provoked tiredness. Laboratory tests showed a considerable increase in blood cell count, with a near doubling of leukocyte and neutrophil counts and a tripling of thrombocyte levels. However, a decline in the levels of inflammatory and organ-specific markers was observed. Cardiological investigation showed significant improvement with gradual resolution of the acute-phase pathological findings. Within 2 months, improvement in exercise capacity was observed with 5-fold and 2-fold reductions in physical intolerance (N = 2, 9.5%) and physical activity-induced fatigue (N = 5, 23.8%), respectively. Normalization of all blood cell lines was observed, and cardiological investigation showed no persistent changes. At the 6-month visit, further improvement in the children's exercise capacity was observed, and both laboratory and cardiological investigation showed no pathological changes.

Conclusions

Most persistent symptoms were reported within the first 2 weeks after the acute phase, with decreased physical activity tolerance and activity-induced fatigue as the main features. A positive trend was observed at each follow-up visit as the spectrum of the children's complaints decreased. Furthermore, rapid normalization of laboratory markers and cardiac abnormalities was observed.