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.

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.

Cardiac Involvement in Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) in Poland.

Multisystem inflammatory syndrome in children (MIS-C) is an immune-mediated complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cardiovascular system is commonly involved. Acute heart failure (AHF) is the most severe complication of MIS-C, leading to cardiogenic shock. The aim of the study was to characterise the course of MIS-C with a focus on cardiovascular involvement, based on echocardiographic (echo) evaluation, in 498 children (median age 8.3 years, 63% boys) hospitalised in 50 cities in Poland. Among them, 456 (91.5%) had cardiovascular system involvement: 190 (48.2%) of patients had (most commonly atrioventricular) valvular insufficiency, 155 (41.0%) had contractility abnormalities and 132 (35.6%) had decreased left ventricular ejection fraction (LVEF < 55%). Most of these abnormalities improved within a few days. Analysis of the results obtained from two echo descriptions (a median of 5 days apart) revealed a >10% increase in LVEF even in children with primarily normal LVEF. Lower levels of lymphocytes, platelets and sodium and higher levels of inflammatory markers on admission were significantly more common among older children with contractility dysfunction, while younger children developed coronary artery abnormality (CAA) more often. The incidence of ventricular dysfunction might be underestimated. The majority of children with AHF improved significantly within a few days. CAAs were relatively rare. Children with impaired contractility as well as other cardiac abnormalities differed significantly from children without such conditions. Due to the exploratory nature of this study, these findings should be confirmed in further studies.

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.

Pediatric Inflammatory Multisystem Syndrome Temporally Associated With SARS-CoV-2 (PIMS-TS) and Serous Effusions in a Child With Severe Hypoalbuminemia: A Case Report.

In April 2020, Pediatric Inflammatory Multisystem Syndrome temporally associated with severe acute respiratory syndrome coronavirus 2 or SARS­CoV­2 (PIMS-TS) was described for the first time in children. Since then, many countries have registered hundreds of cases with clinical similarities to Kawasaki disease. We report the case of a five-year-old boy diagnosed with PIMS-TS who presented myocarditis with serous effusions (pleurisy, ascites, pericarditis) due to severe hypoalbuminemia. This case sheds light on the importance of hypoalbuminemia in evaluating the severity of PIMS-TS and preventing its complications. The patient was successfully treated with intravenous immunoglobulins and oral prednisone.

SARS-CoV-2 variants and the risk of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 among children in Germany.

PURPOSE: To investigate the relationship between the risk of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) in children and the predominance of different SARS-CoV-2 variants of concern (VOC) over time. METHODS: In relation to the Alpha, Delta, and Omicron VOC phases of the pandemic, the risk of developing PIMS-TS was calculated by analyzing data for rtPCR-confirmed SARS-CoV-2 infections reported to the German statutory notification system, along with data captured by a separate, national PIMS-TS registry. Both overall infection rates and age group-specific ratios of PIMS-TS during the different pandemic phases were calculated using the Alpha period as the baseline. RESULTS: The PIMS-TS rate changed significantly over time. When the Alpha VOC was dominant [calendar week (CW) 11 in March-CW 31 in August 2021], the PIMS-TS rate was 6.19 [95% confidence intervals (95% CI) 5.17, 7.20]. When Delta prevailed (CW 32 in August 2021-CW 4 in January 2022), the rate decreased to 1.68 (95% CI 1.49, 1.87). During the Omicron phase (CW 5 in January-CW 16 in April 2022), the rate fell further to 0.89 (95% CI 0.79, 1.00). These changes correspond to a decreased PIMS-TS rate of 73% (rate ratio 0.271, 95% CI 0.222; 0.332) and 86% (rate ratio 0.048, 95% CI 0.037; 0.062), respectively, in comparison to the Alpha period. Rate ratios were nearly identical for all age groups. CONCLUSION: The data strongly suggest an association between the risk for PIMS-TS and the prevailing VOC, with highest risk related to Alpha and the lowest to Omicron. Given the uniformity of the decreased risk across age groups, vaccination against SARS-CoV-2 does not appear to have a significant impact on the risk of children developing PIMS-TS.

Miscellaneous causes of abdominal pain

FAPDs (Functional Abdominal Pain Disorders) are the most common cause of chronic abdominal pain but are largely diagnoses of exclusion. More specific, but much less common, causes of acute and chronic abdominal pain include COVID-19 (PIMS-TS), Helicobacter pylori infection, Yersinia spp. Infection and Familial Mediterranean Fever. © Springer Nature Switzerland AG 2022. All rights reserved.

Kawasaki-like disease related to COVID-19. Perioperative management of a pediatric case

The recently identified COVID-19-related Kawasaki-like disease has been considered one of the phenotypes of the cardiovascular manifestations of the Pediatric Multisystem Inflammatory Syndrome associated with SARS-CoV-2 (PIMS-TS), which stands out for few respiratory symptoms and multiple manifestations cardiovascular, the most important being dilation and eventual coronary aneurysms associated or not with cardiogenic shock. The literature is scarce, so perioperative management is challenging for the anesthesiology team. We present the case of an infant with severe cardiovascular manifestations as a result of this disease that required anesthetic interventions to perform a plethysmography and amputation of his lower extremity. The article describes the most relevant considerations in the perioperative management of patients with this pathology. © 2023 Sociedad de Anestesiologia de Chile. All rights reserved.

COVID-19 mRNA BNT162b2 vaccine immunogenicity among children with a history of paediatric multisystem inflammatory syndrome temporally associated with COVID-19 (PIMS-TS).

We conducted a prospective cohort study of 20 patients with a history of paediatric multisystem inflammatory syndrome temporally associated with COVID-19 (PIMS group, median age seven years, 70% male) and 34 healthy controls without such a history (CONTROL group, median age eight years, 38% male) aged 5-12 years, to assess the immunogenicity of Pfizer-BioNTech COVID-19 mRNA BNT162b2 vaccine (Comirnaty®). Patients received two doses of COVID-19 mRNA BNT162b2 vaccine (10 ug/dose) 21 days apart. Pre-vaccine anti-S SARS-CoV-2 IgG antibodies were measured on the day of the first dose and at the median of 23 days after the second dose. The study was conducted during the COVID-19 wave dominated by the Omicron variant of the virus. Anti-NCP SARS-CoV-2 IgG antibodies were measured twice to evaluate incidents of infection during the study period. Pre-vaccine quantification of both types of antibodies allowed us to differentiate patients into COVID-19 naive and previously infected in order to compare hybrid immunity with vaccine-induced immunity. Before vaccination, anti-S IgG serum geometric mean concentration (GMC) was 61.17 BAU/ml in the PIMS group and 24.97 in the CONTROL group, while post-vaccination GMC was 3879.14 BAU/ml and 3704.87 BAU/ml, respectively, and did not significantly differ between the groups. Hybrid immunity (regardless of PIMS history) resulted in a higher concentration of SARS-CoV-2 anti-S antibodies after vaccination. Four (20%) of the children in the PIMS group and 11 (32%) in the CONTROL group got infected with SARS-CoV-2 during the study period, yet all of them asymptomatically, and this event has not significantly altered post-vaccination anti-S titers. In conclusion, COVID-19 vaccination was highly immunogenic in children, including those with a history of PIMS-TS; hybrid immunity overperforms vaccine-induced immunity in terms of serological response in children. However, vaccination effectiveness in preventing SARS-CoV-2 infections in children should be further evaluated.

Role of Lung Ultrasonography (LUS) as a Tool for Evaluating Children with Pediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 (PIMS-TS).

BACKGROUND: Pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) is a novel entity. The inflammatory process involves the circulatory, digestive, respiratory, and central nervous systems, as well as the skin. Making a diagnosis requires extensive differential diagnoses, including lung imaging. The aim of our study was to retrospectively assess the pathologies found in lung ultrasound (LUS) in children diagnosed with PIMS-TS and to evaluate the usefulness of the examination in diagnostics and monitoring. METHODS: The study group consisted of 43 children diagnosed with PIMS-TS, in whom LUS was performed at least three times, including on admission to hospital, on discharge, and 3 months after disease onset. RESULTS: Pneumonia (mild to severe) was diagnosed in 91% of the patients based on the ultrasound image; the same number had at least one pathology, including consolidations, atelectasis, pleural effusion, and interstitial or interstitial-alveolar syndrome. By the time of discharge, the inflammatory changes had completely regressed in 19% of the children and partially in 81%. After 3 months, no pathologies were detected in the entire study group. CONCLUSION: LUS is a useful tool for diagnosing and monitoring children with PIMS-TS. Inflammatory lesions of the lungs resolve completely when the generalized inflammatory process subsides.

Hemolytic anemia following intravenous immunoglobulins in children with PIMS-TS: Two case reports.

This is the first case report on two children presenting with immediate and severe hemolytic anemia following the administration of high-dose intravenous immunoglobulins (IVIGs) in the context of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). Hemolytic anemia was described as a significant decrease in hemoglobin and an increase in lactate dehydrogenase after the second administration of high-dose IVIGs was performed. Both patients were found to have AB blood group. One of our patients showed massive pallor, weakness, and inability to walk in association with hemolysis. However, in both cases, the anemia was self-limiting and transfusion of red blood cells was not required: both patients recovered without persistent impact. Nonetheless, we aim to draw attention to this widely unknown adverse effect of IVIG, especially in the context of PIMS-TS. We suggest determining the patient's blood group prior to high-dose IVIG infusion and replacing the second IVIG through high-dose steroids or anticytokine therapy. Using IVIGs containing lower titers of specifically anti-A or anti-B antibodies to avoid isoagglutinin-caused hemolytic anemia is desirable; however, the information is not routinely available.

Polymorphism of clinical manifestations, experience of diagnosis and treatment of multisystem inflammatory syndrome associated with COVID-19 in children

Purpose - to analyze the literature data on possible variants of the course of pediatric multisystem inflammatory syndrome (PIMS-TS) in children;to describe our own experience in the diagnosis and treatment of some cases of PIMS-TS in children of different age groups;to present possible variants of clinical manifestations of the above disease;to draw attention to the need for early diagnosis and team care and treatment of such children. This novel clinical syndrome later identified as PIMS-TS temporally associated with SARS-CoV-2. In contrast with KD, PIMS-TS appears to occur in children at an older age with a predominance of gastrointestinal symptoms, hemodynamic instability, and myocardial dysfunction. However, the exact pathomechanism remains to be understood. Nevertheless, the post-viral immunological reaction is postulated to be the underlying mechanistic underpinnings. The paper describes the clinical course of the disease in a 5-year-old boy who complained of abdominal pain and hyperthermia, and the disease was masked by surgical pathology. The phenomena of intoxication syndrome, polyserositis, skin manifestations in the form of a polymorphic rash, hyperemia of the conjunctiva, swelling of the feet and hands increased in dynamics. The course of the disease in a 10-year-old girl who had symptoms of a viral infection is also described. However, upon going to the hospital, both children were diagnosed with a serious condition, they were hospitalized and given appropriate treatment. Therefore, the multifaceted nature of the PIMS-TS' course underlines the need for early recognition and multispecialty care and management. The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies. © 2022 Group of Companies Med Expert, LLC. All rights reserved.

GUIDELINES FOR IMMUNIZATION OF CHILDREN FOLLOWING MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN (MIS-C).

Multisystem inflammatory syndrome in children, MIS-C is also referred to as a paediatric inflammatory multisystem syndrome, PIMS. It is a late complication of SARS-CoV-2 infec-tion. The underlying cause is immunological dysregulation, leading to severe inflammatory processes. Children with PIMS require hospital treatment, the use of immunomodulating drugs, and often intensive care. The high effectiveness of COVID-19 vaccination has been demonstrated in the prevention of MIS-C in adolescents. However, there are no explic-it vaccination recommendations for children who have already suffered from MIS-C. We present a summary of current knowledge on vaccinations against COVID-19 in the context of MIS-C and the Polish guidance of vaccinations for children following MIS-C.Copyright © 2022, Wydawnictwo Czelej Sp. z o.o.. All rights reserved.

Oral lesions in paediatric patients with COVID-19 and Paediatric Inflammatory Multisystem Syndrome: a review

Paediatric patients comprise a small proportion of the SARS-CoV-2 infected population. They usually present with mild symptoms, however a small proportion of them may require intensive care due to shock and multi-organ failure related to Paediatric Inflammatory Multisystem Syndrome temporally associated with SARS-CoV-2 (PIMS-TS). This review article summarises the oral mucosal lesions in children with COVID-19 and PIMS-TS. The most common sites affected are the tongue and lips. Commonly reported lesions include cheilitis, dry and red lips, and tongue swelling. This article is of importance to all healthcare professionals involved in the multidisciplinary care for this group of patients.Copyright © 2021 The Authors

COVID-19 in children: what did we learn from the first wave?

A pandemic caused by the novel coronavirus, severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2), has caused high rates of mortality, predominantly in adults. Children are significantly less affected by SARS-CoV-2 with far lower rates of recorded infections in children compared to adults, milder symptoms in the majority of children and very low mortality rates. A suspected late manifestation of the disease, paediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 (PIMS-TS), has been seen in small numbers of children and has a more severe disease course than acute SARS-CoV-2. The pandemic has meant that children around the world have been kept off school, isolated from their extended family and friends and asked to stay inside. The UK has been declared as being in an economic recession and unemployment rates are increasing. These indirect effects of SARS-CoV-2 are likely to have a significant impact on many children for years to come. Consolidating the knowledge that has accumulated during the first wave of this pandemic is essential for recognising the clinical signs, symptoms and effective treatment strategies for children; identifying children who may be at increased risk of severe SARS-CoV-2 infection; planning the safe delivery of healthcare and non-health related services that are important for childrens' wellbeing; and engaging in, and developing, research to address the things that are not yet known. This article summarises the evidence that has emerged from the early phase of the pandemic and offers an overview for those looking after children or planning services.

Multisystem inflammatory syndrome in children associated with Bacille Calmette-Guérin scar: a case presentation.

BACKGROUND: During Coronavirus disease of 2019 (COVID-19) pandemic, the WHO reported a noticeable increase in Kawasaki disease prevalence in countries where Kawasaki disease is rare. This newly seen disease, unlike typical Kawasaki disease, tends to appear at a later age, has prominent gastrointestinal findings, higher rates of myocarditis and coronary artery involvement and a greater need for admission to the intensive care unit (ICU). Induration of the Bacillus Calmette-Guerin (BCG) scar is a rare finding seen in multisystem inflammatory syndrome (MIS-C). This is the second reported case of erythema and induration of the BCG scar in a 1-year-old boy with MIS-C. CASE PRESENTATION: The Arabic boy presented with high resistant fever, nausea/vomiting, diarrhea, erythematous lips, and conjunctivitis. He later developed induration of his BCG scar, diffuse rash and desquamation on fingers and toes. He had a history of COVID-19 exposure as his IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were positive. Based on his clinical findings and repeated lab results, he was diagnosed with MIS-C with Kawasaki features and treated with intravenous immune globulin (IVIG) followed by methylprenisolone and aspirin. CONCLUSIONS: Reaction at the BCG inoculation site is not a diagnostic criteria for Kawasaki, but it is seen clinically in 30-50% of the patients. We report the case of a 1-year-old boy diagnosed with MIS-C presenting with erythema and induration of BCG scar. Further studies are needed to explore this clinical presentation, especially in the countries that have BCG vaccination programs, and to determine the mechanisms of MIS-C.

Analysis of the impact of the SARS-CoV-2 infection on the pediatric population hospitalized during the pandemic in the Greater Paris University Hospitals.

Background: The clinical characteristics, disease progression and outcome in children affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection appear significantly milder compared to older individuals. Nevertheless, the trends in hospitalization and clinical characteristics in the pediatric population seem to be different over time across the different epidemic waves. Objective: Our aim was to understand the impact of the different COVID-19 variants in the pediatric population hospitalized in the Pediatric Departments of the Public Hospital in the Greater Paris area by the analysis performed with the Assistance Publique-Hopitaux de Paris (AP-HP) Health Data Warehouse. Methods: This is a retrospective cohort study including 9,163 patients under 18 years of age, hospitalized from 1 March 2020 to 22 March 2022, in the Paris area, with confirmed infection by SARS-CoV-2. Three mutually exclusive groups with decreasing severity (Pediatric Inflammatory Multisystem Syndrome (PIMS), symptomatic infection, mild or asymptomatic infection) were defined and described regarding demography, medical history, complication of the SARS-CoV-2 infection, and treatment during admission. Temporal evolution was described by defining three successive waves (March-September 2020, October 2020-October 2021, and November 2021-March 2022) corresponding to the emergence of the successive variants. Results: In the study period, 9,163 pediatric patients with SARS-CoV-2 infection were hospitalized in 21 AP-HP hospitals. The number of patients with SARS-CoV-2 infection increased over time for each wave of the pandemic (the mean number of patients per month during the first wave was 332, 322 during the 2nd, and 595 during the third wave). In the medical history, the most associated concomitant disease was chronic respiratory disease. Patients hospitalized during the third wave presented a higher incidence of pulmonary involvement (10.2% compared to 7% and 6.5% during the first and second waves, respectively). The highest incidence of PIMS was observed during the first and second waves (4.2% in the first and second waves compared to 2.3% in the 3rd wave). Discussion: This analysis highlighted the high incidence of hospitalized children in the Greater Paris Area during the third wave of SARS-CoV-2 pandemic corresponding to the Omicron Covid-19 variant, which is probably an expression of a concomitant SARS-CoV-2, while a decreased incidence of PIMS complication was observed during the same period.

Multicentre observational study on multisystem inflammatory syndrome related to COVID-19 in Argentina.

BACKGROUND: The impact of the Pediatric Inflammatory Multisystem Syndrome temporally-associated with SARS-CoV-2 (PIMS-TS) in low and middle-income countries remains poorly understood. Our aim was to understand the characteristics and outcomes of PIMS-TS in Argentina. METHODS: This observational, prospective and retrospective multicenter study, enrolled patients younger than 18 years-old showing PIMS-TS, Kawasaki disease (KD) or Kawasaki shock syndrome (KSS) manifestations between March 2020 and May 2021. Patients were followed-up until hospital discharge or death (which occurred in one case). The primary outcome was PICU admission. Multiple logistic regression was used to identify variables predicting PICU admission. RESULTS: Eighty-one percent, 82% and 14% of the 176 enrolled patients fulfilled the suspect case criteria for PIMS-TS, KD, and KSS, respectively. Temporal association with SARS-CoV-2 was confirmed in 85% of the patients and 38% were admitted to PICU. The more common clinical manifestations were fever, abdominal pain, rash and conjunctival injection. Lymphopenia was more common among PICU-admitted patients (87% versus 51%, p<0.0001), who also showed a lower platelet count and higher plasmatic levels of inflammatory and cardiac markers. Mitral valve insufficiency, left ventricular wall motion alterations, pericardial effusion and coronary arteries alterations were observed in 30%, 30%, 19.8%, 18.6% of the patients, respectively. Days to initiation of treatment, rash, lymphopenia, and low platelet count did significant independent contributions to PICU admission. CONCLUSION: Rates of severe outcomes of PIMS-TS in the present study agreed with those observed in high-income countries. Together with other published studies, this work helps to better understand this novel clinical entity.

SARS-CoV-2 infection in the context of Kawasaki disease and multisystem inflammatory syndrome in children.

Recent studies have noted an increasing number of Kawasaki-like cases in the pediatric population following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In the literature, the condition is described as multiple inflammatory syndrome in children (MIS-C) or pediatric inflammatory syndrome (PIMS). A similar clinical course of Kawasaki disease (KD) and MIS-C causes difficulties in distinguishing between both conditions. However, the differential diagnosis is crucial since patients with MIS-C can present severe symptoms (myocardial dysfunction, fever, mucocutaneous symptoms) and require more extensive monitoring during treatment than children diagnosed with KD. Along with assessing epidemiological and genetic factors, it is imperative to estimate the risk of developing MIS-C in KD patients with confirmed SARS-CoV-2 infection. Genetic predispositions, such as the ITPKC gene polymorphism in KD, ACE deletion (D) polymorphism in SARS-CoV-2, and inborn errors of immunity (IEIs) in MIS-C affect the regulation of immune system complex clearances and cellular adaptations. The virus has a tropism for both vascular and respiratory cells, which further causes additional symptoms necessitating standard therapy with antithrombotic treatment. The diagnostic criteria for KD, MIS-C, and SARS-CoV-2 help differentiate each condition and optimize treatment strategies. Unfortunately, long-term outcomes in KD patients who develop MIS-C due to SARS-CoV-2 infection have been inadequately documented due to the timing of the pandemic, further displaying the need for longitudinal studies in these patients. This review underlines the differences in diagnosis and treatment of KD and MIS-C. Overall, children with KD may develop MIS-C in the setting of SARS-CoV-2 infection, but further research is needed to outline specific etiologies, prognostic factors, and diagnoses.