How international guidelines recommend treating children who have severe COVID-19 or risk disease progression.

AIM: This study reviewed the current knowledge and guidelines on managing COVID-19 in children and proposed a practical approach to drug treatment. METHODS: We analysed international guidelines from four prominent scientific bodies on treating COVID-19 in children. These were the UK National Institute for Health and Care Excellence, the American National Institutes of Health, the Infectious Diseases Society of America and the Australian National Clinical Evidence Taskforce COVID-19. RESULTS: Most paediatric patients with COVID-19 only require symptomatic treatment. There was limited evidence on treatment recommendations for children with severe COVID-19 or at risk of disease progression. However, several drugs are available for children and we have summarised the guidelines, in order to provide a concise, practical format for clinicians. All the guidelines agree that nirmatrelvir plus ritonavir or remdesivir can be used as prophylaxis for severe COVID-19 in high-risk patients. Remdesivir can also be used for severe COVID-19 cases. Glucocorticosteroids are recommended, particularly in patients requiring oxygen therapy. Tocilizumab or baricitinib should be reserved for patients with progressive disease and/or signs of systemic inflammation. CONCLUSION: The guidelines provide useful advice and a degree of consensus on specific drug treatment for children with severe COVID-19 or at risk of progression.

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.

Pathogenesis, immunology, and immune-targeted management of the multisystem inflammatory syndrome in children (MIS-C) or pediatric inflammatory multisystem syndrome (PIMS): EAACI Position Paper.

Multisystem inflammatory syndrome in children (MIS-C) is a rare, but severe complication of coronavirus disease 2019 (COVID-19). It develops approximately 4 weeks after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and involves hyperinflammation with multisystem injury, commonly progressing to shock. The exact pathomechanism of MIS-C is not known, but immunological dysregulation leading to cytokine storm plays a central role. In response to the emergence of MIS-C, the European Academy of Allergy and Clinical Immunology (EAACI) established a task force (TF) within the Immunology Section in May 2021. With the use of an online Delphi process, TF formulated clinical statements regarding immunological background of MIS-C, diagnosis, treatment, follow-up, and the role of COVID-19 vaccinations. MIS-C case definition is broad, and diagnosis is made based on clinical presentation. The immunological mechanism leading to MIS-C is unclear and depends on activating multiple pathways leading to hyperinflammation. Current management of MIS-C relies on supportive care in combination with immunosuppressive and/or immunomodulatory agents. The most frequently used agents are systemic steroids and intravenous immunoglobulin. Despite good overall short-term outcome, MIS-C patients should be followed-up at regular intervals after discharge, focusing on cardiac disease, organ damage, and inflammatory activity. COVID-19 vaccination is a safe and effective measure to prevent MIS-C. In anticipation of further research, we propose a convenient and clinically practical algorithm for managing MIS-C developed by the Immunology Section of the EAACI.

SARS-CoV-2 Cluster in Nursery, Poland.

We report a cluster of surprisingly high spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated with a single nursery in Poland. Our findings contrast with the presumed negligible role of children in driving the SARS-CoV-2 pandemic. Children 1-2 years of age might be effective SARS-CoV-2 spreaders.

Recurrent assessment of lymphocyte subsets in 32 patients with multisystem inflammatory syndrome in children (MIS-C).

BACKGROUND: Lymphopenia is a hallmark of multisystem inflammatory syndrome in children (MIS-C). We aimed to characterize lymphocyte subsets' shifts and their correlations with other severity markers of MIS-C. METHODS: In this prospective cross-sectional study, we performed peripheral lymphocyte phenotyping in 32 patients with MIS-C. We analyzed lymphocyte subsets at three time points of the disease: the acute (A), convalescent (B), and recovery (C) phases. Based on age-normalized lymphocyte counts, we distinguished two groups of patients: "the mild" (higher lymphocyte counts) and "the severe" (lower lymphocyte counts). In addition, we examined differences between these groups regarding other severity markers. RESULTS: In phase A, 84% of children had lymphopenia. Decreased absolute counts of CD3, CD4, and CD8 cells were observed in, respectively, 88%, 72%, and 84% of patients. The natural killer cells were decreased in 63% and CD19 in 59% of children. "The severe" group had significantly higher procalcitonin and troponin I levels and lower platelets and albumin. Moreover, "the severe" group had hypotension more frequently (73% vs. 20%, p = .008). In phase B, all lymphocyte counts increased, and 32% of children had lymphocytosis. The increase of CD3, CD4, and CD8 counts correlated with some laboratory severity markers (hemoglobin, procalcitonin, D-dimer, lactate dehydrogenase, N-terminal prohormone of brain natriuretic peptide, albumin), but not with steroid use. In phase C, most children had normal lymphocyte counts. CONCLUSIONS: Substantial shifts in lymphocyte counts during MIS-C apply most to T lymphocytes and correlate with the disease severity markers, particularly hypotension prevalence. A proportion of children with MIS-C develops transient lymphocytosis during convalescence.

Serum Klotho is correlated to cardiovascular complications of chronic kidney disease in children.

AIM: Aim of the study was to investigate soluble Klotho (sKl), fibroblast growth factor 23 (FGF23) concentrations, and their correlations with cardiovascular complications in children with CKD. MATERIALS AND METHODS: 38 children with CKD stages 2 - 5 were compared to 38 healthy controls in terms of: plasma FGF23, serum sKl, peripheral and central blood pressure, arterial stiffness (pulse wave velocity - (PWV)), carotid intima media thickness (cIMT), left ventricular mass index (LVMI), and diastolic function. Correlations between FGF23, sKl, and cardiovascular parameters were investigated. RESULTS: The CKD group was characterized by higher FGF23, lower sKl concentrations, higher peripheral and central blood pressure, arterial stiffness, cIMT, left ventricular mass index, and decreased E/A ratio compared to the control group. In CKD children, sKl correlated negatively with diastolic blood pressure (DBP), mean arterial pressure (MAP), central systolic, diastolic, and mean blood pressure, PWV, and LVMI. In multivariate analysis, higher sKl was a significant predictor of lower peripheral and central DBP and lower LVMI and E/A, whereas higher FGF23 was a predictor of higher of LVMI. CONCLUSION: (1) In children with CKD, decreased sKl might be a marker of elevated central blood pressure. (2) Both sKl decrease and FGF23 increase could possibly contribute to left ventricular hypertrophy in this group of patients.

Renalase in children with chronic kidney disease.

Background: Renalase is kidney-derived molecule initially considered as catecholamine-inactivating enzyme. However, recent studies suggest that renalase exerts potent cardio- and nephroprotective actions, not related to its enzymatic activity. Purpose: To assess renalase level in children with chronic kidney disease (CKD). Material and methods: Serum renalase, BMI, arterial stiffness, peripheral and central blood pressure, intima-media thickness (IMT), medications, and biochemical parameters were analyzed in 38 children with CKD (12.23 ± 4.19 years) (stage G2-5). Control group consisted of 38 healthy children. Results: In the study group, GFR was 25.74 ± 8.94 mL/min/1.73 m2; 6 children were dialyzed; 26 had arterial hypertension. Renalase level was higher in the study group compared to control group (p < 0.001). In CKD children renalase correlated (p < 0.05) with BMI Z-score (r = -0.36), alfacalcidol dose (r = 0.41), GFR (r = -0.69), hemoglobin (r = -0.48), total cholesterol (r = 0.35), LDL-cholesterol (r = 0.36), triglycerides (r = 0.52), phosphate (r = 0.35), calcium-phosphorus product (r = 0.35), parathormone (r = 0.58), and pulse wave velocity Z-score (r = 0.42). In multivariate analysis GFR (ß = -0.63, p < 0.001), triglycerides (ß = 0.59, p = 0.002), and alfacalcidol dose (ß = -0.49, p = 0.010) were determinants of renalase. Conclusions: In children with CKD there is a strong correlation between renalase level and CKD stage. Furthermore, in these patients renalase does not correlate with blood pressure but may be a marker of arterial stiffness.

Carotid intima-media thickness in children with idiopathic nephrotic syndrome: A single center cross-sectional study
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AIM: Our aim was to assess common carotid artery intima-media thickness (cIMT) in children with idiopathic nephrotic syndrome (INS) and to find relation between cIMT and clinical and biochemical parameters in these patients. MATERIALS AND METHODS: In 50 children with INS we retrospectively evaluated: cIMT ((mm) and Z-score) and selected clinical and biochemical parameters. The control group consisted of 20 healthy children aged 9.46 ± 2.29 years. RESULTS: Children with INS had higher cIMT (0.45 ± 0.05 vs. 0.40 ± 0.05 (mm), p = 0.0002) and cIMT Z-score (1.72 ± 1.01 vs. 0.43 ± 1.01, p < 0.0001) than the control group. In the INS group, children with arterial hypertension had significantly higher cIMT (p = 0.0148) than normotensive children. In 50 children, with INS we found correlations between cIMT and disease duration (r = 0.40, p = 0.0040), number of INS relapses (r = 0.51, p< 0.0001), cumulative prednisone dose (r = 0.45, p = 0.0010), and BMI (r = 0.35, p = 0.0120); whereas, cIMT Z-score correlated only with the number of INS relapses (r = 0.41, p = 0.0160) and cumulative prednisone dose (r = 0.36, p = 0.0362). We found no relation between cIMT and response to corticosteroids, treatment used, and biochemical parameters. CONCLUSION: 1. Idiopathic nephrotic syndrome predisposes to atherosclerotic lesions in affected children. 2. The severity of atherosclerotic lesions is dependent mainly on the number of INS relapses, but disease vintage, cumulative steroid dose, body mass index, and presence of arterial hypertension may also be predisposing factors.
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[Copeptin in children with chronic kidney disease]. / Kopeptyna u dzieci chorych na przewlekla chorobe nerek.

Studies in adult patients suggest that copeptin (C-terminal fragment of antidiuretin propeptide) is related to kidney and cardiovascular diseases. AIM: The aim was to assess copeptin concentration in children with chronic kidney disease (CKD). MATERIALS AND METHODS: In a group of 38 children with CKD (age: from 4.70 to 18.00 mean 12.23±4.19 years) we evaluated: serum copeptin concentration [ng/mL], age, sex, etiology of CKD, presence of arterial hypertension (AH), medications, glomerular filtration rate (GFR), hemoglobin, calcium-phosphorus metabolism parameters, and lipids. Control group consisted of 38 healthy children aged from 5.51 to 18.0 mean 11.79±3.29 years. RESULTS: Serum copeptin concentration did not differ between children with CKD and healthy children (0.72±0.34 vs. 0.84±0.33 [ng/mL], p=0.088). In children with CKD there were no differences in copeptin concentration depending on sex, presence of AH, and CKD grade. In children with CKD only positive correlation between copeptin and hemoglobin concentrations was found (r=0.35, p=0.031); no other significant correlations between copeptin and clinical and biochemical parameters including GFR were revealed. Also no significant correlations were found between copeptin and evaluated parameters in the control group. CONCLUSIONS: In children copeptin concentration does not seem to be related to kidney function. Copeptin may be a marker of hydration status in children with chronic kidney disease. There is a need for further studies evaluating clinical significance of copeptin in children with chronic kidney disease.

Renalase in Children with Glomerular Kidney Diseases.

Studies suggest that renalase, a renal catecholamine-inactivating enzyme, plays a major role in the pathogenesis of kidney and cardiovascular diseases in adults. This study seeks to determine the role of renalase in children with glomerular kidney diseases. We evaluated the serum renalase, arterial stiffness, intima-media thickness, blood pressure, and clinical and biochemical parameters in 78 children (11.9 ± 4.6 years of age) with glomerulopathies such as idiopathic nephrotic syndrome (40 cases), IgA nephropathy (12 cases), Henoch-Schönlein nephropathy (12 cases), and other glomerulopathies (14 cases). The control group consisted of 38 healthy children aged 11.8 ± 3.3 years. The mean renalase was 25.74 ± 8.94 µg/mL in the glomerulopathy group, which was not significantly different from the 27.22 ± 5.15 in the control group. The renalase level did not differ among various glomerulopathies either. However, proteinuric patients had a higher renalase level than those without proteinuria (28.43 ± 11.71 vs. 24.05 ± 6.23, respectively; p = 0.03). In proteinuric patients, renalase correlated with daily proteinuria. In the entire glomerulopathy group, renalase correlated with age, systolic central blood pressure (BP), diastolic peripheral and central BP, mean peripheral and central BP; peripheral diastolic BP Z-score, glomerular filtration rate, cholesterol, triglycerides, and pulse wave velocity. We conclude that in children with glomerulopathies renalase, although basically not enhanced, may underlie blood pressure elevation and arterial damage.

[Fibroblast growth factor 23 in chronic kidney disease in children]. / Czynnik wzrostu fibroblastów 23 w przewleklej chorobie nerek u dzieci.

Cardiovascular risk in children with chronic kidney disease (CKD) is many times higher compared to their healthy peers, and discovered in year 2000 fibroblast growth factor 23 (FGF23) may be one of the factors responsible. FGF23 together with its cofactor, α-Klotho protein, plays a pivotal role in calcium-phosphorus metabolism in patients with CKD by decreasing secretion of active metabolite of vitamin D and antagonizing phosphate resorption in renal tubules. Studies conducted in recent years revealed that FGF23 directly binds to its receptor on cardiomyocytes and promotes left ventricular hypertrophy. Clinical trials in children with CKD, similarly to adult studies, suggest a key role of this protein in development of calciumphosphorus disturbances. Single studies in small patient groups suggest also a significance of FGF23 in pathogenesis of cardiovascular alterations in this population. Further clinical trials investigating role of FGF23 in development of cardiovascular damage in larger groups of children are necessary, which may open new therapeutic options for these patients in future.

Serum fibroblast growth factor 23 and calcium-phosphorus metabolism parameters in children with chronic kidney disease - preliminary report.

INTRODUCTION: In chronic kidney disease (CKD) the function of all factors regulating mineral metabolism is disturbed, leading inevitably to renal osteodystrophy and vascular calcification. The aimof the study is to assess concentrations of fibroblast growth factor 23 (FGF 23), osteoprotegerin (OPG) and other parameters of calcium-phosphate metabolism in children with CKD. MATERIAL AND METHODS: 37 children with CKD 3-5, aged 1.6-17 years were included in the study. In all children serum levels of calcium (sCa), phosphate (sP), creatinine, alkaline phosphatase (ALP), FGF 23, intact parathormone (PTH), OPG and receptor activator nuclear factor κB ligand (RANKL) were measured. RESULTS: Total calcium concentration was within normal limits in all children included in this study. Hyperphosphatemia was found in 2 children from group CKD 3 (12%), 6 from CKD 4 (54%) and 1 from CKD 5 (11%). FGF 23 level increased consecutively in subsequent CKD stages achieving the highest values in CKD 5 group. In all children with CKD, serum levels of OPG were correlated with FGF 23. In children with CKD 3-4 negative correlation between FGF 23 and PTH (r=-0.45; p=0.02) and positive correlation between FGF 23 and RANKL (r=0,59; p=0.006) has been found. Positive correlation between OPG concentration and HCO3 -and BE levels has been observed, as well as negative correlation between RANKL/OPG ratio and HCO3 -and BE levels. CONCLUSION: Despite maintaining serum calcium, phosphorus and PTH levels within recommended limits, elevated levels of FGF 23 and OPG were observed in children with chronic kidney disease, especially in it's end-stage.

Pathologic Analysis of Twenty-one Appendices From Children With Multisystem Inflammatory Syndrome Compared to Specimens of Acute Appendicitis: A Cross-sectional Study.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a rare, severe complication of coronavirus disease 2019, commonly involving the gastrointestinal tract. Some children with MIS-C undergo appendectomy before the final diagnosis. There are several hypotheses explaining the pathomechanism of MIS-C, including the central role of the viral antigen persistence in the gut, associated with lymphocyte exhaustion. We aimed to examine appendectomy specimens from MIS-C patients and assess their pathologic features, as well as the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens. METHODS: In this cross-sectional study we included 21 children with MIS-C who underwent appendectomy. The control group included 21 sex- and age-matched children with acute appendicitis (AA) unrelated to SARS-CoV-2 infection. Histologic evaluation of appendiceal specimens included hematoxylin and eosin staining and immunohistochemical identification of lymphocyte subpopulations, programmed cell death protein-1 (PD-1) and SARS-CoV-2 nucleocapsid antigen. RESULTS: Appendices of MIS-C patients lacked neutrophilic infiltrate of muscularis propria typical for AA (14% vs. 95%, P < 0.001). The proportion of CD20+ to CD5+ cells was higher in patients with MIS-C (P = 0.04), as was the proportion of CD4+ to CD8+ (P < 0.001). We found no proof of SARS-CoV-2 antigen presence, nor lymphocyte exhaustion, in the appendices of MIS-C patients. CONCLUSIONS: The appendiceal muscularis of patients with MIS-C lack edema and neutrophilic infiltration typical for AA. SARS-CoV-2 antigens and PD-1 are absent in the appendices of children with MIS-C. These findings argue against the central role of SARS-CoV-2 persistence in the gut and lymphocyte exhaustion as the major triggers of MIS-C.

FCGR2/3 polymorphisms are associated with susceptibility to Kawasaki disease but do not predict intravenous immunoglobulin resistance and coronary artery aneurysms.

Introduction: Kawasaki disease (KD) is a pediatric vasculitis that can result in coronary artery aneurysm (CAA) formation, which is a dangerous complication. Treatment with intravenous immunoglobulin (IVIg) significantly decreases the risk of CAA, possibly through competitive binding to Fc-gamma receptors (FcγRs), which reduces the binding of pathological immune complexes. However, ~20% of children have recrudescence of fever and have an increased risk of CAA. Therefore, we aimed to identify genetic markers at the FCGR2/3 locus associated with susceptibility to KD, IVIg resistance, or CAA. Materials and methods: We investigated the association of single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs) at the FCGR2/3 locus with KD susceptibility, IVIg resistance, and CAA risk using a family-based test (KD susceptibility) and case-control analyses (IVIg resistance and CAA risk) in different cohorts, adding up to a total of 1,167 KD cases. We performed a meta-analysis on IVIg resistance and CAA risk including all cohorts supplemented by previous studies identified through a systematic search. Results: FCGR2A-p.166His was confirmed to be strongly associated with KD susceptibility (Z = 3.17, p = 0.0015). In case-control analyses, all of the investigated genetic variations at the FCGR2/3 locus were generally not associated with IVIg resistance or with CAA risk, apart from a possible association in a Polish cohort for the FCGR3B-NA2 haplotype (OR = 2.15, 95% CI = 1.15-4.01, p = 0.02). Meta-analyses of all available cohorts revealed no significant associations of the FCGR2/3 locus with IVIg resistance or CAA risk. Discussion: FCGR2/3 polymorphisms are associated with susceptibility to KD but not with IVIg resistance and CAA formation. Currently known genetic variations at the FCGR2/3 locus are not useful in prediction models for IVIg resistance or CAA risk.

Influenza vaccination from the perspective of health care workers at university hospitals.

BACKGROUND: The influenza vaccination rate of healthcare workers (HWs) in Poland is low. Before implementing methods for promoting influenza vaccination, it is crucial to identify attitudes towards vaccination. We aimed to examine the knowledge and attitudes towards influenza vaccination of HWs at university hospitals. Moreover, we evaluated the incentives for getting influenza vaccination among HWs. METHODS: From September 2020 to October 2020, we surveyed HWs in one children's hospital and two adults' hospitals in Warsaw (Poland). We included only fully and correctly completed surveys into final analysis. RESULTS: A total of 950 questionnaires (85% women, 45% <40 years old, 33% physicians and 48% nurses, 56% working in a children's hospital) were evaluated. Of all HWs, 25% declared they were vaccinated and 54% planned to get vaccinated in the next season. We have analyzed attitudes towards influenza vaccination and motivations to get vaccinated. CONCLUSIONS: Among HWs in academic hospitals, males, people <40 years old, physicians and those working in children's hospital are more likely to get vaccinated and their attitudes towards influenza vaccination are more positive. Of those less likely to get vaccinated, people >40 years old and nurses could be effectively persuaded by free and on-site influenza vaccination. Moreover, free access to vaccination is the strongest motivator for vaccination among all HWs. The attitudes towards mandatory influenza vaccination differ sharply among HWs-while physicians are ready to accept it, nurses are not. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04569019.

Monte Carlo Regression for Evaluating Children's Role in the Pandemic Spread on the Example of Delta COVID-19 Wave.

BACKGROUND: The children's role in transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the familial settings is uncertain. We aimed to assess how often children were the index cases transmitting SARS-CoV-2 into their households during the Delta wave, and to identify risk factors of children being the index case. METHODS: In this prospective survey study, we collected information regarding household members of SARS-CoV-2-positive children tested in a single tertiary hospital. Some patients were tested with polymerase chain reaction and those samples were typed and classified as Delta or non-Delta variant. We have used the Monte Carlo approach to assess predictors of children being the index case in the household. RESULTS: We surveyed 629 families and 515 of them fulfilled inclusion criteria. The child was the index case in 359 (69.71%) households. Attending childcare facilities in all age groups was positively associated with being the index case in the household [nursery, estimate = 1.456, 95% confidence interval (CI): 1.456-1.457, P < 0.001; kindergarten, estimate = 0.899, 95% CI: 0.898-0.900, P = 0.003; school, estimate = 1.23, 95% CI: 1.229-1.231, P = 0.001]. The same association was present in the subgroup of the families with the predominant Delta variant, but not in the subgroup with the predominant non-Delta variant. CONCLUSIONS: Attending childcare and educational facilities might be a significant predictor of a child being the SARS-CoV-2 index case in their household. Children's role in driving the SARS-CoV-2 pandemic changes in consecutive waves. The Monte Carlo approach can be applied to assess risk factors of infectious agents' spread in future epidemics.

Ukrainian War Refugee Children With Particularly Severe Viral Infections: A Case Series Report.

The humanitarian crisis in Ukraine in 2022 led to a massive migration of refugees to Poland. Immigrant children, living in overcrowded humanitarian hubs, were exposed to multiple stressful factors likely affecting their immune systems. This case series study aimed to describe a particularly severe course of common viral infections, in Ukrainian refugee children. We present 2 case series of Ukrainian refugee children: 5 hospitalized due to either adenovirus (AdV) and 8 with rotavirus (RV) infection, admitted within 3 months in each case series, recruited retrospectively. Most patients lived in humanitarian hubs and were neglected on admission (dehydrated, with poor hygiene and anxious). All RV infection cases had symptoms of severe gastroenteritis requiring intravenous rehydration. Metabolic acidosis was present in 6 children, and hypoglycemia in 4 participants. None of them were vaccinated against RV. All children with AdV infection had prolonged fever, dyspnea requiring oxygen therapy and hyperinflammation. In 2 AdV infection cases with no clinical improvement and increasing inflammatory markers, intravenous immunoglobulins and glucocorticosteroids were used. The combination of stressful factors and living in overcrowded hubs during the high prevalence of viral infections led to a particularly severe course of viral infections in Ukrainian refugee children.

Clinical characteristics of children with MIS-C fulfilling classification criteria for macrophage activation syndrome.

Background: Macrophage activation syndrome (MAS) is a potentially life-threatening complication of various inflammatory disorders, including multisystem inflammatory syndrome in children (MIS-C). MIS-C refractory to treatment should raise suspicion of MAS, which can be fatal if a definitive diagnosis is delayed. Unfortunately, there is a lack of data on MAS in children with MIS-C. Objective: Our study aims to analyze the risk factors for the development of MAS in MIS-C, its clinical course and response to treatment, and identify predictive factors for pediatric intensive care. Material and methods: We analyzed data from the Polish MIS-C registry of the MultiOrgan Inflammatory Syndromes COVID-19 Related Study. Patients were diagnosed according to the WHO MIS-C definition and treated according to national guidelines (Polish Pediatric Society) based on international consensus. MAS definition was based on 2016 Classification Criteria for Macrophage Activation Syndrome Complicating Systemic Juvenile Idiopathic Arthritis. Results: Two-hundred and seventy four children met the study inclusion criteria. Fifty-nine patients fulfilled MAS classification criteria, nine of which required admission to the pediatric intensive care unit (PICU). MIS-C patients with MAS were significantly older than patients without MAS (median 11.2 vs. 8.1 years). Multivariable analysis showed that age, symptoms characteristic of atypical Kawasaki disease, and skin erosions were significant factors associated with MAS in MIS-C patients. Analysis of laboratory parameters showed that on admission, MIS-C patients with MAS had significantly lower median lymphocyte and platelet counts, albumin and sodium levels, and higher median levels of C-reactive protein, procalcitonin, ferritin, D-dimers, triglycerides, serum creatinine, urea, and γ-glutamyl transpeptidase, and neutrophil count. Multivariate analysis showed that higher procalcitonin, ferritin, and fibrinogen levels at admission were predictive of MAS. Only elevated troponin level was a factor indicating a requirement of PICU hospitalization for children with MAS. MIS-C patients fulfilling MAS criteria were treated more often with intravenous immunoglobulins and steroids than children without MAS. Children with MAS more often required mechanical ventilation. None of the patients required biological agents. Conclusions: The clinical course of MAS in MIS-C seems milder, treatment less aggressive, and the prognosis better than expected based on the current knowledge on MAS complicating other rheumatological diseases.

Use of broad-spectrum antibiotics in children diagnosed with multisystem inflammatory syndrome temporarily associated with SARS-CoV-2 infection in Poland: the MOIS-CoR study.

OBJECTIVES: Multisystem inflammatory syndrome in children (MIS-C) is the result of an immune response triggered by a previous exposure to SARS-CoV-2. The clinical presentation of MIS-C overlaps with other life-threatening bacterial infections, in which antimicrobials are the mainstay therapy. The aim of study was to describe the use of antibiotics in children with MIS-C in Poland. METHODS: The analysis of 345 children reported from 42 Polish cities to the national MultiOrgan Inflammatory Syndromes COVID-19 Related Study (MOIS-CoR Study) from June 2020 to April 2021. RESULTS: At least one antibiotic was used in 310 (90%) children, mainly third-generation cephalosporin (251/310). Broad-spectrum antibiotics were used in 258 (75%) children and 224 (87%) received this treatment for more than 3 days. Concentrations of serum procalcitonin >2 µg/l and the presence of lower respiratory symptoms were associated with increased odds of receiving any antibiotic. CONCLUSION: Although bacterial infections in patients with MIS-C are uncommon, we show that MIS-C poses a challenge to clinicians who are faced with the decision to start, continue, or stop antimicrobial therapy. Antibiotic stewardship in patients with MIS-C should be improved to ensure that likely pathogens are treated and that antimicrobials are stopped when bacterial infections are excluded and the diagnosis of MIS-C is made.