Background Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) has been described as a novel and often severe presentation of SARS-CoV-2 infection in children. We aimed to describe the characteristics of children admitted to Pediatric Intensive Care Units (PICUs) presenting with MIS-C in comparison with those admitted with SARS-CoV-2 infection with other features such as COVID-19 pneumonia. Methods A multicentric prospective national registry including 47 PICUs was carried out. Data from children admitted with confirmed SARS-CoV-2 infection or fulfilling MIS-C criteria (with or without SARS-CoV-2 PCR confirmation) were collected. Clinical, laboratory and therapeutic features between MIS-C and non-MIS-C patients were compared. Results Seventy-four children were recruited. Sixty-one percent met MIS-C definition. MIS-C patients were older than non-MIS-C patients (p = 0.002): 9.4 years (IQR 5.5–11.8) vs 3.4 years (IQR 0.4–9.4). A higher proportion of them had no previous medical history of interest (88.2% vs 51.7%, p = 0.005). Non-MIS-C patients presented more frequently with respiratory distress (60.7% vs 13.3%, p < 0.001). MIS-C patients showed higher prevalence of fever (95.6% vs 64.3%, p < 0.001), diarrhea (66.7% vs 11.5%, p < 0.001), vomits (71.1% vs 23.1%, p = 0.001), fatigue (65.9% vs 36%, p = 0.016), shock (84.4% vs 13.8%, p < 0.001) and cardiac dysfunction (53.3% vs 10.3%, p = 0.001). MIS-C group had a lower lymphocyte count (p < 0.001) and LDH (p = 0.001) but higher neutrophil count (p = 0.045), neutrophil/lymphocyte ratio (p < 0.001), C-reactive protein (p < 0.001) and procalcitonin (p < 0.001). Patients in the MIS-C group were less likely to receive invasive ventilation (13.3% vs 41.4%, p = 0.005) but were more often treated with vasoactive drugs (66.7% vs 24.1%, p < 0.001), corticosteroids (80% vs 44.8%, p = 0.003) and immunoglobulins (51.1% vs 6.9%, p < 0.001). Most patients were discharged from PICU by the end of data collection with a median length of stay of 5 days (IQR 2.5–8 days) in the MIS-C group. Three patients died, none of them belonged to the MIS-C group. Conclusions MIS-C seems to be the most frequent presentation among critically ill children with SARS-CoV-2 infection. MIS-C patients are older and usually healthy. They show a higher prevalence of gastrointestinal symptoms and shock and are more likely to receive vasoactive drugs and immunomodulators and less likely to need mechanical ventilation than non-MIS-C patients.

Background Bronchiolitis is the most common viral infection of the lower respiratory tract in infants under 2 years of age. The aim of this study was to analyze and compare the seasonal bronchiolitis peaks before and during the SARS-CoV-2 pandemic. Methods Descriptive, prospective, and observational study. Patients with severe bronchiolitis admitted to the Pediatric Intensive Care Unit (PICU) of a referral tertiary hospital between September 2010 and June 2021 were included. Demographic data were collected. Viral laboratory-confirmation was carried out. Each season was analyzed and compared. The daily average temperature was collected. Results 1116 patients were recruited, 58.2% of them males. The median age was 49 days. Respiratory syncytial virus (RSV) was isolated in 782 cases (70.1%). In April 2021, the first and only case of bronchiolitis caused by SARS-CoV-2 was identified. The pre- and post-pandemic periods were compared. There were statistically significant differences regarding: age, 47 vs. 73 days (p = 0.006), PICU and hospital length of stay (p = 0.024 and p = 0.001, respectively), and etiology (p = 0.031). The peak for bronchiolitis in 2020 was non-existent before week 52. A delayed peak was seen around week 26/2021. The mean temperature during the epidemic peak was 10ºC for the years of the last decade and is 23ºC for the present season. Conclusion The COVID-19 pandemic outbreak has led to a clearly observable epidemiological change regarding acute bronchiolitis, which should be studied in detail. The influence of the environmental temperature does not seem to determine the viral circulation.

Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has collapsed health systems worldwide. In adults, the virus causes severe acute respiratory distress syndrome (ARDS), while in children the disease seems to be milder, although a severe multisystem inflammatory syndrome (MIS-C) has been described. The aim was to describe and compare the characteristics of the severe COVID-19 disease in adults and children. Methods This prospective observational cohort study included the young adults and children infected with SARS-CoV-2 between March–June 2020 and admitted to the paediatric intensive care unit. The two populations were analysed and compared focusing on their clinical and analytical characteristics and outcomes. Results Twenty patients were included. There were 16 adults (80%) and 4 children (20%). No mortality was recorded. All the adults were admitted due to ARDS. The median age was 32 years (IQR 23.3–41.5) and the most relevant previous pathology was obesity (n = 7, 43.7%). Thirteen (81.3%) needed mechanical ventilation, with a median PEEP of 13 (IQR 10.5–14.5). Six (37.5%) needed inotropic support due to the sedation. Eight (50%) developed a healthcare-associated infection, the most frequent of which was central line-associated bloodstream infection (n = 7, 71.4%). One patient developed a partial pulmonary thromboembolism, despite him being treated with heparin. All the children were admitted due to MIS-C. Two (50%) required mechanical ventilation. All needed inotropic support, with a median vasoactive-inotropic score of 27.5 (IQR 17.5–30). The difference in the inotropic requirements between the two populations was statistically significant (37.5% vs. 100%, p < 0.001). The biomarker values were higher in children than in adults: mid-regional pro-adrenomedullin 1.72 vs. 0.78 nmol/L (p = 0.017), procalcitonin 5.7 vs. 0.19 ng/mL (p = 0.023), and C-reactive protein 328.2 vs. 146.9 mg/L (p = 0.005). N-terminal pro-B-type natriuretic peptide and troponins were higher in children than in adults (p = 0.034 and p = 0.039, respectively). Conclusions Adults and children had different clinical manifestations. Adults developed severe ARDS requiring increased respiratory support, whereas children presented MIS-C with greater inotropic requirements. Biomarkers could be helpful in identifying susceptible patients, since they might change depending on the clinical features.

During the pandemic caused by the novel coronavirus (COVID-19), lung ultrasound has been used to diagnose and monitor respiratory condition. The aim of the study was to describe lung ultrasound findings in children with a COVID-19 infection. Patients younger than 18 years old and positive for COVID-19, admitted to pediatric tertiary referral hospital were included. They were divided into two groups depending on the presence of respiratory symptoms. Lung ultrasound results were categorized into four degrees according to Soldati et al. score (J Ultrasound Med 39:1–7, 2020 ) and it was also described the presence and type of consolidation. Sixteen patients were recruited. The median age was 11 years old (IQR 2.8–12). Four children (25%) required admission to the intensive care unit. Six patients (37.5%) presented with respiratory symptoms. Most of them showed S.score of 2 and subpleural consolidations were observed in four cases (66.6%). Ten patients (62.5%) presented with non-respiratory symptoms, lung ultrasound showed S.score from 0 to 2. Three (30%) were diagnosed of multisystem inflammatory syndrome and lung ultrasounds showed S.score of 2 with bilateral pleural effusion. Conclusions : Children with COVID-19 and respiratory symptoms mostly showed a S.score of 2 and 3 with subpleural consolidations, upon the lung ultrasound assessment. What is Known : • Lung ultrasound is a useful tool for monitoring patients with respiratory symptoms in both adults and children. Lung ultrasounds are altered in adult patients with COVID-19. What is New : • Lung ultrasound might improve COVID-19 assessment, it could be a useful tool to diagnose and monitor patients throughout the COVID-19 pandemic. Even COVID-19 patients with non-respiratory symptoms have lung alterations that are visible on lung ultrasound. Electronic supplementary material The online version of this article (10.1007/s00431-020-03839-6) contains supplementary material, which is available to authorized users.