SARS-CoV-2 infection may precede and cause various autoimmune and inflammatory diseases, including multisystem inflammatory syndrome in children (MIS-C). Therefore, we aimed to observe the clinical presentation and laboratory, instrumental and other constellations in children with MIS-C, including liver involvement. We present the outcomes from a single-center prospective observational study in which 89 children was included (60 with proven COVID-19, 10 symptomatic with confirmed COVID-19 contact and 19 diagnosed with MIS-C). Laboratory, instrumental, immunological, and clinical investigations were performed. Only 12% (n = 4) from the COVID-19 group (except the ICU cases), we found elevated AST and/or ALT (up to 100). All of the children with elevated transaminase were overweight or obese, presenting along with moderate COVID-19 pneumonia. The majority of children with MIS-C showed typical laboratory constellations with higher levels of IL-6 (120.36 ± 35.56 ng/mL). About half of the children in the MIS-C group (52%, n = 11) showed elevated transaminases. Eleven children (57.9%) presented with abdominal pain, eight (42.1%) with ascites, two (10.5%) with hepatosplenomegaly, and four (21.1%) with symptoms such as diarrhea. Mesenteric lymphadenitis was observed more often in patients with elevated LDH (327.83 ± 159.39, p = 0.077). Ascites was associated with lymphopenia (0.86 ± 0.80, p = 0.029) and elevated LDH. Hepato-splenomegaly was also more frequent in children with lymphopenia (0.5 ± 0.14, p = 0.039), higher troponin (402.00 ± 101.23, p = 0.004) and low ESR. Diarrhea was more frequent in patients with lower CRP (9.00 ± 3.44 vs. 22.25 ± 2.58, p = 0.04), and higher AST and ALT (469.00 ± 349.59 vs. and 286.67 ± 174.91, respectively, p = 0.010), and D-dimer (4516.66 ± 715.83, p = 0.001). Our data suggest that the liver can also be involved in MIS-C, presenting with typical laboratory and instrumental outcomes.

A hydropneumothorax is an uncommon complication of pneumonia, particularly in pediatric patients, and typically arises secondary to conditions such as malignancies, esophageal-pleural fistula, thoracic trauma, or thoracocentesis. While pneumothorax is rarely reported in adults with COVID-19 and is even less common in children, isolated cases have been noted in those with Multisystem Inflammatory Syndrome in Children (MIS-C). A recent alert has also been issued about increased Group A Streptococcus (GAS) infections in Europe. Against this background, the primary aim of this case report is to describe a rare and severe complication of pneumonia in a previously healthy child with MIS-C and a positive throat culture for GAS.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe post-infectious complication associated with SARS-CoV-2. Neurological manifestations occur in approximately one quarter of MIS-C cases, ranging from mild symptoms such as headache and photophobia to severe complications including seizures, encephalopathy, and stroke. This article provides a comprehensive review of the neurological aspects of MIS-C, incorporating evidence from the literature and a detailed case report of a 15-year-old male who presented with acute neurological symptoms, systemic inflammation, and multiorgan involvement. Four main pathophysiological mechanisms have been proposed to explain neurological involvement: cytokine-mediated neuroinflammation, blood–brain barrier disruption, autoimmune responses, and direct viral neuroinvasion. Neuroimaging and EEG findings often support encephalopathic processes, while laboratory and immunological profiles indicate a hyperinflammatory state. The present case also highlights a potential link between severe hyponatremia and neurological complications. Management strategies—such as immunomodulation, anticoagulation, supportive therapy, and neuroprotective interventions—are discussed in this context. The prognosis for MIS-C patients with neurological involvement varies, with severe cases requiring long-term monitoring. This review underscores the importance of early neurological assessment in MIS-C to guide treatment and improve outcomes.

Background: Our goals were to find and grade children with multisystem inflammatory syndrome (MIS‐C) by clinical severity and the degree of different system involvement based on multivariate clinical laboratory data and identify the best predictors and scores for disease prognosis and risk stratification. Methods: We enrolled 51 patients with confirmed MIS‐C from a single center, and 34 general laboratory parameters and markers were included. Results: Using the K ‐means clustering method on kernel principal component analysis (K‐PCA) projections, we identified that our MIS‐C patients could be separated into three clusters. Children belonging to Cluster 3 have the highest levels of ferritin, LDH, ASAT, ALAT, GGT, total bilirubin, direct bilirubin, azotemia, urea, and creatinine, followed by Cluster 2. In contrast, Cluster 1 showed the lowest levels, p < 0.05. Children belonging to Clusters 3 and 2 also needed inotropic support significantly more frequently than Cluster 1 (30% and 10% vs 0%, Fisher exact test p = 0.04). Furthermore, respiratory distress was found only in patients of Clusters 2 and 3 ( p = 0.002). Regarding liver involvement, Clusters 2 and 3 more frequently had cholestasis (61% and 75% vs. 28%, p = 0.012), whereas Cluster 3 was more prominently characterized by an enlarged liver (44% vs. 0% and 5%, p = 0.004). Therefore, our clusters represent different grades, and liver and kidney involvement stages are graded by severity. From ROC curve analysis and several logistic regressions, we identified that age equal to or higher than 9 years old and ferritin levels higher than 470 ng/mL could help distinguish children with more severe kidney and liver involvement with a high probability (ROC AUC = 77 % , p = 0.03 and ROC AUC = 75 % , p = 0.04) approximately equal to the discriminatory potential of creatinine, urea, GGT and total bilirubin. Moreover, levels of LDH with a cutoff of 363 U/l could identify the children within Cluster 3 (ROC AUC = 80 % , p = 0.004). Conclusions: LDH and ferritin, as well as age into consideration, could help the clinical assessment of the underlying severity.