Multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C) is a life-threatening condition that often requires intensive care unit (ICU) admission. The aim of this study was to determine risk factors for severe/life-threatening course of MIS-C. The study included 166 patients (99 boys, 67 girls) aged 4 months–17 years (median 8.2 years). The criterion of severity was the fact of ICU admission. To conduct a comparative analysis, MIS-C patients were divided into two groups: patients hospitalized in the ICU (n = 84, 50.6%) and those who did not need ICU admission (n = 82, 49.4%). Patients with a more severe course of MIS-C were significantly older. They had a higher frequency of signs such as rash, swelling, hepatomegaly, splenomegaly, and neurological and respiratory symptoms. Hypotension/shock and myocardial involvement were much more common in patients with severe MIS-C. These patients had a more significant increase in CRP, creatinine, troponin, and D-dimer levels. Additionally, the presence of macrophage activation syndrome was higher in patients admitted to the ICU. Conclusion: Nineteen predictors of severe course of MIS-C were found, out of which hepatomegaly, splenomegaly, D-dimer > 2568 ng/mL, troponin > 10 pg/mL were mainly associated with the probability of being classified as early predictors of severe MIS-C requiring ICU admission.

Background: Several cases of skin and central nervous system vasculopathy associated with COVID-19 in children have been published, but the information is rather limited. Our study aimed to describe these cases of vasculitis associated with COVID-19 in children. Methods: In the retrospective-prospective case series study we included information regarding four children with COVID-19-associated vasculitis. In every case, we had a morphological description and the etiology was confirmed via real-time polymerase chain reaction during a tissue biopsy. Results: The most involved systems were skin (4/4), respiratory (3/4), cardiovascular (2/4), nervous (1/4), eye (1/4), kidney (1/4), and inner year (1/4). All patients had increased inflammatory markers and thrombotic parameters (D-dimer). No patient met the criteria for multisystem inflammatory syndrome in children. Two patients met polyarteritis nodosa criteria, one met Henoch–Schonlein purpura criteria, and one met unclassified vasculitis criteria. All patients were treated with systemic glucocorticosteroids (two-pulse therapy). Non-biologic DMARDs were prescribed in all cases; 1/4 patients (25%) was treated with intravenous immunoglobuline, and 3/4 (75%) were treated with biologics (etanercept, tocilizumab, and adalimumab). Conclusions: Vasculitis associated with COVID-19 could be a life-threatening condition; SARS-CoV-2 might be a new trigger or etiological agent for vasculitis and other immune-mediated diseases. Further research and collection of similar cases are required.

Hemophagocytic syndrome is a key point in the pathogenesis of severe forms of multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C). The factors associated with hemophagocytosis in patients with MIS-C were assessed in the present study of 94 boys and 64 girls ranging in age from 4 months to 17 years, each of whose HScore was calculated. In accordance with a previous analysis, patients with HScore ≤ 91 (n = 79) and HScore > 91 (n = 79) were compared. Patients with HScore > 91 had a higher frequency of symptoms such as cervical lymphadenopathy, dry cracked lips, bright mucous, erythema/swelling of hands and feet, peeling of fingers, edematous syndrome, hepatomegaly, splenomegaly, and hypotension/shock. They also had a higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and D-dimer levels, and a tendency to anemia, thrombocytopenia, and hypofibrinogenemia. They more often needed acetylsalicylic acid and biological treatment and were admitted to ICU in 70.9% of cases. Conclusion: The following signs of severe MIS-C were associated with HScore > 91: myocardial involvement, pericarditis, hypotension/shock, and ICU admission.

Systemic corticosteroids are continued to be administered in juvenile idiopathic arthritis (JIA) patients, especially in systemic JIA (sJIA), despite the ability of biologic therapy. One of the complications of long-term CS treatment is delayed hip arthritis development with risk of secondary hip osteoarthritis formation and total hip arthroplasty (THA).We compared different types of hip joint lesions in JIA, especially, secondary hip osteoarthritis development and THA rates in systemic and non-systemic JIA, and evaluate systemic corticosteroids contribution to those complications.The study included 753 JIA patients. They were divided into 2 groups: patients with sJIA and non-systemic JIA (nsJIA). Clinical and demographic characteristics, CS treatment regimens were compared.Results. Hip arthritis was found equally often in both groups, but both secondary hip osteoarthritis (19% vs 5,3%) and THA (8.6% vs 1.6%) prevailed in the sJIA. Patients with sJIA had delayed hip involvement (57.9% vs 30.6%; p=0.019), earlier secondary hip osteoarthritis development (4.5 vs 5.1 years after the JIA onset) with younger age of secondary hip osteoarthritis achievement (13.7 vs 15.2 years; р=0.045), they also had higher inflammatory activity, greater systemic corticosteroids administration (94.8% vs 56.1%; р=0.0000001) and higher cumulative systemic corticosteroids dose (3085 mg vs 2000 mg; p=0,005). More than half patients (56.1%) with nsJIA had systemic corticosteroids treatment and impaired calcium-phosphorus metabolism.Conclusion. Systemic corticosteroid treatment and delayed hip involvement are independent predictors of secondary hip osteoarthritis in all JIA categories. Calcium and phosphate metabolism disturbances are additional predictor for secondary hip osteoarthritis in non-systemic JIA categories

Multisystem inflammatory syndrome in children and adolescents associated with SARS-CoV-2 (MBS-D) is a new challenge for pediatricians around the world. Scientific data is updated daily and patient treatment regimens are developed. The involvement of the heart in the inflammatory process complicates the course of the disease and further rehabilitation of patients. The article describes 12 patients with heart disease in the structure of MVS-D, who underwent laboratory tests and instrumental studies, including MRI of the heart, and also provides detailed descriptions of three clinical cases and a review of literature data.

Background: Macrophage activation syndrome (MAS) can be regarded as a key factor determining the severity of multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C), and often requires treatment in the intensive care unit (ICU) to avoid life-threatening complications. No reputable specific criteria for the diagnosis of MAS in MIS-C patients have yet been identified, and criteria currently used for the diagnosis of hemophagocytic syndromes, such as HLH-2004, MAS-2005, and MAS-2016, are not sufficient for MAS in MIS-C. Our goal in this study was to work out the criteria for the early diagnosis of MAS in MIS-C. Methods: One hundred and sixty-six (166) patients with MIS-C were assessed retrospectively. The two most experienced experts independently identified patients with MAS. The patients were divided into three cohorts: MAS (n = 19), without MAS (n = 78), and probable MAS (n = 67). The latter included patients diagnosed with MAS by only one expert, and it was excluded from the analysis. Results: The age of patients with MAS was much higher, and they more frequently had edematous syndrome, hypotension and/or shock, splenomegaly, and CNS involvement. In their blood tests, thrombocytopenia, hypoalbuminemia, and hypertriglyceridemia occurred more often. The level of biomarkers of inflammation, such as ferritin, CRP, troponin, AST, and ALT, was also higher in this group. Increased fibrinogen and D-dimer were also found, demonstrating hypercoagulation in the MAS-MIS-C group. We chose 21 continuous and categorical variables with statistical significance, out of which 2—ferritin > 469 μg/L or platelets < 114 × 10⁹/L—allowed us to discriminate MAS patients. Conclusions: Ferritin > 469 μg/L or platelets < 114 × 10⁹/L can be regarded as key signs to differentiate MAS in MIS-C patients with a sensitivity of 100% and specificity of 94.9%, and they can be used along with other diagnostic methods.