Purpose of the research was to study the structure of the cardiovascular system (CVS) lesions, risk factors and predictors for adverse outcomes in children with Kawasaki disease (KD). Materials and methods used: a single-center retrospective cohort study of 188 patients (126 boys/62 girls) aged 2 months to 11 years old with KD in 2014-2019. Depending on the outcome of the disease, the two groups of patients were identified: those with recovery (171/188, 91%), and with unfavorable outcomes (17/188, 9%) in the form of persistent coronary artery aneurysms (CAA) in 12 (6.4%) cases and death in 5 (2.7%) cases. Authors used the clinical-anamnestic method, clinical and biochemical blood tests and coagulogram. The diagnosis of CVS changes was based on the results of echocardiography, magnetic resonance angiography, coronary angiography and ultrasound of non-coronary vessels. The levels of N-terminal fragment of B-type brain natriuretic peptide (NT-proBNP) and atrial natriuretic peptide precursor (proANP) were determined. Results: CVS lesions in the acute period of KD were detected in 92 (48.9%) patients. Non-coronary changes in the cardiovascular system, represented by myocarditis (25%), pericarditis (9.6%), transient mitral valve insufficiency (26.1%) with valvulitis (4.3%) were determined in the acute and subacute periods of KD. Damage to the coronary arteries (CA) in the acute period, according to echocardiography, was detected in 61 (32.4%) children, of which: coronaritis - in 43 (22.8%), transient ectasia - in 9 (4.7% ), CAA of various sizes - in 49 (26.1%). Predictors of unfavorable KD outcomes are the presence of coronary (p=0.000) and non-coronary changes (p=0.001) in the cardiovascular system during the acute period of the disease, blood clots of any location (64.7% v. 3.5%, p=0.000). Based on the results of univariate logistic regression analysis, significant threshold levels of natriuretic peptides were established to determine the risk of developing adverse KD outcomes: an increase in NT-proBNP in the acute period of KD more than 984 pg/ml with 79% sensitivity, 84.8% specificity, 82.9% overall predictive value; an increase in proANP greater than 1.015 nmol/l with 87.5% a sensitivity, 75.8% specificity and 78.0% overall predictive value. Conclusion: risk factors and predictors for the unfavorable KD outcomes have been identified as follows: the appearance in the acute period of CAA of medium and especially giant sizes, pericarditis, myocarditis, damage to the valvular apparatus, thrombosis of the coronary artery and cardiac cavities, high levels of proANP, NT-proBNP, which can be used as a diagnostic tool in KD with poor outcomes.

Pediatric inflammatory multisystem syndrome (PIMS) associated with the new coronavirus infection is the most severe late complication of the COVID-19 infection in children. We present the Russia’s first clinical observation of a 9 years old girl with PIMS with successful use of extracorporeal membrane oxygenation (ECMO) in treatment. The disease was characterized by rapid progression of myocardial dysfunction, shock, multiple organ failure, secondary hemophagocytic syndrome, and resistance to therapy. Intensive therapy, including glucocorticosteroids, tocilizumab, intravenous immunoglobulin, antiplatelet agents and anticoagulants, respiratory and cardiotonic support, ECMO, renal replacement therapy and antimicrobials have allowed the child to stabilize and recover.

The article describes the difficulties in diagnosing and treating a large pericardial effusion caused by the autoimmune atrophic thyroiditis with a debut in the form of a myxedema coma in a 7 months old child with Down syndrome. The clinical, laboratory and instrumental picture of a rare complication of a hypothyroidism - a hypothyroid (myxedematous) coma, the epidemiology and comorbidity of Down syndrome, autoimmune thyroiditis and hypothyroidism, manifestation of hypothyroidism with pericardial effusion prevailing in the pathological symptom complex are discussed in the article.

Background. New coronaviral infection (COVID-19) in most cases has less severe course in children than in adults. However, there were reports from the number of European countries and from United States (from March 2020) about children with new disease with signs of Kawasaki disease (KD) and toxic shock syndrome (TSS). So it has received one of the names children’s multisystem inflammatory syndrome (CMIS) associated with COVID-19. The aim of the study is to summarize up-to-date information about this disease.Methods. Information search in PubMed database, CDC (USA) and WHO websites, Search for information in PubMed database, on CDC (USA) and WHO websites, analysis of the medical records of observed patient with CMIS.Results. Clinical and laboratoryinstrumental manifestation and outcomes of CMIS in 120 children from Italy, France, Switzerland, England, USA with similar signs were analyzed. Proposed international diagnostic criteria of the disease in comparison with other phenotypically similar diseases (KD, shock syndrome at KD, TSS of Staphylococcal and Streptococcal etiology, macrophage activation syndrome), clinical observation of patient, algorithm of evaluation and management of patients with CMIS are presented.

Sydenham's chorea (SC) is a major clinical criterion in acute rheumatic fever (RF). SC is a late neurological manifestation of acute rheumatic fever which occurs 1 to 6 months after pharyngeal infection with group A betahemolytic streptococci. SC is characterized by clinical symptoms: involuntary hyperkinetic movements, muscular hypotonia, hyperreflexia, gait disturbance, emotional lability. Objective: The aim of the study was to identify frequency, clinical manifestations and the treatment of SC. The study included 56 children 4-17 years old, who were hospitalized in the Morozovskaya children’s clinical city hospital in 2001-2015 with RF. Clinical history, laboratory and instrumental methods (electrocardiography, transthoracic echocardiogram, cranial computed tomography scan and/or magnetic resonance imaging, electroencephalography, electroneuromyography). The study revealed frequent errors (66%) in RF diagnosis before hospitalization. Besides chorea, the clinical manifestations of RF were: carditis (89,3%), arthritis (46,4%), erythema marginatum (10,7%), subcutaneous nodule (1,8%). The peculiarity of our study washighfrequency of chorea (42,9%). Isolated chorea wasseen in 12,5%, mixed chorea - in 30,4% of SC. The clinical manifestations of chorea were typical. The nervous system lesion most often occured in children with a neurological history (p < 0,05). The clinical or laboratory evidence of streptococcal infection were seldom found (p = 0,02) in patients withchorea (45,8%) compared with patients without chorea symptoms (69%). RF issue requires attention from the medical community. SC, especially isolated chorea (29%), is the most challenging manifestation of RF for the differential diagnosis.Chronic rheumatic heart disease can be developed even in patients with isolated chorea (12,5%). In the treatment of SC in addition antibiotics and drugs which affect domamine and GABA metabolism, glucocorticoids (Prednisolone) are needed.