Multisystem inflammatory syndrome in children (COVID-19): cardiovascular complications

Multisystem inflammatory syndrome in children (MIS-C) is characterized by a systemic hyperinflammatory process that can lead to the dysfunction of various organs and systems: generalized damage to the microcirculatory bed due to damage to the endothelium of vessels, multisystem damage, including the cardiovascular system, and toxic shock syndrome. Many cases of MIS-C have already been described; our own clinical observations have accumulated, significant progress has been made in understanding the pathogenesis of MIS-C, and updated criteria for its diagnosis have been established. Materials and methods. A search for information on multisystem inflammatory syndrome in children associated with COVID-19 was conducted in Ukrainian and foreign sources. Examination, treatment, and analysis of 10 clinical cases in children who had MIS-C associated with COVID-19 were conducted. Results. The most typical in the clinic were: fever, skin and mucous membrane lesions, cardiovascular system lesions, and serositis. Laboratory markers: significantly increased inflammatory markers, which correlated with the severity of the disease, in the coagulogram — a moderate increase in D-dimer and fibrinogen. Instrumental studies: myocardial dysfunction, which was accompanied by moderate dilation of the ventricles, impaired mainly systolic function. Rhythm disorders, separation of the pericardial leaves, and dilation of the coronary vessels were observed in 20%. The algorithm for further monitoring of children with cardiovascular complications was developed. During the period 2023–2024, any classic case of MIS-C was registered in the department, which is likely associated with a milder course of SARS-CoV-2 caused by a different strain of the virus. Several authors note that MIS-C 2023–2024 differs from the previous one in that there is no duration of fever, the inflammation threshold is included (C-reactive protein ≥30 mg/l), and the number of organ systems involved is reduced. The frequency of heart damage in MIS-C is uncertain and, according to literature data, mainly correlated with the severity of the disease. In our studies, 80% of patients had cardiovascular pathology. In moderate severity, we more often encountered pericarditis and rhythm and conduction disorders; in severe cases, myocarditis with myocardial dysfunction was revealed. Residual phenomena of cardiovascular damage, such as rhythm and conduction disorders, dilation of coronary arteries, dilation of heart cavities, and wall hypertrophy, can persist after recovery, which requires long-term observation of patients according to the developed algorithm.