Difficulties of differential diagnosis of multisystem inflammatory syndrome associated with SARS-CoV-2 in a teenager (clinical case)

The new coronavirus infection does not lose its relevance, which is due to the ubiquity of the virus, the variety of strains, clinical manifestations and their consequences of COVID-19. In children, one of the severe complications of new coronavirus infection is the multisystem inflammatory syndrome associated with SARS-CoV-2 (MIS-C), which is characterized by a hyperinflammatory response with damage to two or more organs and systems. MIS-C requires differential diagnosis with other diseases with similar symptoms: bacterial infections, sepsis, toxic shock syndrome, Kawasaki syndrome, hemophagocytic syndrome. As an example, the article considers a clinical case of MIS-C in a 13-year-old girl 4 weeks after undergoing new coronavirus infection (confirmed). At the onset of the disease, the leading manifestations were systemic inflammatory response syndrome (fever, increased markers of inflammation) with damage to the cardiovascular system, skin and mucous membranes, lymphadenitis, thrombocytopenia. According to the severity of the condition, the child required observation and treatment in the intensive care unit. The absence of the expected effect of the recommended MIS-C therapy (intravenous immunoglobulin and pulse therapy with methylprednisolone) on the first day did not allow to exclude bacterial infection complicated by sepsis in the above clinical situation, therefore, it was suggested that the combined course of MIS-C and bacterial infection of unspecified etiology, which probably led to a more severe course of the disease. In the outcome of the MIS-C the child had the formation of a long-term depressive state (diagnosed by a psychiatrist), for which the patient received drug therapy and psychological assistance. The described case showed difficulties in the formulation of the final diagnosis due to the presence in the patient of several symptoms and syndromes characteristic of various diseases, the absence of an identified etiological agent and the absence of the expected positive effect with standard therapy of the disease. In addition, a pathology was revealed in the catamnesis, which required dynamic observation of the child by several specialized specialists.