Short-term and medium-term clinical outcomes of multisystem inflammatory syndrome in children: a prospective observational cohort study

Abstract

Background: Even though the incidence of Multisystem Inflammatory Syndrome in children (MIS-C) is decreasing cases are still reported across the world. Studying the consequences of MIS-C enhances our understanding of the disease's prognosis. The objective of this study was to assess short- and medium-term clinical outcomes of MIS-C.

Methods: Prospective observational cohort study at Municipal Children's Hospital Morozovskaya, Moscow, Russia. All children meeting the Royal College of Paediatrics and Child Health (RCPCH), Centers for Disease Control and Prevention (CDC), or the World Health Organization (WHO) MIS-C case definition admitted to the hospital between 17 May and 26 October 2020 were included in the study. All survivors were invited to attend a clinic at 2 and 6 weeks after hospital discharge.

Results: 37 children median age 6 years (interquartile range [IQR] 3.3-9.4), 59.5% (22/37) boys were included in the study. 48.6% (18/37) of patients required ICU care. One child died. All children had increased levels of systemic inflammatory markers during the acute event. Echocardiographic investigations identified abnormal findings in 35.1% (13/37) of children. 5.6% (2/36) of children were presenting with any symptoms six weeks after discharge. By six weeks the inflammatory markers were within the reference norms in all children. The echocardiographic evaluation showed persistent coronary dilatation in one child.

Conclusions: Despite the severity of their acute MIS-C, the majority of children in our cohort fully recovered with none having elevated laboratory markers of inflammation at 6 weeks, few (< 10%) reporting persistent symptoms at 6 weeks, and only one with persistent echocardiographic abnormalities.

Keywords: COVID-19; Children; MIS-C; Multisystem inflammatory syndrome in children; PIMS-TS; Paediatric inflammatory multisystem syndrome temporally associated with COVID-19; SARS-CoV2; Sequelae.

Fig. 1

Study flow chart, showing patients with MIS-C admitted to Municipal Children’s Hospital Morozovskaya between 17 May and 26 October 2020, recruited into the study and subsequent follow-ups

Fig. 2

Radial plots represent the coexistence of the 10 most common symptoms during the acute MIS-C phase and at ‘Follow-up 1’ (2 weeks after discharge) and ‘Follow-up 2’ (6 weeks after discharge). The symptoms are shown for each patient; each segment represents a single patient

Fig. 3

Box plots and parallel plots representing changes in serum markers over time: during the acute MIS-C phase and at ‘Follow-up 1’ (2 weeks after discharge) and ‘Follow-up 2’ (6 weeks after discharge). The horizontal lines in the boxes indicate medians; lower and upper edges of boxes indicate the interquartile range, and the bars extend to the highest and lowest value within 1.5 times the interquartile ranges