Multisystem inflammatory syndrome in neonates (MIS-N): an updated systematic review

Introduction The aim of the study was to summarize and update clinical features and outcomes of multisystem inflammatory syndrome in neonates (MIS-N).Methods A systematic literature search was conducted of studies on MIS-N published in PubMed, MEDLINE, EMBASE, CNKI, and WHO COVID-19 databases between 1 December 2019 and 30 June 2023. Reference lists of selected articles, Google Scholar, and pre-print servers were searched for additional studies. The methodological quality of included studies was assessed.Results Of 1,572 records screened after the initial search, 35 studies involving a total of 201 neonates with MIS-N were included. One study was retrieved from a pre-print server. For those with available data, 34/47 (78.7%) mothers were infected in the third trimester. Of the 199 mothers (two with twin pregnancies), 183 (92.0%) were from India. The median age of neonates at presentation was 2.0 days (interquartile range 1.0-9.5). Over two-thirds (144/201, 71.6%) presented with respiratory distress, while 112 (55.7%) had cardiac involvement, such as ventricular dysfunctions, involvement of coronary arteries, and atrioventricular blocks. Arrhythmias and thrombosis were reported in 15/201 (7.5%) and 2/201 (3.0%) neonates, respectively. All neonates, except one, required critical care; 64/160 (40.0%) required inotropic support and 105/187 (56.1%) required respiratory support, of whom 59/105 (56.2%) were specified to require intubation. The mortality rate was 5.0% (10/201).Discussion/Conclusion MIS-N should be considered in ill neonates presenting with involvement of two or more organ systems, especially among those neonates with cardiorespiratory dysfunctions, in the presence of proven or suspected maternal COVID-19 infection during pregnancy.Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021278717, PROSPERO, identifier CRD42021278717.