Multisystem inflammatory syndrome in children (MISC): A systematic review

The aim of this systematic review was to analyse current literature and reported cases of multisystem inflammatory syndrome in children (MISC), concerning its clinical spectrum, complications associated, therapeutic strategies and distinguishing features of other clinical syndromes.

Extensive literature research was performed in MEDLINE (through PubMed), Scopus and Web of Science from December 2019 to December 2020. First analysis included all article titles and abstracts screening to identify relevant studies, and second analysis included a full-text screening of previously selected studies. Eligibility was assessed independently by two authors, and disagreements were resolved by discussion and consensus. Data were extracted on MISC definition, demographic data, clinical features, diagnostic tests, laboratory analysis and imaging, therapeutical approach and outcomes.

Common symptoms included gastrointestinal (70%), rash (57%) and cardiovascular (52% with shock). Notable differences with Kawasaki disease were identified including age, clinical presentation and cardiac involvement. Thirty per cent presented positive severe acute respiratory syndrome coronavirus-2 reverse transcription polymerase chain reaction and 51% positive serologies. Sixty-two per cent received intravenous immunoglobulin and 42% glucocorticoids. Sixty-two per cent required intensive care and 21 children died (<2%). Severe presentations were associated with neurological symptoms, hepatitis and acute kidney injury.

MISC raises concern on its severe cardiac involvement at presentation, with frequent intensive care and immunomodulatory therapy need. Short-term outcomes seem to be favourable, with cardiac dysfunction recovery and low mortality rates.