Thrombotic risk in children with COVID-19 infection: A systematic review of the literature

Objective: Coagulation and inflammatory parameters are mildly altered in children with SARS-CoV-2 (COVID-19) infection, and laboratory evidence of a proinflammatory and procoagulant state has been noted in multisystem inflammatory syndrome in children (MIS-C). It is not clear whether this pediatric condition is related to thrombotic events. With this study we reviewed the literature for thrombotic complications in children with COVID-19 infection and MIS-C. Data sources: We searched the Medline PubMed Advanced Search Builder, Scopus, Web Of Science, and Google Scholar electronic databases (until 1 January 2021) using the medical subject headings (MeSH) terms and text words (their combinations and truncated synonyms): (THROMBOSIS OR THROMBOPHILIA) AND (CHILD OR CHILDREN OR INFANT) AND (COVID-19 OR SARS-CoV-2). Study eligibility criteria: Inclusion criteria were children with COVID-19 or SARS-COV-2 infection. The search was limited to articles published in English. Exclusion criteria were: reviews of published studies, studies published only as abstracts, letters or conference proceedings, discussion papers, animal studies, or editorials. Results: After screening for duplicates, the initial search yielded 86 records: 12 were case reports involving 19 children; comorbidities were absent or mild in 73.7%. The most common site of thrombosis the lung (21%); the most often used drug was heparin (42%). Two studies were an international survey (n = 337 patients) and a large multicenter study (n = 186 patients with MIS-C). The risk of ischemic stroke in SARS-CoV-2 infection (0.82%) and deep venous thrombosis in MIS-C (4.3%) was lower in children than in adults. Conclusions: Thrombodic or thromboembolic events are rare in pediatric patients with COVID-19 infection and MIS-C. Nonetheless, as in adults, a high index of suspicion should be maintained in children with COVID-19 infection or MIS-C, particularly in those with comorbidities predisposing to thrombotic events.