Multisystem Inflammatory Syndrome in Children

Abstract

1. Gail F. Shust, MD* 2. Vijaya L. Soma, MD* 3. Philip Kahn, MD† 4. Adam J. Ratner, MD, MPH*,‡ 1. *Division of Pediatric Infectious Diseases 2. †Division of Pediatric Rheumatology, Department of Pediatrics 3. ‡Department of Microbiology, New York University Grossman School of Medicine, New York, NY Most children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remain asymptomatic or develop only mild symptoms. However, rare severe cases occur. During spring 2020, a new pediatric syndrome, likely a postinfectious complication of coronavirus disease 2019 (COVID-19), was described. The seminal report discussed 8 children with signs of hyperinflammation and shock and features consistent with Kawasaki disease (KD) or toxic shock syndrome. Initially named pediatric inflammatory multisystem syndrome, it is now commonly called multisystem inflammatory syndrome in children (MIS-C). Alarmingly, patients with MIS-C generally experience more severe disease than children with acute COVID-19, frequently requiring hospitalization and, at times, critical care. Cases of MIS-C have now been reported from many countries. The United States alone has had more than 2,000 cases and 30 deaths meeting the Centers for Disease Control and Prevention (CDC) MIS-C definition (Table). View this table: Table. CDC Case Definition for MIS-C An individual younger than 21 years presenting with fever (temperature ≥100.4°F [≥38.0°C] for ≥24 hours, or report of subjective fever lasting ≥24 hours), laboratory evidence of inflammation (including, but not limited to, ≥1 of the following: elevated C-reactive protein level, erythrocyte sedimentation rate, fibrinogen level, procalcitonin level, D-dimer level, ferritin level, lactic acid dehydrogenase level, interleukin [IL]-6 level, and neutrophil count; reduced lymphocyte count; and low albumin level), and evidence of clinically severe illness requiring hospitalization, with multisystem (≥2) organ involvement; AND no alternative plausible diagnoses; AND positive for current or recent SARS-CoV-2 infection by reverse transcription polymerase chain reaction (RT-PCR), serologic testing, or antigen testing; OR exposure to a suspected or confirmed COVID-19 case within the 4 weeks before the onset of symptoms. Clinical signs and symptoms of MIS-C vary and may include fever, gastrointestinal symptoms, mucocutaneous lesions, hypotension, and shock. Given the clinical overlap among MIS-C, COVID-19, KD, and toxic shock syndrome, and the …