, et al
Characteristics and outcomes of US children and adolescents with multisystem inflammatory syndrome in children (MIS-C) compared with severe acute COVID-19
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Investigators from multiple institutions conducted a case series to identify distinguishing features of multisystem inflammatory syndrome in children (MIS-C) from severe coronavirus disease-19 (COVID-19). Children who were <21 years old, hospitalized at 1 of 66 US hospitals in 31 states between March 15 and October 31, 2020, and who met criteria for MIS-C or severe COVID-19 were eligible.

To identify patients with MIS-C, investigators used the CDC’s case definition for MIS-C, which includes fever, inflammation, multisystem involvement, and positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase-PCR (RT-PCR or antibody test), or recent exposure with no alternative diagnosis. The criteria used for severe COVID-19 was a positive RT-PCR test and severe organ system involvement.

Investigators compared demographics, laboratory values within 48 hours of admission (eg, platelet count, neutrophil to lymphocyte [NRL] ratio, hemoglobin level, c-reactive protein [CRP] and albumin), and other clinical characteristics (eg, presence of 1 or more underlying medical conditions) between patients with MIS-C versus COVID-19 using regression models, with adjusting for potential confounders. Organ system involvement also was compared between patients with MIS-C and COVID-19. Five mutually exclusive organ system categories were used: cardiorespiratory, cardiovascular without respiratory, respiratory without cardiovascular, mucocutaneous without cardiovascular or respiratory, and other organ system not including cardiovascular, respiratory, or mucocutaneous.

There were 1,116 participants included, 48% with MIS-C and 52% with severe COVID-19. Participants with MIS-C (vs severe COVID-19) were more likely to be 6-12 years old (adjusted risk ratio [aRR], 1.51; 95% CI, 1.33, 1.72), be non-Hispanic Black (aRR, 1.43; 95% CI, 1.17, 1.76), have cardiorespiratory (aRR, 2.99; 95% CI, 2.55, 3.50), cardiovascular without respiratory (aRR, 2.49; 95% CI, 2.05, 3.02), or mucocutaneous organ involvement without respiratory or cardiovascular involvement (aRR, 2.29; 95% CI, 1.84, 2.85), and have a NLR >5 (aRR, 1.59; 95% CI, 1.40, 1.80), platelets <150 × 103/μL (aRR, 1.58; 95% CI, 1.43, 1.78), and CRP >100 mg/L (aRR, 1.70; 95% CI, 1.51, 1.92). Participants with severe COVID-19 (vs MIS-C) were more likely to have ≥1 underlying medical condition and another organ system involved that was not cardiovascular, respiratory, or mucocutaneous.

Investigators conclude that there are patterns of organ system involvement and other clinical characteristics that can distinguish MIS-C from severe COVID-19.

Dr Brady has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.

Clinicians caring for a child who presents with shock and multi-organ dysfunction need to consider a broad differential diagnosis, including bacterial sepsis, toxic shock syndromes, Kawasaki disease (KD), and tick-borne illnesses, in addition to MIS-C and severe COVID-19 infection. Initial management for all of these possibilities includes respiratory support, fluid resuscitation, and vasoactive agent support as...

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