Clinical and laboratory markers defining MIS-C and hyperinflammation in COVID-19: a cross-sectional study in a tertiary hospital.

backgroundNumerous inflammatory complications related to COVID are described, including the Multisystem inflammatory Syndrome in Children (MIS-C) and Hyperinflammation. There is a scarcity of studies comparing these two groups.

methodsRetrospective longitudinal outcome-conditioned study. Demographic, clinical, and laboratory variables are analyzed. Patients with history of COVID contact or infection with at least 24 h of fever, two or more systems involved and up to 21 years were included. Patients with no laboratory signal of inflammation or with other diagnoses for the condition were excluded. Demographic and laboratory data are presented as medians with interquartile ranges. Dichotomous variables and prevalences are reported as percentages. A ROC curve analysis was conducted to assess the discriminatory ability of these tests in relation to the MIS-C and hyperinflammation groups.

resultsWe present fifty-four patients, thirty-one with MIS-C and twenty-three with hyperinflammation. The most frequent symptom in the MIS-C group was altered mental status in 61% vs. 46% (p = 0.014) and conjunctival hyperemia in 29% vs. 4% (p = 0.032). The most frequent laboratory findings were hypoalbuminemia in 68% vs. 26% (p = 0.002), increased serum troponin in 42% vs. 26% (p = 0.034), increased d-dimers in 94% vs. 76% (p = 0.015), as well as increased BNP in 55% vs. 17% (p = 0.02). On the other hand, the hyperinflammation group more frequently presented respiratory dysfunction in 57% vs. 13% (p = < 0.001) and serum ferritin equal or greater than 500 ng/mL in 94% vs. 77% (p = 0.046).

conclusionsThis is an original study comparing clinical and laboratory findings between MIS-C and hyperinflammation due to COVID. Altered mental status is more frequently associated with MIS-C while respiratory symptoms are associated with hyperinflammation. In addition, regarding laboratory tests, there is hypoalbuminemia, increase in serum troponin, BNP, and D-dimers specially in the MIS-C group and hyperferritinemia in the hyperinflammation group. Further studies are needed to assess the cutoff point of biological markers such as BNP, troponin, and d-dimers for diagnosis and/or prognosis in the pediatric population with MIS-C.