Distinguishing the overlapping features of severe multi-inflammatory syndrome in children from severe dengue, scrub typhus and other endemic tropical infections—a comparative study from a tertiary care pediatric intensive care unit

Early differentiation between severe multi-inflammatory syndrome in children (MIS-C) and severe presentations of dengue, scrub typhus, and other endemic tropical infections could help clinicians devise appropriate treatment strategies. This study aims to identify the diagnostic markers that may be used to discriminate between MIS-C versus endemic tropical infections, namely dengue and scrub typhus, which frequently occur in endemic areas. A retrospective study was conducted in a pediatric intensive care unit (PICU) of a tertiary care center in New Delhi, India between 2020 and 2023. Comparative analysis of 33 children diagnosed with MIS-C was done versus 77 children with five endemic tropical infections-dengue, scrub typhus, typhoid fever, malaria, and leptospirosis. Rash [63.63% vs. 31.64% (P = 0.005)], conjunctival redness [63.63% vs. 8.86% (P < 0.001)], and altered sensorium [45.45% vs. 22.78% (P = 0.031)] were seen in a greater proportion of MIS-C cases than those with tropical infections. C-reactive protein (CRP) (mg/dl) was significantly higher in children with MIS-C versus those with tropical infections [176.1 (112.61, 198.32) vs. 9.25 (24.05, 69.38), P ≤ 0.001]. Ferritin and lactate dehydrogenase (LDH) were observed to be significantly higher in children with tropical infections compared to those with MIS-C. Using multivariable logistic regression analysis, the odds of having a rash were higher among children with MIS-C than those with dengue [OR = 8.07 (95% CI: 1.22-53.48, P = 0.03)]; followed by altered sensorium [OR = 16.04 (95% CI: 2.06-124.62, P = 0.008)]; myocardial involvement [OR = 7.18 (95% CI: 1.12-45.93, P = 0.037)]; and CRP (>50 mg/dl) [OR = 17.59 (95% CI: 2.69-114.92, P = 0.003)]. The findings of our study suggest that several clinical and laboratory measures could potentially distinguish between patients with severe MIS-C and endemic tropical infections. Clinical markers such as rash, altered sensorium, myocardial involvement, and shock were seen in a greater proportion of cases with MIS-C. Inflammatory markers such as CRP were higher in children with MIS-C, whereas ferritin and LDH were higher in dengue, scrub typhus, typhoid fever, malaria, and leptospirosis.