Comparison of Characteristics and Outcomes of Multisystem Inflammatory Syndrome and Prepandemic Kawasaki's Disease

Objective In this study, our objective is to compare the demographic, clinical, laboratory, and echocardiographic findings of patients with multisystem inflammatory syndrome in children (MIS-C) and Kawasaki's disease (KD) diagnosed in the prepandemic period.

Methods We retrospectively collected data from all pediatric patients who met the Centers for Disease Control and Prevention's MIS-C case definition and who met the American Heart Association's definition of complete KD before the coronavirus disease 2019 pandemic.

Results A total of 37 patients diagnosed with MIS-C and 40 patients diagnosed with complete KD were included. Gastrointestinal findings were significantly higher in the MIS-C group than in the KD group (vomiting [p = 0.009], diarrhea [p = 0.009]). The incidence of thrombocytopenia (48.6%) was significantly higher in the MIS-C group. Regarding inflammatory markers, procalcitonin and ferritin were significantly higher in the MIS-C group (p = 0.032 and p = 0.006) and the erythrocyte sedimentation rate was higher in the KD group (p < 0.001). Pericardial effusion and mitral valve regurgitation were significantly more frequent in the MIS-C group (p = 0.024 and p = 0.001).

Conclusion Although they have similar findings, our current study findings show that MIS-C and KD differ from each other with different clinical and laboratory features. We think that these differences will help clinicians in diagnosis and patient management.