Background and Objectives: Since the first cases of multisystem inflammatory syndrome in children (MIS-C) in April 2020, the diagnostic challenge has been to recognize this syndrome and to differentiate it from other clinically similar pathologies such as Kawasaki disease (KD) and toxic shock syndrome (TSS). Our objective is to compare clinical signs, laboratory data and instrumental investigations between patients with MIS-C, KD and TSS. Materials and Methods: This retrospective observational study was conducted at the Children’s Clinical University Hospital, Latvia (CCUH). We collected data from all pediatric patients Results: In total, 81 patients were included in this study: 39 (48.1%) with KD, 29 (35.8%) with MIS-C and 13 (16.1%) with TSS. In comparison with TSS and KD, patients with MIS-C more often presented with gastrointestinal symptoms (abdominal pain (p p = 0.003)), shortness of breath (p p p p p p = 0.04) and cardiac biomarkers, but lower levels of platelets and lymphocytes (p p p = 0.01). Pathological changes in electrocardiography (ECG) and echocardiography were significantly more often observed in MIS-C patients (p Conclusions: This research shows that MIS-C, KD and TSS have several clinical similarities and additional investigations are required for reaching final diagnosis. All the patients with suspected MIS-C diagnosis should be examined for possible cardiovascular involvement including cardiac biomarkers, ECG and echocardiography.
