A Comparison of Kawasaki Disease during the SARS-CoV-2 Pandemic with Multisystem Inflammatory Syndrome in Children.

Objectives: The purpose of this study was to compare and contrast Kawasaki disease (KD) with multisystem inflammatory syndrome in children (MIS-C) during the SARS-CoV-2 pandemic.

Methods: A retrospective analysis of the medical records of patients diagnosed with KD and MIS-C at a single institution from July 2020 to November 2021 was performed.

Results: The study included 39 MIS-C patients (84.6% male) with a median age of 138 months and 17 KD patients (58.8% male) with a median age of 36 months. The MIS-C patients were older ( < 0.001) and had prolonged hospitalizations ( = 0.023), elevated neutrophil counts ( < 0.001), C-reactive protein ( < 0.001), procalcitonin ( < 0.001), interleukin-6 ( < 0.014), ferritin ( < 0.001), fibrinogen ( < 0.001), troponin I ( = 0.001), NT-proBNP ( < 0.001), and D-dimer levels ( < 0.001). There were more cases of hypotension ( = 0.024), decreased left ventricular function ( = 0.023), and a greater need for corticosteroids ( < 0.001), enoxaparin ( = 0.045), and therapeutic plasma exchange ( < 0.001). Kawasaki disease patients had a greater incidence of rash ( < 0.001), changes in oral mucosa ( < 0.001), conjunctival injection ( < 0.001), extremity changes ( < 0.001), and cervical lymphadenopathy ( < 0.001). They had a longer duration of fever ( < 0.001), elevated white blood cell count ( < 0.001), platelet count ( < 0.001), and alanine aminotransferase level ( < 0.001). The two groups were similar regarding the hemoglobin levels, erythrocyte sedimentation rates, albumin levels, and the frequency of coronary aneurysm, myocarditis, pericarditis, invasive mechanical ventilatory support, and intravenous immunoglobulin treatment.

Conclusions: Advanced patient age, a greater presence of gastrointestinal and cardiac findings associated with hypotension, increased NT-proBNP levels, decreased left ventricular function, the use of various treatment modalities, and longer hospital stays suggest MIS-C, whereas prolonged fever and classical clinical features of KD favor KD.