Gastrointestinal Symptoms in Kawasaki Disease and Multisystem Inflammatory Syndrome in Children

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) are systemic inflammatory diseases sharing clinical and laboratory features. Gastrointestinal (GI) symptoms are common presenting features of both conditions. We aimed to determine the association of GI symptoms and clinical features and outcomes for KD and MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C patients < 18 years of age from 42 sites from January 1, 2020, through October 31, 2023. The association of GI symptoms (abdominal pain, vomiting and diarrhea), demographics, clinical and laboratory features, and cardiac involvement were determined using ordinal logistic regression incorporating interaction terms with diagnosis. We included 883 KD and 1827 MIS-C patients with confirmed diagnostic criteria. The presence of at least one GI symptom (vomiting, abdominal pain, diarrhea) was more prevalent for MIS-C patients (88% versus 57%; p < 0.001). A greater number of GI symptoms was significantly associated with older age and higher adiposity, presentation with shock, intensive care unit admission, inotropic support, and greater immunomodulatory therapy. Greater number of GI symptoms was significantly associated with higher peak markers of inflammation and organ dysfunction, and higher peak NT-proBNP and lower left ventricular ejection fraction, but not with coronary artery involvement. There were few differences related to diagnosis group. A greater number of presenting GI features is associated with features that may indicate a more severe form of KD and MIS-C, including cardiac involvement, and may merit increased attention.