COVID-19 in children and adolescents: MIS(-C)-taken diagnoses

Multisystem inflammatory syndrome in children (MIS-C) is an inflammatory condition associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is characterized by fever, gastro-intestinal symptoms, cardiovascular complications, conjunctivitis, skin involvement, elevated inflammatory markers, and coagulation abnormalities. The current ongoing COVID-19 pandemic causes an increased alertness to MIS-C. In combination with the heterogeneous clinical spectrum, this could potentially lead to diagnostic blindness, misdiagnosis of MIS-C, and overtreatment with expensive IVIG treatment. This report demonstrates the challenge of accurately distinguishing MIS-C from other more common inflammatory pediatric diseases, and the need to act with caution to avoid misdiagnoses in the current pandemic. We present a case series of 11 patients suspected of MIS-C based on the current definitions. Three of them were eventually diagnosed with a different disease.

Current definitions and diagnostic criteria lack specificity which potentially leads to misdiagnosis and overtreatment of MIS-C. We emphasize the need to act with caution in order to avoid MIS(-C)-taken diagnoses in the current pandemic.

• A pediatric multisystem inflammatory disease associated with SARS-CoV-2 has been described (MIS-C). • There are three definitions being used for MIS-C, all including fever for at least 24 h, laboratory evidence of inflammation, clinically severe illness with multi-organ (≥ 2) involvement, and no alternative plausible diagnosis.

• MIS-C has a heterogeneous clinical spectrum without distinctive features compared to more common childhood diseases. Current definitions and diagnostic criteria for MIS-C lack specificity which leads to misdiagnosis and overtreatment. • Amid the current excessive attention to COVID-19 and MIS-C, pediatricians should remain vigilant to avoid mistaken diagnoses.