Overlaping Syndromes: Kawasaki-Like Disease in Pediatric Multisystem Inflammatory Syndrome vs Atypical Kawasaki Disease. British or American? One Case, Many Possibilities

Kawasaki disease is a challenging diagnosis even in typical forms of presentation. The features are represented by long lasting fever, specifi c mucocutaneous signs and coronary artery dilations as expression of medium artery vasculitis of unknown origin. Kawasaki-like disease emerged as a variant of pediatric multisystem inflammatory syndrome (PMIS) associated with COVID-19 infection. A 1 year 9-month-old boy who presented with fever, semiconsistent stools, vomiting, facial edema and hepatomegaly was transferred in our hospital with suspicion of myocarditis due to the clinical presentation, infl ammatory markers and systolic dysfunction. In a few days after presentation, also, dilation of the coronary artery appeared while the child had persistent constant symptomatology. Gradually, a pediatric multisystem infl ammatory syndrome (PMIS) developed, but without positive markers of COVID-19 infection, which remained negative (both antigen and antibodies). So, in front of all elements of PMIS except exposure to SARS-CoV-2, we concluded for an atypical Kawasaki disease with elements of PMIS. But the debate between the elaborated criteria British and American for PMIS are circling around the demonstration of the infection, past or present, making some cases diffi cult to diagnose. In this high affluence of Kawasaki-like disease, with intricated elements of myocarditis and multisystem inflammatory syndrome it is more and more diffi cult to establish a clear diagnosis. While the diagnosis looks complex, the curative treatment goes in the same direction – immunoglobulin, immunosuppressive treatment, inotropic and antiaggregant or anticoagulant treatment.