Fatalities have been rare.In April 2020, a small group of children with evidence of SARS-CoV-2 infection or exposure to COVID-19 were found to display clinical features corresponding to the diagnostic criteria of Kawasaki disease, sometimes accompanied by shock. Kawasaki disease is a rare syndrome which mainly affects young children (adult onset has occasionally been reported). It is a form of vasculitis, where blood vessels become inflamed throughout the body, and it results in a persistent fever. Recovery typically occurs spontaneously, though some children later develop mid-sized or giant coronary artery aneurysms in the heart – a potentially fatal complication. Symptoms of toxic shock (a syndrome caused by bacterial toxins) occasionally occur – an association sometimes referred to as Kawasaki shock syndrome, which is characterized by systolic hypotension or signs of poor perfusion. While the exact cause of Kawasaki disease is unknown, one plausible explanation is that it may stem from an infection triggering an autoimmune and/or autoinflammatory response in children who are genetically predisposed. No specific diagnostic test exists for Kawasaki disease, and its recognition is based on various combinations of clinical and laboratory findings (including persistent fever, widespread rashes, enlarged lymph nodes, conjunctivitis, changes to the mucous membranes, and swollen hands and feet). Characteristics
MIS-C / PIMS-TS is a systemic disorder involving persistent fever, extreme inflammation (hyperinflammation), and organ dysfunction, which is temporally associated with exposure to COVID-19. Onset may be delayed or contemporary with ongoing SARS-CoV-2 infection, which may pass without symptoms.
A set of guidelines proposed by Western New York recommends also evaluating children with clinical features that overlap with the MIS-C case definition, but who have been screened with mild illness and laboratory abnormalities, and who do not have an alternative diagnosis. Differential diagnosis
It is essential to exclude alternative non-infectious and infectious causes of the inflammatory condition, including bacterial sepsis, staphylococcal and streptococcal shock, and infections associated with myocarditis, such as enterovirus. (Coinfection with additional pathogens, including human metapneumovirus and various other microbes, may sometimes occur.) Other potentially unrelated sources of abdominal pain include appendicitis and mesenteric adenitis.Differential diagnosis with Kawasaki disease can be challenging, given the lack of a diagnostic test for either condition. It is not currently known whether the newly described condition is superimposable with Kawasaki disease shock syndrome. Since prompt diagnosis and timely treatment of actual Kawasaki disease is important to prevent complications, a call has been made to "Keep a high suspicion for Kawasaki disease in all children with prolonged fever, but especially in those younger than 1 year of age." Treatment
Due to the limited information available on this rare new diagnosis, clinical management has been largely based on expert opinion, including knowledge acquired from treating Kawasaki disease and other systemic inflammatory disorders of childhood, in addition to experience with COVID-19 in adults. Treatment is tailored for each individual child, with input from the various consulting specialists. Approaches vary.