COVID and the Multisystem Inflammatory Syndrome in Children Save

Lancet Infectious Disease has reviewed the epidemiology, causes, clinical features, and current treatment for the multisystem inflammatory syndrome in children (MIS-C) and adolescents associated with COVID-19, noting severe organ damage can occur pediatric COVID-19 patients who are severely ill. 

While SARS-CoV-2 infections in children tend to be mild and non-fatal, increasing of the more severe MIS-C associated with COVID-19, merits further study. Despite noting differences in the definitions (by WHO, US, UK) of MIS-C, the authors noted: 

• Clinical and laboratory features of MIS-C are similar to those of Kawasaki disease, Kawasaki disease shock syndrome, and toxic shock syndrome>yet there are some distinct features of MIS-C, and it needs a clear clinical and pathophysiological definition 
• MIS-C might be distinct from Kawasaki disease, with features including an age at onset of more than 7 years, a higher proportion of African or Hispanic children affected, and diffuse cardiovascular involvement suggestive of a generalized immune-mediated disease 
• Pathophysiology of MIS-C is still unclear and possible mechanisms include antibody or T-cell recognition of self-antigens (viral mimicry of the host) resulting in autoantibodies, antibody or T-cell recognition of viral antigens expressed on infected cells, formation of immune complexes which activate inflammation, and viral superantigen sequences which activate host immune cells 
• Most cases of MIS-C associated with COVID-19 were managed following the standard protocols for Kawasaki disease, with inotropic or vasoactive agents often required in patients with cardiac dysfunction and hypotension and anticoagulation also used frequently; clinical research is required to prove the effectiveness and safety of these treatments 
• The medium-term to long-term outcomes of MIS-C, such as the sequelae of coronary artery aneurysm formation, remain unknown and close follow-up is important

Management

Currently there are no widely accepted guidelines on the management of MIS-C, but most have recommended:

• a multidisciplinary team approach (pediatric infectious diseases unit, and cardiology, immunology, rheumatology, and intensive care unit teams)
• consider antiviral therapy (if PCR positive for SARS-CoV-2) or immunotherapy, or both
• General supportive care
• Close monitoring for respiratory compromise or hypoxia or cardiac complications (including coronary artery aneurysm formation)