Multisystem Inflammatory Syndrome in Children Related to SARS-CoV-2

Abstract

Although data on the incidence and severity of new coronavirus disease 2019 due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection showed more significant disease among adults and the elderly, a clinical manifestation characterized by a multisystem inflammatory syndrome was described in children (MIS-C). It was initially thought to be specific to children, but recent reports have shown that it can also occur in adults. MIS-C is characterized by a number of multisystemic manifestations resembling other known previously described illnesses, mainly Kawasaki disease, especially in cases with shock, toxic shock syndrome, and macrophage activation syndrome. Available literature shows that our knowledge of MIS-C is largely incomplete. Its development in strict relation with SARS-CoV-2 infection seems documented and, in most cases, can be considered a post-infectious manifestation secondary to an abnormal immune response for some aspects, similar to that seen in adults several days after SARS-CoV-2 infection. However, in a minority of cases, a clinical picture with symptoms fulfilling criteria for MIS-C diagnosis develops during the acute phase of SARS-CoV-2 infection. It is highly likely that the criteria currently used to diagnose MIS-C are too broad, meaning that children with different diseases are included. As clarity on the pathogenesis of MIS-C is lacking, different therapeutic approaches have been used, but no specific therapy is currently available. Further studies are urgently needed to improve our definition of MIS-C, to define the real impact on child health, and to elucidate the best clinical and therapeutic approach and true prognosis.

Surveillance in hospitalized children with infectious diseases in Japan: Pre- and post-coronavirus disease 2019

“…The median age for MIS-C was 9-10 years. This is in marked contrast to KD, which occurs predominately in children ≤5 years old [35,37]. KD is often seen in Asian children, including in Japan, but MIS-C is rarely reported in Asian children, and is recorded predominantly as an issue among African children [35].…”

“…This was described and understood as a disease different from KD, called multisystem inflammatory syndrome in children (MIS-C) [35]. Compared with KD, MIS-C often presents with severe abdominal pain and myocardial dysfunction, and requires intensive care [36,37]. The median age for MIS-C was 9-10 years.…”

COVID-19 in Immunosuppressed Children

“…MIS-C occurs in between 0.011 and 0.31% of children with SARS-CoV-2 infection ( 140 ). MIS-C occurs in older children; has more frequent systemic, myocardial, and gastrointestinal involvement; and complicates with shock more commonly than KD ( 141 ).…”

Síndrome Inflamatória Multissistêmica Pediátrica (SIM-P): Uma análise epidemiológica brasileira

“…Apesar de estes não serem precisamente definidos, existem hipóteses sobre a suscetibilidade genética associada ao desenvolvimento da SIM-P, assim como evidenciado na DK, que sugerem que as mutações em genes que regulam a função de células de defesa permitam o desencadeamento de um intenso processo inflamatório, explicando o motivo de apenas uma minoria de crianças e adolescentes evoluírem com a síndrome, dada a infrequência dessas modificações no genoma humano. Dessa forma, há expectativas de que, caso a teoria seja, posteriormente, confirmada, intervenções médicas possam ser antecipadas em crianças com maiores chances de cursar com a SIM-P e, assim, reduzam a ocorrência de desfechos negativos associados a ela (Esposito et al, 2021).…”