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| EDITORIAL |
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| Year : 2023 | Volume
: 10
| Issue : 2 | Page : 47-48 |
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Phenotyping the multisystem inflammatory syndrome in children
Manu Sundaram1, Grace Van Leeuwen2
1 Paediatric Critical Care Unit, Sidra Medicine, Doha, Qatar
2 Department of Clinical Pediatrics, Weill Cornell Medicine, Doha, Qatar
| Date of Submission | 21-Feb-2023 |
| Date of Acceptance | 28-Feb-2023 |
| Date of Web Publication | 23-Mar-2023 |
Correspondence Address:
Dr. Manu Sundaram
Department of Pediatric Intensive Care, Pediatric Intensive Care Unit, Sidra Medicine, Doha
Qatar
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/jpcc.jpcc_11_23
How to cite this article:
Sundaram M, Leeuwen GV. Phenotyping the multisystem inflammatory syndrome in children. J Pediatr Crit Care 2023;10:47-8 |
During the peak of the COVID-19 pandemic, cases with features similar to Kawasaki disease (KD), toxic shock syndrome (TSS), sepsis, and Macrophage activation syndrome were reported in children with post-COVID-19 infection who were in a hyperinflammatory phase. One of the earliest definitions was from the Royal College of Paediatrics and Child Health (RCPCH) in the UK on the Paediatric Inflammatory Multisystem Syndrome temporally associated with COVID-19 (PIMS Ts). Similarly, the Centers for Disease Control and Disease Prevention (CDC) termed it the multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. The CDC definitions were based on the clinical, laboratory criteria (confirmed) or epidemiologic linkage criteria (probable) and vital records criteria (suspect). As per the RCPCH definition, it was essential to exclude other microbiological causes because of the similarity of presentation. Due to the postinfective and hyperinflammatory state of the syndrome, SARS-CoV-2 polymerase chain reaction testing may be positive or negative. Much has been learned about MIS-C since 2020. Therefore, earlier this year, Son et al. published in Pediatrics a new definition for MIS-C,[1] aiming to improve the feasibility of data collection and decrease misclassification of MIS-C cases, focused on distinguishing MIS-C from severe COVID-19, KD, and TSS.
In the study by Ganguly, et al. [2] published in this issue of the Journal of Pediatric Critical Care, the authors have analyzed cases into the four different phenotypes of MIS-C – Type 1: MIS-C overlapping with acute COVID-19, Type 2: MIS-C with shock/MIS-C with MODS, Type 3: MIS-C KD phenotype, and Type 4: Mild MIS-C/febrile, inflammatory state. The investigators compare these phenotypes in the second wave, including 86 cases during the first wave and 102 cases during the second wave, of whom 71.3% required intensive care. This study has described phenotypic differentiation regarding clinical features, laboratory investigation, and treatment.
Although there were no analyses regarding the statistical significance of the comparisons between groups, these descriptive findings may help increase clinicians' awareness of this broad spectrum of clinical manifestations of MIS-C.
In addition to this paper, other publications have guided phenotypic differentiation and insights into the similarities and differences of the disease between waves. Nygaard et al.[3] compared the incidence and phenotypes of MIS-C in unvaccinated and vaccinated children during the delta wave. They showed that the incidence in unvaccinated children was similar to the incidence during the first wave of the pandemic. They found vaccine effectiveness to be high against MIS-C. Chen et al.[4] revealed that early protection, prevention, and precision treatment could be done based on the immunopathogenesis of the disease. They indicated that a precise strategy for prevention and optimal treatment could be developed by clarifying phenotypes, genetic susceptibility, and hyperinflammatory mechanisms of MIS-C with and without intravenous immunoglobulin resistance. Levy et al.[5] analyzed 171 patients diagnosed with MIS-C: 59 during the alpha wave, 79 during the delta wave, and 33 during the omicron wave, and could demonstrate that MIS-C had a lower incidence and was less severe during the omicron wave than during alpha or delta waves. They presumed it happened due to the omicron variant, previous infection with SARS-CoV-2, vaccination against SARS-CoV-2, and improvement in treatment over time.
In conclusion, MIS-C is a rare acute disorder associated with SARS-CoV-2 infection in children. Multidisciplinary diagnostic and management guidelines have been developed internationally and continue to be updated. The diagnosis of MIS-C is challenging due to different phenotypes and unspecific findings. Early phenotypic differentiation and targeted immunomodulatory therapy can be helpful and must be addressed in more extensive multicentric studies.
| References | |  |
| 1. | Son MBF, Burns JC, Newburger JW. A New Definition for Multisystem Inflammatory Syndrome in Children. Pediatrics 2023;151:e2022060302. doi: 10.1542/peds.2022-060302. PMID: 36624565.  |
| 2. | Ganguly M, Giri PP. Basu S. A single-center experience from Eastern India depicting the epidemiology and phenotypic variations of Multisystem inflammatory syndrome in children (MISC) associated with SARS-CoV2 seen after first wave and second wave of COVID 19. J Pediatr Crit Care 2023;10:49-55. [Full text] |
| 3. | Nygaard U, Holm M, Hartling UB, Glenthøj J, Schmidt LS, Nordly SB, et al. Incidence and clinical phenotype of multisystem inflammatory syndrome in children after infection with the SARS-CoV-2 delta variant by vaccination status: A Danish nationwide prospective cohort study. Lancet Child Adolesc Health 2022;6:459-65. |
| 4. | Chen MR, Kuo HC, Lee YJ, Chi H, Li SC, Lee HC, et al. Phenotype, susceptibility, autoimmunity, and immunotherapy between Kawasaki disease and Coronavirus Disease-19 associated multisystem inflammatory syndrome in children. Front Immunol 2021;12:632890. |
| 5. | Levy N, Koppel JH, Kaplan O, Yechiam H, Shahar-Nissan K, Cohen NK, et al. Severity and incidence of multisystem inflammatory syndrome in children during 3 SARS-CoV-2 pandemic waves in Israel. JAMA 2022;327:2452-4. |
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