Risk factors for haemodynamic compromise in multisystem inflammatory syndrome in children: a multicentre retrospective study.

OBJECTIVES: To identify predictors of a severe clinical course of multisystem inflammatory syndrome in children (MIS-C), as defined by the need for inotropic support. METHODS: This retrospective study included patients diagnosed with MIS-C (according to the CDC definition) in nine Israeli and one US medical centre between July 2020 and March 2021. Univariate and multivariate regression models assessed odds ratio (OR) of demographic, clinical, laboratory and imaging variables during admission and hospitalization for severe disease. RESULTS: Of 100 patients, 61 (61%) were male; mean age 9.65 (4.48) years. Sixty-five patients were hypotensive, 44 required inotropic support. Eleven patients with MIS-C fulfilled Kawasaki disease diagnostic criteria; 87 had gastrointestinal symptoms on admission. Echocardiographic evaluation showed 10 patients with acute coronary ectasia or aneurysm, and 37 with left ventricular dysfunction. In a univariate model, left ventricular dysfunction was associated with severe disease [OR 4.178 (95% CI 1.760, 9.917)], while conjunctivitis [OR 0.403 (95% CI 0.173, 0.938)] and mucosal changes [OR 0.333 (95% CI 0.119, 0.931)] at admission were protective. Laboratory markers for a severe disease course were low values of haemoglobin, platelets, albumin and potassium; and high leukocytes, neutrophils, troponin and brain natriuretic peptide. In multivariate analysis, central nervous system involvement and fever >39.5°C were associated with severe disease. Mucosal involvement showed 6.2-fold lower risk for severe disease. Low haemoglobin and platelet count, and elevated C-reactive protein and troponin levels were identified as risk factors for severe disease. CONCLUSION: Key clinical and laboratory parameters of MIS-C were identified as risk factors for severe disease, predominantly during the disease course and not at the time of admission; and may prompt close monitoring, and earlier, more aggressive treatment decisions. Patients presenting with a Kawasaki-like phenotype were less likely to require inotropic support.

Case Series of Myocarditis Following mRNA COVID Vaccine Compared to Pediatric Multisystem Inflammatory Syndrome: Multicenter Retrospective Study.

INTRODUCTION: Since the development of COVID-19 vaccines, more than 4.8 billion people have been immunized worldwide. Soon after vaccinations were initiated, reports on cases of myocarditis following the second vaccine dose emerged. This study aimed to report our experience with adolescent and young adults who developed post-COVID-19 vaccine myocarditis and to compare these patients to a cohort of patients who acquired pediatric inflammatory multisystem syndrome (PIMS/PIMS-TS) post-COVID-19 infection. METHODS: We collected reported cases of patients who developed myocarditis following COVID-19 vaccination (Pfizer mRNA BNT162b2) from all pediatric rheumatology centers in Israel and compared them to a cohort of patients with PIMS. RESULTS: Nine patients with post-vaccination myocarditis were identified and compared to 78 patients diagnosed with PIMS. All patients with post-vaccination myocarditis were males who developed symptoms following their second dose of the vaccine. Patients with post-vaccination myocarditis had a shorter duration of stay in the hospital (mean 4.4 ± 1.9 vs. 8.7 ± 4.7 days) and less myocardial dysfunction (11.1% vs. 61.5%), and all had excellent outcomes as compared to the chronic changes among 9.2% of the patients with PIMS. CONCLUSION: The clinical course of vaccine-associated myocarditis appears favorable, with resolution of the symptoms in all the patients in our cohort.