Short- and medium-term longitudinal outcomes of children diagnosed with multisystem inflammatory syndrome in children - report from a single centre in Pakistan

Objective: To determine the short- and medium-term cardiac outcomes in children admitted with multisystem inflammatory syndrome in children at a tertiary care centre in Pakistan. Methods: Children fulfilling the criteria for multisystem inflammatory syndrome and admitted to the hospital between April 2020 and March 2022 were enrolled in this prospective longitudinal cohort study. From admission to discharge, laboratory and cardiac parameters were recorded for all patients, who were subsequently followed up in clinics at various intervals. Data analysis was conducted using STATA version 15.0. Results: A total of 51 children were included, with viral myocarditis (41.2%) and toxic shock syndrome (33.3%) being the most common phenotypes. The cardiovascular system was most commonly affected in 27 children (53%) with laboratory evidence of inflammation and myocardial injury with median and interquartile levels of ferritin 1169 (534-1704), C-reactive protein 83 (24-175), lactate dehydrogenase 468 (365-1270), N-terminal pro-B-type natriuretic peptide 8,656 (2,538-31,166), and troponin 0.16 (0.02-2.0). On admission, decreased left ventricular ejection fraction was observed in 58.8% of patients and impaired global longitudinal strain in 33.3%. At discharge, left ventricular ejection fraction had normalised in 83% of patients. Pericardial effusion resolved in all patients, and valvulitis resolved in 86% by 12 months. Paediatric ICU admission was required in 42 (82%) of patients with an overall mortality of 12% (n = 6). Conclusion: Our study finds high hospital mortality for multisystem inflammatory syndrome in children compared to 1-2% from previous studies.