Increasing recognition of paediatric inflammatory multi-system syndrome is a cause of concern. This study aimed to evaluate children with paediatric inflammatory multi-system syndrome and compare the clinical and laboratory features of children with and without cardiac involvement.

We conducted a prospective single-centre study including 57 (male 37, 65%) patients with paediatric inflammatory multi-system syndrome at a tertiary care hospital between November, 2020 and March, 2021. The mean age was 8.8 ± 4.5 years (range, 10 months–16.7 years).

The most frequent symptoms were fever (100%), abdominal pain (65%) and diarrhoea (42%). SARS-CoV-2 PCR and serology tests were positive in 3 (5%) and 52 (91%) patients, respectively. Eight patients required intensive care support. Nineteen patients (33%) had cardiac involvement (valvular regurgitation in 15, left ventricular systolic dysfunction in 11 and coronary artery dilation in 1). The presence and duration of cough and intensive care admissions were significantly higher in children with cardiac involvement than those without it. The cut-off values of troponin T, pro-brain natriuretic peptide and interleukin 6 for predicting cardiac involvement were 11.65 ng/L (95% confidence interval, 0.63–0.90; sensitivity, 0.63; specificity, 0.84; area under the curve: 0.775, p = 0.009), 849.5 pg/mL (95% CI, 0.54–0.86; sensitivity, 0.63; specificity, 0.63; area under the curve: 0.706, p = 0.009) and 39.8 pg/mL (95% CI, 0.54–0.85; sensitivity, 0.63; specificity, 0.60; area under the curve: 0.698, p = 0.023), respectively.

Cardiac involvement in children with paediatric inflammatory multi-system syndrome is common. The risk of cardiac involvement can be predicted by troponin T, pro-brain natriuretic peptide and interleukin 6 levels.