Multisystem Inflammatory Syndrome in Children and Acute Kidney Injury: Retrospective Study of Five Italian PICUs

OBJECTIVES: Multisystem inflammatory syndrome in children (MIS-C) manifests with heart dysfunction and respiratory failure some weeks after a severe acute respiratory syndrome coronavirus disease 2 infection. The aim of our study was to explore the prevalence, severity, timing, and duration of acute kidney injury (AKI) in MIS-C patients. Furthermore, we evaluated which clinical variables and outcomes are associated with AKI. DESIGN: Multicenter retrospective study. SETTING: Five tertiary hospital PICUs in Italy. Data were collected in the first 7 days of PICU admission and renal function was followed throughout the hospital stay. PATIENTS: Patients less than 18 years old admitted to the PICU for greater than 24 hours with MIS-C. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We collected the following data, including: demographic information, inflammatory biomarkers, lactate levels, Pao2/Fio2, ejection fraction, N-terminal pro-B-type natriuretic peptide (NT-proBNP), renal function (serum creatinine, urinary output, fluid balance, and percentage fluid accumulation), Vasoactive-Inotropic Score (VIS), pediatric Sequential Organ Failure Assessment (pSOFA), and Pediatric Index of Mortality 3. AKI was diagnosed in eight of 38 patients (21%) and severe AKI was present in four of eight patients. In all cases, AKI was present at PICU admission and its median (interquartile range) duration was 3.5 days (1.5-5.7 d). We did not identify differences between AKI and no-AKI patients when not making correction for multiple comparisons, for example, in weight, ejection fraction, pSOFA, Pao2/Fio2, and lactates. We failed to identify any difference in these groups in urine output and fluid balance. Exploratory analyses of serial data between no-AKI and AKI patients showed significant differences on lymphocyte count, NT-proBNP value, ejection fraction, pSOFA, Pao2/Fio2, and VIS. CONCLUSIONS: In this multicenter Italian PICU experience, MIS-C is associated with AKI in one-in-five cases. In general, AKI is characterized by an associated reduction in glomerular filtration rate with a self-limiting time course.