BACKGROUND: Multisystem inflammatory syndrome temporally associated with 
COVID-19 (MIS-C) has been described as a novel and often severe presentation of 
SARS-CoV-2 infection in children. We aimed to describe the characteristics of 
children admitted to Pediatric Intensive Care Units (PICUs) presenting with 
MIS-C in comparison with those admitted with SARS-CoV-2 infection with other 
features such as COVID-19 pneumonia.
METHODS: A multicentric prospective national registry including 47 PICUs was 
carried out. Data from children admitted with confirmed SARS-CoV-2 infection or 
fulfilling MIS-C criteria (with or without SARS-CoV-2 PCR confirmation) were 
collected. Clinical, laboratory and therapeutic features between MIS-C and 
non-MIS-C patients were compared.
RESULTS: Seventy-four children were recruited. Sixty-one percent met MIS-C 
definition. MIS-C patients were older than non-MIS-C patients (p = 0.002): 
9.4 years (IQR 5.5-11.8) vs 3.4 years (IQR 0.4-9.4). A higher proportion of them 
had no previous medical history of interest (88.2% vs 51.7%, p = 0.005). 
Non-MIS-C patients presented more frequently with respiratory distress (60.7% vs 
13.3%, p < 0.001). MIS-C patients showed higher prevalence of fever (95.6% vs 
64.3%, p < 0.001), diarrhea (66.7% vs 11.5%, p < 0.001), vomits (71.1% vs 23.1%, 
p = 0.001), fatigue (65.9% vs 36%, p = 0.016), shock (84.4% vs 13.8%, p < 0.001) 
and cardiac dysfunction (53.3% vs 10.3%, p = 0.001). MIS-C group had a lower 
lymphocyte count (p < 0.001) and LDH (p = 0.001) but higher neutrophil count 
(p = 0.045), neutrophil/lymphocyte ratio (p < 0.001), C-reactive protein 
(p < 0.001) and procalcitonin (p < 0.001). Patients in the MIS-C group were less 
likely to receive invasive ventilation (13.3% vs 41.4%, p = 0.005) but were more 
often treated with vasoactive drugs (66.7% vs 24.1%, p < 0.001), corticosteroids 
(80% vs 44.8%, p = 0.003) and immunoglobulins (51.1% vs 6.9%, p < 0.001). Most 
patients were discharged from PICU by the end of data collection with a median 
length of stay of 5 days (IQR 2.5-8 days) in the MIS-C group. Three patients 
died, none of them belonged to the MIS-C group.
CONCLUSIONS: MIS-C seems to be the most frequent presentation among critically 
ill children with SARS-CoV-2 infection. MIS-C patients are older and usually 
healthy. They show a higher prevalence of gastrointestinal symptoms and shock 
and are more likely to receive vasoactive drugs and immunomodulators and less 
likely to need mechanical ventilation than non-MIS-C patients.