Multisystem Inflammatory Syndrome in Children (MIS-C) is a delayed hyperinflammatory condition affecting multiple organ systems. Prominent symptoms include fever, skin rashes, and gastrointestinal symptoms, manifesting prior to critical signs such as cardiac involvement, hypotension, and shock.

To determine if certain demographic, clinical, and laboratory markers are predictive of poor outcomes in patients diagnosed with MIS-C.

This is a retrospective, cross-sectional study (2020-2023) of children who met the 2020 CDC MIS-C criteria. Data on demographics, comorbidities, clinical course, outcomes, laboratory results and 2D Echocardiogram findings were obtained and analyzed.

There were 28 patients with MIS-C, with a median age of 4.5 years. The majority of patients were male (64%). The percentage of neutrophils showed a significant association with hypotension/shock (OR 1.16). White blood cell count (WBC) and ferritin were significantly associated with ICU admission (OR 3.5 and 2.9, respectively). Pericardial effusion was observed in 71.4% while myocarditis was present in 67.9% of patients. The most notable risk factor was HIV infection, which was significantly associated with a more than 50-fold increase in the odds of developing ARDS and 165-fold increase in the odds of mortality; there was only one mortality, and only one patient with documented HIV infection.

The outcome was good in non-immunocompromised patients and the only recorded mortality was a patient not previously known to have HIV. We identified statistically significant factors that were associated with adverse outcome measures, with the limitation of a small sample, such as HIV infection and risk for ARDS and mortality; elevated neutrophil percentage and risk for hypotension/shock; elevated WBC and ferritin and risk for ICU admission; and saw a high prevalence of pericardial effusion and myocarditis in these patients, highlighting the critical role of hyperinflammation and cardiac involvement in disease progression and outcome.