P2.026: Kawasaki disease shock syndrome: creating a multi-institutional registry for a rare childhood critical illness

Background: Kawasaki Disease Shock Syndrome (KDSS) is a rare critical condition in children that requires high level of suspicion for timely diagnosis and treatment. While there are no consensus diagnostic criteria, it is estimated to represent 1.2-7% of Kawasaki disease (KD), and outcomes of the acute illness and coronary vasculitis are unknown. We aimed to build a multi-institutional database to study characteristics and outcomes of KDSS.

Methods: We established a REDCap electronic data capture hosted at CHU Sainte-Justine (Montreal, Canada) for centers to enter retrospective data for matching admissions, 1995-2019. Included were children who met diagnostic criteria for KD and one or both: required admission to the intensive care unit (ICU) or presented with systolic hypotension for age. This interim report includes data from 5 participating centers (Montreal, Seattle, San Francisco, Mexico City and Chandigrah).

Results: Interim analysis reports 71 children who met the above criteria for KDSS: 38 (53.5%) males, median age 5.5 years (range: < 1-20). Diagnosis of KD was established at 9 days (4.5-11) of fever and on admission, 18 (25.4%) of children had an initial different working diagnosis for shock (sepsis, toxic shock syndrome or other). All clinical diagnostic criteria were frequently observed: rash 57 (80.2%), mucosal changes 55 (77.5%), conjunctival injection 55 (77.5%), extremity changes 49 (69%) and lymphadenopathy 37 (52.1%). Incomplete KD criteria were met by 27 (39.7%) of children and were more prevalent among those with initial alternate diagnosis (8 of 18, p< 0.01). Multi-organ systems were involved in 26 (36.7%) children (12.7%, 15.5%, and 8.5% with 2, 3, or ≥4 systems). The median ICU stay was 4 days (range: 2-13) and shock management included volume replacement 47 (68%), inotropic agents 29 (43%), vasoactive agents 22 (34%) ventilatory support 21 (31%) and ECLS 1. Overall, 50% of children were IVIg-resistant: 38% received a 2nd dose, and 8.5% a 3rd dose, and there was a wide variation in use of steroids and biological agents. Two children (2.8%) died on hospital days 1 and 27. Three children (4.2%) were readmitted for recurrent KD without shock after initial discharge.

Conclusion: KDSS is an acute KD presentation that requires critical intervention for shock and risk of death. Children were diagnosed late with multi-organ involvement that required aggressive intervention and were more frequently IVIg non-responders compared to prior reports on KD. The recognition of KDSS has increased significantly during the COVID-19 pandemic due to its clinical overlap with Multisystem Inflammatory Syndrome in Children (MIS-C), emphasizing the need for further investigation and standardized diagnostic criteria. Larger collaboration to collect more clinical reports and review coronary outcomes is underway as this registry develops.