Clinical characteristics and outcomes of Kawasaki disease and multisystem inflammatory syndrome in Arab children during the COVID-19 pandemic: a single-center experience from the middle East.

Background: The emergence of Multisystem Inflammatory Syndrome in Children (MIS-C) during the COVID-19 pandemic has posed new challenges in differentiating it from classical Kawasaki disease (KD). Understanding their distinct presentations and outcomes is crucial for appropriate management strategies. We aimed to characterize and compare the clinical presentations, laboratory findings, cardiac manifestations, and treatment outcomes of KD and MIS-C in pediatric patients during the COVID-19 pandemic at a tertiary care center in Saudi Arabia.

Methods: In this retrospective cohort study, we analyzed data from 41 pediatric patients (ages 0-14 years) diagnosed with either KD (n = 31) or MIS-C (n = 10) between January 2020 and December 2023. Diagnoses were established using the American Heart Association criteria for KD and World Health Organization criteria for MIS-C. Clinical features, laboratory parameters, cardiac findings, and treatment responses were compared between groups.

Results: Among the 41 patients (median age 5.6 years, 56.1% male), KD patients demonstrated significantly higher rates of conjunctivitis (64.5% vs. 0%, p < 0.001) and rash (80.6% vs. 40%, p = 0.014) compared to MIS-C patients. Laboratory findings showed distinct patterns: KD patients had higher ESR (92.9 ± 50.7 vs. 58.4 ± 28.6 mm/hr, p = 0.042) and albumin levels (3.4 ± 0.4 vs. 3.1 ± 0.3 g/dL, p = 0.026), while MIS-C patients exhibited higher ferritin (1907 ± 3602 vs. 239 ± 397 ng/mL, p = 0.05), AST (398 ± 554.7 vs. 39.03 ± 23.8 U/L, p = 0.013), and LDH levels (973 ± 991.1 vs. 297.0 ± 96.6 U/L, p = 0.006). Coronary artery abnormalities were more frequent in KD (35.5% vs. 10% for diameter > 2 mm), with one case developing a coronary aneurysm. One mortality occurred in the MIS-C group due to sepsis.

Conclusions: This study identifies distinct clinical and laboratory profiles between KD and MIS-C during the COVID-19 pandemic. While both conditions can affect the coronary arteries, our findings suggest potentially different pathophysiological mechanisms. These observations may help inform diagnostic approaches and treatment strategies, though larger multicenter studies are needed to validate these findings.