A rare cervical complication of Kawasaki disease: a retrospective study of clinical and radiological features.

Background: Grisel's syndrome (GS) is a rare cervical complication of Kawasaki disease (KD). Evidence from larger cohorts remains limited. We aimed to characterize the clinical and imaging features of KD with GS, identify factors associated with GS, and examine relationships between atlantoaxial instability metrics and local pharyngeal findings. Methods: We conducted a single-center retrospective cohort study involving children with KD treated between 2015 and 2023. KD was diagnosed according to the American Heart Association guidelines. GS was confirmed by clinical and imaging criteria. We collected demographics, clinical features, laboratory indices, and cervical imaging metrics, including the anterior atlanto-dental interval (AADI), lateral atlanto-dental interval (LADI), and retropharyngeal space (RS). GS versus non-GS groups were compared using appropriate parametric/nonparametric and categorical tests. Variables with P<0.10 in univariable analyses were entered into multivariable logistic regression to identify factors associated with GS. Within the GS subset, we stratified by AADI and evaluated correlations among AADI, RS, and cervical lymph-node size. Results: Among 2,137 KD patients, 46 (2.15%) developed GS. GS patients were older (6.97±1.96 Conclusions: GS is an uncommon complication of KD that occurs more often in older children and female patients. Imaging markers of atlantoaxial instability correlate with retropharyngeal crowding and nodal enlargement, while systemic inflammatory indices show limited associations. Early recognition and targeted cervical imaging may aid timely diagnosis and management.