[Clinical analysis of systemic juvenile idiopathic arthritis with Kawasaki disease-like symptoms].

<b>Objective:</b> To analyze the clinical characteristic of systemic juvenile idiopathic arthritis (sJIA) patients with Kawasaki disease like onset symptom. <b>Methods:</b> A case-control study was performed. A total of 24 patients with sJIA with Kawasaki disease-like symptoms at the Department of Rheumatology and Immunology, Children's Hospital of Chongqing Medical University from January 2018 to August 2024 were selected as the Kawasaki disease combined with sJIA group. A total of 96 patients with Kawasaki disease as the Kawasaki disease group and 83 patients with sJIA were selected as the sJIA group. The general information, clinical manifestations, laboratory examinations and complications of the patients were compared among the 3 groups. Differences between groups were assessed by Mann-Whitney <i>U</i> test or Kruskal-Wallis <i>H</i> test and Chi-square test or Fisher's exact test. <b>Results:</b> There were significant differences in age and fever course between Kawasaki disease combined with sJIA groups, Kawasaki disease groups, and sJIA groups (3.4 (2.5, 7.3) <i>vs.</i> 3.4 (1.9, 4.8) <i>vs.</i> 8.8 (5.1, 11.7) years, 24.5 (18.0, 37.3) <i>vs.</i> 23.0 (18.0, 31.0) <i>vs.</i> 7.0 (6.0, 8.0) d, <i>Z</i>=67.09, 138.24, both <i>P</i><0.05). Among the 24 cases of Kawasaki disease combined with sJIA, 20 cases (83%) had joint symptoms and 9 cases (38%) had conjunctival congestion. There were significant differences in the incidence of coronary artery injury between Kawasaki disease combined with sJIA group, Kawasaki disease group and sJIA group (58% (14/24) <i>vs.</i> 44% (42/96) <i>vs.</i> 6% (5/83), <i>χ</i>²=40.50, <i>P</i><0.05). There were significant differences in the risk of macrophage activation syndrome between Kawasaki disease combined with sJIA group, sJIA group and Kawasaki disease group (17% (4/24) <i>vs</i>. 10% (8/83) <i>vs</i>. 0, <i>P</i><0.05). In the Kawasaki disease combined with sJIA group, 11 cases (46%) did not respond after 2 courses of intravenous immunoglobulin (IVIG) treatment, and 21 cases (88%) used glucocorticoids. The use rate of high-dose hormones in the Kawasaki disease combined with sJIA group was higher than that in the sJIA group (29% (7/24) <i>vs.</i> 5% (4/83), <i>χ</i>²=12.95, <i>P</i><0.05). In the group of Kawasaki disease combined with sJIA group, 17 cases (71%) used biological agents, 1 case used adalimumab, and 16 cases received tocilizumab treatment, of which 4 cases were allergic to tocilizumab. In the group of Kawasaki disease combined with sJIA, 11 cases (46%) treated with tocilizumab were followed up regularly for 1 month, and 10 cases were effective. <b>Conclusions:</b> Children with sJIA who present with Kawasaki disease-like clinical symptoms have clinical features of Kawasaki disease and sJIA. Children with Kawasaki disease who present at a young age, have a long fever course, are accompanied by joint symptoms, and are IVIG-resistant need to be alert to the possibility of sJIA and receive timely treatment with hormones and biological agents.