Severe Features of Systemic Juvenile Idiopathic Arthritis in Patients with Congenital Heart Disease.

To describe the clinical features of patients with congenital heart disease (CHD) who subsequently developed systemic juvenile idiopathic arthritis (sJIA). We conducted a retrospective review of patients diagnosed with CHD and sJIA at our institution. Detailed clinical, laboratory and radiographic data were collected from the medical record and reviewed with each patient's primary medical team. Five patients with sJIA and CHD were identified. Each child had a unique cardiac anatomy but all of the patients required surgical repair during the first year of life. Four children had thymectomies at the time of cardiac surgery. Classic signs of sJIA such as fever (n=5), rash (n=5), and arthritis (n=4) developed after surgical intervention in all of the patients. The individuals in this cohort displayed risk factors associated with severe sJIA, including disease onset before 2 years of age (n=5), elevated IL-18 levels (n=5), baseline eosinophilia prior to initiation of biologic disease modifying anti-rheumatic drugs (bDMARDs) (n=4), and positivity for HLA-DRB1*15:01 alleles (n=4). Macrophage activation syndrome (MAS) occurred in 3 patients and sJIA-associated lung disease (sJIA-LD) was identified in 4 patients. Two children died from complications of their cardiac and/or pulmonary disease. We identified an association between CHD and severe forms of sJIA. While these findings will need to be confirmed in larger, multi-center cohorts, the results highlight the importance of considering a diagnosis of sJIA in children with CHD and remaining vigilant for complications such as MAS and sJIA-LD.