Objective To develop a composite disease activity score for systemic JIA (sJIA) and to provide preliminary evidence of its validity. Methods The systemic Juvenile Arthritis Disease Activity Score (sJADAS) was constructed by adding to the four items of the original JADAS a fifth item that aimed to quantify the activity of systemic features. Validation analyses were conducted on patients with definite or probable/possible sJIA enrolled at first visit or at the time of a flare, who had active systemic manifestations, which should include fever. Patients were reassessed 2 weeks to 3 months after baseline. Three versions were examined, including ESR, CRP or no acute-phase reactant. Results A total of 163 patients were included at 30 centres in 10 countries. The sJADAS was found to be feasible and to possess face and content validity, good construct validity, satisfactory internal consistency (Cronbach’s alpha 0.64–0.65), fair ability to discriminate between patients with different disease activity states and between those whose parents were satisfied or not satisfied with illness outcome (P < 0.0001 for both), and strong responsiveness to change over time (standardized response mean 2.04–2.58). Overall, these properties were found to be better than those of the original JADAS and of DAS for RA and of Puchot score for adult-onset Still’s disease. Conclusion The sJADAS showed good measurement properties and is therefore a valid instrument for the assessment of disease activity in children with sJIA. The performance of the new tool should be further examined in other patient cohorts that are evaluated prospectively.

Introduction Most coronavirus disease 2019 (COVID-19) pediatric patients are asymptomatic; however, several neurological manifestations associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection have been reported. Demyelinating events such as acute disseminated encephalomyelitis have been recently included among potential complications of COVID-19. Case Report We describe the case of a 12-year-old boy who developed central nervous system demyelinating lesions following SARS-CoV-2 infection. Two months prior he had been diagnosed with panuveitis but was otherwise healthy. Three weeks after testing positive for SARS-CoV-2, he started to complain of right temporal headache associated with right orbital pain without vision impairment. Brain magnetic resonance imaging showed large leukodystrophy-like demyelinating lesions. Standard electroencephalogram revealed a slow activity on the right hemisphere. His clinical and electroencephalographic course was favorable, with a good response to corticosteroid therapy and infusions of intravenous immunoglobulins. Delayed but complete resolution of brain lesions was noted on imaging. Conclusions Our case contributes to broaden the knowledge regarding the spectrum of possible complications of SARS-CoV-2 infection. The relative lack of clinical manifestations in our patient can be seen as a warning not to underestimate even mild neurological symptoms correlated with COVID-19.