Aim of the study: Systemic juvenile idiopathic arthritis (sJIA) is characterized by systemic inflammation beside arthritis. Many children may have delayed onset of arthritis. We aimed in our study to determine whether the Yamaguchi criteria (for adult onset Still’s disease) can be applied in diagnosis of sJIA, especially in absence of arthritis.
Material and methods: The cross-sectional study included 30 patients diagnosed with sJIA, those patients diagnosed by the treating paediatrician with ‘definite’ sJIA (fulfilling the International League of Associations for Rheumatology [ILAR] classification criteria) or ‘suspected’ sJIA (not fulfilling the ILAR criteria). The fulfilment of the variables in both the ILAR criteria and the Yamaguchi criteria was recorded for each patient at the time of first presentation.
Results: We included 16 boys and 14 girls. Ten patients were diagnosed with suspected sJIA due to the presence of typical systemic features but failed to fulfil the ILAR criteria, especially absence of arthritis in 9 of them. Yamaguchi criteria were fulfilled in a higher number of patients (23/30, 76.7%) as compared to those who fulfilled the ILAR criteria (20/30, 66.7%). All 10 patients with suspected sJIA fulfilled the Yamaguchi criteria, and 11 patients (36.7%) had delayed onset of arthritis. Overall, the 30 patients (100%) in the present study fulfilled either ILAR criteria or Yamaguchi criteria.
Conclusions: There is a subgroup of patients with sJIA in whom arthritis is absent or delayed. The use of the Yamaguchi criteria in this subgroup of patients may be useful for early diagnosis and treatment of sJIA. Thus, further studies are needed to integrate supplementary criteria that increase the strength of both the Yamaguchi and the ILAR criteria.