Figure 1.

Clinical characteristics of children with JIA. Three subgroups with different onset of disease were established: polyarthritis, oligoarthritis and systemic disease. Three stages of JIA activity were also distinguished, based on clinical and laboratory criteria: low activity (joint movement limited, without pain or swelling, no extra-articular symptoms, ESR <20 mm/1st h, CRP <10 mg/l); moderate activity (moderate intensity of arthritis, and/or slight temperature, ESR 20–60 mm/1st h, CRP 10–30 mg/l); and high activity (morning stiffness, pain and/or swelling of joints, and/or hepatosplenomegaly, fever, rash, and raised values for laboratory tests ESR >60 mm/1st h, CRP >30 mg/l).