Uveitis in Juvenile Idiopathic Arthritis

The purpose of the present study was to extend our knowledge of the occurrence, characteristics and prognosis of uveitis in patients with juvenile idiopathic arthritis (JIA: arthritis of unknown cause of at least six weeks' duration in a child under 16 years of age). The occurrence of uveitis was examined retrospectively in subjects entitled under the nationwide sickness insurance scheme to receive specially reimbursed medication for JIA in 5/21 central hospital districts in Finland (population basis about 1 300 000 inhabitants) during 1980, 1985 and 1990. A total of 114 children with JIA were found and uveitis was diagnosed in 16% of them. Uveitis was chronic (duration >6 months) in nine cases, the most severe cases being those three in whom uveitis was detected at the onset of arthritis. In 49 sibling pairs with JIA from the Rheumatism Foundation Hospital uveitis was detected in 26%. These 80 familial JIA cases belonging to 37 families with two or three affected siblings were collected from about 2000 children seen at the Hospital during 15 years. The observed concordance rate for uveitis (three pairs) did not differ from that expected (3.4 pairs). Uveitis was chronic in most instances, but its course was usually mild. In the clinic-based cohort of 426 patients with newly diagnosed JIA from the Rheumatism Foundation Hospital the most important determinants of associated uveitis were early onset of arthritis (at the age of 2 to 4 years) and antinuclear antibody (ANA) positivity. During the mean follow-up time of 4.5 years a total of 104 (24%) children with JIA developed uveitis. The condition was in most cases (99 out of 104) asymptomatic and was found early in the disease process, in a majority of cases during the first four years from the onset of arthritis. Proportionally uveitis was as frequent in rheumatoid factor-seronegative polyarthritis as in oligoarthritis and there was no predominance of girls. The prognosis of uveitis in this prospective series was better than that in most earlier reports; complications in 24% of cases, none of the patients became blind. In the above cohort, 372 children had seronegative oligoarthritis or polyarthritis. Within this group, the activity of arthritis was compared between patients with associated uveitis and