COURSES OF ARTICULAR INVOLVEMENT IN ANA-POSITIVE JUVENILE IDIOPATHIC ARTHRITIS

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[2002] [FRI0253] COURSES OF ARTICULAR INVOLVEMENT IN ANA-POSITIVE JUVENILE

IDIOPATHIC ARTHRITIS

E. Felici 1, S. Magni-Manzoni 2, C. Malattia 2, M. Draghi 2, S. Bianchi 2,

C. Tzialla 2, S. Viola 1, A. i 1, A. Ravelli 1 1Pediatria II, Istituto

G. Gaslini and University of Genova, Genova, 2Dipartimento di Pediatria,

IRCCS Policlinico S. Matteo, Pavia, Italy

Objectives: The presence of antinuclear antibodies (ANA) identifies a

subgroup of children with juvenile idiopathic arthritis (JIA) characterised

by early onset, predominance of females, asymmetric arthritis and risk of

chronic iritis. We investigated the patterns of joint involvement over time

in a group of children with ANA-positive JIA.

Methods: One hundred children fulfilling the 1997 ILAR criteria for JIA and

with at least 2 positive results of ANA determination during the first 6

months of observation were studied. Patients with rheumatoid factor-positive

or psoriatic arthritis were excluded. The cumulative number of joints

involved at disease presentation and after 6, 12, and 24 months was

recorded. At each time point, patients were divided in 4 groups based on the

cumulative number of joints affected: 1 joint; 2-4 joints; 5-10 joints; >=

11 joints.

Results: The table shows the frequency of the 4 patterns of joint

involvement over time.

Of the 94 patients who had <= 4 joints involved at disease presentation, 68

(72%) still had oligoarthritis whereas 26 (28%) had developed polyarthritis

(>= 5 joints involved) after 6 months. The frequency of polyarticular

extension at 6, 12, and 24 months was 20, 29, and 40%, respectively, among

patients with 1 joint involved at presentation and 50, 47%, and 72%,

respectively, among patients with 2-4 joints involved at presentation. At 24

months after disease presentation, only 13% of patients with involvement of

1 joint at disease presentation still had 1 joint involved, but only 10% of

patients with <= 4 joints affected at disease presentation had developed

involvement of >= 11 joints.

0 mos.(n=100) 6 mos.(n=100) 12 mos.(n=93) 24 mos.(n=76)

1 joint 70% 27% 19% 9%

2-4 joints 24% 41% 43% 41%

5-10 joints 4% 21% 26% 38%

>=11 joints 2% 11% 12% 12%

Frequency of the 4 patterns of joint involvement over time

Conclusion: In our series of JIA, a consistent proportion (28%) of

ANA-positive patients who had <= 4 joints involved at disease presentation

had developed a polyarticular pattern of disease as early as after 6 months.

The frequency of polyarticular extension among patients with oligoarthritis

at 6 months was 33% at 12 months and 48% at 24 months.

Paediatric rheumatology