Monoarticular JIA - a Distinct Clinical Entity Save

Monoarticular Juvenile Idiopathic Arthritis (monoJIA) is typically classified under oligoarticular JIA, but a recent study suggests it is a separate entity.

The analysis of 347 patients with oligoJIA, included patients with at least two years follow-up and compared oligo JIA ot mono JIA, looking at clinical and laboratory variables and clinical outcomes.

The study compared 229 oligoJIA against 196 monoarticular onset; with 60% of the latter having persistent monoJIA. The mean follow-up was 11.4 years.

Progression from a monoarticular onset to oligoarticular course occurred in 78 patients (38.8%) with in 3 years of onset.

Compared to oligoJIA, monoJIA had a:

• later age at onset (6.1 vs. 4.7 years)
• lower female prevalence (70.3 vs. 83.4%)
• higher hypermobility (61.9 vs. 46.3%)
• lower frequency of uveitis (14.4 vs. 34.1%)
• less ANA+ (68.6 vs. 89.5%)
• better long-term outcome.

MonoJIA appears to have a different clinical profile and behaves differently that oligo JIA (those with 2-4 joints involved). This could affect future classification criteria and therapeutic approaches.