A subclinical synovitis seen on MRI examination in children with clinically inactive juvenile idiopathic arthritis (JIA) is predictive of disease flare, suggests a new study published in the journal Arthritis Care & Research.

The study included 90 children with JIA who underwent contrast-enhanced MRI from 2012 to 2016.  Each joint was evaluated for synovitis, tenosynovitis and bone marrow edema. Their disease outcomes were retrospectively analysed. At the time of study entry, about 17% of patients were not on any medication on account of their disease being in remission, while the rest 83.3% were on medications, mainly biologics. Inactive disease was defined as no arthritis, fever, serositis, rash, splenomegaly, lymphadenopathy or uveitis; a normal erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) level; physician global assessment indicating no active disease with duration of morning stiffness ≤15 minutes.

MRI showed subclinical synovitis in 65.5% children and bone marrow edema in 46.7%. A disease flare was reported in 63.3% of patients during follow-up.

About 44% of those who were in clinical remission on medication at baseline stopped their treatment, while 36% reduced dose and frequency of use. Seventy-two percent of children who discontinued their treatment experienced a disease flare; a disease flare was also reported in 53% of children who had reduced their original dose or continued their medication in the previously prescribed doses. Progression of joint damage was seen in 31.5% evident on x-ray.

Nearly 75% of patients with subclinical synovitis reported a disease flare compared with around 42% of those with no residual synovitis on MRI. A high MRI score for bone marrow edema and age > 17 years strongly predicted progression of joint damage.

Treatment of JIA aims to prevent disease progression and induce clinical remission. This study shows evidence of subclinical inflammation that persists in a large majority of JIA patients even though their disease is clinically in remission. MRI during follow up can help predict the risk of disease flare and joint deterioration with timely management in order to prevent physical disability.

(Source: Medpage Today, July 22, 2021 & Arthritis Care Res (Hoboken). 2021 Jul 19. doi: 10.1002/acr.24757)