AB1007 PREVALENCE AND CHARACTERISTICS OF TEMPORO-MANDIBULAR JOINT (TMJ) INVOLVEMENT IN A COHORT OF YOUNG ADULT PATIENTS WITH DIAGNOSIS OF JUVENILE IDIOPATHIC ARTHRITIS (JIA) AND NON-JIA CHRONIC INFLAMMATORY ARTHROPATIES
Authors: Adriano Lercara, Gloria Crepaldi, Francesco Licciardi, Marco Davico, Stefano Cirillo, Sarah Marouen, Enrica Vandelli, Yves-Marie Pers, Claudia Lomater
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> TMJ is involved in about 50% of JIA cases, often bilateral and asymptomatic in up to 71% of cases<sup>1</sup>. Adult patients with JIA have been shown to have, compared to healthy individuals, higher rate of dysfunction and anatomical abnormalities<sup>2</sup>. Clinical examination has been shown to have high specificity but low sensitivity in revealing TMJ inflammation<sup>3</sup>. To date MRI is the gold standard to assess TMJ involvement <sup>4</sup> <h3>Objectives</h3> To investigate the prevalence of TMJ involvement in young adults with JIA and young adults with non-JIA inflammatory rheumatisms. <h3>Methods</h3> Patients were recruited prospectively in 2 clinical centers. Inclusion criteria were: patients &lt;35 years diagnosed with JIA who had undergone transition from the pediatric to the adult rheumatologist, and patients diagnosed with non-JIA inflammatory arthropathies. All patients were assessed for joint count, clinical examination for TMJs (tenderness to palpation, swelling, signs of damage such as joint crepitations, lateral deviation, retrognathia and decreased mouth opening), evaluation of global disease activity with composite indexes and underwent MRI of the TMJs to detect inflammation (bone marrow edema, effusion, synovial thickening) or damage (condylar flattening, erosions, disk abnormalities); MRIs with either inflammation or damage were considered pathological. Demographic and clinical characteristics were described using frequency or median and interquartile range (IQR), depending on the distribution of the variable. Differences between groups were analyzed using the Mann-Whitney U test and the χ<sup>2</sup> test when appropriate. The significance was set at p-value ≤ 0.05. <h3>Results</h3> 19 patients were included in the JIA group and 8 patients in the non-JIA group. Patients' demographic and disease characteristics were reported in Table 1. MRI results are collected in Table 2. There are no statistically significant differences between groups for the presence of inflammation on MRI, while damage (in particular, disk abnormalities) is more likely in JIA rather than non-JIA patients (p= 0.02). Joint effusion is more likely to be mild rather than moderate/severe in JIA patients (p = 0.04). <h3>Conclusion</h3> It was found that it is more likely to find damage on MRI in patients of both groups rather than inflammation. Both groups show the same frequency of TMJ involvement, suggesting that TMJ involvement must be sought by the adult rheumatologist as it not only affects JIA patients, but also those with adult-onset inflammatory arthropathies. <h3>References</h3> [1] Billiau AD, et al. J Rheumatol. 2007 Sep;34(9):1925–33 [2] Arvidsson LZ, et al. Radiology 2010 Jul;256(1):191–200 [3] Koos B, et al. J Rheumatol. 2014 Sep;41(9):1871–7 [4] Hemke R, et al. Eur Radiol. 2014 Feb;24(2):327–34. <h3>Disclosure of Interests</h3> None declared