LAUSR

Background Juvenile dermatomyositis (JDM) is characterized by the presence of microangiopathy which can be assesed by nailfold capillaroscopy (NFC), a simple and noninvasive imaging technique. Morphological abnormalities in scleroderma NFC are well described, but it is known that they may be present in other autoimmune diseases, such as JDM. Objectives To describe the capillary morphological abnormalities assessed by NFC in a series of patients diagnosed with JDM in contrast with patients diagnosed with juvenile idiopathic arthritis (JIA). Methods A cross-sectional descriptive study in which 34 patients were recruited sequentially and randomly, 15 with JDM and 19 with JIA, from the Rheumatology department of Niño Jesus Hospital between September-November (2018). Demographic, clinical, analytical data, presence and subtype of calcinosis, active treatment, HAQ, patient and physician global assessment (PGA), cutaneous assessment tool (CAT) and manual muscle testing (MMT8) validated for JDM were collected. One observer performed blindly, both for clinic and diagnosis, a NFC initially using a videodermatoscope in order to obtain a wide view of the vascular bed and then with a videocapillaroscope (x500), which recorded 2-4 images per finger (except thumbs) to be analyzed far ahead. The presence of a decreased nailfold capillary density (NCD, capillary n°/mm≤6), architectural derangement (disorganization), neoangiogenesis, giant capillaries (ø>50μm, pathological if ≥1), enlarged loops (ø20-50μm) and microhaemorrhages, both pathological present in ≥2 fingers were evaluated. Neovascular pattern was defined as the sum of NCD, disorganization and neoangiogenesis with frequent haemorrhages and giants (active and late scleroderma pattern). Results The descriptive analysis of the main variables is shown in table1. Patients with JIA: all received active treatment, 95% MTX (33% concomitant with anti-TNF, 1 TCZ and 16% CE) and 1 anti-TNF. 26% active uveitis. Two patients presented morphological abnormalities: 1 neoangiogenesis and another enlarged loops. Patients with JDM: 73% received MTX (18% concomitant with CE, 73%Igs and 1 RTX). Three patients had active calcinosis: 2 mixed (circumscribed and cutis) and 1 calcinosis cutis. 2 had previous calcinosis (both circumscribed). 87% presented for the first-time weakness but none had current weakness (MMT8 40). 67% presented morphological abnormalities: NCD 33%, disorganization 40%, neoangiogenesis 53%, enlarged loops 27%, giants 20% and microhaemorrhages 13%. All patients with calcinosis (active or previous) presented disorganization and neoangiogenesis, NCD 80%, giants 60%, enlarged loops and microhaemorrhages 40%. 50% of patients with JDM had a neovascular pattern, of which 80% had a previous or current history of calcinosis. Conclusion Patients with JDM presented more abnomalities in NFC compared to patients with JIA. Neovascular pattern was observed in half of patients, who have previous or current history of calcinosis. Consequently, NFC could be a useful imaging technique in routine clinical practice to evaluate skin activity in patients with JDM. References [1] Wu Q. Juvenile dermatomyositis: Latest advances Best Pract Res Clin Rheumatol.2017 Aug;31(4):535-557. 2.Barth Z. Assesment of microvascular abnormalities by Nailfold Capillaroscopy in Juvenile Dermatomyosistis after medium to long-term follow up. Arthritis Care Res (Hoboken). 2018 May;70(5):768-776.Abstract AB0939 TABLE 1 DEMOGRAPHIC, CLINICAL AND ANALYTICAL CHARACTERISTICS Sex% ♀63 ♂38 Age (yr) 11 Disease duration (mn) 57 ESR/CRP 7/0.3 Patient/physician global assessment (PGA) 0/2 HAQ 0.14 Initial/current CAT BM 3/0 CPK 101 LDH 261 Initial/current MMT8 35/40 Disclosure of Interests None declared