Ab0918 clinical and serological features of dermatomyositis in tunisia

Background The spectrum of dermatomyositis (DM), as all idiopathic inflammatory myopathies (IIM), has been evolving steadily from a pathology characterized by muscle weakness and cutaneous rash to a disease with a wide range of systemic manifestations and various muscular phenotypes. Objectives The aim of our study was to describe the epidemiological, clinical and paraclinical features of DM in a Tunisian cohort. Methods We conducted a retrospective and monocentric study, over a 21-year period. All patients who fulfilled the 2017 ACR/EULAR classification criteria for IIM and were classified among the group “DM” were included. Results Among 85 patients with IIM, 46 were classified with DM (54%). The gender ratio (M/F) was 0,4. The mean age at diagnosis was 48,4 ± 14.8 years. Cutaneous manifestations revealed the diagnosis of DM in 82% of cases. Other revealing symptoms were: muscular weakness (20%), joint involvement (18%), pulmonary involvement (11%) and general symptoms (2.6%). Muscular weakness was noted in all patients, myalgia in 87% and amyotrophy in 11% of patients. Motor deficit was predominantly proximal and symmetric in all patients, affecting the hip flexors in 98% of cases, upper limbs in 87% and/or axial muscles in 28%. Distal muscles were affected in 11% of patients. Other involved muscle groups were: oesophageal muscles (59%), laryngeal muscles (15%) and myocardium (4%). High Creatine kinase levels were noted in 87 % of cases with a median level of 1896 IU/L [IQQ=861-4952]. Muscle biopsy, performed in 37 patients, showed perimysial infiltrate (44%), necrosis/regeneration foci (34%), endomysial infiltrate (31%), microangiopathy (16%), muscular atrophy (13%), perifascicular atrophy (9%) and interstitial fibrosis (6%). Cutaneous signs (100%) included eyelid erythema (85%), heliotropic rash (72%), Gottron’s papules (61%), manicure sign (30%), Gottron’s sign (22%), psoriasiform rash (22%), Raynaud syndrome (20%), vasculitis lesions (15%), telangiectasia (9%), skin ulcerations (9%), calcinosis (9%), skin necrosis (7%), panniculitis (7%) and mechanic’s hands (2%). Pulmonary involvement (26%) was represented by diffuse infiltrative lung disease (17%) and inhalation pneumopathy (9%). Arthralgias were noted in 37% of patients and synovitis in 13%. Antinuclear antibodies were found in 65% of patients. Myositis specific antibodies were found in 16 patients (for n=21 available data): anti RNA synthetase (n=6), anti SRP (n=2), anti Mi-2 (n=4), anti-TIF1-γ (n=2), anti MDA5 (n=1) and anti NXP2 (n=1). Twelve patients (26%) were diagnosed with cancer associated myositis. In terms of therapy, all patients were treated with oral corticosteroids. Immunosuppressive therapy, employed in 85% of patients, was indicated for muscular manifestations (90%) and ILD (10%). Intravenous immunoglobulin was administered in seven patients (15%). The median duration of follow up was 44,5 months. On the date of the last consultation, complete clinical and biological remission of muscular manifestations was noted in 70%. Clinical and radiological stability of ILD was noted in seven patients and regression of radiological infiltrates in one patient. Clinical remission of skin manifestations was noted in 87% of patients, at the cost of cutaneous sequelae in 9%. Overall, a relapse was noted in 57% of patients. Seven patients (15%) have died, after a median period of 12 months. Conclusion This study highlighted the heterogeneity among DM patients, as evidenced by the variety of systemic manifestations at onset and during the disease course and of immunological data. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests None Declared.