(1135) Antisynthetase Syndrome: Took Her Breath Away

Introduction: Anti-synthetase syndrome is a rare myopathy presenting with respiratory and rheumatological complaints, here we present one such case.

Description: A 59-year-old female seen at rheumatology clinic with pain, swelling and paresthesias of bilateral hands for two months. Her blood pressure was 110/60, heart rate 70, respiratory rate 14, and oxygen saturation 98%. Hand x-rays showed osteoarthritis and she was started on non-steroid anti-inflammatory drugs. Subsequently, she had multiple hospital visits due to recurrent pleuropericardial effusion presenting as dyspnea. At her first visit, chest imaging was clear apart from mild pleural effusion and she was discharged on 3 litres continuous oxygen. At her second visit, thoracentesis was performed which yielded 700ml exudative, non-malignant fluid. She was started on prednisone and hydroxychloroquine. By her third visit, anti-synthetase syndrome was confirmed, positive for anti-OJ and EJ antibodies. She was switched to mycophenolate with continued prednisone. At her latest visit, she again presented with pleuropericardial effusion. Her mycophenolate and prednisone doses were increased and repeat thoracentesis was performed.

Discussion: Anti-synthetase syndrome is a rare autoimmune disease with prevalence of 9/100 000. It is characterized by antibodies against aminoacyl tRNAs and is a type of idiopathic inflammatory myopathy. Symptoms overlap with other myopathies, making diagnosis difficult. Presentations include fever, myositis, arthritis, interstitial lung disease (ILD), serositis, ‘mechanics’ hands, and rash. Dyspnea is typically the main complaint usually due to ILD, but some cases of pleuropericardial effusion have also been reported. These effusions are exudative and are common in anti-PL12 patients. Anti-synthetase antibodies are also checked prior to diagnosis, including Jo1, PL7, PL12, OJ, and EJ. The type of antibody determines the presentation and disease course. While there are diagnostic criteria, none are universally agreed upon, making the diagnosis difficult. Prognosis is poor as the disease is progressive and there is no standardized treatment. Most treatments are symptom directed with hydroxychloroquine for rash, physical therapy for myositis, and immunosuppression via steroids as first-line with adjunctive immunotherapy.