Anti-Synthetase Syndrome: An Under-Recognized Entity (P07.220)

Abstract

Objective: To highlight the in-homogeneity in clinical presentation as well as use of different treatment options in three patients with anti-synthetase syndrome. Background Anti-synthetase syndrome is characterized by a necrotizing autoimmune myopathy (NAM), joint involvement, interstitial lung disease and/or connective tissue disorders (CTD) associated with anti-tRNA- synthetase antibodies as an epiphenomenon. Design/Methods: Case series. Results: 1) A 54 y/o lady presented with three weeks of proximal muscle weakness requiring assistance in getting up from a sitting position. On examination deltoids and hip flexors were weak bilaterally. Laboratory testing revealed elevated creatine kinase (CK = 6090 IU/L), positive ANA 1:40 and Jo-1(>8) antibody. CT chest showed thin-walled cystic emphysematous change in the right lower lobe.2) A 50 y/o man developed difficulty walking and getting up from chair five months prior to his initial visit. Formal muscle strength was normal throughout. He had elevated CK (796 IU/l), aldolase and TSH with positive Anti-PL-12 auto-antibody. CT chest and pulmonary function testing were normal.3) A 62 y/o lady presented with lower extremity weakness, joint swelling, lower extremity rash and shortness of breath for two months. Examination was consistent with proximal muscle weakness. CK (2240 IU/L), ANA (1:640) and Anti Jo-1 (>8) were elevated. CT chest demonstrated fibrotic lung changes with lower lobe predominance.EMG in all patients demonstrated fibrillation potentials and myopathic units. Muscle biopsies were consistent with NAM. Patients 1 and 3 received IVIG and methylprednisone while patient 2 received prednisone and methotrexate. Patients 1 and 2 had complete resolution of symptoms. Conclusions: A high index of suspicion must be maintained for anti-synthetase syndrome in patients with NAM, despite the absence of an identifiable CTD and milder symptoms. NAM may herald the presence of an anti-synthetase antibody the prognostic value of which, is an area of future research. Disclosure: Dr. Mehndiratta has nothing to disclose. Dr. Farheen has nothing to disclose. Dr. Chitravas has nothing to disclose. Dr. Cohen has nothing to disclose. Dr. Katirji has nothing to disclose.