A CASE OF ANTISYNTHETASE SYNDROME: THE IMPORTANCE OF HISTORY IN DISTINGUISHING ETIOLOGY OF INTERSTITIAL LUNG DISEASE IN A COVID-19 WORLD

ABSTRACT

SESSION TITLE Systemic Diseases Causing Pulmonary Havoc SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 1015 am - 1110 am INTRODUCTION: In the coronavirus disease 2019 (COVID-19) era, the etiology of interstitial lung disease (ILD) should remain broad to ensure accurate diagnosis and the proper treatment of patients. Vital to the art of medicine is taking a comprehensive history, and anchoring on a common diagnosis such as COVID-19 can result in early dismissal of alternate etiologies that physicians have an obligation to explore. CASE PRESENTATION A 58-year-old male with a history of diabetes, hypothyroidism, and hypertension presented to the emergency department (ED) with dyspnea and fever. Initial CT chest imaging was significant for reticular and fibrotic changes with peripheral ground-glass and solid nodular opacities, some with areas of central clearing. Despite negative PCR testing, he was diagnosed with COVID-19 and discharged on oxygen with pulmonary follow-up. He continued to have arthralgias, proximal muscle weakness, low-grade fevers, and weight loss. He re-presented to the ED and was admitted for hypovolemia and further exploration into a potential autoimmune etiology of his symptoms. Labs were significant for a creatine kinase of 3,381 U/L, positive autoimmune antibodies [ANA (1320), Jo-1 (>8.0 U), and SS-A/Ro (1.4 U)], and elevated ESR and CRP (30 mm/hr and 81 mg/L). Repeat CT revealed persistent parenchymal changes. Bronchoscopy was performed without anatomical abnormalities, and bronchoalveolar lavage (BAL) fluid was normal in appearance and negative for infectious etiologies. Though the patient was a farmer and possessed risk factors for hypersensitivity pneumonitis, lack of lymphocytic predominance on BAL, negative hypersensitivity panel, and uncharacteristic CT findings helped exclude this diagnosis. The patient was diagnosed with antisynthetase syndrome and treated with pulse dose intravenous solumedrol before transitioning to prednisone with resolution of muscle weakness and radiographic improvement in lung infiltrates. Muscle biopsy was deferred given the rapid clinical response and serum markers consistent with the diagnosis. DISCUSSION: Antisynthetase syndrome is a rare cause of ILD and often presents with myositis, arthritis, skin changes, Raynaud's phenomenon, and fever [1]. These symptoms, combined with the aminoacyl-tRNA synthetase antibody—most commonly the Jo-1 antibody—help confirm the diagnosis [2]. Due to a lack of established diagnostic criteria, muscle biopsy is often used to exclude other causes of myositis [3]. The ILD associated with antisynthetase syndrome is a significant cause of morbidity and mortality, and delay in diagnosis can lead to progression of lung injury. CONCLUSIONS: Chest imaging findings in COVID-19 are nonspecific, and post-COVID lung disease often presents similarly to other ILDs [1]. Because of this, history and physical exam remain crucial tools to reflect on alternate diagnoses for ILD and will continue to be necessary as we evolve through this COVID-19 era. Reference #1 Devi HG, Pasha MM, Padmaja MS, Halappa S. Antisynthetase Syndrome A Rare Cause for ILD. Journal of Clinical and Diagnostic Research JCDR. 2016;10(3)OD08. doi10.7860/JCDR/2016/16872.7361 Reference #2 Cavagna L, Trallero-Araguás E, Meloni F, et al. Influence of Antisynthetase Antibodies Specificities on Antisynthetase Syndrome Clinical Spectrum Time Course. Journal of Clinical Medicine. 2019;8(11). doi10.3390/jcm8112013 Reference #3 Schmidt J. Current Classification and Management of Inflammatory Myopathies. J Neuromuscul Dis. 2018;5(2)109-129. doi 10.3233/JND-180308. PMID 29865091;PMCID PMC6004913. DISCLOSURES No relevant relationships by Dustin Norton No relevant relationships by Alyssa Simon No relevant relationships by Kang Rui Xiang