ANTISYNTHETASE SYNDROME PRESENTING AS INTERSTITIAL LUNG DISEASE: A CASE OF ANCHORING BIAS DURING THE COVID-19 PANDEMIC

ABSTRACT

SESSION TITLE Dyspne Mysteries SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 0135 pm - 0235 pm INTRODUCTION: Anti-synthetase (AS) syndrome is characterized by interstitial lung disease (ILD), arthritis, myositis, fever, or Raynaud's phenomenon in the presence of an AS autoantibody (1). At least 70% of patients with AS syndrome develop ILD (2), and it represents the major cause of mortality in these patients with a 10 year survival rate of 73%. In a small cohort study, the anti-PL-12 antibody subtype was found to be strongly associated with ILD (3). CASE PRESENTATION A 35 year old female with a history of tobacco use disorder presented to the hospital with three months of recurrent subjective fevers, non-productive cough, and dyspnea on exertion. She denied arthralgias, muscle weakness and hemoptysis. She initially presented to her primary care physician with these symptoms and was prescribed amoxicillin for streptococcal pharyngitis. The patient continued to be symptomatic and was treated empirically for COVID-19 pneumonia twice despite two negative COVID-19 tests and without any significant clinical improvement in her respiratory status. On admission, she was febrile, tachycardic, and had a new oxygen requirement with bilateral coarse breath sounds on exam. She had no leukocytosis and her COVID-19 test was negative. CT angiography of the chest showed extensive mixed reticular and airspace opacities with peribronchial predilection and peripheral sparing (figure 1). A bronchial alveolar lavage was notable only for neutrophilia (19%) and eosinophilia (4%). Rheumatological workup revealed elevated rheumatoid factor, positive antinuclear antibody (140), weakly positive anti–Sjögren's-syndrome-related antigen A antibody (50 AU/ml), undetectable anti-Jo-1 antibody and positive anti-PL-12 antibody. Pulmonary function testing revealed a TLC of 40% and DLCO of 28%, consistent with a restrictive pattern. Considering the patient's organizing pneumonia, positive antibodies, and findings of "mechanic's hands,” the patient was diagnosed with anti-synthetase syndrome with ILD. She was started on oral prednisone and mycophenolate mofetil. On follow-up, she was noted to have symptomatic improvement and stable hypoxia without clinical signs of disease progression. DISCUSSION: During the coronavirus pandemic, the resemblance of COVID-19 pneumonia to other diseases, in the absence of conscious suspicion for other etiologies, can lead to anchoring and availability bias thereby delaying diagnosis and appropriate treatment. Additionally, anti-synthetase syndrome should be considered in the differential diagnosis of ILD even in the absence of arthritis and myositis, as respiratory symptoms are often the first presenting signs. CONCLUSIONS: Increased responsibility is required of diagnosticians to exercise due diligence and active recognition of COVID availability and anchor bias to avoid missing crucial diagnoses. Reference #1 Cojocaru, Manole, Inimioara Mihaela Cojocaru, and Bogdan Chicos. "New insights into antisynthetase syndrome.” Maedica 11.2 (2016) 130. Reference #2 Marco, Joanna L., and Bridget F. Collins. "Clinical manifestations and treatment of antisynthetase syndrome.” Best Practice & Research Clinical Rheumatology 34.4 (2020) 101503. Reference #3 Kalluri, Meena, et al. "Clinical profile of anti-PL-12 autoantibody cohort study and review of the literature.” Chest 135.6 (2009) 1550-1556. DISCLOSURES No relevant relationships by Mario Flores No relevant relationships by David Jackson No relevant relationships by Lisa Saa No relevant relationships by Abu Baker Sheikh