SESSION TITLE: Medical Student/Resident Pulmonary Manifestations of Systemic Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Granulomatosis with polyangiitis (GPA) is a type of ANCA-associated vasculitis affecting small and medium-size vessels. Usually associated with necrotizing granulomas, this disease commonly involves both the upper and lower respiratory tracts as well as the kidneys. Lung and cardiac involvement are common, however initial presentation with pleural effusion and pericardial effusion in the absence of uremic pericarditis has been reported in only a handful of cases. CASE PRESENTATION: Our patient was a 58-year-old woman with no prior medical history who presented to the emergency department with monocular vision loss, and shortness of breath. The initial evaluation was remarkable for normal renal function, lactic acidosis, troponin elevation as well as elevated CRP and ESR. In addition, CT chest showed a large pericardial effusion, bilateral pleural effusions(R>L), and right pulmonary infiltrates. MRI brain showed findings suspicious for acute or subacute lacunar infarcts within the mid pons and bilateral basal ganglia, and paranasal sinus disease. The myriad of symptoms that she described on admission raised the concern for a systemic process including unusual infections potentially related to her recent stay in Scotland, rheumatologic diseases like vasculitis or possible malignancy. Diagnostic thoracentesis revealed an exudative effusion. Infectious workup was negative including HIV test. cANCA was positive as well as antiproteinase 3 antibodies. Skin biopsy showed a medium-size vessel leukocytoclastic vasculitis and septal panniculitis. Given the findings, she was started on high dose steroids for suspicion of GCA, with a significant improvement of her symptoms, including resolution of dyspnea. DISCUSSION: In patients with GPA, lung involvement is frequent, as it will commonly present as parenchymatous lesions in 48-73% at presentation and 85-92% during the course of the disease. Pleural involvement is rarely seen usually present in 10% of this patient population, and it usually manifests as pleural thickening and pleural effusion. When a pleural effusion is present, usually unilateral, exudative, sterile, associated with predominant neutrophils and low glucose concentration. Pericardial effusion and cardiac tamponade have been linked to constrictive pericarditis due to uremia and not to the inflammatory process of the autoimmune disease per se. Our patient presented with pericardial effusion in the absence of uremia which raises the possibility of being linked to the autoimmune state. CONCLUSIONS: This case helps us illustrate the importance of keeping the differential diagnosis broad when approaching a patient with multisystem involvement. It is important to contemplate vasculitis in our differential diagnosis to be able to order the appropriate testing to avoid delay in the diagnosis and to be able to start treatment in a timely manner. Reference #1: Blundell AG, Roe S. Wegener's granulomatosis presenting as a pleural effusion. BMJ. 2003;327(7406):95-6. Reference #2: Chin M, Leblanc A, Souza C, et al. A severe pleural complication associated with granulomatosis with polyangiitis. Respir Med Case Rep. 2019;28:100933. Reference #3: Parmar MK, Alikhan M, Hsu VM, Borham A. Echocardiogram: The GPS to GPA's Heart (Granulomatosis with Polyangiitis). Case Rep Rheumatol. 2019;2019:7609386. DISCLOSURES: No relevant relationships by Daniel Colon Hidalgo, source=Web Response No relevant relationships by Sri Mahathi Kalipatnapu, source=Web Response No relevant relationships by Maria Jose Zabala Ramirez, source=Web Response