TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: The diagnosis of lung malignancy can often be incidental. We present a hemodynamically unstable patient with COVID-19 and pericardial effusion, subsequently diagnosed with metastatic adenocarcinoma of the lung. CASE PRESENTATION: A 54-year-old male with no significant medical history was diagnosed with COVID-19 two weeks prior to presentation. He had dyspnea on exertion since that time and presented to the hospital after having an abnormal CXR and leukocytosis on out-patient testing. His blood pressure was 95/68 with a heart rate of 129. EKG revealed atrial fibrillation and electrical alternans. He had mildly elevated BNP and troponin, with lactic acidosis. Bilateral opacities were noted on CXR. A large effusion concerning for tamponade was noted on bedside echo. He underwent immediate pericardiocentesis and had 2L serosanguinous fluid drained. After initial stabilization, he was found to have extensive bilateral lower extremity DVT and PE.Repeat TTE showed residual effusion with tamponade physiology observed. Despite the findings on imaging, a pericardial window was not pursued due to concerns of anesthesia induction in the setting of a new PE. He underwent placement of a pericardial drain instead. After the procedure, heparin drip was initiated with an IVC filter placed soon after. The patient eventually had a pericardial window placed. His arrhythmia was chemically converted back to sinus rhythm. On POD5, the drains were removed.Autoimmune workup of the fluid was within normal limits, but cytology resulted in a diagnosis of adenocarcinoma positive for TTF-1. Thus, he was diagnosed with stage IV adenocarcinoma of the lung. CT revealed multiple lytic lesions with diffuse lymphadenopathy. MRI showed no evidence of brain metastasis. He was transitioned to apixaban at discharge, with out-patient oncology follow-up. DISCUSSION: A small study of 31 patients showed pericardial effusion was an independent risk factor predicting severity of COVID-19 infection, with reports of the virus being detected in pericardial fluid.[1,2] While virus infection can cause pericardial effusion, other causes should not be ignored in the workup. With hemodynamic instability, immediate intervention is warranted despite the risk involved with pericardiocentesis. In patients with large volume of pericardial effusion extracted, 5% of them will suffer from paradoxical hemodynamic instability and pulmonary edema afterwards, a condition known as pericardial decompression syndrome.[3] The increased venous return after decompression will compress the LV, based on the principle of ventricular coupling, reducing the cardiac output. Treatment for this condition is supportive. CONCLUSIONS: While COVID-19 is known to cause pericardial effusion, other causes, such as malignancy, should not be forgotten and should always remain in our differential. The risk involved with immediate pericardiocentesis goes beyond cardiac injury. REFERENCE #1: Chen Q, Xu L, Dai Y, et al. Cardiovascular manifestations in severe and critical patients with COVID -19. Clin Cardiol. 2020;43(7):796-802. REFERENCE #2: Farina A, Uccello G, Spreafico M, Bassanelli G, Savonitto S. SARS-CoV-2 detection in the pericardial fluid of a patient with cardiac tamponade. Eur J Intern Med. 2020;76:100-101. REFERENCE #3: Prabhakar Y, Goyal A, Khalid N, et al. Pericardial decompression syndrome: A comprehensive review. World J Cardiol. 2019;11(12):282-291. DISCLOSURES: No relevant relationships by Rumon Chakravarty, source=Web Response No relevant relationships by Vernon Chan, source=Web Response