TAKE A CHILL PILL: CRYOBIOSPY USED TO DIAGNOSE ISOLATED PULMONARY CAPILLARITIS CAUSING DIFFUSE ALVEOLAR HEMORRHAGE

Abstract

SESSION TITLE: Medical Student/Resident Diffuse Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Diffuse alveolar hemorrhage(DAH) is associated with three histopathologic patterns: pulmonary capillaritis (PC), bland pulmonary hemorrhage, and diffuse alveolar damage. PC is most commonly caused by systemic autoimmune processes and in the absence of evidence of systemic disease is known as isolated pulmonary capillaritis (IPC), which is limited to the lung. Transbronchial cryobiopsy is a bronchoscopic alternative to surgical lung and transbronchial biopsy that uses cryoforceps to quickly freeze at -196ºC to preserve it for immunohistochemical analysis. We describe a case of cryobiopsy used for histopathological diagnosis of IPC in a case of DAH. CASE PRESENTATION: A 70 year-old male presented to the ED with severe hemoptysis. He was intubated for acute hypoxic respiratory failure. CT Chest showed bilateral ground-glass and airspace opacities. BAL showed progressively hemorrhagic effluent on serial aliquots on 2 occasions, confirming diagnosis of DAH. He received high-dose IV steroids. Autoimmune work-up, including antinuclear antibody(ANA), ANCA antibody, myeloperoxidase antibody, proteinase-3 antibody, anti-double stranded DNA, anti-cyclic citrullinated peptide, anticardiolipin antibody, C3, C4, anti-ground basement membrane(GBM) were negative twice. Therefore, tissue diagnosis was pursued. Transbronchial cryobiopsy was performed. Biopsy revealed mild expansion of the alveolar walls, scattered foci of fibrin present within the airspaces, collections of hemosiderin-laden macrophages, focal areas of increased neutrophils within the capillary network of alveolar walls with reactive endothelial changes, and no evidence of large vessel vasculitis. In the setting of negative autoimmune workup, this indicated isolated pulmonary capillaritis. With mycophenolate mofetil and prolonged steroid taper, he recovered with no recurrence of hemoptysis on 6 month follow-up. DISCUSSION: IPC is a rare entity causing DAH with favorable prognosis when treated. Thus, pursuing tissue diagnosis in DAH with negative autoimmune workup has important treatment implications. Cryobiopsy has a diagnostic yield of 75-91%-superior to that of transbronchial lung biopsy, while surgical lung biopsy is a major invasive procedure with mortality rate of 1-5%. While the use of cryobiopsy remains limited to centers of expertise, with complications of pneumothorax and hemorrhage reported, it is a promising and cost-effective approach which can be considered to establish a diagnosis in DAH of unclear etiology. CONCLUSIONS: Cryobiopsy should be considered to establish a diagnosis in diffuse alveolar hemorrhage of unclear etiology. Reference #1: Thompson, Gwen, Mary Klecka, Anja C. Roden, Ulrich Specks, and Rodrigo Cartin-Ceba. "Biopsy-proven Pulmonary Capillaritis: A Retrospective Study of Aetiologies including an In-depth Look at Isolated Pulmonary Capillaritis.” Respirology 21.4 (2016): 734-38 DISCLOSURES: No relevant relationships by Raed Alalawi, source=Web Response No relevant relationships by Abdul Khan, source=Web Response No relevant relationships by Nehan Sher, source=Web Response No relevant relationships by Daniel Yu, source=Web Response