Acute exacerbation of interstitial lung disease after cryoprobe lung biopsy

Abstract

Introduction When compared to conventional transbronchial lung biopsy (TBLB), flexible cryoprobe transbronchial lung biopsy (FCLB) provides larger and higher quality specimens associated with less artifact and higher diagnostic yield in interstitial lung disease (ILD) [1-3]. Additionally, unlike lung resection or TBLB, FCLB has not been associated with acute exacerbation of ILD (AEILD) based on currently available literature. Case report A 59-year-old woman with a history of non-specific interstitial pneumonitis, COPD and tobacco use presented with one day of dyspnea on exertion and increased oxygen requirement but no other respiratory symptoms. She was in respiratory distress while on BiPAP of 12/8 cmH2O and 85% FiO2 with HR: 111 bpm, BP: 133/71 mmHg, RR: 46, SpO2: 95%. Exam showed diffuse fine crackles and use of respiratory accessory muscles. CXR revealed diffuse bilateral pulmonary infiltrates consistent with ARDS (fig.1). Patient eventually required endotracheal intubation. Three weeks prior to her admission, she underwent right middle lobe FCLB -pathology showed diffuse interstitial fibrosis with mild chronic interstitial inflammation and focal organization, without evidence of granulomas, viral cytopathic changes, dysplasia or malignancy. Methylprednisolone was started on day 2 of hospitalization with progressive clinical improvement and extubation after 7 days of lung protective mechanical ventilation. Blood cultures, HIV test, bronchoalveolar lavage for AFB, bacterial and fungal cultures, viral respiratory panel, Legionella antigen, and CMV titer were negative. Serologic studies for connective tissue diseases, vasculitis and hypersensitivity studies were unrevealing. Patient was discharged after 13 days of hospitalization. With no evidence of recent environmental exposure, or infections or rheumatologic diseases, we posited that this could be a case of AEILD after FCLB. Discussion and clinical relevance Incidence AEILD after lung resection or TBLB has been reported in the range of 2-7% [3-4] with a post-operative mortality ranging from 33% to 100% [3-5]. The risk for AEILD is not related to the pre-operative level of pulmonary function [6] and its exact etiology and pathogenesis remains unknown. Given the recent clinical applications of Cryoprobe lung biopsy in the diagnosis of a variety of lung diseases, our report presents a unique case of AEILD as a complication of FCLB -a phenomenon not yet reported in the literature. (Figure Presented).