A Case of Acute Interstitial Pneumonia during the COVID-19 Pandemic

ABSTRACT

IntroductionAcute respiratory distress syndrome (ARDS) typically has a precipitating cause. The most common histological finding in ARDS is diffuse alveolar damage (DAD). DAD is described as injury to the endothelium and alveolar cell lining. Acute interstitial pneumonia (AIP) is defined by the sudden development of bilateral pulmonary infiltrates without a precipitating cause with histological DAD. Case PresentationWe present the case of a 60-year old male with a past medical history of hypertension and hyperlipidemia who initially presented with dyspnea and a two week history of polyarthralgias. He was a current one pack per day smoker and worked an office job in the HVAC industry. His Chest CT showed impressive multi-lobe ground glass opacities. He was treated with oxygen, dual antibiotics and empiric steroids. Extensive infectious workup including PCR respiratory virus panel, fungal testing, urine antigens for Legionella and Streptococcus Pneumonia, and multiple COVID-19 tests were all negative. Autoimmune and vasculitis testing only had a positive ANA 1160 titer with a nucleolar pattern. Left lung transbronchial biopsies with infectious bronchoalveloar lavage were non-diagnostic. A larger surgical pathology specimen was obtained through video assisted thorascopic surgery (VATS) with biopsies taken from three lobes. His pathology was consistent with organizing diffuse alveolar damage with hyaline membranes suggestive of the acute phase of DAD with no evidence of granulomas or vasculitis. In the idiopathic form, this is consistent with AIP. His severe hypoxic and hypercapneic respiratory failure was treated with permissive hypercapnea and high PEEP strategy (7.24pH/89 pCO2). Extracorporeal membrane oxygenation (ECMO) was considered but he was not a candidate. He developed a spontaneous left lung pneumothorax due to barotrauma. He was treated with high dose intravenous pulse dosed steroids with minimal improvement. His case was discussed with the transplant team, and he was not a candidate due to prolonged mechanical ventilation and inability to give consent. His code status was changed to comfort care and he passed away. DiscussionPatients diagnosed with AIP are treated with supportive care including mechanical ventilation and intravenous pulse dose corticosteroids. There have been cases of patients receiving single lung transplants for AIP and surviving. Extracorporeal membrane oxygenation (ECMO) can be considered as bridge to recovery or lung transplant in AIP. Although the patient we described was not a candidate for either. Despite being amidst the COVID-19 pandemic, other rare causes of fulminant respiratory failure still exist, such as AIP.