A CASE OF ADULT UNILATERAL LUNG HYPERLUCENCY

Abstract

SESSION TITLE: Tuesday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: Both Swyer-James McLeod (SJM) syndrome and Congenital Lobar Emphysema (CLE) are rare conditions which may appear radiographically identical, characterized by hyperlucency of one or more lung lobes resulting in hyperexpansion and compression of normal lung tissue. CLE is a developmental anomaly more commonly presenting in the neonatal population within the first few weeks of life as respiratory distress. Those diagnosed beyond the neonatal period are typically still diagnosed within the pediatric time frame due to recurrent pulmonary infections. SJM presents similarly but is more likely an incidental finding developing over time by a childhood viral infection resulting in bronchiolitis obliterans and reduced pulmonary vasculature. CASE PRESENTATION: We present a case of a 30-year-old, non-smoker, El Salvadorean male with no medical history who presented with acute nausea, emesis and mild dyspnea. On exam he had noticeably decreased breath sounds over the right hemithorax and abdominal guarding. While being worked up for esophageal perforation, a CT Chest showed evidence of significant right lung emphysema with mediastinal shift. Consolidation and layered air fluid levels in the right lower lobe were concerning for atelectasis and pneumonia. A mild respiratory acidosis and hypercarbia suggested a chronic process. Esophageal perforation was ruled out with a barium swallow and bronchoscopy showed right bronchial obstruction. Bronchoalveolar lavage did not grow acid fast bacilli or fungal organisms but demonstrated extra-cellular bacteria and CMV. Alpha-1 Anti-Trypsin level was within normal limits. Spirometry showed significant obstruction and reduced lung volumes with an FVC of 1.58 L. Of note, he had presented to clinic two years ago for dyspnea, advised to get a chest x-ray and prescribed an inhaler but was subsequently lost to follow up. Ultimately, this patient’s nausea and vomiting was attributed to impressive over-distension of his right lung and compression of mediastinal structures. He was treated for pneumonia with plans for right lung pneumonectomy once clinically stable. DISCUSSION: We describe an unusual case of unilateral hyperlucency and emphysema. It remains unclear whether it is more consistent with CLE or SJM. Our patient’s somewhat incidental presentation may lead us to think that this is a manifestation of SJM, however the severe emphysematous changes and mediastinal shift suggest that this may be an unusually late presentation of CLE. Given his background from El Salvador, a broad differential for infectious etiology may suggest SJM although this case may be attributed to CLE from congenital CMV as described before[1]. CONCLUSIONS: Consideration of SJM or CLE is necessary especially in the pediatric population as early radiologic findings may be misinterpreted as pneumonia leading to delay in diagnosis. Timely definitive treatment with pneumonectomy may preserve lung volume. Reference #1: Carrol, Enitan D., et al. "Congenital lobar emphysema in congenital cytomegalovirus infection.” Pediatric radiology26.12 (1996): 900-902 DISCLOSURES: No relevant relationships by Nisha Donthi, source=Web Response no disclosure on file for Eric Libre; no disclosure on file for Andrei Minciunescu; No relevant relationships by Shubha Srinivas, source=Web Response