View Abstract

A3596 - A Case of Nocardia Cyriacigeorgica Lung Infection Presenting with a Progressive Obstructive Ventilatory Defect and Worsening Lung Nodules in an Immunocompetent Host with Previous History of Mild Bronchiectasis
Author Block: G. Ivashchuk1, M. Sanchez Sierra Marino2, R. Arauco Brown3; 1Internal Medicine, University of Texas at Rio Grande Valley at Doctors Hospital at Renaissance, McAllen, TX, United States, 2Family Medicine, University of Texas at Rio Grande Valley, Weslaco, TX, United States, 3University of Texas at Rio Grande Valley, Pulmonary and Sleep Center of the Valley - Advanced Lung Disease Clinic, McAllen, TX, United States.
Introduction: Nocardia cyriacigeorgica was initially reported as an agent capable of causing invasive lung disease in humans in 2008 and more recent reports could suggest that hosts affected by this bacteria do not exhibit the typical risk factors associated with classic Nocardial infection. Case Report: A 58-year-old, never-smoker and immunocompetent female with past medical history of acid reflux disease induced mild bronchiectasis was referred to our clinic with two years of fatigue, anorexia, progressive dyspnea and persistent productive cough. The patient was not exposed to systemic steroids before the beginning of her disease. Initial investigation at a different center was remarkable for serial lung imaging showing her well known bronchiectasis but worsening bilateral micro-nodules with tree-in-bud pattern. The patient had serial pulmonary function tests (PFTs) that revealed a mixed restrictive and obstructive ventilatory defect with remarkable progression of the obstructive component. As part of an interstitial lung disease workup, the patient underwent an open lung biopsy that was reported as non-diagnostic but cultures from the excised lung tissue were reported as positive for an acid-fast organism that was unable to be characterized. On our initial evaluation, the patient appeared chronically ill, hypoxemic and in mild respiratory distress. A complete serologic workup for interstitial lung disease was re-ordered with unrevealing results. PFTs on our initial evaluation were remarkable for severe airway obstruction with an FEV1 of 0.82 (35% of predicted). A bronchoscopy with bronchoalveolar lavage was completed. The alveolar fluid was positive for Nocardia cyriacigeorgica. Brain imaging was negative. The patient was started on linezolid and pulmonary rehabilitation with dramatic improvement in her respiratory symptoms, radiographic changes and overall functional condition. Discussion: Nocardia species represent a group of well-known pathogens which mostly affects immunocompromised hosts. N. cyriacigeorgica was believed to be a new emergent pathogen until a recent NIH directed study using a DNA-DNA hybridization method demonstrated that N. cyriacigeorgica corresponds to the previously described N. asteroids strain with drug pattern VI (well known disease causative). Recent literature suggests that N. cyriacigeorgica would be more commonly isolated from immunocompetent hosts in which the only risk factor appear to be a structural or functional lung abnormality as chronic bronchitis or bronchiectasis. Despite bronchiectasis and centrilobular nodular opacities had being reported as radiographic findings in immunocompetent patients with pulmonary nocardiosis, the clinical presentation with progressive airway obstruction in association with worsening micro-nodules resembling bronchiolitis had not being previously described with this Nocardia species.