Snapshot A 40-year-old woman presents to the emergency room for fever and cough for the past few nights. Her past medical history includes systemic lupus erythematosus, for which she is currently on a long prednisone taper. On physical exam, she is in moderate distress and dyspneic. There are bilateral crackles and rhonchi on pulmonary exam. A chest radiograph shows multifocal consolidation. She is started on antibiotics following a bronchoalveolar lavage. Introduction Classification Nocardia an aerobic gram + bacteria with branching filaments weakly acid fast urease + and catalase + transmission inhalation direct contact with skin break Associated conditions pulmonary nocardiosis in immunocompromised patients cutaneous nocardiosis can happen in immunocompetent patients Epidemiology Demographics mainly in immunocompromised patients Location pulmonary (most common) may spread to central nervous system Risk factors immunocompromised status chronic steroid use HIV infection trauma ETIOLOGY Pathogenesis Nocardia can inhibit phagolysosome fusion immunocompromised patients, especially those with defective cell-mediated immunity, are at higher risk Presentation Symptoms constitutional symptoms weight loss night sweats Physical exam fever pulmonary nocardiosis cough dyspnea sputum production chest pain pleural effusion neurologic nocardiosis focal neurologic defects based on location of abscess altered mental status cutaneous nocardiosis nodular lymphangitis painful lymphadenopathy with drainage cellulitis Imaging Chest radiography indication pulmonary nocardiosis findings multifocal consolidation cavitary lesions Computed tomography (CT) of the brain indication suspected central nervous system involvement findings abscesses appear as rim-enhancing lesions Studies Labs gram + staining with multi-branching beaded filamentous bacteria Ziehl-Neelsen stain weakly acid fast culture Making the diagnosis based on clinical presentation and isolation of organism Differential Actinomyces infection distinguishing factors although Actinomyces is also gram + and forms branching filaments, it is not acid fast and causes oral/facial abscesses associated with dental procedures SNAP treatment Sulfa for Nocardia; Actinomyces uses Penicillin Tuberculosis distinguishing factor negative PPD Treatment Medical trimethoprim-sulfamethoxazole (TMP-SMX) indication all patients carbapenems indication patients contraindicated to TMP-SMX Complications Disseminated infection