SESSION TITLE: Infectious Disease Cases - Student/Resident
SESSION TYPE: Student/Resident Case Report Slide
PRESENTED ON: Monday, October 26, 2015 at 11:00 AM - 12:00 PM
INTRODUCTION: Nocardiae are aerobic actinomycetes found in soil and aquatic environments. Invasive nocardiosis mostly occurs in immunocompromised hosts. Nocardia cyracigeorgica is an emerging species, but cases are reported infrequently in the literature (1). We report the second known case of post-influenza necrotizing pneumonia due to Nocardia spp. and the first due to N. cyriacigeorgica (2).
CASE PRESENTATION: A 77-year-old male with a history of ongoing smoking, COPD and type 2 diabetes presented with a 3-week history of cough and dyspnea. He was treated as an outpatient for pneumonia with two trials of oral moxifloxacin, but had progressive shortness of breath. He was admitted to hospital and treated with ceftriaxone and doxycycline, but developed hypoxemic respiratory failure shortly after admission requiring intubation and ventilation. CT chest revealed extensive airspace disease bilaterally with a thin-walled cavitary lesion in the right lower lobe measuring 6.0 cm x 3.3 cm. Microbiology studies from BAL revealed branching and beaded gram positive bacilli (eventually identified as N. cyriacigeorgica, sensitive to TMP-SMX, ceftriaxone and doxycycline, but resistant to moxifloxacin) and positive PCR testing for influenza A H3. Testing was negative for AFB, TB, PCP, legionella, and HIV. TMP-SMX and oseltamavir were added after the BAL. Imaging of the brain was not done due to clinical instability. The patient had ongoing fevers and high FiO2 requirements and died on day 22 of admission.
DISCUSSION: The incidence of pulmonary nocardiosis is increasing, likely due to improved microbiological identification and a larger population of immunocompromised patients. Risk factors in immunocompetent hosts include COPD and bronchiectasis, potentially owing to impaired local defenses subsequent to structural changes in the bronchi (3). Our patient had COPD, but had not received prolonged corticosteroid therapy and his diabetes was well controlled. Post-influenza pneumonia is a well-described entity and the increased severity of bacterial infection may relate to the virus “priming” the lungs (2). The typical presentation for pulmonary nocardiosis is a subacute infection resulting in abscess formation, and rarely empyema. Our patient had rapidly progressing disease and a large cavitary lesion.
CONCLUSIONS: Pulmonary nocardiosis should be considered in refractory cases of pneumonia and Nocardiae as a cause of post-influenza necrotizing pneumonia.
Reference #1: Schlaberg, R., et al. "Nocardia cyriacigeorgica, an emerging pathogen in the United States." Journal of clinical microbiology 46.1 (2008): 265-273.
Reference #2: Sawai, T., et al. “A case of community-acquired pneumonia due to influenza A virus and Nocardia farcinica co-infection.” Journal of Infection and Chemotherapy 20 (2014): 506-508.
Reference #3: Riviere, F., et al. "Pulmonary nocardiosis in immunocompetent patients: can COPD be the only risk factor?." European Respiratory Review 20.121 (2011): 210-212.
DISCLOSURE: The following authors have nothing to disclose: Brent Guy, Gur Chandhoke, Daniel Ricciuto
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