Nocardiosis: The Great Imitator

Abstract

SESSION TITLE: Bacterial Infections 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Nocardia species are filamentous gram positive bacteria which typically infect immunocompromised individuals. Lung is the primary site of infection in more than two-thirds of the patients.1 We present a case of pulmonary nocardiosis in a patient with non-resolving chronic obstructive pulmonary disease (COPD) exacerbation. CASE PRESENTATION: A 65-year-old female with history of very severe COPD secondary to alpha 1 antitrypsin deficiency and sulfonamide allergy presented with shortness of breath and productive cough for 2 weeks. She had 4 episodes of COPD exacerbation over last 1 year treated with systemic steroids. After treatment for COPD exacerbation with cefuroxime and prednisone for 1 week, and later with dexamethasone, moxifloxacin and doxycycline for 6 days, she had no improvement in symptoms. Initial sputum culture was negative and chest X-ray (CXR) revealed chronic interstitial scarring with no focal infiltrate. On exam, she was ill-appearing, with oxygen saturation of 89% on 4 liters of oxygen and bilateral end-expiratory wheezing on lung auscultation. CXR showed a new density in right lung base. Repeat sputum culture was positive for partially acid-fast staining, filamentous, branching rods. Computed tomography (CT) of chest demonstrated multiple inflammatory-appearing nodular opacities throughout right lung field. She was started on amikacin and minocycline for presumptive diagnosis of pulmonary nocardiosis. After desensitization, antibiotics were changed to trimethoprim-sulfamethoxazole (TMP-SMX) and imipenem. After 3 weeks imipenem was stopped. Final sputum culture grew Nocardia cyriacigeorgica, sensitive to TMP-SMX, amikacin, and imipenem, with intermediate sensitivity to minocycline. After 6 weeks, TMP-SMX was switched to minocycline as patient developed a rash. Patient completed 6 months of therapy and follow-up CT scan showed resolution of infiltrates. She has since been doing well. DISCUSSION: Pulmonary nocardiosis is often difficult to diagnose as it presents with non-specific symptoms, such as fever, cough, and dyspnea, as well as non-specific radiographic findings, like nodular and/or consolidative infiltrates. More so, given the fastidious nature of Nocardia, it can take up to 21 days to grow on routine cultures. A high index of suspicion is warranted in immunocompromised patients, including those with frequent steroid use, as well as those with structural lung disease.1 CONCLUSIONS: Nocardiosis may imitate COPD exacerbation which can make diagnosis challenging. Moreover, glucocorticoids used for treatment of underlying lung disease may worsen the infection. TMP-SMX is first-line treatment for pulmonary nocardiosis, with minocycline as a well-established alternative.1 Neither of these antibiotics are part of typical empiric regimens which may explain initial treatment failure in our patient. Reference #1: Lederman ER, Crum N. A case series and focused review of nocardiosis: clinical and microbiologic aspects. Medicine. 2004;83(5):300-313 DISCLOSURE: The following authors have nothing to disclose: Mayanka Kamboj, Lydia Winnicka, Sukriti Kamboj, Amirahwaty Abdullah No Product/Research Disclosure Information