SESSION TYPE: Infectious Disease Cases II
PRESENTED ON: Tuesday, October 23, 2012 at 11:15 AM - 12:30 PM
INTRODUCTION: Nocardia infection most commonly occurs in hosts with impaired cell-mediated immunity but has also been reported in individuals with pulmonary alveolar proteinosis, mycobacterial disease, chronic granulomatous diseases, and chronic obstructive pulmonary disease following even a short course of systemic corticosteroids. Patients typically experience cough, purulent or blood-streaked sputum, night sweats, and pleuritic chest pain. Diagnosis is commonly delayed because presenting symptoms are nonspecific and indolent.
CASE PRESENTATION: A 40 year old male 11 months status post allogenic bone marrow transplant for acute myeloid leukemia complicated by graft-versus-host disease presented for evaluation of several months of cough. He had been treated with systemic steroids for the prior 3 months. Previous courses of antibiotics provided no clinical benefit. He had minimal sputum production and no hemoptysis, sinus congestion, fever, or systemic symptoms. His physical exam was unremarkable. A computed tomography (CT) scan of the chest was notable for a solitary multilobulated 3.5cm mass in the left apex without mediastinal lymphadenopathy. Transthoracic needle biopsy demonstrated acute organizing pneumonia. AFB, GMS and CMV stains were negative and the culture grew Nocardia. Therapy was initiated with trimethoprim-sulfamethoxazole and doxycycline. Brain magnetic resonance imaging scan was negative for disseminated disease. Subsequent bacterial speciation confirmed Nocardia higoensis/shimofusensis susceptible to trimethoprim-sulfamethoxazole and intermediately to doxycycline. Follow-up CT chest three months later demonstrated a near-complete resolution of the lesion in left apex. Trimethoprim-sulfamethoxazole was continued to complete a 6 month course.
DISCUSSION: Radiographic manifestations of Nocardiosis most typically include airspace consolidation, cavitating nodules and empyema. The occurrence of a solid pulmonary mass is very uncommon (<2%). Lesions are not well encapsulated and hematogenous spread occurs in 50% of cases. Two novel species of Nocardia, N. higoensis and N. shimofusensis have recently been identified as unique species based on 16S rRNA gene sequence analysis. These species were the cause of the infection.
CONCLUSIONS: We report a case of Nocardia infection presenting as a solitary pulmonary mass that was successfully treated with trimethoprim-sulfamethozaole. Nocardia higoensis/shimofusensis, a recently identified species was the etiology of this infection. Diagnosis was delayed, in part, due to the indolent and nonspecific symptoms at presentation.
1) Kageyama A et al. Nocardia shimofusensis, isolated from soil, and Nocardia higoensis, isolated from a patient with lung nocardiosis in Japan. Int J Syst Evol Microbiol. 2004;54(Pt 6):1927-31.
2) Blackmon KN et al. Pulmonary nocardiosis: computed tomography features at diagnosis. J Thorac Imaging. 2011;26(3):224-9.
DISCLOSURE: The following authors have nothing to disclose: Lioudmila Karnatovskaia, Salvador Alvarez, Margaret Johnson
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