SESSION TYPE: Infectious Disease Student/Resident Case Report Posters I
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: Pulmonary nocardiosis is a rare gram-positive bacterial infection that usually occurs in immunocompromised individuals. Our patient had a history of solid organ transplantation.
CASE PRESENTATION: A 60-year-old male, ex-smoker, presented with fever, dry cough and night sweats of 2 weeks duration. History was significant for diabetes mellitus and cardiac transplantation 6 months prior. His medications included mycophenolate, tacrolimus and prednisone. Vital signs were significant for temperature of 100.5 F. Rest of the physical examination was unremarkable. Laboratory data showed a leukocyte count of 8800/µL (neutrophils-84%). Chest X-ray and chest computed tomography (CT) showed multifocal pneumonia (Fig. 1, 2). CT-guided biopsy and culture identified Nocardia asteroides. Head CT showed no central nervous system (CNS) involvement. Patient was treated with intravenous imipenem and oral minocycline and discharged with plan to continue treatment for one year.
DISCUSSION: Nocardiosis typically occurs in immunocompromised patients with deficiency in cell-mediated immunity as in solid organ or hematopoietic stem cell transplant, HIV infection, steroid therapy, diabetes mellitus or malignancy. CNS dissemination is common in nocardiosis. Relapse or progression despite appropriate therapy is frequent. Pulmonary nocardiosis usually presents with fever, night sweats, dyspnea, cough, hemoptysis and pleuritic chest pain. Radiological findings seen include solitary/multiple nodules, lung masses (with or without cavitation), reticulonodular and interstitial infiltrates, lobar consolidation and pleural effusions . Hence, initial misdiagnosis as mycobacterial/fungal infections, or malignancy is common. Nocardia species are not naturally found in the respiratory tract and isolation in sputum almost always indicates infection. Due to slow growth in the laboratory, invasive procedures to obtain adequate samples are often mandated. A presumptive diagnosis of nocardiosis can be made if partially acid-fast filamentous branching rods are visualized in clinical specimens. All immunocompromised patients and those with CNS involvement should be treated for at least one year, with the exception of isolated cutaneous infections. Clinical and radiographic response to therapy should be monitored and the duration of treatment modified based on these factors . Individuals without reversible immunosuppression should be placed on indefinite therapy with trimethoprim-sulfomethoxazole, doxycyline, or minocycline .
CONCLUSIONS: Pulmonary nocardiosis can present as multifocal pneumonia in a patient with suppressed cell-mediated immunity. Timely diagnosis and appropriate duration of therapy are cornerstones for recovery.
1) Kanne J,Yandown D, Mohammed TL. CT Findings of Pulmonary Nocardiosis. AJR. 2011; 197:W266-W272.
2) Martínez R, Reyes S, Menéndez R. Pulmonary nocardiosis: risk factors, clinical features, diagnosis and prognosis. Curr Opin Pulm Med. 2008 May;14(3):219-27.
DISCLOSURE: The following authors have nothing to disclose: Anupam Kumar, Veena Panduranga, Shine Raju, Ranjit Joseph, Michael Lawlor
No Product/Research Disclosure InformationUniversity of Connecticut Health Center, Farmington, CT