Computed Tomography Features of Pulmonary Nocardiosis in Immunocompromised and Immunocompetent Patients

BACKGROUND Nocardiosis primarily occurs in the setting of immunocompromising conditions. However, it may also occur in immunocompetent patients. We described computed tomography features of pulmonary nocardiosis and compared immunocompetent and immunocompromised patients. MATERIAL/METHODS CT images of 25 patients (Mean age of 39.5 years; 76% male) with pulmonary nocardiosis proved by bronchoalveolar lavage or biopsy were reviewed by two experienced pulmonary radiologists and detailed findings were reported on. Fourteen patients (56%) were immunocompetent, while 44% had an underlying immunocompromising condition, including chronic granulomatous disease (CGD) (n=4), diabetes mellitus (DM) (n=2), malignancy (n=2), HIV (n=1), concomitant CGD and DM (n=1), and steroid therapy for nephrotic syndrome (n=1). RESULTS Most patients had bilateral involvement with no zonal predominance. Multiple pulmonary nodules (96%) were the most common CT findings, followed by consolidation (76%) and cavity (52%). Other findings included bronchiectasis (48%), pleural thickening (40%), ground glass opacity (32%), mass-like consolidation (20%), intrathoracic lymphadenopathy (16%), pleural effusion (12%), reticular infiltration (4%), and pericardial effusion (4%). There was no statistically significant difference in the CT findings of immunocompromised and immunocompetent groups. CONCLUSIONS Pulmonary nocardiosis presents mainly as multiple pulmonary nodules, consolidations, and cavity in both immunocompromised and immunocompetent patients. However, these features are more suggestive of nocardiosis in the setting of an underling immunocompromised condition.