CT Features of Pulmonary Nocardiosis

OBJECTIVE: Our goal was to identify the CT features of pulmonary nocardiosis, specifically in AIDS patients versus other immunocompromised hosts. MATERIALS AND METHODS: Twenty-four patients with pulmonary nocardiosis were identified; medical records, CT scans, and chest radiographs were reviewed. Five patients had HIV disease, 17 had other causes of immunosuppression, and 2 had normal immunity. RESULTS: CT features of pulmonary nocardiosis included one or more nodules/masses (20/24 cases, 83%), cavitation (8, 33%), consolidation/infiltrates (8, 33%), and pleural thickening (7, 29%). All AIDS patients with nocardiosis had multiple (four or more) nodules detected on CT and 80% (4/5) had cavitation compared with 21% each of non-AIDS patients (p < 0.01 for multiple nodules, p < 0.045 for cavitation). CONCLUSION: CT features of pulmonary nocardiosis are varied, and AIDS patients are more likely to display cavitation and multiple nodules. Although not widely recognized, Nocardia infection should be included in the differential diagnosis of an unexplained nodule or progressive cavitary process in HIV-positive patients.