Clinical characteristics of pulmonary nocardiosis in immunocompetent patients

Abstract

Introduction: Pulmonary nocardiosis is a rare but serious infection typically in immunosuppressed patients (ISPs). However, it is also known to occur in immunocompetent patients (ICPs). Objectives: We investigated clinical features of pulmonary nocardiosis in ICPs in comparison with ISPs. Methods: We performed a retrospective review of all patients diagnosed with pulmonary nocardiosis at Chiba University Hospital from 2004 to 2014. Results: Thirty patients with pulmonary nocardiosis were identified and ten were considered to be colonized. Of all patients with pulmonary nocardiosis, twelve patients were ICPs (mean age 69 years), while eighteen were ISPs (mean age 55 years). Three of the ISPs had disseminated nocardiosis. Although ISPs were infected mainly by Nocardia nova (50%), ICPs were affected by various Nocardia species. ICPs exhibited nonspecific symptoms such as cough (67%), sputum (58%), fever (25%), haemoptysis (25%), and chest pain (8%), which were not different from ISPs on a statistically significant basis. Compared with ISPs, chest CT findings of ICPs showed a higher prevalence of bronchiectasis (67% vs 6%, p 3cm) (8.3% vs 75.0%, p=.01) and cavities (16.7% vs 75.0%, p=.02). Eight ICPs (66%) were successfully treated in an outpatient clinic, while all ISPs needed to be admitted for antibiotic infusion therapies. Conclusion: Pulmonary nocardiosis should be one of the differential diagnoses in ICPs who show symptoms and radiologic findings similar to those of chronic lower respiratory tract infections.