Clinical spectrum and outcome of pulmonary nocardiosis: 5-year experience

Background: Pulmonary nocardiosis is a rare but a life-threatening infection caused by Nocardia spp. The diagnosis is often missed and delayed resulting in delay in appropriate treatment and thus higher mortality. Aim: In this study, we aim to evaluate the clinical spectrum and outcome of patients with pulmonary nocardiosis. Methods: A retrospective, 5-year (2009-2014) review of demographic profile, risk factors, clinical manifestations, imaging findings, treatment, and outcome of patients with pulmonary nocardiosis admitted to a tertiary care hospital. Results: The median age of the study subjects was 54 years (range, 16-76) and majority of them (75%) were males. The risk factors for pulmonary nocardiosis identified in our study were long-term steroid use (55.6%), chronic lung disease (52.8%), diabetes (27.8%), and solid-organ transplantation (22.2%). All the patients were symptomatic, and the most common symptoms were cough (91.7%), fever (78%), and expectoration (72%). Almost two-third of the patients were initially misdiagnosed and the alternative diagnosis included pulmonary tuberculosis ( n = 7), community-acquired pneumonia ( n = 5), lung abscess ( n = 4), invasive fungal infection ( n = 3), lung cancer ( n = 2), and Wegener's granulomatosis ( n = 2). The most common radiographic features were consolidation (77.8%) and nodules (56%). The mortality rate for indoor patients was 33% despite treatment. Higher mortality rate was observed among those who had brain abscess (100.0%), HIV positivity (100%), need for mechanical ventilation (87.5%), solid-organ transplantation (50%), and elderly (age > 60 years) patients (43%). Conclusion: The diagnosis of pulmonary nocardiosis is often missed and delayed resulting in delay in appropriate treatment and thus high mortality. A lower threshold for diagnosing pulmonary nocardiosis needs to be exercised, in chest symptomatic patients with underlying chronic lung diseases or systemic immunosuppression, for the early diagnosis, and treatment of this uncommon but potentially lethal disease. Despite treatment mortality remains high, especially in those with brain abscess, HIV positivity, need for mechanical ventilation, solid-organ transplantation, and elderly.