# Pulmonary Nocardiosis in an Immunocompetent Host: A Diagnostic Challenge Requiring Multimodal Evaluation

## TL;DR

This paper discusses a rare case of lung infection caused by Nocardia in a patient with a healthy immune system, highlighting the need for advanced diagnostic methods.

## Contribution

The novelty lies in presenting a rare case of pulmonary nocardiosis in an immunocompetent individual and emphasizing multimodal diagnostics for timely diagnosis.

## Key findings

- Pulmonary nocardiosis can occur in immunocompetent individuals with chronic lung disease.
- Multimodal diagnostic approaches are crucial for diagnosing non-resolving pneumonia cases.
- Endobronchial ultrasound-guided transbronchial needle aspiration confirmed the Nocardia infection in this case.

## Abstract

Pulmonary nocardiosis is a rare opportunistic infection usually affecting immunocompromised hosts but can present in immunocompetent individuals with chronic lung disease, creating diagnostic challenges. We describe the case of a 72-year-old woman with pulmonary fibrosis who had progressive pneumonia unresponsive to standard therapy. Despite multiple non-diagnostic bronchoscopies, cultures from an endobronchial ultrasound-guided transbronchial needle aspiration of a mediastinal lymph node ultimately confirmed Nocardia species. This case underscores the importance of considering nocardiosis in non-resolving pneumonia among immunocompetent patients and highlights the role of multimodal, invasive diagnostics in establishing a timely diagnosis and guiding targeted therapy.