# The Uncommon Suspect: Pseudomonas aeruginosa and Cavitary Lung Lesions in an Immunocompetent Patient

## TL;DR

A rare case of Pseudomonas aeruginosa causing cavitary lung lesions in an otherwise healthy man is presented, emphasizing the need for thorough diagnostic approaches.

## Contribution

This paper reports a rare case of Pseudomonas aeruginosa causing cavitary pneumonia in an immunocompetent patient.

## Key findings

- Pseudomonas aeruginosa can cause cavitary lung lesions in immunocompetent individuals.
- Bronchoscopy with BAL is effective in diagnosing rare cases of Pseudomonas pneumonia.
- Targeted antibiotic therapy improved clinical and radiographic outcomes in this case.

## Abstract

Cavitary lung lesions pose a formidable diagnostic challenge due to their multifaceted etiologies. While tuberculosis and other prevalent pathogens typically dominate discussions, instances of community-acquired Pseudomonas aeruginosa (P. aeruginosa) pneumonia leading to cavitation in immunocompetent individuals remain exceptionally rare. Herein, we present a compelling case of such pneumonia in a 61-year-old man with a past medical history of hypertension and coronary artery disease who presented with cough, chest pain, and subjective fever. Chest imaging revealed cavitary lung lesions, which is atypical for community-acquired pneumonia (CAP). Initial workup excluded common CAP pathogens, following which bronchoscopy with bronchoalveolar lavage (BAL) definitively diagnosed P. aeruginosa, prompting targeted antibiotic therapy. Treatment led to clinical and radiographic improvement. P. aeruginosa rarely causes CAP, especially in immunocompetent patients, and cavitary lesions further complicate diagnosis. This case highlights the importance of considering P. aeruginosa in CAP with unusual features and emphasizes the utility of bronchoscopy with BAL for diagnosis and guiding management.