<i>Legionella </i>Causing Lung Abscess in an Immunocompetent Patient

Abstract

Legionella lung abscess (LLA) is known to develop from pneumonia and Legionnaires’ disease in immunocompromised patients and aspiration. Literature review showed reports of aspiration pneumonia in immunocompetent patients; however, no such was found between LLA and immunocompetency. A 53-year-old male with history of depression and paraumbilical hernia presented for chest pain, which was right sided, started acutely, constant, radiated to the back, and exaggerated with taking deep breaths. The patient denied all other symptoms. Social history was only pertinent for being an active 35 pack-year smoker. The patient was recently admitted one month ago for viral meningitis from Echovirus. On physical exam, the patient was vitally stable, had absent breath sounds in the right middle lobe, and was significantly tender at the right anterior chest. Labs revealed elevated sedimentation rate and C-reactive protein. Imaging demonstrated a right middle lobe lung abscess. Throughout the hospital course, Legionella pneumophila serogroup 1 (LPS1) was found to be positive on urine antigen, sputum polymerase chain reaction, and sputum cultures. The patient was switched to intravenous levofloxacin and ampicillin-sulbactam. Upon symptomatic resolution, the patient was discharged home with recommendations for a follow-up chest computed tomography and diagnostic bronchoscopy. We hypothesize that smoking causes neutrophilic stasis within the lung and the development of the LLA. Treatment includes intravenous long term antibiotics and possibly drainage.