BACKGROUNDLegionella is an important community-acquired pneumonia pathogen. Although the elderly are especially susceptible to Legionella, few studies have looked at comparative radiographic features of Legionella pneumonia in this population. The aim of this study was to explore the chest radiographic characteristics of community-acquired Legionella pneumonia in the elderly.

METHODSSerial chest radiographs obtained in 34 patients hospitalized with serologically proven Legionella pneumonia were retrospectively reviewed. Chest X-ray features of an aged group of ≥ 65 years were assessed and compared with a non-aged group of <65 years old with regard to initial patterns and distributions of pulmonary abnormalities, accompanying signs, and progression.

RESULTSThe most common initial presentation was a patchy alveolar infiltrate involving a single lobe, most often the lower lobe. There was no middle or lingular lobe involvement in the aged group patients, but bilateral pleural effusion was significantly more common in this group. In the aged group patients, radiographic progression following adequate therapy, despite a clinical response, was more often noted and the radiographs were less likely to have returned to the premorbid state at discharge, but the differences were not significant between the two groups.

CONCLUSIONThe discrepancy between imaging findings and clinical symptoms seems more prominent in community-acquired Legionella pneumonia in the elderly.