title: Chest radiographic characteristics of community-acquired Legionella pneumonia in the elderly.
abstract: BACKGROUND
  Legionella 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.
  
  
  METHODS
  Serial 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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  The discrepancy between imaging findings and clinical symptoms seems more prominent in community-acquired Legionella pneumonia in the elderly.
authors.affiliation: Department of Geriatric Medicine, Peking University First Hospital, Beijing 100034, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Geriatric Medicine, Peking University First Hospital, Beijing 100034, China. Email: lxm2128@163.com.
authors.forename: Xinmin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing 100034, China.
authors.forename: Luzeng
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing 100034, China.
authors.forename: Jianxing
authors.initials: J
authors.lastname: Qiu
mesh_terms: D000293:Adolescent; D000328:Adult; D017714:Community-Acquired Infections / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007875:Legionella / Q000472:pathogenicity*; D007877:Legionnaires' Disease / Q000000981:diagnostic imaging*; D008168:Lung / Q000000981:diagnostic imaging / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000000981:diagnostic imaging*; D011859:Radiography; D012189:Retrospective Studies; D055815:Young Adult