Lung - nontumor
Infections
Legionella pneumophila / Legionnaires disease

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 24 February 2017, last major update September 2011

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: Legionella pneumophila [title] OR Legionnaires disease [title] pulmonary

Cite this page: Legionella pneumophila / Legionnaires disease. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungnontumorlegion.html. Accessed April 27th, 2017.
Clinical Features
  • Initial public attention after epidemic in Philadelphia, Pennsylvania (US) convention of American Legion
  • Caused by Legionella species, a short, Gram negative bacillus (Wikipedia)
  • Retrospective review disclosed sporadic cases since early 1900s
  • Pontiac fever is caused by same bacteria, but without pneumonia, and often subclinical
  • Hilar lymph nodes infected in 50% of cases at autopsy; 25% have spread to other organs
  • Causes: contaminated water in water cooling tanks, drinking water conduits, air conditioning systems and other contained indoor water storage systems
  • Immunosuppressed patients, especially organ transplant recipients, are especially vulnerable to severe disease
  • Interaction with macrophages and dendritic cell subtypes appears to be important for resolution (Front Microbiol 2011;2:126)
Treatment
  • Erythromycin or other antibiotics, but high mortality in immunocompromised
Micro Description
  • Extensive bronchopneumonia to lobar pneumonia with intra-alveolar neutrophils, macrophages, fibrin; often with leukocytoclastic neutrophilic infiltrate, small vessel vasculitis and necrosis
Micro Images

Images hosted on other servers:

Gram stain

Silver stain

Immunofluorescence staining

Cytology Images

Images hosted on other servers:

Impression smear from lung

Positive Stains
  • Dieterle silver stain, monoclonal fluorescent reagent
Electron Microscopy Images

Images hosted on other servers:

Legionella pneumophila