Last reviewed: 19 Sep 2021
Last updated: 27 Jul 2021

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • known acquaintance with Legionella
  • fever
  • headache
  • crackles/rhonchi

Other diagnostic factors

  • productive cough
  • dyspnoea
  • nausea/vomiting
  • abdominal pain
  • hypoxia
  • tachycardia

Risk factors

  • non-municipal water supply
  • recent residential plumbing repair
  • smoking
  • cytotoxic chemotherapy
  • corticosteroids
  • electric water heater
  • working >40 hours per week
  • recent travel
  • diabetes mellitus
  • professional driver
  • use of whirlpool spas
  • living close to a cooling tower
  • filling nebuliser, humidifiers, ventilator tubing, or lavage equipment with tap water
  • close proximity to a decorative fountain
  • consumption of Legionella pneumophila-contaminated ice
  • delivery by water birth
  • exposure to contaminated compost
  • exposure to rainwater

Diagnostic investigations

1st investigations to order

  • FBC
  • complete metabolic profile
  • chest x-ray
  • urine antigen detection of Legionella pneumophila serogroup 1
  • sputum Gram stain
  • cultures

Investigations to consider

  • Legionella pneumophila serology
  • direct fluorescent antibody (DFA) assay
  • Legionella pneumophila polymerase chain reaction (PCR)

Treatment algorithm

Contributors

Authors

Forest W. Arnold, DO, MSc, FIDSA
Forest W. Arnold

Associate Professor of Medicine

Division of Infectious Diseases

Department of Medicine

School of Medicine

University of Louisville

Louisville

KY

Disclosures

FWA declares that he has no competing interests.

Acknowledgements

Dr Forest W. Arnold would like to gratefully acknowledge Dr Allen Griffin, a previous contributor to this topic. AG declares that he has no competing interests.

Peer reviewers

Victor L. Yu, MD

Professor of Medicine

University of Pittsburgh

Pittsburgh

PA

Disclosures

VLY declares that he has no competing interests.

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