Community-acquired pneumonia: urinary antigen detection helped diagnose legionellosis.

Clinical bottom line (level 4)

  1. A twentieth of patients with pneumonia had legionella pneumonia.
  2. In patients with pneumonia, a positive urinary antigen detection test helped to diagnose legionella pneumonia.
Ruf et al: Annals of Internal Medicine 1990; 162: 1341-1348
Expires November 2003

The study

Setting: university hospital, Germany

1243 patients (aged ?, ?% male) community-acquired pneumonia or nosocomial pneumonia

Excluded if
  • pulmonary tuberculosis
  • HIV
  • pulmonary infiltrates due to noninfectious causes (eg. pulmonary infarction, congestive heart failure, complications secondary to tumour stenosis)



    • Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
    Reference standard:
    • radiographic demonstration of pulmonary infiltrates and autopsy was accepted for nosocomial cases
    Diagnostic test: serum antibody detection, examination of respiratory secretions, culture and detect fluorescent antibody test- any positive test was defined as a case of legionellosis.

    The evidence


    diagnostic test number of patients sensitivity for
    legionella pneumonia
    (95% CI)    		 LR+ LR-
    urinary antigen detection 32 80.0%
    (67.6% to 92.4%)
    serum antibody detection 17 36.2%
    (22.4% to 49.9%)
    examination of respiratory secretions 7 25.9%
    (9.40% to 42.5%)
    culture of respiratory secretions 3 11.1%
    (-0.74% to 23.0%)
    detect fluorescent antibody tests of respiratory secretions 6 22.2%
    (6.54% to 37.9%)
    total 56

    • 4.5% of pneumonia cases were diagnosed to be legionellosis. This was 5.9% of nosocomial pneumonia and 3.4% of community-acquired pneumonia cases.
    • If further verified this may be useful in real clinical settings .

    Citation

    1. Ruf B, Schurmann D, Horbach I, et al: Prevalence and diagnosis of Legionella pneumonia: A 3-year prospective study with emphasis on application of urinary antigen detection. Annals of Internal Medicine 1990; 162: 1341-1348
    Search Terms: pneumonia and diagnosis in Medline
    Contributor: Clare Wotton and Musab Hayatli, November 1999
    Reviewer: Mitsuhiro Kamei

    Clinical Question.
    Patient pneumonia
    Intervention or Exposure serum antibody detection, examination of respiratory secretions, examination of lung tissue or antigen detection in urine
    Comparison radiography
    Outcome legionella pneumonia