Community-acquired pneumonia: sputum counter-current electrophoresis helped to diagnose cause.

Clinical bottom line (level 4)

  1. In patients with suspected pneumococcal pneumonia, sputum counter-current electrophoresis helped diagnosis.
  2. In patients with suspected pneumonia, streptococcus pneumoniae caused a third of infections.
  3. In patients with suspected pneumonia, mycoplasma pneumonia caused a sixth of infections.
Research Committee of the British Thoracic Society and Public Health Laboratory Service: Quarterly Journal of Medicine 1987; 239: 195-220
Expires March 2003

The study

Setting: 25 hospitals, UK

453 patients (aged mean 48 years, 61% male) community-acquired pneumonia, defined as an acute illness with radilogical pulmonary shadowing which was either at least segmental or present in more than one lobe, and which was neither pre-existing nor of other known cause

Excluded if
  • aged <15 or >74 years old
  • pneumonia not the main reason for admission or was an expected terminal event
  • pneumonia was distal to bronchial obstruction due to a foreign body or carcinoma
  • pneumonia due to pulmonary tuberculosis
  • failed to attend further follow-up


    • Almost half of patients were given antibiotics prior to admission.
    Independent unblinded reference standard, applied in all patients from a consecutive inappropriate spectrum.
    Reference standard:
    Diagnostic test: Gram's stain, sputum culture, blood culture, sputum counter-current immunoelectrophoresis, urine counter-current immunoelectrophoresis and serum counter-current electrophoresis

    The evidence


    differential diagnosis number of patients prevalence
    (95% CI)
    streptococcus pneumoniae 154 34.0%
    (29.6% to 38.4%)
    mycoplasma pneumoniae 81 17.9%
    (14.4% to 21.4%)
    influenza A virus 32 7.10%
    (4.70% to 9.40%)
    haemophilus influenzae 26 5.70%
    (3.60% to 7.90%)
    chlamydia psittaci 13 2.90%
    (1.30% to 4.40%)
    other known causes 37 8.17%
    (5.65% to 10.7%)
    unknown microbiology 150 33.1%
    (28.8% to 37.5%)


    diagnostic test number of patients sensitivity for
    pneumococcal pneumonia
    (95% CI)    		 LR+ LR-
    Gram's stain 21 14.8%
    (8.95% to 20.6%)
    sputum culture 35 23.7%
    (16.8% to 30.5%)
    blood culture 37 26.1%
    (18.8% to 33.3%)
    sputum counter-current electrophoresis 102 85.7%
    (79.4% to 92.0%)
    urine counter-current elecetrophoresis 54 44.6%
    (35.8% to 53.5%)
    serum counter-current electrophoresis 12 8.89%
    (4.09% to 13.7%)
    total 142

    Comments

    1. Likelihood ratios were not given.
    2. Further informtion is necessary before recommending this as a diagnostic test

    Citation

    1. Research Committee of the British Thoracic Society , and Public Health Laboratory Service : Community-acquired pneumonia in adults in British hospitals in 1982-1983: A survey of aetiology, mortality, prognostic factors and outcome.. Quarterly Journal of Medicine 1987; 239: 195-220
    Search Terms: community-acquired pneumonia and diagnosis in Medline
    Contributor: Clare Wotton and Musab Hayatli, November 1999
    Reviewer: Mitsuhiro Kamei

    Clinical Question.
    Patient community-acquired pneumonia
    Intervention or Exposure pneumococcal diagnostic tests
    Comparison
    Outcome diagnosis