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Phasic characteristics of inspiratory crackles of bacterial and atypical pneumonia
  1. Y Norisue1,
  2. Y Tokuda2,
  3. M Koizumi3,
  4. T Kishaba3,
  5. S Miyagi4
  1. 1
    Department of Medicine, University of Hawaii John A Burns School of Medicine, Honolulu, Hawaii, USA
  2. 2
    St Luke’s Life Science Institute, Tokyo, Japan
  3. 3
    Department of Medicine, Okinawa Chubu Hospital, Okinawa, Japan
  4. 4
    Muribushi Residency Program Center, Okinawa, Japan
  1. Dr Y Norisue, Department of Medicine, 1356 Lusitana Street, 7th Floor, Honolulu, HI 96813, USA; norisue_yasuhiro{at}


Background: No known physical findings are available to differentiate between bacterial pneumonia (BP) and atypical pneumonia (AP) in patients with community-acquired pneumonia (CAP).

Objective: To evaluate the possible differences in phasic characteristics of inspiratory crackles between BP and AP in patients with CAP.

Methods: Retrospective chart reviews were conducted to obtain phasic characteristics of inspiratory crackles (early, early-to-mid, late and pan-inspiratory crackles) in AP and BP groups in a community teaching hospital in Japan (n = 183).

Results: 100 patients with BP and 83 patients with AP were evaluated. Patients with BP were significantly more likely to present with pan-inspiratory crackles (49 (49.0) vs 5 (6.0); p<0.0001), whereas patients with AP were more likely to present with late inspiratory crackles (28 (33.7) vs 9 (9.0); p<0.0001) (mean (SD)). Among pneumonia patients with audible crackles, the sensitivity and specificity of pan-inspiratory crackles for BP were 83.1% and 85.7%, respectively, and the sensitivity and specificity of late inspiratory crackles for AP were 80.0% and 84.7%, respectively.

Discussion: In patients with CAP and audible crackles, phasic characteristics of inspiratory crackles may be used to distinguish AP from BP. Prospective studies are needed to confirm these findings.

  • pneumonia
  • auscultation
  • crackles
  • sensitivity
  • specificity

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  • See Editorial, p 393

  • Funding: None.

  • Competing interests: None.

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