Phasic characteristics of inspiratory crackles of bacterial and atypical pneumonia.

Abstract

No known physical findings are available to differentiate between bacterial pneumonia (BP) and atypical pneumonia (AP) in patients with community-acquired pneumonia (CAP). To evaluate the possible differences in phasic characteristics of inspiratory crackles between BP and AP in patients with CAP. 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). 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. 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.