Diffuse alveolar damage (DAD) is the underlying pathological finding in most cases of acute respiratory distress syndrome (ARDS). The objective of this study was to compare clinical criteria for ARDS secondary to community acquired pneumonia with autopsy findings of DAD and to determine the discrepancy rate between the two.

We compared prospectively obtained clinical diagnosis of ARDS secondary to community acquired pneumonia with autopsy findings of DAD and pneumonia. Forty nine patients dead with a clinical diagnosis of ARDS secondary to pneumonia who underwent autopsy between 1986 and 2004 in our ICU were included with systematic histopathological analysis of all lung lobes. The discrepancy rate between the premortem clinical diagnosis of ARDS secondary to pneumonia and DAD at autopsy was determined. Seven patients were found to have neither infection nor DAD at autopsy. Six patients showed pathologic signs of DAD without evidence of infection. Out of 38 patients meeting clinical criteria for ARDS secondary to pneumonia and proven pneumonia at autopsy, 25 met criteria for DAD at autopsy. Therefore, 18 out of 49 patients who were clinically diagnosed with ARDS did not actually show pathological signs of DAD, resulting in a discrepancy rate of 37%. Despite an acceptable correspondence between clinical criteria for ARDS secondary to pneumonia and autopsy findings of DAD a significant number of patients had neither signs of DAD nor infection.