The pathology of nosocomial pneumonia.

Of patients who die in the intensive care unit (ICU), the mortality rate is significantly higher in those who develop nosocomial bacterial pneumonias. Pneumonia is difficult to diagnose clinically in patients with acute lung injury, so the "gold standard" for a pneumonia diagnosis has been its histopathologic presence in autopsy lung specimens. The potential pitfalls in the proper sampling of the lung at autopsy and how the histopathological appearance may be altered in a diffusely injured lung are discussed. Pathologists are encouraged to carefully analyze and evaluate bronchoalveolar lavage (BAL) and protected specimen brush (PSB) specimens obtained from patients before death to help determine if pneumonia is present.