Community-acquired pneumonia as the initial manifestation of serious underlying diseases.

Purpose: Community-acquired pneumonia is common among patients with coexisting illnesses and it can be the initial manifestation of these comorbid diseases. The objectives of our study were to evaluate the frequency of this association and to analyze whether certain characteristics could predict the presence of unknown comorbid conditions.

Subjects And Methods: Over a 5-year period, we prospectively studied 660 consecutive patients with community-acquired pneumonia seen at our institution.