Pneumonia is defined as a lower respiratory tract infection involving alveolar consolidation, distinguished clinically and radiographically from tracheobronchial infection by evidence of infection plus consolidation. Pneumonias are classified by the setting and host state in which they arise (community-acquired, hospital-acquired, and immunocompromised-host pneumonia), a distinction that matters because each category is associated with different causative organisms and therefore different antibiotic regimens. This classification framework sits within respiratory medicine's broader approach to infectious disease, linking anatomical site of infection, severity stratification, and microbiological likelihood to guide empirical treatment.
Pneumonia is defined as a lower respiratory tract infection involving alveolar consolidation, distinguished clinically and radiographically from tracheobronchial infection by evidence of infection pl…