Pathology and clinical features of pneumonia

Abstract

Pneumonia is an infectious process resulting from the invasion and overgrowth of pathogenic microorganisms in lung parenchyma, the breakdown of respiratory tract defense mechanisms, and the production of intraalveolar exudates. The development of pneumonia and its severity are influenced by the balance between pathogen factors (eg, virulence and inoculum size) and host factors (eg, loss of protective upper airway reflexes).