Pulmonary infections are common and are caused by a wide range of organisms.
Pathology
Micro-organisms responsible may enter the lung by three potential routes:
- via the tracheobronchial tree
- most commonly due to inhalation of droplets of secretions from another infected human
- environmental exposure e.g. fungal spores
- via the pulmonary vasculature
- direct injection e.g. intravenous drug use
- secondary seeding from distant infection e.g. infective bacterial endocarditis
- via direct spread from infection in the mediastinum, chest wall, or upper abdomen
Pulmonary infections may also be divided according to macroscopic appearances into:
-
consolidation
- lobar pneumonia
- lobular pneumonia (or bronchopneumonia)
- pulmonary abscess
- interstitial pneumonia
Alternatively, the causative agent may be used to categorize infections. Having said that, in many cases a particular agent may cause a number of radiographic and pathological appearances depending on the stage of the infection and on the immune status of the host.
Please refer to the following articles for discussion of specific entities: