85 - Pathology of Lung Infection Flashcards
Most important determinant of whether a lung infection becomes clinical or not
Intact immune system
What causes classical pattern of pneumonia?
Traditional bacteria
- Aerobic bacteria, known to medicine for a long time (as can be cultured easily)
S pneumoniae, H influenzae, Klebsiella pneumoniae, P aerusinosa, Legionella pneumophila
Strict definition of pneumonia
Inflammation of the lung
Two patterns of acute bacterial pneumonia
Acute bronchopneumonia
Acute lobar pneumonia
Most common form of acute inflammation of the lung
Acute bronchopneumonia
Prototypical atypical bacteria causing pneumonia
Mycoplasma
Patients with a much higher risk of G- bacterial pneumonia
Those who acquire it in a hospital
When was acute lobar pneumonia more common?
Pre-antibiotic era
Five principle defence mechanisms of the lung
Cough reflex Mucociliary function Secretion clearance Alveolar macrophage phagocytic action Clearance of fluid from pulmonary circulation
Five principle ways in which lung defences can be subverted
Loss of cough reflex
Impairment of mucociliary function
Accumulation of secretions (EG: CF)
Interference with alveolar macrophage function
Pulmonary oedema/congestive heart failure
How does bronchopneumonia present grossly?
Discrete patches of inflammation (spots), not necessarily limited by lobes.
Often bilateral.
Where does bronchopneumonia begin?
In terminal bronchioles, hence multifocal distribution.
How does lobar pneumonia begin?
Inflammatory oedema spreads throughout a lobe.
Indicative of a highly-pathogenic organism.
Difference in virulence of organisms that cause bronchopneumonia and lobar pneumonia
Bronchopneumonia often caused by less-pathogenic pathogens.
Most-common cause of lobar pneumonia
S pneumoniae
Second-most-common cause of lobar pneumonia
H influenzae
