Bronchopneumonia (Lobular pneumonia)
There are two main types of acute bacterial pneumonia : bronchopneumonia (with lobular topography) and lobar pneumonia (lobar topography).
Bronchopneumonia (Lobular pneumonia) is an acute exudative suppurative inflammation of the lungs characterized by foci of consolidation surrounded by normal parenchyma.
Generally, it is produced by bacteria : staphylococcus, streptococcus, Haemophilus influenzae, proteus, Escherichia coli.
Bronchopneumonia affects one or more lobes, being frequently bilateral and basal. Macroscopically, one can identify multiple foci of condensation (1 - 3 cm diameter), white-yellowish, imprecisely circumscribed, centered by bronchiole, separated by normal lung parenchyma. In children, it has a tendency to confluence, resulting in large condensation area (pseudolobar pneumonia) (Figure 1).
Microscopy : foci of inflammatory condensation centered by a bronchiole with acute bronchiolitis (suppurative exudate rich in neutrophils in the lumen, foci of ulceration of the epithelium and parietal inflammation). The alveolar lumens surrounding the bronchia are filled with neutrophils ("leukocytic alveolitis"). Capillaries in the alveolar walls show congestion. Inflammatory foci are separated by normal, aerated parenchyma. (Figures 2, 3 and 4)
Figure 2 : Bronchopneumonia : focus of inflammatory condensation centered by a bronchiole. (H&E, ob. x10)
Figure 3 : Bronchopneumonia : focus of inflammatory condensation centered by a bronchiole. (H&E, ob. x10)
Figure 4 : Bronchopneumonia (detail) : central area of a focus of inflammatory condensation - bronchiola with acute bronchiolitis. (H&E, ob. X20)