This is an extremely common disease that tends to occur in vulnerable two extremes of life -infancy and old age.
Gross appearance:
1. Bilateral (rarely unilateral), gray-red, elevated, focal areas of palpable consolidation and suppuration with intervening normal lung tissue.
2. At the base of the lung, the lesion is more extensive and often fuses together resembling lobar pneumonia (confluent bronchopneumonia).
Microscopic features:
There are acute (neutrophilic) suppurative exudates filling airspaces and airways, usually about bronchi and bronchioles.
There is patchy exudative consolidation of the peribronchial and peribronchiolar lung parenchyma.
Resolution of the exudates usually restores normal lung structure, but organization may occur resulting in fibrous scarring in some cases, or aggressive disease may produce abscesses.
A predominantly interstitial pattern of inflammation is seen in some pediatric infections.
Secondary bronchopneumonia occurs as a complication:
In children- Diphtheria, measles, whooping cough.
In adults - Influenza, typhoid and paratyphoid fevers