Bronchopneumonia

Bronchopneumonia (Lobular pneumonia) - is one of two types of bacterial pneumonia as classified by gross anatomic distribution of consolidation (solidification). In bacterial pneumonia, invasion of the lung parenchyma by bacteria produces an inflammatory immune response. This response leads to a filling of the alveolar sacs with exudate. The loss of air space and its replacement with fluid is called consolidation. In bronchopneumonia, or lobular pneumonia, there are multiple foci of isolated, acute consolidation, affecting one or more pulmonary lobes.

It should be noted that although these two patterns of pneumonia, lobar and lobular, are the classic anatomic categories of bacterial pneumonia, in clinical practice the types are difficult to apply, as the patterns usually overlap. Bronchopneumonia (lobular) often leads to lobar pneumonia as the infection progresses. The same organism may cause one type of pneumonia in one patient, and another in a different patient. From the clinical standpoint, far more important than distinguishing the anatomical subtype of pneumonia, is identifying its causative agent and accurately assessing the extent of the disease.

Pathology
Macroscopically: Multiple (focus - geometry) foci of consolidation are present in the basal lobes, often bilateral. These lesions are 2-4 cm in diameter, grey-yellow, dry, often centered by a bronchia, are poorly delimited and have the tendency to confluence, especially in children.

Microscopically: A focus of inflammatory condensation is centered by a bronchiola with acute bronchiolitis (suppurative exudate - pus - in the lumen and parietal inflammation). Alveolar lumens surrounding the bronchia are filled with neutrophils ("leukocytic alveolitis"). Massive congestion is present. Inflammatory foci are separated by normal, aerated parenchyma. Photos at: 1