Lobular pneumonia. Etiology, pathogenesis and pathomorphology
In lobular (broncho) pneumonia the foci of inflammatory consolidation is distributed in patches throughout several lobes, frequently bilateral and bases. The symptoms of lobular pneumonia are the same as lobar pneumonia, main etiological causes are:
- S. aureus
- H. influenzae
- P. aeruginosa
- E. Coli
- K. pneumoniae
- Proteus spp
Lobular pneumonia is more common in elderly and young patients, and is more commonly hospital acquired than community acquired.
Remember: lobar pneumonia = one whole lobe, uniform consolidation, fibrinous exudate, usually pneumococcus. Lobular (broncho)pneumonia = patchy foci centred on bronchioles, often bilateral and basal, suppurative exudate, typical in infants, the elderly, bedridden and hospitalised patients.
Pathomorphologically, the lung substance immediately surrounding the areas of consolidation is usually hyperemic and edematous, but other areas of the lung are generally preserved. Pleural involvement is less common than in lobar pneumonia, and the histologic reaction consists of focal suppurative exudate that fills the bronchi, bronchioles and adjacent alveolar spaces, with little fibrin.
Gross: bronchopneumonia. Multiple patchy, slightly raised, pale foci of consolidation centred on bronchioles, with aerated lung between them.
Image: “Bronchopneumonia (3679910356)” by Yale Rosen from USA, CC BY-SA 2.0, via Wikimedia Commons.