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Bronchopneumonia

For medical students2 min readUpdated 2026-10-10

Bronchopneumonia (Bronchopneumonia), or focal pneumonia, is secondary inflammation of the pulmonary parenchyma developing around small bronchi or bronchioles due to impaired bronchial drainage function.

Lesion localizationPredominantly in the posterior and posterior-inferior segments of the lungs

Primary conditionImpaired bronchial drainage function

Common etiologyPneumococcal infection with fibrinous exudate

Prognosis in Pseudomonas infectionEstimated mortality is around 50%

Morphogenesis and Pathways of Development

The key condition for the development of an inflammatory process in the respiratory divisions is impaired bronchial drainage, which is facilitated by factors such as hypothermia, intoxication, or anesthesia. Infection penetrates into the alveolar ducts and alveoli from primarily affected bronchi.

The main pathways for the spread of inflammation to the lung tissue include:

Intrabronchial (descending) — the most common variant of the process spreading.
Peribronchial — observed in destructive bronchitis and bronchiolitis.
Hematogenous — occurs in generalized infection and septicopyemia.
Aspiration, hypostatic, and postoperative — special categories associated with the activation of autoinfection (such as primary parenchymal damage from gastric acid).

Macro- and Microscopic Appearance

Macroscopically, foci of bronchopneumonia are dense, airless, vary in size, and are located around the bronchi. According to the size of the foci, miliary, acinar, lobular, confluent lobular, segmental, and polysegmental forms are distinguished.

The microscopic structure of a focus includes:

Center of inflammation — forms around a small bronchus or bronchiole, showing signs of catarrhal bronchitis or bronchiolitis (serous, mucous, purulent, or mixed types).
Exudate — fills the lumens of alveoli and bronchioles; it can be serous, purulent, or hemorrhagic.
Periphery — represented by unchanged lung tissue with signs of perifocal emphysema.

Etiological Forms and Features

Clinical and morphological features of the process depend on the pathogen:

Pneumococcal — the most frequent form, characterized by foci with fibrinous exudate and marked microbial edema at the periphery.
Staphylococcal — proceeds with destructive bronchitis, a tendency to necrosis, suppuration, and abscess formation.
Streptococcal — predominantly affects the lower lobes of the lungs, distinguished by a prominent interstitial component.
Pseudomonas aeruginosa and Escherichia coli — frequent nosocomial infections prone to hematogenous dissemination, coagulative necrosis, and abscess formation.
Fungal (Candida species) — accompanied by an accumulation of polymorphonuclear leukocytes, eosinophils, and the formation of breakdown cavities.

Complications and Outcomes

Complications of bronchopneumonia are divided into pulmonary and extrapulmonary. If a focus is located subpleurally, pleuritis may develop. One of the most severe and dangerous complications is acute respiratory distress syndrome (ARDS), which has a high mortality rate. In favorable cases, the disease ends in recovery. A fatal outcome may result from the pneumonia itself, purulent complications, or cardiopulmonary failure.

Mnemonic

Drainage impaired, bronchus inflamed, microbe down the alveolus framed!

Frequently asked questions

What pulmonary complications can develop in bronchopneumonia?

Pulmonary complications of bronchopneumonia depend on the etiology and severity of the disease course.

Pleuritis — develops when the inflammatory focus has a subpleural location and may be purulent.
Lung abscess — formation of acute or chronic purulent cavities (especially in staphylococcal, streptococcal, and Pseudomonas infections).
Acute respiratory distress syndrome — a severe complication characterized by high mortality.
Bronchiectasis — arises against the background of marked destruction of lung tissue.
Carnification — organization of exudate with replacement of the pulmonary parenchyma by connective tissue.
Pneumatocele and cysts — specific to staphylococcal pneumonia.
Fibrosis — marked interstitial fibrosis as an outcome of the disease.

What extrapulmonary complications are typical for bronchopneumonia?

Extrapulmonary complications of bronchopneumonia are similar to those of lobar pneumonia and are associated with the generalization of infection via lymphatic and circulatory pathways.

Purulent mediastinitis — occurs with lymphogenous spread.
Pericarditis — a consequence of lymphogenous generalization.
Metastatic brain abscesses — develop with hematogenous seeding.
Purulent meningitis — a severe hematogenous complication.
Acute ulcerative and polypoid-ulcerative endocarditis — often proceeds with tricuspid valve involvement.
Purulent arthritis — the result of hematogenous spread of infection.
Peritonitis — occurs with hematogenous generalization.

How does the macroscopic appearance of bronchopneumonia differ from lobar pneumonia?

The main macroscopic difference lies in the extent of lung tissue involvement and the pattern of the inflammatory process.

Feature	Bronchopneumonia	Lobar Pneumonia
Extent of involvement	Focal character (from miliary to polysegmental foci)	Infiltration of an entire lung lobe (lobar pneumonia)
Localization	Foci form around bronchi, more often in posterior and posterior-inferior segments	Encompasses one or more lobes with mandatory pleural involvement
Characteristics	Dense, airless foci of various sizes	Fibrinous inflammation of a lobe

What is the main condition necessary for the development of bronchopneumonia?

The main condition for development is impaired bronchial drainage function, which leads to the penetration of microorganisms into the respiratory zones.

What are the main pathways for the spread of inflammation to the lung tissue?

They include the intrabronchial (descending) pathway—the most common, peribronchial (in destructive bronchitis), and the hematogenous pathway in septicopyemia.

In which parts of the lungs are foci of bronchopneumonia most commonly localized?

Foci form around the bronchi, predominantly in the posterior and posterior-inferior segments of the lungs.

What causes can lead to a fatal outcome in bronchopneumonia?

Death may be due to the pneumonia itself, the development of purulent complications, or cardiopulmonary failure.

Go deeper

Friedländer's lobar pneumonia and its differences from classic lobar pneumonia
Pathogenesis of aspiration and hypostatic pneumonias
Morphological features of staphylococcal destructive processes in the lungs
The role of mucociliary clearance in the development of nosocomial pneumonias
Comparative characteristics of exudate across various pathogens