Bronchopneumonia is characterized by  patchy exudative consolidation of lung parenchyma due to terminal bronchiolitis with consolidation of peribronchial alveoli.

It is a common community acquired pneumonia.

Causative organisms:    Visit: Pulmonary Pathology Online

1)  Staphylococci ;  2) Streptococci  ;  3) Pneumococci ; 

4) Haemophilus influenzaea  ;   5)  Pseudomonas aeruginosa ; 

6) Coliform bacteria .

Visit:Lobar Pneumonia ; Pulmonary Infection ; Pneumocystis Pneumonia

Clinical:

Patients present with fever, cough and purulent sputum.

Etiology:

- Bronchopneumonia is common in hospitalized patients.

- Bronchopneumonia may occur as a complication of some disease.

Eg. In children - Diphtheria , Measles , Whooping Cough .

      In adults -  Influenza,  typhoid  & paratyphoid fever etc.

- It is often seen in two extremes of life (in infants & old age).

- Most bronchopneumonia cases are caused by organisms aspirated from the mouth.

Predisposing factors:

Some patients are unable to clear their lungs due to medication, old age, physical weakness and pulmonary fibrosis.

Patients who are immobile develop retention of secretions; thus, most commonly involves the lower lobes.

Cilia not functioning- hereditary dyskinesis,  squamous metaplasia, cigarette smoking, gas exposure.

Alcohol ,tobacco and oxygen therapy interfering with the ability of the alveolar macrophages to kill bacteria.

Bacteria grow within secretions collected in the chest.   Eg. in chronic bronchitis, cystic fibrosis or an obstructing malignant tumour.

Pulmonary edema fluid is a good culture media.

Pathogenesis:

There is initial terminal bronchiolitis with patchy consolidation of peribronchial lung tissue.

Bronchioles are plugged by the swollen mucosa and their secretion. As a result  air cannot enter the alveoli.

The imprisoned air in the alveoli is absorbed causing collapse of the alveoli.

Collapsed areas are surrounded by areas of compensatory emphysema.

[Consolidated areas are surrounded, from inside outwards, by areas of congestion, collapse and emphysema ].

Resolution of the exudate usually restores normal lung structure.

Organization may occur and result in fibrous scarring  in some cases.

Aggressive disease may produce abscesses.

Gross:  Image1 ; Image2 ; Image3 ;  

1. Bilateral (less often unilateral), gray-red, patchy consolidation with intervening normal lung tissue.

2. Nodular, elevated, edematous to hemorrhagic-purulent areas.

3. Lesion is more extensive at the base of the lung and often fuses together resembling lobar pneumonia (confluent bronchopneumonia).

Microscopic feature: Image1 ; Image2 ; Image3 ; Image4 ;

1. Bronchial wall is infiltrated with polymorphs, blood vessels are congested and bronchial lumen contains pus and desquamated epithelium. (Bronchocentric lesion)

2. Peribronchial lung alveoli are consolidated with purulent exudates (polymorphs & fibrin).

3. Escherichia coli pneumonias are mostly interstitial.

4. Parenchymal destruction depends on the organism .

Image5 ; Image6 ;   Image7 ;   Image8 ; Image9.

Complications:

1. Pulmonary fibrosis.

2. Bronchiectasis

3. Lung abscess

4. Empyema

5. Bacteraemia with abscess in other organs