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, 18:03, 19 February 2011
[[Image:Chronic bronchopneumonia.jpg|right|thumb|150px|<small><center>Chronic bronchopneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Originates and extends from terminal bronchioles
*Acute inflammatory exudate initially fills '''alveolar spaces''' radiating from the bronchioles causing areas of solidification of lung tissue termed '''consolidation'''
*In bronchopneumonia this consolidation is oriented around terminal bronchioles
*Most commonly occurs in '''cranioventral lung lobes''' and correlates with '''aerogenous''' portal of entry and gravitation of infectious droplets
*Most common form of pneumonia seen in domestic animals and the most common causes are bacterial and mycoplasma infections or aspiration
*Gross pathology:
**Affected parts are firmer (consolidated) than surrounding non-affected tissue
**Colour varies from red to pink to grey depending upon the stage of infection
**Extent of the lesion varies with the aetiological agent and the lobulation/septation of the species
*Micro pathology:
**Early cases centred upon the bronchiolar alveolar junction with exudation, which extends into neighbouring alveoli
**Exudate contains many [[Neutrophils|neutrophils]], macrophages and oedema
**Alveolar capillaries are hyperaemic
**Some haemorrhages in severe cases - later stages contain more cells than fluid
*Spread of the inflammation within the lung is usually by extension from lobule to lobule along the airways, or by necrosis of alveoli and septa in the case of toxin-producing bacteria
*Sequel to bronchopneumonia:
**Mild catarrhal inflammation resolves in 7 days and the lung is back to normal within 3 weeks
**More severe inflammation becomes chronic with fibrosis or [[Bronchiectasis|bronchiectasis]]
**[[Lungs Inflammatory - Pathology#Pulmonary abscesses|Abscess]] formation with pyogenic bacteria
**'''Pleuritis''' in severe fibrinous pneumonia with adhesions
**Death in fulminating cases due to hypoxaemia and toxaemia
*'''Suppurative bronchopneumonia'''
**Purulent or mucopurulent exudate in airways
**Generally confined to individual nodules, more obvious in species with prominent lobulation
**Sometimes referred to as '''lobular pneumonia'''
**Lung colour changes from red to grey to white with time
**Good exapmle are '''enzootic pneumonias''' of [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|cattle]], [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of lambs|sheep]] and [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of pigs|pigs]]
*'''Fibrinous pneumonia'''
**Predominantly fibrous exudate
**Exudate moves through pulmonary tissue to involve whole lung lobe
**Sometimes referred to as '''lobar pneumonia''' (below)
**Generally more severe than suppurative pneumonias
**Externally - severe congestion and haemorrhage, intense red colour with fibrinous plaques
**May develop into sequestra of necrotic tissue encapsulated by connective tissue
**Microscopically - massive exudation of plasma proteins into bronchioles and alveoli
**Rarely resolves completely, leaves scars - pulmonary fibrosis and [[Pleural Cavity & Membranes Inflammatory - Pathology#Pleuritis|pleural adhesions]]
[[Category:Pneumonia]]