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Lungs Inflammatory - Pathology (view source)
Revision as of 10:20, 29 September 2010
, 10:20, 29 September 2010no edit summary
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For an overview of respiratory infections see [[Respiratory System Inflammation - Pathology|Respiratory system - inflammation]]
==Pneumonia - Introduction and Classification==
==Pneumonia - Introduction and Classification==
[[Image:Acute fibrinous pneumonia.jpg|right|thumb|100px|<small><center>Acute fibrinous pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Acute fibrinous pneumonia.jpg|right|thumb|150px|<small><center>Acute fibrinous pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Pneumonia
*Pneumonia
**Inflammation that takes place in the '''alveoli and their walls'''
**Inflammation that takes place in the '''alveoli and their walls'''
=='''Bronchopneumonia'''==
=='''Bronchopneumonia'''==
[[Image:Chronic bronchopneumonia.jpg|right|thumb|100px|<small><center>Chronic bronchopneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[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
*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'''
*Acute inflammatory exudate initially fills '''alveolar spaces''' radiating from the bronchioles causing areas of solidification of lung tissue termed '''consolidation'''
=='''Bronchointerstitial pneumonia'''==
=='''Bronchointerstitial pneumonia'''==
*May be considred as a variation of bronchopneumonia
*May be considred as a variation of bronchopneumonia
*A hybrid of bronchopneumonia and interstitial pneumonia in which the interstitial inflammation (inflammation of alveolar walls) is restricted to alveoli in the vicinity of terminal bronchioles from which the infections spread
*A hybrid of bronchopneumonia and interstitial pneumonia in which the interstitial inflammation (inflammation of alveolar walls) is restricted to alveoli in the vicinity of terminal bronchioles from which the infections spread
=='''Lobar pneumonia'''==
=='''Lobar pneumonia'''==
*May be considred as a variation of bronchopneumonia and can be described as an aggressive fulminating bronchopneumonia
*May be considred as a variation of bronchopneumonia and can be described as an aggressive fulminating bronchopneumonia
*Entire lung lobes or major parts of lung lobes are uniformly consolidated
*Entire lung lobes or major parts of lung lobes are uniformly consolidated
=='''Interstitial pneumonia'''==
=='''Interstitial pneumonia'''==
[[Image:Interstitial pneumonia micro.jpg|right|thumb|100px|<small><center>Interstitial pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Interstitial pneumonia micro.jpg|right|thumb|150px|<small><center>Interstitial pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Lung inflammation that occurs primarily in '''alveolar walls''' rather than in alveolar spaces
*Lung inflammation that occurs primarily in '''alveolar walls''' rather than in alveolar spaces
*Can be widely distributed but is often most severe in '''caudal lung lobes'''
*Can be widely distributed but is often most severe in '''caudal lung lobes'''
*Diffuse or patchy damage to alveolar septa, may be acute or chronic
*Diffuse or patchy damage to alveolar septa, may be acute or chronic
Examples:
Examples:
====Acute bovine pulmonary emphysema and oedema (ABPEE)====
====Acute bovine pulmonary emphysema and oedema (ABPEE)====
[[Image:Fog fever 1.jpg|right|thumb|100px|<small><center>Fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Fog fever 1.jpg|right|thumb|150px|<small><center>Fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Fog fever 2.jpg|right|thumb|100px|<small><center>Fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Fog fever 2.jpg|right|thumb|150px|<small><center>Fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Tracheal haemorrhage in fog fever.jpg|right|thumb|100px|<small><center>Tracheal haemorrhages in fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Tracheal haemorrhage in fog fever.jpg|right|thumb|150px|<small><center>Tracheal haemorrhages in fog fever (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Synonym: '''fog fever'''
*Synonym: '''fog fever'''
*Ingestion of sweet potatoes ifested with ''Fusarium solani'' mould or pasture contaminated with stinkweed or purple mint, rapeseed and kale also cause pulmonary oedema, emphysema and interstitial pneumonia
*Ingestion of sweet potatoes ifested with ''Fusarium solani'' mould or pasture contaminated with stinkweed or purple mint, rapeseed and kale also cause pulmonary oedema, emphysema and interstitial pneumonia
[[Image:Paraquat poisoning.jpg|right|thumb|100px|<small><center>Paraquat poisoning (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Paraquat poisoning.jpg|right|thumb|150px|<small><center>Paraquat poisoning (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
====Paraquat poisoning====
====Paraquat poisoning====
*In dogs and cats
*In dogs and cats
*Free radical release causes damage to air-blood barrier
*Free radical release causes damage to air-blood barrier
====Diffuse alveolitis====
====Diffuse alveolitis====
[[Image:Diffuse fibrosing alveolitis.jpg|right|thumb|100px|<small><center>Diffuse fibrosing alveolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Diffuse fibrosing alveolitis.jpg|right|thumb|150px|<small><center>Diffuse fibrosing alveolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Chronic disease of adult cattle occuring sporadically
*Chronic disease of adult cattle occuring sporadically
*Probably caused by repeated subclinical incidents of fog fever or farmer's lung
*Probably caused by repeated subclinical incidents of fog fever or farmer's lung
**Hypersensitivity of ingested or inhaled moulds
**Hypersensitivity of ingested or inhaled moulds
**May occur as an outbreak or sporadically in adult cattle
**May occur as an outbreak or sporadically in adult cattle
*'''Hypersensitivity diseases''' often cause an lymphocytic interstitial pneumonia
*'''Hypersensitivity diseases''' often cause an lymphocytic interstitial pneumonia
*Chronic interstitial pneumonia progresses to fibrosis
*Chronic interstitial pneumonia progresses to fibrosis
**Sometimes called '''pneumonitis'''
**Sometimes called '''pneumonitis'''
=='''Embolic pneumonia'''==
=='''Embolic pneumonia'''==
*Lung inflammation caused by '''haematogenous spread '''of infections into the lung
*Lung inflammation caused by '''haematogenous spread '''of infections into the lung
*No orientation around airways and can be in '''any''' lung region but most often affects '''caudal lobes'''
*No orientation around airways and can be in '''any''' lung region but most often affects '''caudal lobes'''
*The inflammation is oriented '''around blood vessels''', usually venules or alveolar capillaries in which septic emboli localise
*The inflammation is oriented '''around blood vessels''', usually venules or alveolar capillaries in which septic emboli localise
=='''Granulomatous pneumonia'''==
=='''Granulomatous pneumonia'''==
[[Image:Granulomatous mycotic pneumonia.jpg|right|thumb|100px|<small><center>Granulomatous mycotic pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Granulomatous mycotic pneumonia.jpg|right|thumb|150px|<small><center>Granulomatous mycotic pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Variable number and distribution of caseous or non-caseous granulomas throughout the lung
*Variable number and distribution of caseous or non-caseous granulomas throughout the lung
*Must be distinguished from neoplasms
*Must be distinguished from neoplasms
*Caused by agents resistant to phagocytosis, mostly [[Respiratory Fungal Infections - Pathology#Blastomycosis|fungi]], [[Respiratory Bacterial Infections - Pathology#Tuberculosis|''Mycobacterium bovis'']], [[Respiratory Bacterial Infections - Pathology#Rhodococcus equi|''Rhodococcus equi'']], foreign material, [[Feline Infectious Peritonitis|FIP]]
*Caused by agents resistant to phagocytosis, mostly [[Respiratory Fungal Infections - Pathology#Blastomycosis|fungi]], [[Respiratory Bacterial Infections - Pathology#Tuberculosis|''Mycobacterium bovis'']], [[Respiratory Bacterial Infections - Pathology#Rhodococcus equi|''Rhodococcus equi'']], foreign material, [[Feline Infectious Peritonitis|FIP]]
*Micro: centre of necrotic tissue surrounded by macrophages, connective tissue and lymphocytes
*Micro: centre of necrotic tissue surrounded by macrophages, connective tissue and lymphocytes
=='''Verminous pneumonia'''==
=='''Verminous pneumonia'''==
[[Image:Parasitic pneumonia.jpg|right|thumb|100px|<small><center>Parasitic pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Parasitic pneumonia.jpg|right|thumb|150px|<small><center>Parasitic pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Lesions in the lung may be due to:
*Lesions in the lung may be due to:
**Parasites passing through the lung as part of their migration e.g. [[Respiratory Parasitic Infections - Pathology#Ascaris suum|''Ascaris suum'']] in the pig, aberrant migration in the case of flukes;
**Parasites passing through the lung as part of their migration e.g. [[Respiratory Parasitic Infections - Pathology#Ascaris suum|''Ascaris suum'']] in the pig, aberrant migration in the case of flukes;
*May be infiltrate of eosinophils in pulmonary interstitium and bronchoalveolar spaces
*May be infiltrate of eosinophils in pulmonary interstitium and bronchoalveolar spaces
*[[Lungs Ventilation - Pathology#Atelectasis (Collapse)|Atelectasis]] and [[Lungs Ventilation - Pathology#Emphysema|emphysema]] may result due to obstruction
*[[Lungs Ventilation - Pathology#Atelectasis (Collapse)|Atelectasis]] and [[Lungs Ventilation - Pathology#Emphysema|emphysema]] may result due to obstruction
=Stages of pneumonia=
=Stages of pneumonia=
[[Image:Acute exudative pneumonia.jpg|right|thumb|100px|<small><center>Acute exudative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Acute exudative pneumonia.jpg|right|thumb|150px|<small><center>Acute exudative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Acute exudative pneumonia - gross.jpg|right|thumb|100px|<small><center>Acute exudative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Acute exudative pneumonia - gross.jpg|right|thumb|150px|<small><center>Acute exudative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Regardless of the pattern, all pneumonias pass through three stages:
*Regardless of the pattern, all pneumonias pass through three stages:
**'''Exudative phase'''
**'''Exudative phase'''
**'''Repair phase'''
**'''Repair phase'''
***Resolution of pneumonia is accomplished by transformation of type II cells to type I cells
***Resolution of pneumonia is accomplished by transformation of type II cells to type I cells
=Pulmonary abscesses=
=Pulmonary abscesses=
[[Image:Multiple pulmonary abscesses.jpg|right|thumb|100px|<small><center>Multiple pulmonary abscesses (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Multiple pulmonary abscesses.jpg|right|thumb|150px|<small><center>Multiple pulmonary abscesses (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Commonly found post mortem
*Commonly found post mortem
*Can be a consequence of:
*Can be a consequence of:
# '''Aspiration''' of foreign material (see [[Lungs Inflammatory - Pathology#Aspiration pneumonia|aspiration pneumonia]])
# '''Aspiration''' of foreign material (see [[Lungs Inflammatory - Pathology#Aspiration pneumonia|aspiration pneumonia]])
# Direct '''penetration'''
# Direct '''penetration'''
*The pattern of abscessation can suggest the aetiology i.e. multiple widespread abscesses suggest a haematogenous origin; isolated cranioventral abscesses usually arise from suppurative pneumonia.
*The pattern of abscessation can suggest the aetiology i.e. multiple widespread abscesses suggest a haematogenous origin; isolated cranioventral abscesses usually arise from suppurative pneumonia.
='''Infectious causes of pneumonia'''=
='''Infectious causes of pneumonia'''=
{| cellpadding="5" cellspacing="0" border="1"
{| cellpadding="5" cellspacing="0" border="1"
| .
| .
='''Other forms of pneumonia'''=
='''Other forms of pneumonia'''=
===Aspiration pneumonia===
===Aspiration pneumonia===
[[Image:Acute necrotising pneumonia.jpg|right|thumb|100px|<small><center>Acute necrotising pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Acute necrotising pneumonia.jpg|right|thumb|150px|<small><center>Acute necrotising pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Inhalation pneumonia.jpg|right|thumb|100px|<small><center>Aspiration pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Inhalation pneumonia.jpg|right|thumb|150px|<small><center>Aspiration pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Response of the lungs to aspirated foreign material will depend on the nature of the material (e.g. food), the bacterial load and the distribution of the material within the lungs
*Response of the lungs to aspirated foreign material will depend on the nature of the material (e.g. food), the bacterial load and the distribution of the material within the lungs
*Mild bronchopneumonia can develop into a severe necrotising pneumonia and in very severe cases can progress to gangrenous pneumonia (below)
*Mild bronchopneumonia can develop into a severe necrotising pneumonia and in very severe cases can progress to gangrenous pneumonia (below)
===Gangrenous pneumonia===
===Gangrenous pneumonia===
[[Image:Gangrenous pneumonia.jpg|right|thumb|100px|<small><center>Gangrenous pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Gangrenous pneumonia.jpg|right|thumb|150px|<small><center>Gangrenous pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Can occur following severe infections in which tissue becomes necrotic and is then invaded by putrefactive saprophytes, however this is rare.
*Can occur following severe infections in which tissue becomes necrotic and is then invaded by putrefactive saprophytes, however this is rare.
*The usual cause is administration of medicines (intended for the oesophagus!) or as a sequel to aspiration pneumonia
*The usual cause is administration of medicines (intended for the oesophagus!) or as a sequel to aspiration pneumonia
*The dead tissue undergoes liquefactive necrosis forming a cavity which is surrounded by intense hyperaemia and inflammation
*The dead tissue undergoes liquefactive necrosis forming a cavity which is surrounded by intense hyperaemia and inflammation
===Lipid pneumonia===
===Lipid pneumonia===
[[Image:Lipid pneumonia.jpg|right|thumb|100px|<small><center>Lipid pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Lipid pneumonia.jpg|right|thumb|150px|<small><center>Lipid pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Associated with inhalation of oil, paraffin, etc.
*Associated with inhalation of oil, paraffin, etc.
*Reaction dominated by macrophages which fill the alveoli and interstitial thickening (mononuclear cells and fibrosis)
*Reaction dominated by macrophages which fill the alveoli and interstitial thickening (mononuclear cells and fibrosis)
===Uraemic pneumonia===
===Uraemic pneumonia===
*Severe uraemia causes increased permeability of the blood-air barrier and therefore can cause [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]]
*Severe uraemia causes increased permeability of the blood-air barrier and therefore can cause [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]]
*In addition to the oedema, there may also be degeneration and calcification of smooth muscle and connective tissue fibres
*In addition to the oedema, there may also be degeneration and calcification of smooth muscle and connective tissue fibres
*Lungs do not collapse on opening the thorax in severe cases
*Lungs do not collapse on opening the thorax in severe cases
===Fetal pneumonia===
===Foetal pneumonia===
*Especially foals and farm species
*Especially foals and farm species
*Due to aspiration of amniotic fluid contaminated with meconium and bacteria
*Due to aspiration of amniotic fluid contaminated with meconium and bacteria