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Created page with "right|thumb|100px|<small><center>Interstitial emphysema (Image sourced from Bristol Biomed Image Archive with permission)</center></small> [[..."
[[Image:Interstitial emphysema.jpg|right|thumb|100px|<small><center>Interstitial emphysema (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Interstitial emphysema micro.jpg|right|thumb|100px|<small><center>Histology of interstitial emphysema (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Alveolar emphysema.jpg|right|thumb|100px|<small><center>Alveolar emphysema(Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Destructive emphysema - horse.jpg|right|thumb|100px|<small><center>Destructive emphysema - horse(Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Excessive amount of air within the lungs
*In animals it is always secondary to other lesions
*In severe cases, the lungs fail to deflate upon opening the thoracic cavity, there are imprints of the ribs on the pleural surface of the lung
*'''Interstitial emphysema'''
**The presence of air within the connective tissues and lymphatics of the lung
**Mainly interlobular septae - also subpleural and around vessels/ airways
**It implies that there is forced respiration
**Mainly significant in the cow which by the nature of its well developed interlobular septae is susceptible to the lesion
**It is not an uncommon agonal (to a minor degree as a reaction to slaughter in normal animals) event in the cow
**More significantly, it is a prominent feature of [[Lungs Inflammatory - Pathology#Interstitial pneumonia|acute interstitial pneumonia]], chronic pneumonia, [[Bovine Respiratory Syncytial Virus|RSV infection]], [[Lungs Inflammatory - Pathology#Acute bovine pulmonary emphysema and oedema (ABPEE)|Acute Bovine pulmonary Edema and Emphysema]] in cattle
*'''Alveolar emphysema'''
**The term ‘emphysema’ strictly speaking refers to alveolar emphysema and is classified by human pathologists as : "A condition of the lung characterised by abnormal, permanent enlargement of the air spaces …. Accompanied by destruction of their walls and without obvious fibrosis"
**Permanent abnormal enlargement of airspaces distal to the terminal bronchioles with evidence of destruction of the alveolar walls, usually proteolytic digestion of elastin by macrophages
**Forms air bubbles in pulmonary parenchyma
**The mechanism is poorly understood but involves excessive macrophage activity in the alveoli due to [[Bronchitis#Chronic bronchiolitis|chronic bronchiolitis]], partial obstruction of the bronchioles; and the force of inspiration being greater than that of expiration
**Naturally occurring emphysema is, however of little clinical significance in domestic animals with the following exceptions :
***[[Congenital Lobar Emphysema|'''Congenital lobar emphysema in dogs''']] - occurs secondary to aplasia or hypoplasia of bronchial cartilage.
***[[Recurrent Airway Obstruction|'''Chronic obstructive pulmonary disease in the horse (COPD)''']] Note, however, that emphysema is an inconsistent feature of the pathology in this disease.
***In older animals, there may be a degree of alveolar emphysema along the ventral borders of lung lobes, however, it is of little clinical significance
*'''Compensatory'''
**Adjacent to an area of consolidation (inflammation)
**Consolidation tends to reduce the lung volume, the thoracic cavity remains the same volume and some lobules undergo a slight degree of emphysema
**Gross pathology:
***Alveolar - affected part enlarged and paler than normal
***Interstitial - prominent gas-filled interlobular septa
**Micro pathology:
***Alveolar - enlarged airspaces with destruction of intervening capillary walls, the free ends of the broken walls may thickened due to retraction
***Interstitial - septal lymphatics dilated with air; in unresolved chronic pneumonias in cattle, this emphysema may spread to the local lymphatics and even to the subcutaneous tissue along the back of the animal
[[Category:Respiratory System - Degenerative Pathology]]
[[Category:Lungs - Degenerative Pathology]]
[[Image:Interstitial emphysema micro.jpg|right|thumb|100px|<small><center>Histology of interstitial emphysema (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Alveolar emphysema.jpg|right|thumb|100px|<small><center>Alveolar emphysema(Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Destructive emphysema - horse.jpg|right|thumb|100px|<small><center>Destructive emphysema - horse(Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Excessive amount of air within the lungs
*In animals it is always secondary to other lesions
*In severe cases, the lungs fail to deflate upon opening the thoracic cavity, there are imprints of the ribs on the pleural surface of the lung
*'''Interstitial emphysema'''
**The presence of air within the connective tissues and lymphatics of the lung
**Mainly interlobular septae - also subpleural and around vessels/ airways
**It implies that there is forced respiration
**Mainly significant in the cow which by the nature of its well developed interlobular septae is susceptible to the lesion
**It is not an uncommon agonal (to a minor degree as a reaction to slaughter in normal animals) event in the cow
**More significantly, it is a prominent feature of [[Lungs Inflammatory - Pathology#Interstitial pneumonia|acute interstitial pneumonia]], chronic pneumonia, [[Bovine Respiratory Syncytial Virus|RSV infection]], [[Lungs Inflammatory - Pathology#Acute bovine pulmonary emphysema and oedema (ABPEE)|Acute Bovine pulmonary Edema and Emphysema]] in cattle
*'''Alveolar emphysema'''
**The term ‘emphysema’ strictly speaking refers to alveolar emphysema and is classified by human pathologists as : "A condition of the lung characterised by abnormal, permanent enlargement of the air spaces …. Accompanied by destruction of their walls and without obvious fibrosis"
**Permanent abnormal enlargement of airspaces distal to the terminal bronchioles with evidence of destruction of the alveolar walls, usually proteolytic digestion of elastin by macrophages
**Forms air bubbles in pulmonary parenchyma
**The mechanism is poorly understood but involves excessive macrophage activity in the alveoli due to [[Bronchitis#Chronic bronchiolitis|chronic bronchiolitis]], partial obstruction of the bronchioles; and the force of inspiration being greater than that of expiration
**Naturally occurring emphysema is, however of little clinical significance in domestic animals with the following exceptions :
***[[Congenital Lobar Emphysema|'''Congenital lobar emphysema in dogs''']] - occurs secondary to aplasia or hypoplasia of bronchial cartilage.
***[[Recurrent Airway Obstruction|'''Chronic obstructive pulmonary disease in the horse (COPD)''']] Note, however, that emphysema is an inconsistent feature of the pathology in this disease.
***In older animals, there may be a degree of alveolar emphysema along the ventral borders of lung lobes, however, it is of little clinical significance
*'''Compensatory'''
**Adjacent to an area of consolidation (inflammation)
**Consolidation tends to reduce the lung volume, the thoracic cavity remains the same volume and some lobules undergo a slight degree of emphysema
**Gross pathology:
***Alveolar - affected part enlarged and paler than normal
***Interstitial - prominent gas-filled interlobular septa
**Micro pathology:
***Alveolar - enlarged airspaces with destruction of intervening capillary walls, the free ends of the broken walls may thickened due to retraction
***Interstitial - septal lymphatics dilated with air; in unresolved chronic pneumonias in cattle, this emphysema may spread to the local lymphatics and even to the subcutaneous tissue along the back of the animal
[[Category:Respiratory System - Degenerative Pathology]]
[[Category:Lungs - Degenerative Pathology]]