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Created page with " ===Acute bronchitis/bronchiolitis=== [[Image:bronchiolitis.jpg|right|thumb|100px|<small><center>Bronchiolitis (Image sourced from Bristol Biomed Image Archive with permission)</..."
===Acute bronchitis/bronchiolitis===
[[Image:bronchiolitis.jpg|right|thumb|100px|<small><center>Bronchiolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Inflammation of the bronchi - bronchitis
*Inflammation of the bronchioles - bronchiolitis
*Types... as expected, depending on the severity and type of insult/injury:
**serous
**catarrhal
**purulent
**fibrinous
**necrotizing
**granulomatous
*Acute inflammation passes through the same stages as in [[Rhinitis#Rhinitis|rhinitis]]
*Evolution to chronic inflammation may occur following chronic or repeated infections or irritation by parasitic, allergic agents or inhaled substances.
===Chronic bronchitis===
*The quantity of mucus is increased following mucus gland and goblet cell hyperplasia
*The mucosa is thickened due to:
**mucus gland hyperplasia
**leukocytic infiltrates
**lymphocytes, plasma cells, macrophages, eosinophils
**'''squamous [[Cell Growth Disorders#Metaplasia|metaplasia]]''' of the lining epithelium (ciliated epithelium replaced by more resistent but relatively non-functional squamous epithelium) - affects [[Respiratory System General Introduction - Pathology#Mucociliary escalator|mucociliary clearance]]
*In dogs
**Bronchial irritation and mucus hypersectretion causes chronic intractable cough
**At post-mortem, trachea and lower airways are full of mucoid or mucopurulent exudate
***Underlying bronchial mucos is thickened, hyperaemic and oedematous
***May be a coexisting bronchopneumonia
***Smooth muscle hypertrophy in pulmonary arteries -> [[Lungs Circulatory - Pathology#Pulmonary hypertension|'''pulmonary hypertension''']] -> [[Cor Pulmonale|'''cor pulmonale''']]
===Chronic bronchiolitis===
[[Image:Chronic bronchiolitis.jpg|right|thumb|100px|<small><center>Chronic bronchiolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Alterations in the bronchiolar fluid and wall, depending on the severity and chronicity of the injury.
*Normal serous, bronchiolar fluid may become mucoid because of a goblet cell metaplasia associated with the epithelial hyperplasia
*Mucous is more viscous than serous fluid and therefore may not be cleared from the airways by the usual clearance mechanisms (eg: cystic fibrosis in people - the underlying cause of the airway pathology is the decreased water content of the airway mucous, leading to airway plugging, and increased risk of secondary infection)
*The normally thin bronchiolar walls can become thickened with fibrous connective tissue and infiltrated by leukocytes (macrophages, lymphocytes, plasma cells, +/- eosinophils).
*Potential aetiologies
**Infectious agents by either
***Extension from an upper airway infection
***Lower respiratory tract infections
****e.g. [[Bovine Parainfluenza - 3|Parainfluenza virus type 3]], [[Bovine Respiratory Syncytial Virus|Bovine respiratory syncytial virus]], [[Adenoviridae|adenoviruses]], [[:Category:Mycoplasmas|Mycoplasma spp]].
**Bronchiolitis often occurs with many causes of pneumonia
**Foreign bodies eg: grass seeds
**Irritants
**Parasites
**Allergens
**Metabolic activation of compounds by Clara cells in the bronchioles (eg: [[Lungs Inflammatory - Pathology#Acute bovine pulmonary emphysema and oedema (ABPEE)|Fog Fever in cattle]])
*Bronchioles are more susceptible to obstruction than bronchi and the epithelium is highly susceptible to injury due to [[Respiratory System General Introduction - Pathology#Bronchioles|changed anatomy]]
===Sequelae of bronchitis or bronchiolitis===
*Resolution of inflammation, removal of cellular debris and lumenal exudate with minimal mural fibrosis ... return to normal function.
*Obstruction of the airways following:
*Plugging of the lumen by mucus, [[Neutrophils|neutrophils]] and cellular debris
*Severe thickening of the airway walls
*Bronchoconstriction following contraction of smooth muscle surrounding the airways eg: hypersensitivity response, asthma +/- hypertrophy of airway smooth muscle
*Depending on severity can result in:
**Dyspnoea
**Increased respiratory noise (crackles, wheezes)
**Reduced oxygenation, exercise intolerance, lethargy
**Collapse of areas of the lung ([[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]])
**Overinflation of other parts of the lung ([[Lungs Ventilation - Pathology#Emphysema|emphysema]])
**Chronic cough
**[[Lungs Inflammatory - Pathology|Pneumonia]] following inhalation of inflammatory exudate/infectious material within it
='''Infectious causes of bronchitis or bronchiolitis'''=
{| cellpadding="5" cellspacing="0" border="1"
| .
| [[:Category:Respiratory Viral Infections|'''VIRAL''']]
| [[Respiratory Bacterial Infections - Pathology|'''BACTERIAL''']]
| [[Respiratory Fungal Infections - Pathology|'''FUNGAL''']]
| [[Respiratory Parasitic Infections - Pathology|'''PARASITIC''']]
|-
| '''Dogs'''
| [[Canine Infectious Tracheobronchitis|Infectious canine tracheitis]]
| [[Canine Infectious Tracheobronchitis|Infectious canine tracheitis]]
| .
| [[Capillaria|''Capillaria aerophila'']]
|-
| .
| [[Canine Distemper Virus|Canine distemper]]
| .
| .
| [[Crenosoma vulpis|''Crenosoma vulpis'']]
|-
| .
| [[Canine Parainfluenza - 2|Parainfluenza- 2]]
| .
| .
| .
|-
| .
| [[Canine Adenovirus 1]] and [[Canine Adenovirus 2]]
| .
| .
| .
|-
| '''Cats'''
| .
| .
| .
| ''[[Aelurostrongylus abstrusus]]''
|-
| .
| .
| .
| .
| [[Capillaria|''Capillaria aerophila'']]
|-
| '''Horses'''
| [[Equine Influenza|Equine influenza]]
| .
| .
| ''[[Dictyocaulus arnfieldi]]''
|-
| .
| [[Equine Adenovirus]]
| ''[[Streptococcus equi subsp. zooepidemicus]]''
| .
| .
|-
| .
| .
| [[Rhodococcus equi|''Rhodococcus equi'']]
| .
| .
|-
| .
| [[Equine Viral Arteritis|Equine viral arteritis]]
| .
| .
| .
|-
| '''Cattle'''
| [[Infectious Bovine Rhinotracheitis|Infectious bovine rhinotracheitis]]
| subclinical [[Cillia-Associated Respiratory Bacillus|''CAR bacillus'']]
| .
| ''[[Dictyocaulus viviparus]]''
|-
| .
| [[Bovine Parainfluenza - 3|Parainfluenza- 3]]
| [[Pneumonic Pasteurellosis|Pneumonic pasteurellosis]]
| .
| .
|-
| .
| [[Bovine Respiratory Syncytial Virus|Respiratory syncytial virus]]
| [[Necrotic Laryngitis]]
| .
| .
|-
| .
| .
| [[Enzootic Pneumonia - Calves|Enzootic pneumonia of calves]]
| .
| .
|-
| .
| .
| [[Enzootic Pneumonia - Calves|''Mycoplasmal'' pneumonia]]
| .
| .
|-
| '''Sheep'''
| [[Bovine Parainfluenza - 3|Parainfluenza- 3]]
| subclinical [[Cillia-Associated Respiratory Bacillus|''CAR bacillus'']]
| .
| ''[[Protostrongylus rufescens|Protostrongylus]]'' spp.
|-
| .
| [[Sheep Pulmonary Adenomatosis]]
| [[Enzootic Pneumonia - Lambs|Enzootic pneumonia of lambs]]
| .
| [[Dictyocaulus filaria|''Dictyocaulus filaria'']]
|-
| '''Pigs'''
| [[Swine Influenza|Swine influenza]]
| [[Pasteurellosis - Pigs|''Pasteurella multocida'']]
| .
| ''[[Metastrongylus]]'' spp.
|-
| .
| .
| [[Contagious Porcine Pleuropneumonia|Contagious porcine pleuropneumonia]]
| .
| .
|-
| .
| .
| [[Glasser's Disease|Glasser's disease]]
| .
| .
|-
| .
| .
| [[Atrophic Rhinitis|''Bordetella bronchiseptica'']]
| .
| .
|-
|}
==Test yourself with the Bronchi and Bronchioles Pathology Flashcards==
[[Bronchi_and_Bronchioles_Flashcards_-_Pathology|Bronchi and Bronchioles Pathology Flashcards]]
[[Category:Bronchi and Bronchioles - Pathology]]
[[Category:Respiratory System - Inflammatory Pathology]]