Changes

===Acute bronchitis/bronchiolitis===

===Acute bronchitis/bronchiolitis===

[[Image:bronchiolitis.jpg|right|thumb|100px|<small><center>Bronchiolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

[[Image:bronchiolitis.jpg|right|thumb|100px|<small><center>Bronchiolitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

***Underlying bronchial mucos is thickened, hyperaemic and oedematous

***Underlying bronchial mucos is thickened, hyperaemic and oedematous

***May be a coexisting bronchopneumonia

***May be a coexisting bronchopneumonia

***Smooth muscle hypertrophy in pulmonary arteries -> [[Lungs Circulatory - Pathology#Pulmonary hypertension|'''pulmonary hypertension''']] -> [[Cor Pulmonale|'''cor pulmonale''']]

***Smooth muscle hypertrophy in pulmonary arteries -> [[Pulmonary Hypertension|'''pulmonary hypertension''']] -> [[Cor Pulmonale|'''cor pulmonale''']]

**Parasites

**Parasites

**Allergens

**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]])

**Metabolic activation of compounds by Clara cells in the bronchioles (eg: [[Acute Bovine Pulmonary Emphysema and Oedema|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]]

*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]]

**Increased respiratory noise (crackles, wheezes)

**Increased respiratory noise (crackles, wheezes)

**Reduced oxygenation, exercise intolerance, lethargy

**Reduced oxygenation, exercise intolerance, lethargy

**Collapse of areas of the lung ([[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]])

**Collapse of areas of the lung ([[Atelectasis|atelectasis]])

**Overinflation of other parts of the lung ([[Lungs Ventilation - Pathology#Emphysema|emphysema]])

**Overinflation of other parts of the lung ([[Pulmonary Emphysema|emphysema]])

**Chronic cough

**Chronic cough

**[[Lungs Inflammatory - Pathology|Pneumonia]] following inhalation of inflammatory exudate/infectious material within it

**[[Pneumonia Overview|Pneumonia]] following inhalation of inflammatory exudate/infectious material within it

='''Infectious causes of bronchitis or bronchiolitis'''=

='''Infectious causes of bronchitis or bronchiolitis'''=