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| | [[Image:COPD.jpg|right|thumb|100px|<small><center>COPD (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] | | [[Image:COPD.jpg|right|thumb|100px|<small><center>COPD (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] |
| | [[Image:COPD scanning micrograph.jpg|right|thumb|100px|<small><center>COPD scanning electron micrograph (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] | | [[Image:COPD scanning micrograph.jpg|right|thumb|100px|<small><center>COPD scanning electron micrograph (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] |
| − | *Synonyms: '''Recurrent Airway Obstruction (RAO) '''(correct current terminology), "heaves", "broken wind"
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| − | *COPD is one of the most common conditions encountered in adult horses and is a major cause of loss of performance
| + | ==Description== |
| − | *It is an asthma-like syndrome of the bronchioloalveolar region
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| − | *The aetiopathogenesis of COPD is not fully understood, but is thought primarily to be caused by an immune-mediated hypersensitivity response to inhaled allergens commonly found in mouldy hay or bedding and in stable dust (eg: spores from ''Faenia rectivirgula'', [[Aspergillus spp.|''Aspergillus fumigatus'']], and [[:Category:Actinomycetes|''Thermoactinomyces vulgaris'']])
| + | ==Signalment== |
| − | *The immune reaction is considered primarily to be a type III hypersensitivity (antigen-antibody complex mediated)
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| − | **Type I and type IV hypersensitivity reactions may also play a role
| + | ==Diagnosis== |
| − | *Repeated episodes of inflammation in the lower airways, especially the bronchioles, results in chronic changes that cause obstruction of the lower airways, sometimes followed by [[Lungs Ventilation - Pathology#Emphysema|alveolar emphysema]]
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| − | *The histological features are what you would predict given this pathogenesis:
| + | ===Clinical Signs=== |
| − | **Luminal accumulation of exudate made up of thick mucus (goblet cell metaplasia), [[Neutrophils|neutrophils]] and cellular debris
| + | ===Diagnostis Imaging=== |
| − | **This can predispose to, and is often accompanied by, secondary bacterial infection eg: ''[[Streptococcus equi subsp. zooepidemicus]]''
| + | ===Laboratory Tests=== |
| − | **Thickened mucosa - epithelial hyperplasia, chronic inflammatory cell infiltrate with variable numbers of eosinophils in the airway wall
| + | ===Pathology=== |
| − | **Peribronchiolar fibrosis
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| − | **Bronchospasm
| + | ==Treatment== |
| − | *When susceptible horses are exposed to inhaled allergens they develop airway inflammation and respiratory dysfunction
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| − | *Typically, susceptible horses are clinically normal when at pasture, but develop signs of disease shortly (hours to days) after being housed
| + | ==Links== |
| − | *Clinical signs are what you would predict from a chronic inflammatory process in the airways:
| + | ==Refences== |
| − | **Coughing (following activation of coughing reflexes due to inflammation in the airways, mechanical pressure on the airway walls associated with the accumulation of intraluminal exudate)
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| − | **Nasal discharge (usually bilateral - mucopurulent tracheal exudate on bronchoscopy)
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| − | **Increased respiratory rate (compensation for reduced tidal volume following the reduction in airway lumen diameter)
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| − | **Pronounced effort during inspiration with an obvious abdominal component (may result in a "heave-line" in the flank due to hypertrophy of the abdominal muscles - reduced airway diameter results in increased resistance to air flow, so more inspiratory effort required for same airflow rates)
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| − | **Wheezing and crackling lung sounds on auscultation at the end of inspiration and expiration - caused by bubbles in mucus collapsing
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| | [[Category:Allergic Respiratory Diseases]] | | [[Category:Allergic Respiratory Diseases]] |
| | [[Category:To Do - Lizzie]] | | [[Category:To Do - Lizzie]] |
| | [[Category:Horse]] | | [[Category:Horse]] |
