Flashcards in Inflammatory Airway Disease Deck (18):
What are the characteristics of IAD
mucoid or mucopurulent exudate in nasopharynx, a non-septic inflammation,
What are some possible causes?
dust, molds, pollutants inhaled, but the exact cause is unknown
CLinical signs of IAD
poor athletic performance is the big one, but lack of fever, coughing, and maybe EIPH. Often subclinical
Dx of IAD is...
TW for culture, BAL to look for Mast cells, PMNs, or eosinophils (>2%, >5%, and >1%), endoscopic exam finding exudate. THis is a R/O disease causing poor performance
Treatment for IAD is
Change something in the environment like the possible causes. Some people give corticosteroids but we need to rule out bacterial infection first (TW). THat is important to know before we give bronchodilators as well.
Sodium cromoglycate is good (if mast cells from BAL)
and decrease EIPH
Prevalence of IAD
20-65% in race horses, 85% of coughing horses have this
Who mainly gets IAD?
young performance horses
What does IAD rarely cause?
auscultable pulmonary abnormalities
What age does RAO usually hit?
middle to older
What is RAO associated with?
stabling and exposure to dust, hay and molds. Summer pastures this is less common
What is the etiology of RAO?
respirable organic dust
Hay and bedding - hypersensitivity to dusts or molds in poorly cured hay --> Aspergillus fumigatus and Faenia rectivirgula
pollen on some pastures (SPAOPD)
What is the pathogenesis?
Inhalation of the agent --> infiltration of neutrophils --> inflammatory change to airways --> edema (acute) --> airway remodelling (chronic) with mucus metaplasia, sm msc hypertrophy, peribronchiolar fibrosis and inflammation --> Mucus accumulation from increased production and viscoelasticity --> bronchospasm --> decreased lung compliance --> increased resistance --> increased work to breathe --> arterial hypoxemia (no hypercapnia)
Clinical signs of RAO
chronic spont cough
mucopurulent nasal discharge
accented expiratory effort
increased resp rate and maybe respiratory distress
adventitious lung sounds (wheezes and crackles)
What is not a clinical sign of RAO
Dx of RAO
Wheezes on exp,
crackels in insp and exp
percussion may have expanded lung field
interstitial and bronchiolar pattern on rads
TTW and endoscopy - exudate (not sensitive) and neutrophils with copious mucous
BAL - THis is the most important. Higher than the normal 5-10% neutrophils or up to 25% in stabled horses. There will be increase in mucous and non-degen neutrophils
THe others: arterial blood gas, atropine/glycopyrr test, CBC, chem,
The stupid ones are intradermal skin testing and serum allergen testing
Tx of RAO
environmental management!!! - decrease dust, give rest, pasture, soak hay, ventilate
Drugs - corticosteroids (inhaled or systemic)
What are the corticosteroids we use for RAO?
dexamethasone and prednisolone for systemics
fluticasone, beclomethasone given by nebulizers, aeromasks, or metered dose inhalers