Respiratory Disorders

Question 1

What is the etiology, epidemiology and pathogenesis of Recurrent Airway Obstruction (RAO) in horses?

Answer 1

Etiology: Genetic predisposition + allergen exposure
Epidemiology: ~14% horses, >7 year old
Pathogenesis: Allergen exposure recruits lymphocytes to the airways, then neutrophils, causes mucoid plug, bronchospasm and blocking of lower airway

Question 2

What is the etiology, epidemiology and pathogenesis of Inflammatory Airway Disease (IAD)?

Answer 2

Etiology: unknown. Predisposed areas: stalls, traveling, etc.
Epidemiology: any horse. More common in young. Young racehorses seem to be a common subset.
Pathogenesis: unknown. Can see neutrophils or eosinophils in airway. Recruits cells to the lower airways causing inflammation.

Question 3

What is the etiology, epidemiology and pathogenesis of Exercise Induced Pulmonary Hemmorhage (EIPH)?

Answer 3

Etiology: thought to be increased hydrostatic pressure
Epidemiology: basically any horse that exercises, racehorses clearly will see more evidence
Pathogensis: not totally clear

Question 4

What are the clinical signs associated with RAO?

Answer 4

Heave line! Increased expiratory effort. Nostril flaring. Anorexia

Question 5

What are the clinical signs of Inflammatory Airway Disease (IAD)?

Answer 5

Non-specific signs, so a dx challenge. Basically looks like an out of shape person: increased effort while exercising, takes longer to recover, may have a cough that last for a couple weeks. While at rest they are fine.

Question 6

How would you diagnose Recurrent Airway Obstruction (RAO)?

Answer 6

1. BAL: >25% neutrophils

2. Endoscopy to visualize narrowing/mucoid plugs

Question 7

How would you diagnose Inflammatory Airway Disease (IAD)?

Answer 7

1. BAL: mild increase of mixed cells such as neutrophils, mast cells, eosinophils
2. Endoscopy to visualize mucous, can grade
   Important to rule out RAO! These horses with IAD will be fine at rest

Question 8

How would you diagnose Exercise Induced Pulmonary Hemorrhage?

Answer 8

1. Endoscopy within 90 mins after exercise to visualize blood
2. BAL to retrieve hemosiderin if it’s been a while since exercise

Question 9

How would you treat a horse with RAO?

Answer 9

Dust control is key! Inhaled or Systemic corticosteroids, Omega-3 Fatty Acids and controlling bedding/ventilation/access to fresh air

Question 10

How would you treat a horse with IAD?

Answer 10

Provide environmental change suggestions as you would with RAO, (i.e. dust control, etc). Control the inflammation with corticosteroids: Fluticasone, Dexamethasone. Supplement with Omega-3 Fatty Acids.

Question 11

How would you treat a horse with EIPH?

Answer 11

Furosemide, Rest. Also be sure to treat any underlying causes: infection, cardiac arrythmias, etc.

Question 12

In which disease do you see fever before shedding?

Answer 12

Strangles! This helps you with outbreak situations.