Non Infx Lung Dz 2

Question 1

List the corticosteroids that are effective in reducing the airway inflammation associated with equine asthma

Answer 1

Systemics: Dexmethasone and prednisolone

Inhaled: Fluticasone and Ciclesonide

Question 2

Explain the benefits and disadvantages of choosing corticosteroids that are administered systemically.

Answer 2

Advantages of systemic: they’re less expensive and less labor and equipment intense

Disadvantages: systemic distribution affects overall immune response, horses are more susceptible to infection, heavy parasite load, skin disease, increases risk for laminitis, especially dexamethasone at higher doses

Question 3

Advantages and disadvantages of inhaled corticosteroids therapy

Answer 3

Advantages: local effect -> rapidly degenerated when enters blood, minimal side effects, best choice for long term maintenance

Disadvantages: more expensive and labor/equipment intense

Question 4

Describe additional clinical problems associated with advanced, chronic asthma

Answer 4

when you’re rechecking these animals the meds can only be stopped if airway inflammation is resolved, if neutrophilic inflammation is still present in BAL, clinical compromise will return once treatment is stopped. Compromised horses that are untreated will lose weight and may have bronchiectasis if they do not improve with treatment

Question 5

Explain the pathogenesis of inflammatory airway disease

Answer 5

It’s mostly race horses < 2yrs old:
1. Injury to the airway epithelium
2. Mucociliary disruption
3. Accumulation of mucus and debris
4. Persistent epithelial inflammation and injury
5. Additional mucociliary damage
6. Accumulation of mucus and debris

This cycle keeps going likely because horses are returned to training too quickly and never fully heal

Question 6

T/F: bacteria is consistently cultured from TTW

Answer 6

F

Question 7

Describe and justify a plan to confirm diagnosis of IAD

Answer 7

1. Hx of young racehorse with a cough, mucus and exercise intolerance
2. Transtracheal wash or bronchoalveolar lavage
   - the typical inflammatory aspirate will show neutrophils, no bacteria, mast cells or eosinophils
3. Manage the environment by keeping the horse away from dust and the track -> turn them out on pasture and if they don’t improve then consider medicating

Question 8

Explain the pathogenesis of EIPH

Answer 8

This is more common in 2-4 yr old female hoses with a fast burst of speed (barrel racing, eventing, racetrack). Extreme negative pressure in the alveoli of the horse during inspiration due to expansion of the thorax to overcome resistance to airflow while there is extreme positive pressure in the capillary due to increased blood flow which leads to them becoming fragile and increased tansmural pressure that causes capillary rupture. The hemorrhage causes inflammation and promotes new vessels that are weak and then rupture.

Question 9

Describe and justify a plan to confirm the diagnosis of EIPH

Answer 9

Endoscopy is very effective and BAL is the method of choice to ID Hemosiderophages (macrophages engulfing RBC’s)

Question 10

where would you see EIPH in a radiograph

Answer 10

Dorsal caudal lung field

Question 11

Develop a treatment plan for treating EIPH

Answer 11

1. Furosemide seems to the the most effective because it reduces the plasma and blood volume and may be a bronchodilator (promotes PGE2 production).
   - give it to them 1 hour before exercise, and pull water = 80% decrease in EIPH
2. Nasal dilators: the nose strip reduces EIPH by 33%
3. Equine concentrated serum: IgG and other immunoglobulins make the capillaries more flexible , increases oncotic pressure, and improves coagulation resulting in a 62% reduction in EIPH