Equine Upper Respiratory track

Question 1

Recall normal cytological findings of tracheal wash and bronchoalveolar lavage specimens

Answer 1

Tracheal wash: <20% neutrophils
Bronchoalveolar lavage: <5% neutrophils
Macrophage majority
Eosinophils and Mast cells very low

Question 2

List appropriate diagnostic tests for further investigation of lower respiratory tract disease

Answer 2

Tracheal wash-
Bronchoalveolar lavage

Question 3

Differentiate Infectious respiratory disease and Equine asthma

Answer 3

Answer yes to any of these questions to consider infectious cause

Pyrexia?
Is the horse unwell?
Enlarged lymph nodes
Other animals affected

Question 4

Formulate appropriate management regimens for the control of severe equine asthma

Answer 4

24-hour turnout if possible
Low dust housing
Low dust feed
Good ventilation
Stable management- avoid deep bedding/groom outside/damp all feeds
Location of feed and bedding store

Question 5

Plan appropriate diagnostic tests for further investigation of lower respiratory tract disease

Answer 5

Tracheal wash
Bronchoalveolar lavage
Haematology & serum biochemistry
Arterial blood gas analysis
Thoracic ultrasonography
Thoracentesis
Radiography

Question 6

Differentiate between severe EA and mild-moderate EA

Answer 6

Severe equine asthma
Adult horses with lower airway inflammation and obstruction associated with frequent coughing and increased respiratory effort at rest
Obstruction reversed by bronchodilators or environmental change

Mild to moderate equine asthma
Any age horse with chronic cough (>4 weeks) and/or poor performance
No infection detected and no increased respiratory effort at rest
Excess tracheobronchial mucus and/or increased ratio neutrophils, eosinophils and/or mast cells in BAL fluid

Question 7

Plan effective therapeutic interventions for the control, or treatment, of severe equine asthma

Answer 7

Corticosteroids (Systemic/Inhalational)
Bronchodilators must be used in combination with corticosteroids and management control

Question 8

Give examples of systemic corticosteroids and attached risk

Answer 8

Prednisolone or Dexamethasone risk for laminitis

Question 9

Give examples of inhaled corticosteroids

Answer 9

Aservo Equihaler- Ciclesonide
Fluticasone propionate- Most potent
Beclomethasone dipropionate- Cheaper

Question 10

Give examples of β2 adrenergic agonists bronchodilators

Answer 10

β2 adrenergic agonists
Clenbuterol-Intravenous
Salbutamol (albuterol)- Short acting - rescue
Salmeterol- Longer term control

Question 11

Give examples of Anticholinergics bronchodilators and potential side effects

Answer 11

Atropine-Systemic
Immediate rescue when in severe respiratory distress
Side effects on gastrointestinal tract
Prolonged reduction in intestinal motility
Cannot repeat dose

Buscopan
Systemic

Ipratropium
Inhaled
Longer action than β2 s

Question 12

What does SPA-SEA mean

Answer 12

Summer pasture associated-severe equine asthma

Question 13

Differentiate between Tracheal wash and bronchoalveolar lavage

Answer 13

TW reflects whole lung and trachea while BAL samples alveoli and distal bronchioles, might miss focal pathology
TW has a messy sample while BAL has cleaner sample- cytology correlates with pulmonary histopathology and cells have better morphology
TW is less invasive
TW sample can be submitted for culture while BAL cannot
TW is cheaper

Question 14

Differentiate between SEA and MMEA

Answer 14

Signalment (Age- MEA young adults, SEA >7 years)
Clinical signs( MEA: No dyspnoea at rest)
Diagnostic testing (Neutrophil for MEA: 5-20%/ SEA: >25%)
Prognosis (MEA: Short duration, low risk of reoccurrence, can resolve spontaneously)

Question 15

What does EIPH mean

Answer 15

Exercised induced pulmonary haemorrhage

Question 16

Suggest some hypothesis for EIPH

Answer 16

Most popular - stress failure of pulmonary capillaries
Maybe associated with mild/moderate equine asthma?
Low alveolar pressure?
Upper airway obstruction?
Mechanical forces associated with locomotion?
Often associated with poor performance

Question 17

List presenting and clinical signs of EIPH

Answer 17

Presenting Signs
none (!)
+/- post exercise/race epistaxis
+/- poor performance
+/- repeated swallowing post exercise/race
+/- prolonged recovery post exercise/race
Clinical signs
none
+/- epistaxis
+/- abnormal lung sounds (rarely)

Question 18

How to treat EIPH

Answer 18

Unknown aetiology so no obvious therapy
Rest for two to four weeks
Address LRT inflammation
Prophylaxis - frusemide (0.3-0.6 mg/kg IV 3-4 hours before fast exercise)- CANT BE USED BEFORE RACING

Question 19

What is interstitial lung disease

Answer 19

Acute or chronic inflammatory process of alveolar walls and adjoining bronchiolar interstitium

Question 20

List causes of interstitial lung disease

Answer 20

Toxic agents
Infectious agents
Idiopathic

Question 21

Equine multinodular pulmonary fibrosis (EMPF) is an example of an interstitial lung disease summarise

Answer 21

A progressive fibrosing lung disease associated with presence of EHV-5
EHV-5 infects many horses but only causes fibrosis in a few
Older horses
Tachypnoea and tachycardia, weight loss, pyrexia
Wheezes and crackles

Question 22

How do we diagnose EMPF

Answer 22

Differentiate from severe equine asthma
Prove it is NOT reversible – administer a short acting bronchodilator?
Differentiate from infectious pneumonia
BAL cytology - nonseptic neutrophilia
BAL samples
Presence of EHV-5
Radiography
Prompted by above (and non-response)
Diffuse, nodular interstitial pattern
Ultrasonography
Diffuse pleural thickening
May identify nodules superficial in lung
Biopsy