Disease of the Equine Head & Neck 1 Flashcards
What are the functions of the upper airway?
- Conduit: – airflow to & from lung
- Filtering: – Mucus
- Protection: – of lower airway from aspiration
- Olfaction
- Phonation
- Swallowing
- Thermoregulation
***Horses = obligate nasal breathers
What is a horse’s respiratory rate, tidal volume + minute vntilation at rest?
– Respiratory rate 15 breaths per minute
– Tidal volume 5L
– Minute ventilation 75L
At exercise what is the minute ventilation?
1500L (20X increase)
What occurs when airway lumen narrows?
*Horses cannot switch to mouth breathing
1.Increased airflow resistance
2.Increased negative pressure on inspiration
3. Unsupported structures collapse
4. URT obstruction
5. Noise + reduced oxygen delivery
Why is URT disease important?
*Common in horses
*Can be life threatening
What are clinical signs of URT diseases?
- Respiratory noise / distress
- Dysphagia
- Coughing
- Exercise Intolerance
- Nasal discharge – Blood, Purulent material, Ingesta
- Facial deformity
- Neurological signs
What should be checked with nasal discharge?
*Unilateral / bilateral
*Duration
*Nature of discharge - blood / purulent / food material
*Evidence of trauma
What should be checked with respiratory noise?
*Severity of obstruction
*When (rest/exercise)
*Inspiratory / expiratory / both
*What does the noise sound like? - whistle / roar / gurgle / snoring
*Continuous / intermittent
What should be assessed at rest?
- General physical examination at rest
– Examine all body systems
– Concurrent disease
– Respiratory rate & character
– Nostril flare
– AUSCULTATION of thorax and trachea
– REBREATHING - Assess for other causes of poor performance:
– Lameness
– Cardiac disease
What should be examined with the head?
- Symmetry
- Nasal / ocular discharge
- Airflow from both nostrils
- Percussion of sinuses
- Palpation of larynx
- Previous surgical scars
What should be examined at exercise?
> if complaint = noise at exercise / poor performance associated with noise
*If abnormal noise heard
1.When does it occur - throughout exercise / when pushed
2.Quality / pitch - whistle / roar / gurgle / snoring
3. Stride phase
What diagnostic imaging can be used for the head?
- ENDOSCOPY
- RADIOGRAPHY
- SINOSCOPY
- CT
- Ultrasonography
- Magnetic Resonance Imaging (MRI)
What are the main indications for use of resting endoscopy?
*Nasal discharge / malodour
*Respiratory noise
*Dysphagia
Why is exercising endoscopy useful?
Many causes of URT obstructions only seen at exercise.
What are the advantages and disadvantages of radiography?
Advantages =
-images can be obtained from its portable machines
-Easy to perform
Disadvantages
- complex anatomy
- 2 dimensional
