Equine Respiratory Disease Flashcards
What history do we need about a horse?
Age - congenital defects/URT infections (young)/asthma (middle-aged)
Environment - new horses/local endemics/vaccination history/dust exposure
Prior medical problems
Present medical problems - when started, what signs, at rest or only at exercise?
What should we check in a physical exam of a horse?
Demeanour Stance Nasal discharge Submandibular lymph nodes Respiratory rate/effort Heave line?
How can we auscultate a horse using rebreathing?
If sounds normal at rest and not showing increased respiratory effort
Bag over nose, then keep stethoscope on after bag removed
Slow to recover, crackles, wheezes?
How do we carry out endoscopy on a horse?
Pass up ventral meatus of nose
Examine URT down to tracheal bifurcation
Guttural pouches
Resting/exercising endoscopy
What is sinoscopy?
Endoscope sinuses via a trephine or a flap.
What radiography should we carry out in these horses?
Variety of views of the head
Lateral-lateral thorax
Need about 5 plates to fit in all the chest
What can we CT scan in standing sedated horses?
Nasal turbinates Paranasal sinuses Teeth Nasopharynx Guttural pouches Skull
What swabs can we do in these horses?
Nasal
Nasopharyngeal
(Bacterial culture, viral, PCR)
What tubes do we use for samples from washes?
EDTA tube - cytology
Plain tube - culture
Describe a tracheal wash.
At the level of the trachea
Respiratory secretions/cells that accumulate in trachea are a collection from entire LRT
General sample but cells can have degenerated so may not be accurate
Most frequently used in practice
Describe bronchoalveolar lavage.
At the level of the lungs
Samples a specific peripheral lung segment only
More invasive (requires sedation)
More accurate
But only samples specific area so could miss disease
How do we carry out a bronchoalveolar lavage in a horse?
Sedate
Either use long scope or BAL tube
Horse will cough!
Once in the lung and stuck, need to keep pressure (scope) or inflate cuff (tube)
Instil 300-500ml saline
Then draw back up 50-80%
Froth is surfactant - shows you have a good sample
What can we use ultrasound for in these horses?
Peripheral lung disorders.
Describe Dorsal Displacement of the Soft Palate (DDSP).
Most commonly occurs in racehorses during strenuous exercise
Can be seen in sport/pleasure horses
Associated with poor performance and abnormal expiratory noise (gurgle) - reduced air supply
Cause not clearly understood
How do we diagnose DDSP?
With exercising endoscopy.
How do we treat DDSP?
Rest
Surgery - soft palate cautery / laryngeal tie-forward
Describe arytenoid cartilage collapse.
Recurrent laryngeal nerve innervates CAD muscle, which opens the larynx (abducts arytenoid cartilages)
Left nerve really long so end dies off
Affects left side of larynx in large horses
What are the clinical signs of arytenoid cartilage collapse?
Inspiratory noise (whistling/roaring) Exercise intolerance
How do we diagnose arytenoid cartilage collapse?
Resting endoscopy - gives some information
Exercising endoscopy - best
How do we treat arytenoid cartilage collapse?
Ventricolochordectomy (‘Hobday’) removes the noise
If exercise intolerant, then prosthetic laryngoplasty (tie-back) to hold open cartilages (risk of aspiration pneumonia)
Describe sinusitis.
Accumulation of exudate within sinus cavities
Primary = sequela of viral or bacterial URT
Secondary = usually to dental disease
Main clinical sign = nasal discharge
How do we diagnose sinusitis?
Endoscopy (check for other causes)
X-ray
CT
Sinoscopy - can treat / lavage at same time
Need to treat underlying cause if secondary
Describe guttural pouch mycosis.
Fungal infection of guttural pouch
Can be life-threatening
What are the clinical signs of guttural pouch mycosis?
Epistaxis (nosebleed) - 50% die with repeated bleeds
Some have cranial nerve dysfunction