Disease of Equine head + neck 3 Flashcards
What separates the nasopharynx + oropharynx?
*Soft palate
The pharynx lacks rigid support by bone, What does this mean it’s prone to?
*Collapse
What is the function of the pharynx?
*Passage of air
*Passage of ingesta
What innervates the pharynx?
*CN 5, 10 + 11
*Cervical nerves
What is the function of the larynx?
*Breathing
*Protect lower airway
*Vocalisation
What are the 4 parts of the larynx?
*Cricoid cartilage
*Thyroid cartilage
*Epiglottis
*Paired arytenoid cartilages
What are the 3 processes of the arytenoid cartilages?
*Muscular process - cAD muscles attachment (cricoarytenoideus dorsalis)
*Corniculate process - in the airway
*Vocal process - vocal cord attachment
What causes opening of the glottis? (abduction)
*Cricoarytenoideus dorsalis muscle
-innervation = recurrent laryngeal nerve
What causes closure of the glottis? (Adduction)
*Cricoarytenoideus lateralis muscle
-innervation = recurrent laryngeal nerve
What are key presenting signs of disease of the larynx + pharynx?
*Respiratory noise - inspiratory
*Exercise intolerance
*Poor performance
What can be used to diagnose larynx + pharynx problems?
*Endoscopy
-at rest = look at structures
-at exercise = dynamic problems
*Ultrasound
*Radiography
*CT
*MRI
What are clinical signs of pharynx problems?
*Poor performance
*Resp noise
*Dysphagia
*Resp distress
*Nasal discharge
*Coughing
What are key disorders of the pharynx?
Dorsal displacement of the soft palate (DDSP)
-intermittent / persistent
*Naso-pharyngeal collapse
*Pharyngeal lymphoid hyperplasia
*Cleft palate
*Foreign body
*Pharyngeal mass
What is intermittent DDSP?
*Dynamic condition - only during intense exercise (dynamic endoscopy for Dx)
*Soft palate displaces = expiratory obstruction, horse slows down
What is persistent DDSP?
*Soft palate permanently displaced over epiglottis - can’t replace on swallowing
-may have nasal discharge with food material
What are pathogenesis of intermittent DDSP?
Neuromuscular dysfunction - pharyngeal branch of Vagus (CN x)
*Lower airway disease
*Structural abnormalities
How is DDSP diagnosed?
Endoscopy - exercising
What is intermittent DDSP conervative treatment?
*Maturity - happens more in youngsters
*get horse fit - train resp muscles
*Change tack - keep mouth closed
*Tongue tie
What are surgical treatment of intermittent DDSP?
*Tie larynx forward - best efficacy
*Palatoplasty - burn so that scarring + thicker soft palate + more stable
What happens with nasopharyngeal collapse in neonates?
*Dysphagia
*Self resolves
What can cause dynamic pharyngeal collapse?
*Neck flexion - dressage / show ponies
What is seen wtih cleft palate?
*Congenital - can cause inhalational pneumonia
*Milk seen coming from nostrils
What is diagnosis + treatment of cleft palate?
*Dx = oral exam - endoscopy
*Surgical repair - but not often attempted as difficult + expensive
*Get off milk so inhalation less likely + feed solid material
What are laryngeal disorders?
Recurrent laryngeal neuropathy (RLN)
* Fourth branchial arch defect (4-BAD)
* Dynamic laryngeal disorders
* Arytenoid chondritis
* Epiglottic abnormalities
What are key clinical signs of laryngeal disorders?
- Respiratory noise
- Poor performance
- Dysphagia
- Coughing
- Respiratory distress
What side is RLN (recurrent laryngeal neuropathy) more common?
Left - longer as it goes to aortic arch = more prone to injury
How is a RLN diagnosed?
*Large breeds
*History - poor performance
*Endoscopy - asymmetry of arytenoid cartilage
What are the different grades of laryngeal function
*Grade 1 = normal
*Grade 2 = can fully abduct but doesn’t stay there
*Grade 3 = can’t fully abduct
*Grade 4 = complete paralysis
How do you treat RLN?
*Tie back -out of the way (prosthetic laryngoplasty)
*Arytenoidectomy
*Laryngeal re-innervation - nerve graft
What are complications of prosthetic laryngoplasty? (tie back)
*Coughing
*Seroma
*Infection
*Dysphagia
*Prosthetic failure
*Chondritis
What are DDx for laryngeal paralysis?
*Unilateral
=guttural pouch mycosis, previous surgery, perivascular injection
*Bilateral
= Hepatic disease, toxicity, post anaesthetic complication
What is laryngeal dysplasia?
*Congenital - 4/6th branchial arch deformity
*LAryngeal dysfunction - limited abduction of right arytenoid
What can be done about vocal cord collapse?
*V loud noise
*Tx = vocalcordectomy
What is epiglottic entrapment? Tx?
*Epiglottic cartilage trapped by subepiglottic tissue
*CS = resp noise, coughing
*Dx = endoscopy
*Tx = laser resection
What is sub epiglottic cyst? What can be done?
*Congenital
*Dx = endoscopy
*Tx = laser excision / snare excision
What is arytenoid chondritis? What can be done?
*Infection of arytenoid cartilage = resp noise, obstruction
*Dx = endoscopy
*Tx = antibiotics, arytenoidectomy
