Lecture 20/21 11/7/24 Flashcards
Which structures make up the larynx anatomy?
-palatine tonsils
-corniculate process
-cuneiform process
-vocal fold
-epiglottis
What is the function of the caudal laryngeal nerve?
innervates the larynx to allow for abduction and adduction
What does the cranial laryngeal nerve supply?
-taste buds
-laryngeal mucosa
-cricothyroideus muscles
What is the normal function of the larynx?
-laryngeal cartilages abduct on inhalation and adduct on exhalation
-dogs that are breathing hard may keep the cartilages fully abducted
What is laryngeal paralysis?
inability to abduct or adduct the arytenoids
What are the characteristics of congenital laryngeal paralysis?
-associated with congenital polyneuropathies
-seen in siberian huskies, bouviers, bull terriers, dalmations, and rottweilers
What are the characteristics of acquired laryngeal paralysis?
-most commonly occurs with geriatric-onset laryngeal paralysis/polyneuropathy
-can also occur with trauma and neoplasia
-seen in older golden and labrador retrievers and setters
What are the clinical signs of acquired laryngeal paralysis?
-voice change
-gagging
-coughing
-dyspnea
-exercise intolerance
-pneumonia
-syncope
-cyanosis
-hind limb weakness
-dysphagia
-regurg.
-megaesophagus
How is acquired laryngeal paralysis diagnosed?
-auscultation
-neurologic eval.
-thoracic rads
-contrast esophagram
-thyroid panel
-laryngoscopy
What are the characteristics of using laryngoscopy to assess laryngeal function?
-pre-oxygenate dog
-want lightest anesthetic plane possible
-compare arytenoid movement to resp cycle
-want to avoid propofol, ketamine+diazepam, and alfaxalone when possible due to risk of false positive test
What are the treatment options for laryngeal paralysis, based on severity?
mild:
-treat obesity
-control stress
-avoid inciting factors like heat or excitement
severe:
-unilateral arytenoid lateralization/tieback
What are the indications for a tieback procedure?
-dyspnea
-exercise intolerance
-cyanosis
-poor quality of life
What are the cons of tieback surgery?
-does not resolve coughing or polyneuropathy
-increases lifelong risk of aspiration pneumonia
What are additional surgical options for laryngeal paralysis?
-shorten elongated soft palates
-remove everted laryngeal saccules
-permanent tracheostomy for severely affected dogs
What is a laryngeal stent?
knobbed silicone tracheal stent that holds the larynx open and can be left in permanently in dogs with laryngeal paralysis
What are the characteristics of normal tracheal anatomy?
-trachea is supported by series of incomplete, C-shaped cartilage rings
-ring ends are dorsally connected by trachealis muscle
-trachea bifurcates into bronchi
What are the characteristics of tracheal collapse?
-progressive, irreversible tracheal weakening
-dorsal muscle and ligament become relaxed
-cartilage loses rigidity
-dynamic collapse occurs with cough or rapid breathing
-tracheal lumen eventually flattens
-inflammation decreases ciliated cells and increases mucus viscosity
What is the presentation of collapsing trachea?
-middle aged toy/small breed dogs
-cough that may be stimulated with tracheal palpation
-dyspnea
-cyanosis
-syncope
Which factors exacerbate tracheal collapse?
-obesity
-coughing
-exercise
-heat stress
-ET tube placement
-airway infections
-airborne irritants
-heart enlargement
-neck pressure
-elongated soft palate
Which diagnostics are used to identify collapsing trachea?
-CBC/chem
-thoracic rads
-fluoroscopy
-tracheoscopy
What are the characteristics of tracheoscopy?
-laryngeal exam done at induction
-evaluate trachea and bronchi
-grade collapse along entire tracheal length
-take measurements for stents
-obtain airway samples for culture and cytology as needed
-risky due to dogs not being intubated during procedure
What are the medical management options for collapsing trachea?
-weight control
-cough suppressants
-sedation for excitement
-environmental modification
-steroids
-antibiotics for secondary infection
-bronchodilators for concurrent lung disease
When should treatment of collapsing trachea go beyond medical management?
-cough is no longer responding to treatment
-cough disrupts dog’s ability to eat, drink, and sleep
-dog responds to medical management but has cyanosis or severe dyspnea
-quality of life is declining
What are the characteristics of an intraluminal stent?
-need anesthesia to measure and place
-expensive device
-does not treat bronchial collapse
-causes irritation and coughing
-can cause dogs to develop excess mucus or granulation tissue
What are common causes of tracheal trauma?
-bite wounds
-endotracheal cuff over-inflation
-intubation with metal stylet
What are the treatment options for tracheal trauma?
-conservative treatment for small lacerations
-surgical repair of trachea if severe dyspnea, progressive pneumothorax, or worsening clinical signs occur
