Laryngeal Disease Flashcards
In what 3 ways does the larynx of cats differ from dogs?
- arytenoid cartilage lacks cuneiform and corniculate processes
- aryepiglottic folds are absent
- sids of the epiglottis connect directly to the cricoid lamina by laryngeal mucosa
What are the major manifestations of laryngeal disease?
- nasal, pharyngeal, and laryngeal stridor (high pitched)
- inspiratory/expiratory wheeze
- inspiratory dyspnea, loud snoring, gagging
- dry, raw cough
- cyanosis, syncope, collapse
- changes in voice/sound of bark
- painful swallowing
What is laryngeal paralysis?
dysfunction of the recurrent laryngeal nerve impairs the function of the cricoarytenoideus dorsalis muscle, which causes impairment of artytenoid cartilage abduction during inspiration —> stridor, respiratory distress
What causes the stridor associated with laryngeal paralysis?
vocal folds oscillate, which causes a roaring noise
What is the most common signalment for congenital, early onset, and acquired laryngeal paralysis? What causes each?
CONGENITAL = Bouvier des Flanders, Siberian Husky; neuronal degeneration
EARLY ONSET = Dalmatian, Rottweiler, Bullterrier, Leonberger; generalized neurologic disease
ACQUIRED = Labradors*, St. Bernard, Irish Setter, Newfoundland, Brittany Spaniels; idiopathic age-related decline in nerve or muscle function
What neuromuscular disease, accidental trauma, and iatrogenic surgical trauma are proposed etiologies to acquired laryngeal paralysis?
NEURO = geriatric-onset larygneal paralysis polyneuropathy syndrome (GOLP)***
ACCIDENTAL TRAUMA = chronic tugging on collars
SURGERY = tracheal surgery, thyroidectomy, parathyroidectomy
What is the most common presentation of laryngeal paralysis in dogs?
BILATERAL DISEASE
- inspiratory stridor worsens with exercise
- exercise intolerance
- respiratory distress
- voice change
- cyanosis
- coughing while eating or drinking
- hyperthermia, collapse
How does unilateral presentation of laryngeal paralysis compare?
tends to be subtle and surgery is not necessary
- conservative management: keeping cool, decrease exercise, weight control
What are the 3 general steps to emergency stabiilzation of patients in acute respiratory stress due to laryngeal paralysis? What can be performed if nothing is working?
- improve ventilation with oxygen supplementation, sedation, or intubation
- reduce laryngeal edema with short-acting steroids, like Dexamethasone
- minimize stress - cool down, sedate with Butorphanol, Acepromazine, Gabapentin, or Hydromorphone
emergency tracheostomy —> poor long term outcome
What is thought to be the etiology of laryngeal paralysis in cats? How do they present?
polyneuropathy
SAME AS DOGS
- tachypnea
- stridor
- change in phonation
- cough
What is the best way to diagnose laryngeal paralysis? What else can be part of the plan?
airway examination by laryngoscopy
- neurologic exam: commonly cause by geriatric polyneuropathy, so other nerves may be affected (commonly muscle atrophy)
- CBC, chem, UA, thyroid evaluation
- thoracic radiographs/US
How are laryngoscopies performed to diagnose laryngeal paralysis?
light anesthesia AND Doxapram to exaggerate respiratory action
- arytenoid should abduct with inspiration
What surgery is recommended for patients with laryngeal paralysis? What is the goal?
unilateral lateralization of the arytenoid with sutures to mimic the action of cricoarytenoideus dorsalis muscle (UNILATERAL to minimize risk of aspiration)
double the size of the laryngeal opening to provide enough area to relieve clinical signs, but minimize complications
What are the 3 most common complications associated with arytenoid lateralization?
- dysphagia - commonly resolves in a few days
- aspiration - can cause pneumonia, most common in dogs with underlying neurologic disease
- implant failure - suture breaks, tears out, fractures muscular processes (esp. in old dogs with brittle cartilage)
Other than unilateral arytenoid lateralization (tie back), what are 3 other options for surgeries?
- partial laryngectomy - vocal cord and partial artytenoid excision
- bilateral ventriculocordectomy - lowers rate of pneumonia, but there is a higher recurrence of clinical signs due to narrowing of the rima glottis
- laryngeal stents